Merge pull request #1 from OLEGSHA/master

Uhhh pull

docs/CONTRIBUTING.md

@@ -0,0 +1,69 @@
+# Contributing Guidelines
+
+This document lists conventions adopted by Progressia developers.
+
+## git
+
+### Branches
+Progressia repository contains a `master` branch and several "feature" branches.
+
+`master` is expected to contain a version of the game suitable for demonstration and forking/branching. Do not commit directly to `master` without OLEGSHA's approval.
+- `master` must always correctly build without compiler warnings (see below).
+- `master` must always pass all unit tests.
+- `master` must always be able to launch successfully.
+- `master` must always only contain working features.
+- `master` should not contain excessive debug code.
+- `master` must always have its code and filenames formatted (see below).
+
+"Feature" branches are branches dedicated to the development of a single feature. When the feature reaches completion the branch is merged into `master` and removed. Intermediate merges into `master` may occur when some fitting milestone is reached. Intermediate merges from `master` may be done as necessary. Merges between "feature" branches should generally be avoided.
+
+When beginning work on a new feature, create a new branch based on `master` (or on another "feature" branch if absolutely necessary). Use `all-small-with-dashes` to name the branch: `add-trees` or `rebalance-plastics` are good names. Do not fix unrelated bugs or work on unrelated features in a "feature" branch - create a new one, switch to an existing one or commit directly to `master` if the changes are small enough.
+
+"Feature" branches may not be formatted properly. Formatting is required before merging into `master` or other branches.
+
+### Commits
+- Commits must leave the branch in a state that builds without compiler warnings (see below).
+- Changes should be grouped in commits semantically. Avoid committing many small related changes in sequence; if necessary, wait and accumulate them. Avoid committing unrelated changes together; if necessary, split staged changes into several commits. This should normally result in about 1-2 commits for a day's work.
+- Commit bulk changes (renaming, formatting, ...) separately. Don't ever commit whitespace changes outside formatting commits.
+- Message format:
+
+```
+Short description of changes
+<empty line>
+- Enumeration of changes
+  - Nest when appropriate
+- Use dashes only
+- List not needed for small commits
+```
+
+Example:
+
+```
+Changed packages for relations, renamed Face to ShapePart
+
+- Added BlockRelation as an abstract superclass to existing relations
+  - Must be given an absolute "up" direction before use
+- Moved AbsFace, AbsRelation and BlockRelation to .world.rels
+- Renamed Face to ShapePart to reduce confusion with AbsFace
+```
+
+- Only commit changes described in the commit message. Please double-check staged files before committing.
+- Avoid merge conflicts. Pull before committing.
+- Better sign commits than not. See: [git](https://git-scm.com/book/en/v2/Git-Tools-Signing-Your-Work), [GitHub](https://docs.github.com/en/github/authenticating-to-github/managing-commit-signature-verification).
+
+## Code
+
+### Warnings
+Make sure that all committed code contains no compiler warnings. This specifically includes unused imports, unused private members, missing `@Override`s and warnings related to generics.
+
+Warnings about unknown tokens in `@SuppressWarnings` are temporarily ignored. Please disable them in your IDE.
+
+### Code Style
+Formatting code is important.
+
+- The format is specified within the files inside `/templates_and_presets/eclipse_ide`. Import the specifications into Eclipse or IntelliJ IDEA and use the IDEs' format feature. Alternatively format the code manually in accordance with existing files.
+- Only use tabs for indentation. Never indent with spaces even when wrapping lines. This is to ensure that indentation does not break when tab width is different.
+- Don't use `I` prefix for interfaces (not `IDoable` but `Doable`).
+- Prioritize readability over compactness. Do not hesitate to use (very) long identifiers if they aid comprehension.
+- Document all mathematics unless it is trivial, especially when using math notation for variable names.
+- Use proper English when writing comments. Avoid boxes in comments. Use `//` for single-line comments.

src/main/java/ru/windcorp/progressia/client/Client.java

@@ -24,7 +24,7 @@ import ru.windcorp.progressia.client.graphics.world.Camera;
 import ru.windcorp.progressia.client.graphics.world.EntityAnchor;
 import ru.windcorp.progressia.client.graphics.world.LocalPlayer;
 import ru.windcorp.progressia.client.world.WorldRender;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.common.world.entity.EntityData;
 
 public class Client {
@@ -36,7 +36,7 @@ public class Client {
 
 	private final ServerCommsChannel comms;
 
-	public Client(WorldData world, ServerCommsChannel comms) {
+	public Client(DefaultWorldData world, ServerCommsChannel comms) {
 		this.world = new WorldRender(world, this);
 		this.comms = comms;
 

src/main/java/ru/windcorp/progressia/client/ClientState.java

@@ -21,7 +21,7 @@ package ru.windcorp.progressia.client;
 import ru.windcorp.progressia.client.comms.localhost.LocalServerCommsChannel;
 import ru.windcorp.progressia.client.graphics.GUI;
 import ru.windcorp.progressia.client.graphics.world.LayerWorld;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.server.ServerState;
 import ru.windcorp.progressia.test.LayerAbout;
 import ru.windcorp.progressia.test.LayerTestUI;
@@ -41,7 +41,7 @@ public class ClientState {
 
 	public static void connectToLocalServer() {
 
-		WorldData world = new WorldData();
+		DefaultWorldData world = new DefaultWorldData();
 
 		LocalServerCommsChannel channel = new LocalServerCommsChannel(
 			ServerState.getInstance()

src/main/java/ru/windcorp/progressia/client/graphics/Colors.java

@@ -34,7 +34,13 @@ public class Colors {
 		DEBUG_BLUE = toVector(0xFF0000FF),
 		DEBUG_CYAN = toVector(0xFF00FFFF),
 		DEBUG_MAGENTA = toVector(0xFFFF00FF),
-		DEBUG_YELLOW = toVector(0xFFFFFF00);
+		DEBUG_YELLOW = toVector(0xFFFFFF00),
+	
+		LIGHT_GRAY = toVector(0xFFCBCBD0),
+		BLUE = toVector(0xFF37A2E6),
+		HOVER_BLUE = toVector(0xFFC3E4F7),
+		DISABLED_GRAY = toVector(0xFFE5E5E5),
+		DISABLED_BLUE = toVector(0xFFB2D8ED);
 
 	public static Vec4 toVector(int argb) {
 		return toVector(argb, new Vec4());

src/main/java/ru/windcorp/progressia/client/graphics/GUI.java

@@ -24,6 +24,7 @@ import java.util.List;
 
 import com.google.common.eventbus.Subscribe;
 
+import ru.windcorp.progressia.client.graphics.backend.GraphicsInterface;
 import ru.windcorp.progressia.client.graphics.input.CursorEvent;
 import ru.windcorp.progressia.client.graphics.input.FrameResizeEvent;
 import ru.windcorp.progressia.client.graphics.input.InputEvent;
@@ -57,15 +58,24 @@ public class GUI {
 	}
 
 	public static void addBottomLayer(Layer layer) {
-		modify(layers -> layers.add(layer));
+		modify(layers -> {
+			layers.add(layer);
+			layer.onAdded();
+		});
 	}
 
 	public static void addTopLayer(Layer layer) {
-		modify(layers -> layers.add(0, layer));
+		modify(layers -> {
+			layers.add(0, layer);
+			layer.onAdded();
+		});
 	}
 
 	public static void removeLayer(Layer layer) {
-		modify(layers -> layers.remove(layer));
+		modify(layers -> {
+			layers.remove(layer);
+			layer.onRemoved();
+		});
 	}
 
 	private static void modify(LayerStackModification mod) {
@@ -78,12 +88,33 @@ public class GUI {
 
 	public static void render() {
 		synchronized (LAYERS) {
-			MODIFICATION_QUEUE.forEach(action -> action.affect(LAYERS));
-			MODIFICATION_QUEUE.clear();
+			
+			if (!MODIFICATION_QUEUE.isEmpty()) {
+				MODIFICATION_QUEUE.forEach(action -> action.affect(LAYERS));
+				MODIFICATION_QUEUE.clear();
+				
+				boolean isMouseCurrentlyCaptured = GraphicsInterface.isMouseCaptured();
+				Layer.CursorPolicy policy = Layer.CursorPolicy.REQUIRE;
+				
+				for (Layer layer : LAYERS) {
+					Layer.CursorPolicy currentPolicy = layer.getCursorPolicy();
+					
+					if (currentPolicy != Layer.CursorPolicy.INDIFFERENT) {
+						policy = currentPolicy;
+						break;
+					}
+				}
+				
+				boolean shouldCaptureMouse = (policy == Layer.CursorPolicy.FORBID);
+				if (shouldCaptureMouse != isMouseCurrentlyCaptured) {
+					GraphicsInterface.setMouseCaptured(shouldCaptureMouse);
+				}
+			}
 			
 			for (int i = LAYERS.size() - 1; i >= 0; --i) {
 				LAYERS.get(i).render();
 			}
+			
 		}
 	}
 

src/main/java/ru/windcorp/progressia/client/graphics/Layer.java

@@ -31,15 +31,52 @@ public abstract class Layer {
 
 	private final AtomicBoolean isValid = new AtomicBoolean(false);
 	
+	/**
+	 * Represents various requests that a {@link Layer} can make regarding the
+	 * presence of a visible cursor. The value of the highest layer that is not
+	 * {@link #INDIFFERENT} is used.
+	 */
+	public static enum CursorPolicy {
+		/**
+		 * Require that a cursor is visible.
+		 */
+		REQUIRE,
+
+		/**
+		 * The {@link Layer} should not affect the presence or absence of a
+		 * visible cursor; lower layers should be consulted.
+		 */
+		INDIFFERENT,
+
+		/**
+		 * Forbid a visible cursor.
+		 */
+		FORBID
+	}
+	
+	private CursorPolicy cursorPolicy = CursorPolicy.INDIFFERENT;
+
 	public Layer(String name) {
 		this.name = name;
 	}
 	
+	public String getName() {
+		return name;
+	}
+
 	@Override
 	public String toString() {
 		return "Layer " + name;
 	}
 	
+	public CursorPolicy getCursorPolicy() {
+		return cursorPolicy;
+	}
+	
+	public void setCursorPolicy(CursorPolicy cursorPolicy) {
+		this.cursorPolicy = cursorPolicy;
+	}
+
 	void render() {
 		GraphicsInterface.startNextLayer();
 
@@ -79,4 +116,12 @@ public abstract class Layer {
 		return GraphicsInterface.getFrameHeight();
 	}
 	
+	protected void onAdded() {
+		// Do nothing
+	}
+	
+	protected void onRemoved() {
+		// Do nothing
+	}
+
 }

src/main/java/ru/windcorp/progressia/client/graphics/backend/GraphicsBackend.java

@@ -192,4 +192,18 @@ public class GraphicsBackend {
 		GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
 		return vidmode.refreshRate();
 	}
+	
+	public static boolean isMouseCaptured() {
+		return glfwGetInputMode(windowHandle, GLFW_CURSOR) == GLFW_CURSOR_DISABLED;
+	}
+	
+	public static void setMouseCaptured(boolean capture) {
+		int mode = capture ? GLFW_CURSOR_DISABLED : GLFW_CURSOR_NORMAL;
+		glfwSetInputMode(windowHandle, GLFW_CURSOR, mode);
+		
+		if (!capture) {
+			glfwSetCursorPos(windowHandle, FRAME_SIZE.x / 2.0, FRAME_SIZE.y / 2.0);
+		}
+	}
+	
 }

src/main/java/ru/windcorp/progressia/client/graphics/backend/GraphicsInterface.java

@@ -82,4 +82,12 @@ public class GraphicsInterface {
 		GraphicsBackend.setVSyncEnabled(GraphicsBackend.isVSyncEnabled());
 	}
 	
+	public static boolean isMouseCaptured() {
+		return GraphicsBackend.isMouseCaptured();
+	}
+	
+	public static void setMouseCaptured(boolean capture) {
+		GraphicsBackend.setMouseCaptured(capture);
+	}
+
 }

src/main/java/ru/windcorp/progressia/client/graphics/backend/LWJGLInitializer.java

@@ -65,8 +65,6 @@ class LWJGLInitializer {
 
 		GraphicsBackend.setWindowHandle(handle);
 
-		glfwSetInputMode(handle, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
-
 		glfwMakeContextCurrent(handle);
 		glfwSwapInterval(0);	// TODO: remove after config system is added
 	}

src/main/java/ru/windcorp/progressia/client/graphics/flat/RenderTarget.java

@@ -29,8 +29,8 @@ import glm.vec._3.Vec3;
 import glm.vec._4.Vec4;
 import ru.windcorp.progressia.client.graphics.Colors;
 import ru.windcorp.progressia.client.graphics.backend.Usage;
-import ru.windcorp.progressia.client.graphics.model.Face;
-import ru.windcorp.progressia.client.graphics.model.Faces;
+import ru.windcorp.progressia.client.graphics.model.ShapePart;
+import ru.windcorp.progressia.client.graphics.model.ShapeParts;
 import ru.windcorp.progressia.client.graphics.model.Shape;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
 import ru.windcorp.progressia.client.graphics.texture.Texture;
@@ -84,7 +84,7 @@ public class RenderTarget {
 
 	private final Deque<TransformedMask> maskStack = new LinkedList<>();
 	private final Deque<Mat4> transformStack = new LinkedList<>();
-	private final List<Face> currentClipFaces = new ArrayList<>();
+	private final List<ShapePart> currentClipFaces = new ArrayList<>();
 
 	private int depth = 0;
 
@@ -94,8 +94,8 @@ public class RenderTarget {
 
 	protected void assembleCurrentClipFromFaces() {
 		if (!currentClipFaces.isEmpty()) {
-			Face[] faces = currentClipFaces.toArray(
-				new Face[currentClipFaces.size()]
+			ShapePart[] faces = currentClipFaces.toArray(
+				new ShapePart[currentClipFaces.size()]
 			);
 			currentClipFaces.clear();
 
@@ -189,16 +189,13 @@ public class RenderTarget {
 
 	public void addCustomRenderer(Renderable renderable) {
 		assembleCurrentClipFromFaces();
-		assembled.add(
-			new Clip(
-				maskStack,
-				getTransform(),
-				renderable
-			)
-		);
+		
+		float depth = this.depth--;
+		Mat4 transform = new Mat4().translate(0, 0, depth).mul(getTransform());
+		assembled.add(new Clip(maskStack, transform, renderable));
 	}
 
-	protected void addFaceToCurrentClip(Face face) {
+	protected void addFaceToCurrentClip(ShapePart face) {
 		currentClipFaces.add(face);
 	}
 
@@ -270,7 +267,7 @@ public class RenderTarget {
 		fill(Colors.toVector(color));
 	}
 
-	public Face createRectagleFace(
+	public ShapePart createRectagleFace(
 		int x,
 		int y,
 		int width,
@@ -280,7 +277,7 @@ public class RenderTarget {
 	) {
 		float depth = this.depth--;
 
-		return Faces.createRectangle(
+		return ShapeParts.createRectangle(
 			FlatRenderProgram.getDefault(),
 			texture,
 			color,
@@ -291,7 +288,7 @@ public class RenderTarget {
 		);
 	}
 
-	public Face createRectagleFace(
+	public ShapePart createRectagleFace(
 		int x,
 		int y,
 		int width,

src/main/java/ru/windcorp/progressia/client/graphics/font/SpriteTypeface.java

@@ -33,8 +33,8 @@ import gnu.trove.stack.TIntStack;
 import gnu.trove.stack.array.TIntArrayStack;
 import ru.windcorp.progressia.client.graphics.Colors;
 import ru.windcorp.progressia.client.graphics.backend.Usage;
-import ru.windcorp.progressia.client.graphics.model.Face;
-import ru.windcorp.progressia.client.graphics.model.Faces;
+import ru.windcorp.progressia.client.graphics.model.ShapePart;
+import ru.windcorp.progressia.client.graphics.model.ShapeParts;
 import ru.windcorp.progressia.client.graphics.model.Shape;
 import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
 import ru.windcorp.progressia.client.graphics.model.ShapeRenderProgram;
@@ -144,7 +144,7 @@ public abstract class SpriteTypeface extends Typeface {
 		return new Shape(
 			Usage.STATIC,
 			getProgram(),
-			Faces.createRectangle(
+			ShapeParts.createRectangle(
 				getProgram(),
 				getTexture(c),
 				Colors.WHITE,
@@ -167,7 +167,7 @@ public abstract class SpriteTypeface extends Typeface {
 		private final Renderable unitLine = new Shape(
 			Usage.STATIC,
 			getProgram(),
-			Faces.createRectangle(
+			ShapeParts.createRectangle(
 				getProgram(),
 				null,
 				Vectors.UNIT_4,
@@ -257,7 +257,7 @@ public abstract class SpriteTypeface extends Typeface {
 
 		private class SDWorkspace extends SpriteTypeface.Workspace {
 
-			private final Collection<Face> faces = new ArrayList<>();
+			private final Collection<ShapePart> faces = new ArrayList<>();
 
 			private final Vec3 origin = new Vec3();
 			private final Vec3 width = new Vec3();
@@ -298,7 +298,7 @@ public abstract class SpriteTypeface extends Typeface {
 			workspace.height.sub(workspace.origin);
 
 			workspace.faces.add(
-				Faces.createRectangle(
+				ShapeParts.createRectangle(
 					getProgram(),
 					texture,
 					color,
@@ -314,7 +314,7 @@ public abstract class SpriteTypeface extends Typeface {
 			return new Shape(
 				Usage.STATIC,
 				getProgram(),
-				workspace.faces.toArray(new Face[workspace.faces.size()])
+				workspace.faces.toArray(new ShapePart[workspace.faces.size()])
 			);
 		}
 

src/main/java/ru/windcorp/progressia/client/graphics/gui/BasicButton.java

@@ -0,0 +1,151 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package ru.windcorp.progressia.client.graphics.gui;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Objects;
+import java.util.function.Consumer;
+
+import org.lwjgl.glfw.GLFW;
+
+import com.google.common.eventbus.Subscribe;
+
+import ru.windcorp.progressia.client.graphics.font.Font;
+import ru.windcorp.progressia.client.graphics.gui.event.ButtonEvent;
+import ru.windcorp.progressia.client.graphics.gui.event.EnableEvent;
+import ru.windcorp.progressia.client.graphics.gui.event.FocusEvent;
+import ru.windcorp.progressia.client.graphics.gui.event.HoverEvent;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutAlign;
+import ru.windcorp.progressia.client.graphics.input.KeyEvent;
+
+public abstract class BasicButton extends Component {
+	
+	private final Label label;
+
+	private boolean isPressed = false;
+	private final Collection<Consumer<BasicButton>> actions = Collections.synchronizedCollection(new ArrayList<>());
+
+	public BasicButton(String name, String label, Font labelFont) {
+		super(name);
+		this.label = new Label(name + ".Label", labelFont, label);
+
+		setLayout(new LayoutAlign(10));
+		addChild(this.label);
+
+		setFocusable(true);
+		reassembleAt(ARTrigger.HOVER, ARTrigger.FOCUS, ARTrigger.ENABLE);
+
+		// Click triggers
+		addListener(KeyEvent.class, e -> {
+			if (e.isRepeat()) {
+				return false;
+			} else if (
+				e.isLeftMouseButton() ||
+				e.getKey() == GLFW.GLFW_KEY_SPACE ||
+				e.getKey() == GLFW.GLFW_KEY_ENTER
+			) {
+				setPressed(e.isPress());
+				return true;
+			} else {
+				return false;
+			}
+		});
+		
+		addListener(new Object() {
+			
+			// Release when losing focus
+			@Subscribe
+			public void onFocusChange(FocusEvent e) {
+				if (!e.getNewState()) {
+					setPressed(false);
+				}
+			}
+			
+			// Release when hover ends
+			@Subscribe
+			public void onHoverEnded(HoverEvent e) {
+				if (!e.isNowHovered()) {
+					setPressed(false);
+				}
+			}
+			
+			// Release when disabled
+			@Subscribe
+			public void onDisabled(EnableEvent e) {
+				if (!e.getComponent().isEnabled()) {
+					setPressed(false);
+				}
+			}
+			
+			// Trigger virtualClick when button is released
+			@Subscribe
+			public void onRelease(ButtonEvent.Release e) {
+				virtualClick();
+			}
+			
+		});
+	}
+
+	public BasicButton(String name, String label) {
+		this(name, label, new Font());
+	}
+
+	public boolean isPressed() {
+		return isPressed;
+	}
+	
+	public void click() {
+		setPressed(true);
+		setPressed(false);
+	}
+
+	public void setPressed(boolean isPressed) {
+		if (this.isPressed != isPressed) {
+			this.isPressed = isPressed;
+			
+			if (isPressed) {
+				takeFocus();
+			}
+
+			dispatchEvent(ButtonEvent.create(this, this.isPressed));
+		}
+	}
+	
+	public BasicButton addAction(Consumer<BasicButton> action) {
+		this.actions.add(Objects.requireNonNull(action, "action"));
+		return this;
+	}
+	
+	public boolean removeAction(Consumer<BasicButton> action) {
+		return this.actions.remove(action);
+	}
+	
+	public void virtualClick() {
+		this.actions.forEach(action -> {
+			action.accept(this);
+		});
+	}
+
+	public Label getLabel() {
+		return label;
+	}
+	
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/Button.java

@@ -0,0 +1,79 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package ru.windcorp.progressia.client.graphics.gui;
+
+import glm.vec._4.Vec4;
+import ru.windcorp.progressia.client.graphics.flat.RenderTarget;
+import ru.windcorp.progressia.client.graphics.font.Font;
+import ru.windcorp.progressia.client.graphics.Colors;
+
+public class Button extends BasicButton {
+
+	public Button(String name, String label, Font labelFont) {
+		super(name, label, labelFont);
+	}
+	
+	public Button(String name, String label) {
+		this(name, label, new Font());
+	}
+
+	@Override
+	protected void assembleSelf(RenderTarget target) {
+		// Border
+		
+		Vec4 borderColor;
+		if (isPressed() || isHovered() || isFocused()) {
+			borderColor = Colors.BLUE;
+		} else {
+			borderColor = Colors.LIGHT_GRAY;
+		}
+		target.fill(getX(), getY(), getWidth(), getHeight(), borderColor);
+		
+		// Inside area
+		
+		if (isPressed()) {
+			// Do nothing
+		} else {
+			Vec4 backgroundColor;
+			if (isHovered() && isEnabled()) {
+				backgroundColor = Colors.HOVER_BLUE;
+			} else {
+				backgroundColor = Colors.WHITE;
+			}
+			target.fill(getX() + 2, getY() + 2, getWidth() - 4, getHeight() - 4, backgroundColor);
+		}
+		
+		// Change label font color
+		
+		if (isPressed()) {
+			getLabel().setFont(getLabel().getFont().withColor(Colors.WHITE));
+		} else {
+			getLabel().setFont(getLabel().getFont().withColor(Colors.BLACK));
+		}
+	}
+	
+	@Override
+	protected void postAssembleSelf(RenderTarget target) {
+		// Apply disable tint
+		
+		if (!isEnabled()) {
+			target.fill(getX(), getY(), getWidth(), getHeight(), Colors.toVector(0x88FFFFFF));
+		}
+	}
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/Checkbox.java

@@ -0,0 +1,149 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.client.graphics.gui;
+
+import glm.vec._2.i.Vec2i;
+import glm.vec._4.Vec4;
+import ru.windcorp.progressia.client.graphics.Colors;
+import ru.windcorp.progressia.client.graphics.flat.RenderTarget;
+import ru.windcorp.progressia.client.graphics.font.Font;
+import ru.windcorp.progressia.client.graphics.font.Typefaces;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutAlign;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutHorizontal;
+
+public class Checkbox extends BasicButton {
+	
+	private class Tick extends Component {
+
+		public Tick() {
+			super(Checkbox.this.getName() + ".Tick");
+			
+			setPreferredSize(new Vec2i(Typefaces.getDefault().getLineHeight() * 3 / 2));
+		}
+		
+		@Override
+		protected void assembleSelf(RenderTarget target) {
+			
+			int size = getPreferredSize().x;
+			int x = getX();
+			int y = getY() + (getHeight() - size) / 2;
+			
+			// Border
+			
+			Vec4 borderColor;
+			if (Checkbox.this.isPressed() || Checkbox.this.isHovered() || Checkbox.this.isFocused()) {
+				borderColor = Colors.BLUE;
+			} else {
+				borderColor = Colors.LIGHT_GRAY;
+			}
+			target.fill(x, y, size, size, borderColor);
+			
+			// Inside area
+			
+			if (Checkbox.this.isPressed()) {
+				// Do nothing
+			} else {
+				Vec4 backgroundColor;
+				if (Checkbox.this.isHovered() && Checkbox.this.isEnabled()) {
+					backgroundColor = Colors.HOVER_BLUE;
+				} else {
+					backgroundColor = Colors.WHITE;
+				}
+				target.fill(x + 2, y + 2, size - 4, size - 4, backgroundColor);
+			}
+			
+			// "Tick"
+			
+			if (Checkbox.this.isChecked()) {
+				target.fill(x + 4, y + 4, size - 8, size - 8, Colors.BLUE);
+			}
+		}
+
+	}
+
+	private boolean checked;
+
+	public Checkbox(String name, String label, Font labelFont, boolean check) {
+		super(name, label, labelFont);
+		this.checked = check;
+		
+		assert getChildren().size() == 1 : "Checkbox expects that BasicButton contains exactly one child";
+		Component basicChild = getChild(0);
+		
+		Group group = new Group(getName() + ".LabelAndTick", new LayoutHorizontal(0, 10));
+		removeChild(basicChild);
+		setLayout(new LayoutAlign(0, 0.5f, 10));
+		group.setLayoutHint(basicChild.getLayoutHint());
+		group.addChild(new Tick());
+		group.addChild(basicChild);
+		addChild(group);
+		
+		addAction(b -> switchState());
+	}
+	
+	public Checkbox(String name, String label, Font labelFont) {
+		this(name, label, labelFont, false);
+	}
+	
+	public Checkbox(String name, String label, boolean check) {
+		this(name, label, new Font(), check);
+	}
+	
+	public Checkbox(String name, String label) {
+		this(name, label, false);
+	}
+
+	public void switchState() {
+		setChecked(!isChecked());
+	}
+	
+	/**
+	 * @return the checked
+	 */
+	public boolean isChecked() {
+		return checked;
+	}
+	
+	/**
+	 * @param checked the checked to set
+	 */
+	public void setChecked(boolean checked) {
+		this.checked = checked;
+	}
+
+	@Override
+	protected void assembleSelf(RenderTarget target) {
+		// Change label font color
+		
+		if (isPressed()) {
+			getLabel().setFont(getLabel().getFont().withColor(Colors.BLUE));
+		} else {
+			getLabel().setFont(getLabel().getFont().withColor(Colors.BLACK));
+		}
+	}
+	
+	@Override
+	protected void postAssembleSelf(RenderTarget target) {
+		// Apply disable tint
+		
+		if (!isEnabled()) {
+			target.fill(getX(), getY(), getWidth(), getHeight(), Colors.toVector(0x88FFFFFF));
+		}
+	}
+	
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/Component.java

@@ -19,18 +19,23 @@
 package ru.windcorp.progressia.client.graphics.gui;
 
 import java.util.Collections;
+import java.util.EnumMap;
 import java.util.List;
+import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.lwjgl.glfw.GLFW;
 
 import com.google.common.eventbus.EventBus;
+import com.google.common.eventbus.Subscribe;
 
 import glm.vec._2.i.Vec2i;
 import ru.windcorp.progressia.client.graphics.backend.InputTracker;
 import ru.windcorp.progressia.client.graphics.flat.RenderTarget;
 import ru.windcorp.progressia.client.graphics.gui.event.ChildAddedEvent;
 import ru.windcorp.progressia.client.graphics.gui.event.ChildRemovedEvent;
+import ru.windcorp.progressia.client.graphics.gui.event.EnableEvent;
 import ru.windcorp.progressia.client.graphics.gui.event.FocusEvent;
 import ru.windcorp.progressia.client.graphics.gui.event.HoverEvent;
 import ru.windcorp.progressia.client.graphics.gui.event.ParentChangedEvent;
@@ -62,6 +67,8 @@ public class Component extends Named {
 	private Object layoutHint = null;
 	private Layout layout = null;
 	
+	private boolean isEnabled = true;
+
 	private boolean isFocusable = false;
 	private boolean isFocused = false;
 
@@ -285,10 +292,31 @@ public class Component extends Named {
 		return this;
 	}
 
+	/**
+	 * Checks whether this component is focusable. A component needs to be
+	 * focusable to become focused. A component that is focusable may not
+	 * necessarily be ready to gain focus (see {@link #canGainFocusNow()}).
+	 * 
+	 * @return {@code true} iff the component is focusable
+	 * @see #canGainFocusNow()
+	 */
 	public boolean isFocusable() {
 		return isFocusable;
 	}
 	
+	/**
+	 * Checks whether this component can become focused at this moment.
+	 * <p>
+	 * The implementation of this method in {@link Component} considers the
+	 * component a focus candidate if it is both focusable and enabled.
+	 * 
+	 * @return {@code true} iff the component can receive focus
+	 * @see #isFocusable()
+	 */
+	public boolean canGainFocusNow() {
+		return isFocusable() && isEnabled();
+	}
+
 	public Component setFocusable(boolean focusable) {
 		this.isFocusable = focusable;
 		return this;
@@ -337,7 +365,7 @@ public class Component extends Named {
 				return;
 			}
 
-			if (component.isFocusable()) {
+			if (component.canGainFocusNow()) {
 				setFocused(false);
 				component.setFocused(true);
 				return;
@@ -379,7 +407,7 @@ public class Component extends Named {
 				return;
 			}
 
-			if (component.isFocusable()) {
+			if (component.canGainFocusNow()) {
 				setFocused(false);
 				component.setFocused(true);
 				return;
@@ -433,12 +461,51 @@ public class Component extends Named {
 		return null;
 	}
 	
+	public boolean isEnabled() {
+		return isEnabled;
+	}
+	
+	/**
+	 * Enables or disables this component. An {@link EnableEvent} is dispatched
+	 * if the state changes.
+	 * 
+	 * @param enabled {@code true} to enable the component, {@code false} to
+	 *                disable the component
+	 * @see #setEnabledRecursively(boolean)
+	 */
+	public void setEnabled(boolean enabled) {
+		if (this.isEnabled != enabled) {
+			if (isFocused() && isEnabled()) {
+				focusNext();
+			}
+			
+			if (isEnabled()) {
+				setHovered(false);
+			}
+
+			this.isEnabled = enabled;
+			dispatchEvent(new EnableEvent(this));
+		}
+	}
+
+	/**
+	 * Enables or disables this component and all of its children recursively.
+	 * 
+	 * @param enabled {@code true} to enable the components, {@code false} to
+	 *                disable the components
+	 * @see #setEnabled(boolean)
+	 */
+	public void setEnabledRecursively(boolean enabled) {
+		setEnabled(enabled);
+		getChildren().forEach(c -> c.setEnabledRecursively(enabled));
+	}
+
 	public boolean isHovered() {
 		return isHovered;
 	}
 
 	protected void setHovered(boolean isHovered) {
-		if (this.isHovered != isHovered) {
+		if (this.isHovered != isHovered && isEnabled()) {
 			this.isHovered = isHovered;
 
 			if (!isHovered && !getChildren().isEmpty()) {
@@ -502,7 +569,7 @@ public class Component extends Named {
 	}
 
 	protected void handleInput(Input input) {
-		if (inputBus != null) {
+		if (inputBus != null && isEnabled()) {
 			inputBus.dispatch(input);
 		}
 	}
@@ -598,6 +665,17 @@ public class Component extends Named {
 		}
 	}
 
+	/**
+	 * Schedules the reassembly to occur.
+	 * <p>
+	 * This method is invoked in root components whenever a
+	 * {@linkplain #requestReassembly() reassembly request} is made by one of
+	 * its children. When creating the dedicated root component, override this
+	 * method to perform any implementation-specific actions that will cause a
+	 * reassembly as soon as possible.
+	 * <p>
+	 * The default implementation of this method does nothing.
+	 */
 	protected void handleReassemblyRequest() {
 		// To be overridden
 	}
@@ -638,6 +716,135 @@ public class Component extends Named {
 		getChildren().forEach(child -> child.assemble(target));
 	}
 	
+	/*
+	 * Automatic Reassembly
+	 */
+
+	/**
+	 * The various kinds of changes that may be used with
+	 * {@link Component#reassembleAt(ARTrigger...)}.
+	 */
+	protected static enum ARTrigger {
+		/**
+		 * Reassemble the component whenever its hover status changes, e.g.
+		 * whenever the pointer enters or leaves its bounds.
+		 */
+		HOVER,
+
+		/**
+		 * Reassemble the component whenever it gains or loses focus.
+		 * <p>
+		 * <em>Component must be focusable to be able to gain focus.</em> The
+		 * component will not be reassembled unless
+		 * {@link Component#setFocusable(boolean) setFocusable(true)} has been
+		 * invoked.
+		 */
+		FOCUS,
+
+		/**
+		 * Reassemble the component whenever it is enabled or disabled.
+		 */
+		ENABLE
+	}
+
+	/**
+	 * All trigger objects (event listeners) that are currently registered with
+	 * {@link #eventBus}. The field is {@code null} until the first trigger is
+	 * installed.
+	 */
+	private Map<ARTrigger, Object> autoReassemblyTriggerObjects = null;
+
+	private Object createTriggerObject(ARTrigger type) {
+		switch (type) {
+		case HOVER:
+			return new Object() {
+				@Subscribe
+				public void onHoverChanged(HoverEvent e) {
+					requestReassembly();
+				}
+			};
+		case FOCUS:
+			return new Object() {
+				@Subscribe
+				public void onFocusChanged(FocusEvent e) {
+					requestReassembly();
+				}
+			};
+		case ENABLE:
+			return new Object() {
+				@Subscribe
+				public void onEnabled(EnableEvent e) {
+					requestReassembly();
+				}
+			};
+		default:
+			throw new NullPointerException("type");
+		}
+	}
+
+	/**
+	 * Requests that {@link #requestReassembly()} is invoked on this component
+	 * whenever any of the specified changes occur. Duplicate attempts to
+	 * register the same trigger are silently ignored.
+	 * <p>
+	 * {@code triggers} may be empty, which results in a no-op. It must not be
+	 * {@code null}.
+	 * 
+	 * @param triggers the {@linkplain ARTrigger triggers} to
+	 *                 request reassembly with.
+	 * @see #disableAutoReassemblyAt(ARTrigger...)
+	 */
+	protected synchronized void reassembleAt(ARTrigger... triggers) {
+
+		Objects.requireNonNull(triggers, "triggers");
+		if (triggers.length == 0)
+			return;
+
+		if (autoReassemblyTriggerObjects == null) {
+			autoReassemblyTriggerObjects = new EnumMap<>(ARTrigger.class);
+		}
+
+		for (ARTrigger trigger : triggers) {
+			if (!autoReassemblyTriggerObjects.containsKey(trigger)) {
+				Object triggerObject = createTriggerObject(trigger);
+				addListener(trigger);
+				autoReassemblyTriggerObjects.put(trigger, triggerObject);
+			}
+		}
+
+	}
+
+	/**
+	 * Requests that {@link #requestReassembly()} is no longer invoked on this
+	 * component whenever any of the specified changes occur. After a trigger is
+	 * removed, it may be reinstalled with
+	 * {@link #reassembleAt(ARTrigger...)}. Attempts to remove a
+	 * nonexistant trigger are silently ignored.
+	 * <p>
+	 * {@code triggers} may be empty, which results in a no-op. It must not be
+	 * {@code null}.
+	 * 
+	 * @param triggers the {@linkplain ARTrigger triggers} to remove
+	 * @see #reassemblyAt(ARTrigger...)
+	 */
+	protected synchronized void disableAutoReassemblyAt(ARTrigger... triggers) {
+
+		Objects.requireNonNull(triggers, "triggers");
+		if (triggers.length == 0)
+			return;
+
+		if (autoReassemblyTriggerObjects == null)
+			return;
+
+		for (ARTrigger trigger : triggers) {
+			Object triggerObject = autoReassemblyTriggerObjects.remove(trigger);
+			if (triggerObject != null) {
+				removeListener(trigger);
+			}
+		}
+
+	}
+
 	// /**
 	// * Returns a component that displays this component in its center.
 	// * @return a {@link Aligner} initialized to center this component

src/main/java/ru/windcorp/progressia/client/graphics/gui/Group.java

@@ -16,18 +16,13 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package ru.windcorp.progressia.common.world.tile;
+package ru.windcorp.progressia.client.graphics.gui;
 
-public interface TileReference {
+public class Group extends Component {
 
-	TileData get();
-
-	int getIndex();
-
-	TileDataStack getStack();
-
-	default boolean isValid() {
-		return get() != null;
+	public Group(String name, Layout layout) {
+		super(name);
+		setLayout(layout);
 	}
 
 }

src/main/java/ru/windcorp/progressia/client/graphics/gui/Label.java

@@ -83,6 +83,11 @@ public class Label extends Component {
 		return font;
 	}
 	
+	public void setFont(Font font) {
+		this.font = font;
+		requestReassembly();
+	}
+
 	public String getCurrentText() {
 		return currentText;
 	}
@@ -96,11 +101,7 @@ public class Label extends Component {
 		float startX = getX() + font.getAlign() * (getWidth() - currentSize.x);
 
 		target.pushTransform(
-			new Mat4().identity().translate(startX, getY(), -1000) // TODO wtf
-																	// is this
-																	// magic
-																	// <---
-				.scale(2)
+			new Mat4().identity().translate(startX, getY(), 0).scale(2)
 		);
 
 		target.addCustomRenderer(font.assemble(currentText, maxWidth));

src/main/java/ru/windcorp/progressia/client/graphics/gui/Panel.java

@@ -15,14 +15,66 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
- 
 package ru.windcorp.progressia.client.graphics.gui;
 
-public class Panel extends Component {
+import java.util.Objects;
+
+import glm.vec._4.Vec4;
+import ru.windcorp.progressia.client.graphics.Colors;
+import ru.windcorp.progressia.client.graphics.flat.RenderTarget;
+
+public class Panel extends Group {
+
+	private Vec4 fill;
+	private Vec4 border;
+
+	public Panel(String name, Layout layout, Vec4 fill, Vec4 border) {
+		super(name, layout);
+		
+		this.fill = Objects.requireNonNull(fill, "fill");
+		this.border = border;
+	}
 	
 	public Panel(String name, Layout layout) {
-		super(name);
-		setLayout(layout);
+		this(name, layout, Colors.WHITE, Colors.LIGHT_GRAY);
+	}
+	
+	/**
+	 * @return the fill
+	 */
+	public Vec4 getFill() {
+		return fill;
+	}
+	
+	/**
+	 * @param fill the fill to set
+	 */
+	public void setFill(Vec4 fill) {
+		this.fill = Objects.requireNonNull(fill, "fill");
+	}
+	
+	/**
+	 * @return the border
+	 */
+	public Vec4 getBorder() {
+		return border;
+	}
+	
+	/**
+	 * @param border the border to set
+	 */
+	public void setBorder(Vec4 border) {
+		this.border = border;
+	}
+	
+	@Override
+	protected void assembleSelf(RenderTarget target) {
+		if (border == null) {
+			target.fill(getX(), getY(), getWidth(), getHeight(), fill);
+		} else {
+			target.fill(getX(), getY(), getWidth(), getHeight(), border);
+			target.fill(getX() + 2, getY() + 2, getWidth() - 4, getHeight() - 4, fill);
+		}
 	}
 
 }

src/main/java/ru/windcorp/progressia/client/graphics/gui/RadioButton.java

@@ -0,0 +1,205 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.client.graphics.gui;
+
+import org.lwjgl.glfw.GLFW;
+
+import glm.vec._2.i.Vec2i;
+import glm.vec._4.Vec4;
+import ru.windcorp.progressia.client.graphics.Colors;
+import ru.windcorp.progressia.client.graphics.flat.RenderTarget;
+import ru.windcorp.progressia.client.graphics.font.Font;
+import ru.windcorp.progressia.client.graphics.font.Typefaces;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutAlign;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutHorizontal;
+import ru.windcorp.progressia.client.graphics.input.KeyEvent;
+
+public class RadioButton extends BasicButton {
+	
+	private class Tick extends Component {
+
+		public Tick() {
+			super(RadioButton.this.getName() + ".Tick");
+			
+			setPreferredSize(new Vec2i(Typefaces.getDefault().getLineHeight() * 3 / 2));
+		}
+		
+		private void cross(RenderTarget target, int x, int y, int size, Vec4 color) {
+			target.fill(x + 4, y, size - 8, size, color);
+			target.fill(x + 2, y + 2, size - 4, size - 4, color);
+			target.fill(x, y + 4, size, size - 8, color);
+		}
+		
+		@Override
+		protected void assembleSelf(RenderTarget target) {
+			
+			int size = getPreferredSize().x;
+			int x = getX();
+			int y = getY() + (getHeight() - size) / 2;
+			
+			// Border
+			
+			Vec4 borderColor;
+			if (RadioButton.this.isPressed() || RadioButton.this.isHovered() || RadioButton.this.isFocused()) {
+				borderColor = Colors.BLUE;
+			} else {
+				borderColor = Colors.LIGHT_GRAY;
+			}
+			cross(target, x, y, size, borderColor);
+			
+			// Inside area
+			
+			if (RadioButton.this.isPressed()) {
+				// Do nothing
+			} else {
+				Vec4 backgroundColor;
+				if (RadioButton.this.isHovered() && RadioButton.this.isEnabled()) {
+					backgroundColor = Colors.HOVER_BLUE;
+				} else {
+					backgroundColor = Colors.WHITE;
+				}
+				cross(target, x + 2, y + 2, size - 4, backgroundColor);
+			}
+			
+			// "Tick"
+			
+			if (RadioButton.this.isChecked()) {
+				cross(target, x + 4, y + 4, size - 8, Colors.BLUE);
+			}
+		}
+
+	}
+
+	private boolean checked;
+	
+	private RadioButtonGroup group = null;
+
+	public RadioButton(String name, String label, Font labelFont, boolean check) {
+		super(name, label, labelFont);
+		this.checked = check;
+		
+		assert getChildren().size() == 1 : "RadioButton expects that BasicButton contains exactly one child";
+		Component basicChild = getChild(0);
+		
+		Group group = new Group(getName() + ".LabelAndTick", new LayoutHorizontal(0, 10));
+		removeChild(basicChild);
+		setLayout(new LayoutAlign(0, 0.5f, 10));
+		group.setLayoutHint(basicChild.getLayoutHint());
+		group.addChild(new Tick());
+		group.addChild(basicChild);
+		addChild(group);
+		
+		addListener(KeyEvent.class, e -> {
+			if (e.isRelease()) return false;
+			
+			if (e.getKey() == GLFW.GLFW_KEY_LEFT || e.getKey() == GLFW.GLFW_KEY_UP) {
+				if (this.group != null) {
+					this.group.selectPrevious();
+					this.group.getSelected().takeFocus();
+				}
+				
+				return true;
+			} else if (e.getKey() == GLFW.GLFW_KEY_RIGHT || e.getKey() == GLFW.GLFW_KEY_DOWN) {
+				if (this.group != null) {
+					this.group.selectNext();
+					this.group.getSelected().takeFocus();
+				}
+				return true;
+			}
+			
+			return false;
+		});
+		
+		addAction(b -> setChecked(true));
+	}
+	
+	public RadioButton(String name, String label, Font labelFont) {
+		this(name, label, labelFont, false);
+	}
+	
+	public RadioButton(String name, String label, boolean check) {
+		this(name, label, new Font(), check);
+	}
+	
+	public RadioButton(String name, String label) {
+		this(name, label, false);
+	}
+	
+	/**
+	 * @param group the group to set
+	 */
+	public RadioButton setGroup(RadioButtonGroup group) {
+		
+		if (this.group != null) {
+			group.selectNext();
+			removeAction(group.listener);
+			group.buttons.remove(this);
+			group.getSelected(); // Clear reference if this was the only button in the group
+		}
+		
+		this.group = group;
+		
+		if (this.group != null) {
+			group.buttons.add(this);
+			addAction(group.listener);
+		}
+		
+		setChecked(false);
+		
+		return this;
+	}
+	
+	/**
+	 * @return the checked
+	 */
+	public boolean isChecked() {
+		return checked;
+	}
+	
+	/**
+	 * @param checked the checked to set
+	 */
+	public void setChecked(boolean checked) {
+		this.checked = checked;
+		
+		if (group != null) {
+			group.listener.accept(this); // Failsafe for manual invocations of setChecked()
+		}
+	}
+
+	@Override
+	protected void assembleSelf(RenderTarget target) {
+		// Change label font color
+		
+		if (isPressed()) {
+			getLabel().setFont(getLabel().getFont().withColor(Colors.BLUE));
+		} else {
+			getLabel().setFont(getLabel().getFont().withColor(Colors.BLACK));
+		}
+	}
+	
+	@Override
+	protected void postAssembleSelf(RenderTarget target) {
+		// Apply disable tint
+		
+		if (!isEnabled()) {
+			target.fill(getX(), getY(), getWidth(), getHeight(), Colors.toVector(0x88FFFFFF));
+		}
+	}
+	
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/RadioButtonGroup.java

@@ -0,0 +1,119 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.client.graphics.gui;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.function.Consumer;
+
+public class RadioButtonGroup {
+
+	private final Collection<Consumer<RadioButtonGroup>> actions = Collections.synchronizedCollection(new ArrayList<>());
+	final List<RadioButton> buttons = Collections.synchronizedList(new ArrayList<>());
+	
+	private RadioButton selected = null;
+	
+	Consumer<BasicButton> listener = b -> {
+		if (b instanceof RadioButton && ((RadioButton) b).isChecked() && buttons.contains(b)) {
+			select((RadioButton) b);
+		}
+	};
+	
+	public RadioButtonGroup addAction(Consumer<RadioButtonGroup> action) {
+		this.actions.add(Objects.requireNonNull(action, "action"));
+		return this;
+	}
+	
+	public boolean removeAction(Consumer<BasicButton> action) {
+		return this.actions.remove(action);
+	}
+	
+	public List<RadioButton> getButtons() {
+		return Collections.unmodifiableList(buttons);
+	}
+	
+	public synchronized RadioButton getSelected() {
+		if (!buttons.contains(selected)) {
+			selected = null;
+		}
+		return selected;
+	}
+	
+	public synchronized void select(RadioButton button) {
+		if (button != null && !buttons.contains(button)) {
+			throw new IllegalArgumentException("Button " + button + " is not in the group");
+		}
+		
+		getSelected(); // Clear if invalid
+		
+		if (selected == button) {
+			return; // Terminate listener-setter recursion
+		}
+		
+		if (selected != null) {
+			selected.setChecked(false);
+		}
+		
+		selected = button;
+		
+		if (selected != null) {
+			selected.setChecked(true);
+		}
+		
+		actions.forEach(action -> action.accept(this));
+	}
+	
+	public void selectNext() {
+		selectNeighbour(+1);
+	}
+	
+	public void selectPrevious() {
+		selectNeighbour(-1);
+	}
+	
+	private synchronized void selectNeighbour(int direction) {
+		if (getSelected() == null) {
+			if (buttons.isEmpty()) {
+				throw new IllegalStateException("Cannot select neighbour button: group empty");
+			}
+			
+			select(buttons.get(0));
+		} else {
+			RadioButton button;
+			int index = buttons.indexOf(selected);
+			
+			do {
+				index += direction;
+				
+				if (index >= buttons.size()) {
+					index = 0;
+				} else if (index < 0) {
+					index = buttons.size() - 1;
+				}
+				
+				button = buttons.get(index);
+			} while (button != getSelected() && !button.isEnabled());
+			
+			select(button);
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/event/ButtonEvent.java

@@ -0,0 +1,60 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package ru.windcorp.progressia.client.graphics.gui.event;
+
+import ru.windcorp.progressia.client.graphics.gui.BasicButton;
+
+public class ButtonEvent extends ComponentEvent {
+	
+	public static class Press extends ButtonEvent {
+		public Press(BasicButton button) {
+			super(button, true);
+		}
+	}
+	
+	public static class Release extends ButtonEvent {
+		public Release(BasicButton button) {
+			super(button, false);
+		}
+	}
+	
+	private final boolean isPress;
+
+	protected ButtonEvent(BasicButton button, boolean isPress) {
+		super(button);
+		this.isPress = isPress;
+	}
+	
+	public static ButtonEvent create(BasicButton button, boolean isPress) {
+		if (isPress) {
+			return new Press(button);
+		} else {
+			return new Release(button);
+		}
+	}
+
+	public boolean isPress() {
+		return isPress;
+	}
+
+	public boolean isRelease() {
+		return !isPress;
+	}
+	
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/event/EnableEvent.java

@@ -0,0 +1,11 @@
+package ru.windcorp.progressia.client.graphics.gui.event;
+
+import ru.windcorp.progressia.client.graphics.gui.Component;
+
+public class EnableEvent extends ComponentEvent {
+
+	public EnableEvent(Component component) {
+		super(component);
+	}
+	
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/layout/LayoutFill.java

@@ -0,0 +1,78 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+ 
+package ru.windcorp.progressia.client.graphics.gui.layout;
+
+import static java.lang.Math.max;
+
+import glm.vec._2.i.Vec2i;
+import ru.windcorp.progressia.client.graphics.gui.Component;
+import ru.windcorp.progressia.client.graphics.gui.Layout;
+
+public class LayoutFill implements Layout {
+
+	private final int margin;
+	
+	public LayoutFill(int margin) {
+		this.margin = margin;
+	}
+
+	public LayoutFill() {
+		this(0);
+	}
+
+	@Override
+	public void layout(Component c) {
+		c.getChildren().forEach(child -> {
+
+			int cWidth = c.getWidth() - 2 * margin;
+			int cHeight = c.getHeight() - 2 * margin;
+
+			child.setBounds(
+				c.getX() + margin,
+				c.getY() + margin,
+				cWidth,
+				cHeight
+			);
+
+		});
+	}
+
+	@Override
+	public Vec2i calculatePreferredSize(Component c) {
+		Vec2i result = new Vec2i(0, 0);
+
+		c.getChildren().stream()
+			.map(child -> child.getPreferredSize())
+			.forEach(size -> {
+				result.x = max(size.x, result.x);
+				result.y = max(size.y, result.y);
+			});
+
+		result.x += 2 * margin;
+		result.y += 2 * margin;
+
+		return result;
+	}
+
+	@Override
+	public String toString() {
+		return getClass().getSimpleName() + "(" + margin + ")";
+	}
+
+}

src/main/java/ru/windcorp/progressia/client/graphics/gui/layout/LayoutGrid.java

@@ -98,15 +98,26 @@ public class LayoutGrid implements Layout {
 			if (!isSummed)
 				throw new IllegalStateException("Not summed yet");
 			
+			int width, height;
+			
+			if (column == columns.length - 1) {
+				width = parent.getWidth() - margin - columns[column];
+			} else {
+				width = columns[column + 1] - columns[column] - gap;
+			}
+			
+			if (row == rows.length - 1) {
+				height = parent.getHeight() - margin - rows[row];
+			} else {
+				height = rows[row + 1] - rows[row] - gap;
+			}
+
 			child.setBounds(
 				parent.getX() + columns[column],
-				parent.getY() + rows[row],
+				parent.getY() + parent.getHeight() - (rows[row] + height),
 
-				(column != (columns.length - 1) ? (columns[column + 1] - columns[column] - gap)
-					: (parent.getWidth() - margin - columns[column])),
-
-				(row != (rows.length - 1) ? (rows[row + 1] - rows[row] - gap)
-					: (parent.getHeight() - margin - rows[row]))
+				width,
+				height
 			);
 		}
 	}
@@ -132,10 +143,9 @@ public class LayoutGrid implements Layout {
 			GridDimensions grid = calculateGrid(c);
 			grid.sum();
 
-			int[] coords;
 			for (Component child : c.getChildren()) {
-				coords = (int[]) child.getLayoutHint();
-				grid.setBounds(coords[0], coords[1], child, c);
+				Vec2i coords = (Vec2i) child.getLayoutHint();
+				grid.setBounds(coords.x, coords.y, child, c);
 			}
 		}
 	}
@@ -149,11 +159,10 @@ public class LayoutGrid implements Layout {
 
 	private GridDimensions calculateGrid(Component parent) {
 		GridDimensions result = new GridDimensions();
-		int[] coords;
 
 		for (Component child : parent.getChildren()) {
-			coords = (int[]) child.getLayoutHint();
-			result.add(coords[0], coords[1], child.getPreferredSize());
+			Vec2i coords = (Vec2i) child.getLayoutHint();
+			result.add(coords.x, coords.y, child.getPreferredSize());
 		}
 
 		return result;

src/main/java/ru/windcorp/progressia/client/graphics/gui/menu/MenuLayer.java

@@ -0,0 +1,117 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.client.graphics.gui.menu;
+
+import org.lwjgl.glfw.GLFW;
+
+import glm.vec._2.i.Vec2i;
+import ru.windcorp.progressia.client.graphics.Colors;
+import ru.windcorp.progressia.client.graphics.GUI;
+import ru.windcorp.progressia.client.graphics.font.Font;
+import ru.windcorp.progressia.client.graphics.gui.Component;
+import ru.windcorp.progressia.client.graphics.gui.GUILayer;
+import ru.windcorp.progressia.client.graphics.gui.Label;
+import ru.windcorp.progressia.client.graphics.gui.Layout;
+import ru.windcorp.progressia.client.graphics.gui.Panel;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutAlign;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutFill;
+import ru.windcorp.progressia.client.graphics.gui.layout.LayoutVertical;
+import ru.windcorp.progressia.client.graphics.input.InputEvent;
+import ru.windcorp.progressia.client.graphics.input.KeyEvent;
+import ru.windcorp.progressia.client.graphics.input.bus.Input;
+import ru.windcorp.progressia.client.localization.MutableString;
+import ru.windcorp.progressia.client.localization.MutableStringLocalized;
+
+public class MenuLayer extends GUILayer {
+
+	private final Component content;
+	private final Component background;
+	
+	private final Runnable closeAction = () -> {
+		GUI.removeLayer(this);
+	};
+	
+	public MenuLayer(String name, Component content) {
+		super(name, new LayoutFill(0));
+		
+		setCursorPolicy(CursorPolicy.REQUIRE);
+		
+		this.background = new Panel(name + ".Background", new LayoutAlign(10), Colors.toVector(0x66000000), null);
+		this.content = content;
+		
+		background.addChild(content);
+		getRoot().addChild(background);
+	}
+	
+	public MenuLayer(String name, Layout contentLayout) {
+		this(name, new Panel(name + ".Content", contentLayout));
+	}
+	
+	public MenuLayer(String name) {
+		this(name, new LayoutVertical(20, 10));
+	}
+	
+	public Component getContent() {
+		return content;
+	}
+	
+	public Component getBackground() {
+		return background;
+	}
+	
+	protected void addTitle() {
+		String translationKey = "Layer" + getName() + ".Title";
+		MutableString titleText = new MutableStringLocalized(translationKey);
+		Font titleFont = new Font().deriveBold().withColor(Colors.BLACK).withAlign(0.5f);
+		
+		Label label = new Label(getName() + ".Title", titleFont, titleText);
+		getContent().addChild(label);
+		
+		Panel panel = new Panel(getName() + ".Title.Underscore", null, Colors.BLUE, null);
+		panel.setLayout(new LayoutFill() {
+			@Override
+			public Vec2i calculatePreferredSize(Component c) {
+				return new Vec2i(label.getPreferredSize().x + 40, 4);
+			}
+		});
+		getContent().addChild(panel);
+	}
+	
+	protected Runnable getCloseAction() {
+		return closeAction;
+	}
+	
+	@Override
+	protected void handleInput(Input input) {
+		
+		if (!input.isConsumed()) {
+			InputEvent event = input.getEvent();
+			
+			if (event instanceof KeyEvent) {
+				KeyEvent keyEvent = (KeyEvent) event;
+				if (keyEvent.isPress() && keyEvent.getKey() == GLFW.GLFW_KEY_ESCAPE) {
+					getCloseAction().run();
+				}
+			}
+		}
+		
+		super.handleInput(input);
+		input.consume();
+	}
+	
+}

src/main/java/ru/windcorp/progressia/client/graphics/model/BlockFaceVectors.java

@@ -18,23 +18,23 @@
  
 package ru.windcorp.progressia.client.graphics.model;
 
-import static ru.windcorp.progressia.common.world.block.BlockFace.*;
+import static ru.windcorp.progressia.common.world.rels.AbsFace.*;
 
 import com.google.common.collect.ImmutableMap;
 
 import glm.vec._3.Vec3;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 class BlockFaceVectors {
 
 	private static BlockFaceVectors createInner(BlockFaceVectors outer) {
-		ImmutableMap.Builder<BlockFace, Vec3> originBuilder = ImmutableMap.builder();
+		ImmutableMap.Builder<AbsFace, Vec3> originBuilder = ImmutableMap.builder();
 
-		ImmutableMap.Builder<BlockFace, Vec3> widthBuilder = ImmutableMap.builder();
+		ImmutableMap.Builder<AbsFace, Vec3> widthBuilder = ImmutableMap.builder();
 
-		ImmutableMap.Builder<BlockFace, Vec3> heightBuilder = ImmutableMap.builder();
+		ImmutableMap.Builder<AbsFace, Vec3> heightBuilder = ImmutableMap.builder();
 
-		for (BlockFace face : getFaces()) {
+		for (AbsFace face : getFaces()) {
 			Vec3 width = outer.getWidth(face);
 			Vec3 height = outer.getHeight(face);
 
@@ -59,36 +59,36 @@ class BlockFaceVectors {
 
 	static {
 		OUTER = new BlockFaceVectors(
-			ImmutableMap.<BlockFace, Vec3>builder()
+			ImmutableMap.<AbsFace, Vec3>builder()
 
-				.put(TOP, new Vec3(-0.5f, +0.5f, +0.5f))
-				.put(BOTTOM, new Vec3(-0.5f, -0.5f, -0.5f))
-				.put(NORTH, new Vec3(+0.5f, -0.5f, -0.5f))
-				.put(SOUTH, new Vec3(-0.5f, +0.5f, -0.5f))
-				.put(WEST, new Vec3(+0.5f, +0.5f, -0.5f))
-				.put(EAST, new Vec3(-0.5f, -0.5f, -0.5f))
+				.put(POS_Z, new Vec3(-0.5f, +0.5f, +0.5f))
+				.put(NEG_Z, new Vec3(-0.5f, -0.5f, -0.5f))
+				.put(POS_X, new Vec3(+0.5f, -0.5f, -0.5f))
+				.put(NEG_X, new Vec3(-0.5f, +0.5f, -0.5f))
+				.put(POS_Y, new Vec3(+0.5f, +0.5f, -0.5f))
+				.put(NEG_Y, new Vec3(-0.5f, -0.5f, -0.5f))
 
 				.build(),
 
-			ImmutableMap.<BlockFace, Vec3>builder()
+			ImmutableMap.<AbsFace, Vec3>builder()
 
-				.put(TOP, new Vec3(0, -1, 0))
-				.put(BOTTOM, new Vec3(0, +1, 0))
-				.put(NORTH, new Vec3(0, +1, 0))
-				.put(SOUTH, new Vec3(0, -1, 0))
-				.put(WEST, new Vec3(-1, 0, 0))
-				.put(EAST, new Vec3(+1, 0, 0))
+				.put(POS_Z, new Vec3(0, -1, 0))
+				.put(NEG_Z, new Vec3(0, +1, 0))
+				.put(POS_X, new Vec3(0, +1, 0))
+				.put(NEG_X, new Vec3(0, -1, 0))
+				.put(POS_Y, new Vec3(-1, 0, 0))
+				.put(NEG_Y, new Vec3(+1, 0, 0))
 
 				.build(),
 
-			ImmutableMap.<BlockFace, Vec3>builder()
+			ImmutableMap.<AbsFace, Vec3>builder()
 
-				.put(TOP, new Vec3(+1, 0, 0))
-				.put(BOTTOM, new Vec3(+1, 0, 0))
-				.put(NORTH, new Vec3(0, 0, +1))
-				.put(SOUTH, new Vec3(0, 0, +1))
-				.put(WEST, new Vec3(0, 0, +1))
-				.put(EAST, new Vec3(0, 0, +1))
+				.put(POS_Z, new Vec3(+1, 0, 0))
+				.put(NEG_Z, new Vec3(+1, 0, 0))
+				.put(POS_X, new Vec3(0, 0, +1))
+				.put(NEG_X, new Vec3(0, 0, +1))
+				.put(POS_Y, new Vec3(0, 0, +1))
+				.put(NEG_Y, new Vec3(0, 0, +1))
 
 				.build()
 		);
@@ -100,29 +100,29 @@ class BlockFaceVectors {
 		return inner ? INNER : OUTER;
 	}
 
-	private final ImmutableMap<BlockFace, Vec3> origins;
-	private final ImmutableMap<BlockFace, Vec3> widths;
-	private final ImmutableMap<BlockFace, Vec3> heights;
+	private final ImmutableMap<AbsFace, Vec3> origins;
+	private final ImmutableMap<AbsFace, Vec3> widths;
+	private final ImmutableMap<AbsFace, Vec3> heights;
 
 	public BlockFaceVectors(
-		ImmutableMap<BlockFace, Vec3> origins,
-		ImmutableMap<BlockFace, Vec3> widths,
-		ImmutableMap<BlockFace, Vec3> heights
+		ImmutableMap<AbsFace, Vec3> origins,
+		ImmutableMap<AbsFace, Vec3> widths,
+		ImmutableMap<AbsFace, Vec3> heights
 	) {
 		this.origins = origins;
 		this.widths = widths;
 		this.heights = heights;
 	}
 
-	public Vec3 getOrigin(BlockFace face) {
+	public Vec3 getOrigin(AbsFace face) {
 		return origins.get(face);
 	}
 
-	public Vec3 getWidth(BlockFace face) {
+	public Vec3 getWidth(AbsFace face) {
 		return widths.get(face);
 	}
 
-	public Vec3 getHeight(BlockFace face) {
+	public Vec3 getHeight(AbsFace face) {
 		return heights.get(face);
 	}
 }

src/main/java/ru/windcorp/progressia/client/graphics/model/Shape.java

@@ -30,10 +30,10 @@ import ru.windcorp.progressia.client.graphics.backend.VertexBufferObject;
 public class Shape implements Renderable {
 
 	private final ShapeRenderProgram program;
-	private final Face[] faces;
+	private final ShapePart[] parts;
 	private final Usage usage;
 
-	private FaceGroup[] groups;
+	private ShapePartGroup[] groups;
 
 	private ByteBuffer vertices;
 	private ShortBuffer indices;
@@ -45,33 +45,33 @@ public class Shape implements Renderable {
 	private VertexBufferObject verticesVbo;
 	private VertexBufferObject indicesVbo;
 
-	public Shape(Usage usage, ShapeRenderProgram program, Face... faces) {
+	public Shape(Usage usage, ShapeRenderProgram program, ShapePart... parts) {
 		this.program = program;
-		this.faces = faces;
+		this.parts = parts;
 		this.usage = usage;
 
-		configureFaces();
+		configureParts();
 		program.preprocess(this);
 
 		assembleBuffers();
 	}
 
-	private void configureFaces() {
-		for (Face face : faces) {
-			face.setShape(this);
+	private void configureParts() {
+		for (ShapePart part : parts) {
+			part.setShape(this);
 		}
 	}
 
 	private void assembleBuffers() {
 		// TODO optimize: only update faces that requested it
 
-		sortFaces();
+		sortParts();
 		resizeBuffers();
 
-		for (Face face : faces) {
-			assembleVertices(face);
-			assembleIndices(face);
-			face.resetUpdateFlags();
+		for (ShapePart part : parts) {
+			assembleVertices(part);
+			assembleIndices(part);
+			part.resetUpdateFlags();
 		}
 
 		this.vertices.flip();
@@ -85,110 +85,110 @@ public class Shape implements Renderable {
 
 	private void resizeBuffers() {
 		int verticesRequired = 0, indicesRequired = 0;
-		for (Face face : faces) {
-			verticesRequired += face.getVertices().remaining();
-			indicesRequired += face.getIndices().remaining();
+		for (ShapePart part : parts) {
+			verticesRequired += part.getVertices().remaining();
+			indicesRequired += part.getIndices().remaining();
 		}
 
-		if (this.vertices == null || vertices.capacity() < verticesRequired) {
+		if (vertices == null || vertices.capacity() < verticesRequired) {
 			this.vertices = BufferUtils.createByteBuffer(verticesRequired);
 		} else {
-			this.vertices.position(0).limit(verticesRequired);
+			vertices.position(0).limit(verticesRequired);
 		}
 
-		if (this.indices == null || this.indices.capacity() < indicesRequired) {
+		if (indices == null || indices.capacity() < indicesRequired) {
 			this.indices = BufferUtils.createShortBuffer(indicesRequired);
 		} else {
-			this.indices.position(0).limit(indicesRequired);
+			indices.position(0).limit(indicesRequired);
 		}
 	}
 
-	private void assembleVertices(Face face) {
-		face.locationOfVertices = this.vertices.position();
+	private void assembleVertices(ShapePart part) {
+		part.locationOfVertices = this.vertices.position();
 
-		insertVertices(face);
-		linkVerticesWith(face);
+		insertVertices(part);
+		linkVerticesWith(part);
 	}
 
-	private void insertVertices(Face face) {
-		ByteBuffer faceVertices = face.getVertices();
+	private void insertVertices(ShapePart part) {
+		ByteBuffer partVertices = part.getVertices();
 
-		faceVertices.mark();
-		this.vertices.put(faceVertices);
-		faceVertices.reset();
+		partVertices.mark();
+		this.vertices.put(partVertices);
+		partVertices.reset();
 	}
 
-	private void linkVerticesWith(Face face) {
+	private void linkVerticesWith(ShapePart part) {
 		int limit = vertices.limit();
 		int position = vertices.position();
 
-		vertices.limit(position).position(face.getLocationOfVertices());
-		face.vertices = vertices.slice();
+		vertices.limit(position).position(part.getLocationOfVertices());
+		part.vertices = vertices.slice();
 
 		vertices.position(position).limit(limit);
 	}
 
-	private void assembleIndices(Face face) {
-		short vertexOffset = (short) (face.getLocationOfVertices() / program.getBytesPerVertex());
+	private void assembleIndices(ShapePart part) {
+		short vertexOffset = (short) (part.getLocationOfVertices() / program.getBytesPerVertex());
 
-		face.locationOfIndices = indices.position();
+		part.locationOfIndices = indices.position();
 
-		ShortBuffer faceIndices = face.getIndices();
+		ShortBuffer partIndices = part.getIndices();
 
-		if (faceIndices == null) {
-			for (int i = 0; i < face.getVertexCount(); ++i) {
+		if (partIndices == null) {
+			for (int i = 0; i < part.getVertexCount(); ++i) {
 				this.indices.put((short) (vertexOffset + i));
 			}
 		} else {
-			for (int i = faceIndices.position(); i < faceIndices.limit(); ++i) {
-				short faceIndex = faceIndices.get(i);
-				faceIndex += vertexOffset;
-				this.indices.put(faceIndex);
+			for (int i = partIndices.position(); i < partIndices.limit(); ++i) {
+				short partIndex = partIndices.get(i);
+				partIndex += vertexOffset;
+				this.indices.put(partIndex);
 			}
 		}
 	}
 
-	private void sortFaces() {
-		Arrays.sort(faces);
+	private void sortParts() {
+		Arrays.sort(parts);
 	}
 
 	private void assembleGroups() {
-		int unique = countUniqueFaces();
-		this.groups = new FaceGroup[unique];
+		int unique = countUniqueParts();
+		this.groups = new ShapePartGroup[unique];
 
-		if (faces.length == 0)
+		if (parts.length == 0)
 			return;
 
-		int previousHandle = faces[0].getSortingIndex();
+		int previousHandle = parts[0].getSortingIndex();
 		int start = 0;
 		int groupIndex = 0;
 
-		for (int i = 1; i < faces.length; ++i) {
-			if (previousHandle != faces[i].getSortingIndex()) {
+		for (int i = 1; i < parts.length; ++i) {
+			if (previousHandle != parts[i].getSortingIndex()) {
 
-				groups[groupIndex] = new FaceGroup(faces, start, i);
+				groups[groupIndex] = new ShapePartGroup(parts, start, i);
 				start = i;
 				groupIndex++;
 
-				previousHandle = faces[i].getSortingIndex();
+				previousHandle = parts[i].getSortingIndex();
 			}
 		}
 
 		assert groupIndex == groups.length - 1;
-		groups[groupIndex] = new FaceGroup(faces, start, faces.length);
+		groups[groupIndex] = new ShapePartGroup(parts, start, parts.length);
 	}
 
-	private int countUniqueFaces() {
-		if (faces.length == 0)
+	private int countUniqueParts() {
+		if (parts.length == 0)
 			return 0;
 
 		int result = 1;
-		int previousHandle = faces[0].getSortingIndex();
+		int previousHandle = parts[0].getSortingIndex();
 
-		for (int i = 1; i < faces.length; ++i) {
-			if (previousHandle != faces[i].getSortingIndex()) {
+		for (int i = 1; i < parts.length; ++i) {
+			if (previousHandle != parts[i].getSortingIndex()) {
 				result++;
-				previousHandle = faces[i].getSortingIndex();
+				previousHandle = parts[i].getSortingIndex();
 			}
 		}
 
@@ -238,11 +238,11 @@ public class Shape implements Renderable {
 		return program;
 	}
 
-	public Face[] getFaces() {
-		return faces;
+	public ShapePart[] getParts() {
+		return parts;
 	}
 
-	public FaceGroup[] getGroups() {
+	public ShapePartGroup[] getGroups() {
 		return groups;
 	}
 

src/main/java/ru/windcorp/progressia/client/graphics/model/ShapePart.java

@@ -24,7 +24,7 @@ import java.util.Objects;
 
 import ru.windcorp.progressia.client.graphics.texture.Texture;
 
-public class Face implements Comparable<Face> {
+public class ShapePart implements Comparable<ShapePart> {
 
 	private static final ShortBuffer GENERATE_SUCCESSIVE_LATER = null;
 
@@ -40,7 +40,7 @@ public class Face implements Comparable<Face> {
 	private ShortBuffer userIndices;
 	private boolean userIndicesUpdated = true;
 
-	public Face(
+	public ShapePart(
 		Texture texture,
 		ByteBuffer vertices,
 		ShortBuffer indices
@@ -50,7 +50,7 @@ public class Face implements Comparable<Face> {
 		setIndices(indices);
 	}
 
-	public Face(
+	public ShapePart(
 		Texture texture,
 		ByteBuffer vertices
 	) {
@@ -155,7 +155,7 @@ public class Face implements Comparable<Face> {
 		return vertices;
 	}
 
-	public Face setVertices(ByteBuffer vertices) {
+	public ShapePart setVertices(ByteBuffer vertices) {
 		this.vertices = Objects.requireNonNull(vertices, "vertices");
 		markForVertexUpdate();
 		return this;
@@ -202,7 +202,7 @@ public class Face implements Comparable<Face> {
 		return userIndices.remaining();
 	}
 
-	public Face setIndices(ShortBuffer indices) {
+	public ShapePart setIndices(ShortBuffer indices) {
 		if (indices == null) {
 			indices = GENERATE_SUCCESSIVE_LATER;
 		}
@@ -245,7 +245,7 @@ public class Face implements Comparable<Face> {
 	}
 
 	@Override
-	public int compareTo(Face o) {
+	public int compareTo(ShapePart o) {
 		return Integer.compare(getSortingIndex(), o.getSortingIndex());
 	}
 

src/main/java/ru/windcorp/progressia/client/graphics/model/ShapePartGroup.java

@@ -21,13 +21,13 @@ package ru.windcorp.progressia.client.graphics.model;
 import ru.windcorp.progressia.client.graphics.texture.Texture;
 import ru.windcorp.progressia.client.graphics.texture.TexturePrimitive;
 
-public class FaceGroup {
+public class ShapePartGroup {
 
 	private final TexturePrimitive texture;
 	private final int indexCount;
 	private final int byteOffsetOfIndices;
 
-	FaceGroup(Face[] faces, int start, int end) {
+	ShapePartGroup(ShapePart[] faces, int start, int end) {
 
 		Texture t = faces[start].getTexture();
 		this.texture = t == null ? null : t.getSprite().getPrimitive();
@@ -36,7 +36,7 @@ public class FaceGroup {
 		int indexCount = 0;
 
 		for (int i = start; i < end; ++i) {
-			Face face = faces[i];
+			ShapePart face = faces[i];
 
 			assert this.texture == null
 				? (face.getTexture() == null)

src/main/java/ru/windcorp/progressia/client/graphics/model/ShapeParts.java

@@ -25,14 +25,14 @@ import glm.vec._3.Vec3;
 import glm.vec._4.Vec4;
 import ru.windcorp.progressia.client.graphics.model.ShapeRenderProgram.VertexBuilder;
 import ru.windcorp.progressia.client.graphics.texture.Texture;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
-public class Faces {
+public class ShapeParts {
 
-	private Faces() {
+	private ShapeParts() {
 	}
 
-	public static Face createRectangle(
+	public static ShapePart createRectangle(
 		ShapeRenderProgram program,
 		Texture texture,
 		Vec4 colorMultiplier,
@@ -82,19 +82,19 @@ public class Faces {
 				}
 			);
 
-		return new Face(
+		return new ShapePart(
 			texture,
 			builder.assemble(),
 			buffer
 		);
 	}
 
-	public static Face createBlockFace(
+	public static ShapePart createBlockFace(
 		ShapeRenderProgram program,
 		Texture texture,
 		Vec4 colorMultiplier,
 		Vec3 blockCenter,
-		BlockFace face,
+		AbsFace face,
 		boolean inner
 	) {
 		BlockFaceVectors vectors = BlockFaceVectors.get(inner);

src/main/java/ru/windcorp/progressia/client/graphics/model/ShapeRenderProgram.java

@@ -116,7 +116,7 @@ public class ShapeRenderProgram extends Program {
 
 		try {
 			enableAttributes();
-			for (FaceGroup group : shape.getGroups()) {
+			for (ShapePartGroup group : shape.getGroups()) {
 				renderFaceGroup(group);
 			}
 		} finally {
@@ -182,7 +182,7 @@ public class ShapeRenderProgram extends Program {
 		indices.bind(BindTarget.ELEMENT_ARRAY);
 	}
 
-	protected void renderFaceGroup(FaceGroup group) {
+	protected void renderFaceGroup(ShapePartGroup group) {
 		TexturePrimitive texture = group.getTexture();
 
 		if (texture != null) {
@@ -206,12 +206,12 @@ public class ShapeRenderProgram extends Program {
 	}
 
 	public void preprocess(Shape shape) {
-		for (Face face : shape.getFaces()) {
+		for (ShapePart face : shape.getParts()) {
 			applySprites(face);
 		}
 	}
 
-	private void applySprites(Face face) {
+	private void applySprites(ShapePart face) {
 		if (face.getTexture() == null)
 			return;
 

src/main/java/ru/windcorp/progressia/client/graphics/model/Shapes.java

@@ -24,7 +24,7 @@ import glm.vec._3.Vec3;
 import glm.vec._4.Vec4;
 import ru.windcorp.progressia.client.graphics.backend.Usage;
 import ru.windcorp.progressia.client.graphics.texture.Texture;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 public class Shapes {
 
@@ -50,7 +50,7 @@ public class Shapes {
 		boolean flip
 	) {
 
-		Face top = Faces.createRectangle(
+		ShapePart top = ShapeParts.createRectangle(
 			program,
 			topTexture,
 			colorMultiplier,
@@ -60,7 +60,7 @@ public class Shapes {
 			flip
 		);
 
-		Face bottom = Faces.createRectangle(
+		ShapePart bottom = ShapeParts.createRectangle(
 			program,
 			bottomTexture,
 			colorMultiplier,
@@ -70,7 +70,7 @@ public class Shapes {
 			flip
 		);
 
-		Face north = Faces.createRectangle(
+		ShapePart north = ShapeParts.createRectangle(
 			program,
 			northTexture,
 			colorMultiplier,
@@ -80,7 +80,7 @@ public class Shapes {
 			flip
 		);
 
-		Face south = Faces.createRectangle(
+		ShapePart south = ShapeParts.createRectangle(
 			program,
 			southTexture,
 			colorMultiplier,
@@ -90,7 +90,7 @@ public class Shapes {
 			flip
 		);
 
-		Face east = Faces.createRectangle(
+		ShapePart east = ShapeParts.createRectangle(
 			program,
 			eastTexture,
 			colorMultiplier,
@@ -100,7 +100,7 @@ public class Shapes {
 			flip
 		);
 
-		Face west = Faces.createRectangle(
+		ShapePart west = ShapeParts.createRectangle(
 			program,
 			westTexture,
 			colorMultiplier,
@@ -165,16 +165,16 @@ public class Shapes {
 
 		public PppBuilder(
 			ShapeRenderProgram program,
-			Map<BlockFace, Texture> textureMap
+			Map<AbsFace, Texture> textureMap
 		) {
 			this(
 				program,
-				textureMap.get(BlockFace.TOP),
-				textureMap.get(BlockFace.BOTTOM),
-				textureMap.get(BlockFace.NORTH),
-				textureMap.get(BlockFace.SOUTH),
-				textureMap.get(BlockFace.EAST),
-				textureMap.get(BlockFace.WEST)
+				textureMap.get(AbsFace.POS_Z),
+				textureMap.get(AbsFace.NEG_Z),
+				textureMap.get(AbsFace.POS_X),
+				textureMap.get(AbsFace.NEG_X),
+				textureMap.get(AbsFace.NEG_Y),
+				textureMap.get(AbsFace.POS_Y)
 			);
 		}
 

src/main/java/ru/windcorp/progressia/client/graphics/texture/ComplexTexture.java

@@ -21,7 +21,7 @@ package ru.windcorp.progressia.client.graphics.texture;
 import java.util.Map;
 
 import glm.vec._2.Vec2;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 public class ComplexTexture {
 
@@ -54,14 +54,14 @@ public class ComplexTexture {
 		);
 	}
 
-	public Map<BlockFace, Texture> getCuboidTextures(
+	public Map<AbsFace, Texture> getCuboidTextures(
 		int x,
 		int y,
 		int width,
 		int height,
 		int depth
 	) {
-		return BlockFace.mapToFaces(
+		return AbsFace.mapToFaces(
 			get(
 				x + depth + width,
 				y + height + depth,
@@ -86,7 +86,7 @@ public class ComplexTexture {
 		);
 	}
 
-	public Map<BlockFace, Texture> getCuboidTextures(
+	public Map<AbsFace, Texture> getCuboidTextures(
 		int x,
 		int y,
 		int size

src/main/java/ru/windcorp/progressia/client/graphics/world/Camera.java

@@ -29,6 +29,9 @@ import glm.mat._4.Mat4;
 import glm.vec._3.Vec3;
 import ru.windcorp.progressia.client.graphics.backend.GraphicsInterface;
 import ru.windcorp.progressia.client.graphics.world.Camera.Anchor.Mode;
+import ru.windcorp.progressia.client.world.entity.NPedModel;
+import ru.windcorp.progressia.common.util.Matrices;
+import ru.windcorp.progressia.common.util.Vectors;
 
 public class Camera {
 
@@ -60,13 +63,13 @@ public class Camera {
 			}
 		}
 
-		void getCameraPosition(Vec3 output);
+		Vec3 getCameraPosition(Vec3 output);
 
-		void getCameraVelocity(Vec3 output);
+		Vec3 getCameraVelocity(Vec3 output);
 
-		float getCameraYaw();
+		Vec3 getLookingAt(Vec3 output);
 		
-		float getCameraPitch();
+		Vec3 getUpVector(Vec3 output);
 
 		Collection<Mode> getCameraModes();
 
@@ -84,14 +87,11 @@ public class Camera {
 	 */
 
 	private final Vec3 lastAnchorPosition = new Vec3();
-	private float lastAnchorYaw;
-	private float lastAnchorPitch;
+	private final Vec3 lastAnchorLookingAt = new Vec3();
+	private final Vec3 lastAnchorUpVector = new Vec3();
 
 	private final Mat4 lastCameraMatrix = new Mat4();
 
-	private final Vec3 lastAnchorLookingAt = new Vec3();
-	private final Vec3 lastAnchorUp = new Vec3();
-
 	{
 		invalidateCache();
 	}
@@ -108,6 +108,9 @@ public class Camera {
 	 */
 
 	public void apply(WorldRenderHelper helper) {
+		if (NPedModel.flag) {
+//			System.out.println("Camera.apply()");
+		}
 		applyPerspective(helper);
 		rotateCoordinateSystem(helper);
 
@@ -149,26 +152,34 @@ public class Camera {
 	}
 
 	private void applyDirection(WorldRenderHelper helper) {
-		float pitch = anchor.getCameraPitch();
-		float yaw = anchor.getCameraYaw();
+		anchor.getLookingAt(lastAnchorLookingAt);
+		anchor.getUpVector(lastAnchorUpVector);
 
-		helper.pushViewTransform()
-			.rotateY(-pitch)
-			.rotateZ(-yaw);
+		lookAt(helper.pushViewTransform());
+	}
 
-		this.lastAnchorYaw = yaw;
-		this.lastAnchorPitch = pitch;
+	private void lookAt(Mat4 result) {
+		Vec3 f = this.lastAnchorLookingAt;
+		Vec3 s = Vectors.grab3();
+		Vec3 u = Vectors.grab3();
 		
-		this.lastAnchorLookingAt.set(
-			cos(pitch) * cos(yaw),
-			cos(pitch) * sin(yaw),
-			sin(pitch)
-		);
-		this.lastAnchorUp.set(
-			cos(pitch + PI_F / 2) * cos(yaw),
-			cos(pitch + PI_F / 2) * sin(yaw),
-			sin(pitch + PI_F / 2)
+		f.cross(this.lastAnchorUpVector, s);
+		s.normalize();
+		
+		s.cross(f, u);
+		
+		Mat4 workspace = Matrices.grab4();
+		workspace.set(
+			+f.x, -s.x, +u.x,    0,
+			+f.y, -s.y, +u.y,    0,
+			+f.z, -s.z, +u.z,    0,
+			   0,    0,    0,    1
 		);
+		result.mul(workspace);
+		Matrices.release(workspace);
+		
+		Vectors.release(s);
+		Vectors.release(u);
 	}
 
 	private void applyPosition(WorldRenderHelper helper) {
@@ -247,8 +258,6 @@ public class Camera {
 
 	private void invalidateCache() {
 		this.lastAnchorPosition.set(Float.NaN);
-		this.lastAnchorYaw = Float.NaN;
-		this.lastAnchorPitch = Float.NaN;
 
 		this.lastCameraMatrix.set(
 			Float.NaN,
@@ -270,7 +279,7 @@ public class Camera {
 		);
 
 		this.lastAnchorLookingAt.set(Float.NaN);
-		this.lastAnchorUp.set(Float.NaN);
+		this.lastAnchorUpVector.set(Float.NaN);
 	}
 
 	public Anchor.Mode getMode() {
@@ -289,14 +298,6 @@ public class Camera {
 		return currentModeIndex;
 	}
 
-	public float getLastAnchorYaw() {
-		return lastAnchorYaw;
-	}
-
-	public float getLastAnchorPitch() {
-		return lastAnchorPitch;
-	}
-
 	public Vec3 getLastAnchorPosition() {
 		return lastAnchorPosition;
 	}
@@ -310,7 +311,7 @@ public class Camera {
 	}
 
 	public Vec3 getLastAnchorUp() {
-		return lastAnchorUp;
+		return lastAnchorUpVector;
 	}
 
 }

src/main/java/ru/windcorp/progressia/client/graphics/world/EntityAnchor.java

@@ -59,24 +59,32 @@ public class EntityAnchor implements Anchor {
 	}
 
 	@Override
-	public void getCameraPosition(Vec3 output) {
+	public Vec3 getCameraPosition(Vec3 output) {
+		if (output == null) output = new Vec3();
 		model.getViewPoint(output);
-		output.add(entity.getPosition());
+		output.add(model.getPosition());
+		return output;
 	}
 
 	@Override
-	public void getCameraVelocity(Vec3 output) {
+	public Vec3 getCameraVelocity(Vec3 output) {
+		if (output == null) output = new Vec3();
 		output.set(entity.getVelocity());
+		return output;
 	}
 
 	@Override
-	public float getCameraYaw() {
-		return entity.getYaw();
+	public Vec3 getLookingAt(Vec3 output) {
+		if (output == null) output = new Vec3();
+		model.getLookingAt(output);
+		return output;
 	}
 	
 	@Override
-	public float getCameraPitch() {
-		return entity.getPitch();
+	public Vec3 getUpVector(Vec3 output) {
+		if (output == null) output = new Vec3();
+		model.getUpVector(output);
+		return output;
 	}
 
 	@Override

src/main/java/ru/windcorp/progressia/client/graphics/world/LayerWorld.java

@@ -41,6 +41,8 @@ import ru.windcorp.progressia.common.Units;
 import ru.windcorp.progressia.common.collision.Collideable;
 import ru.windcorp.progressia.common.collision.colliders.Collider;
 import ru.windcorp.progressia.common.util.FloatMathUtil;
+import ru.windcorp.progressia.common.util.Vectors;
+import ru.windcorp.progressia.common.world.GravityModel;
 import ru.windcorp.progressia.common.world.entity.EntityData;
 import ru.windcorp.progressia.test.CollisionModelRenderer;
 import ru.windcorp.progressia.test.TestPlayerControls;
@@ -57,6 +59,8 @@ public class LayerWorld extends Layer {
 		super("World");
 		this.client = client;
 		this.inputBasedControls = new InputBasedControls(client);
+		
+		setCursorPolicy(CursorPolicy.FORBID);
 	}
 
 	@Override
@@ -197,16 +201,25 @@ public class LayerWorld extends Layer {
 		entity.getVelocity().mul((float) Math.exp(-FRICTION_COEFF / entity.getCollisionMass() * tickLength));
 	}
 
-	private static final float MC_g = Units.get("32  m/s^2");
-	private static final float IRL_g = Units.get("9.8 m/s^2");
-
 	private void tmp_applyGravity(EntityData entity, float tickLength) {
+		GravityModel gm = ClientState.getInstance().getWorld().getData().getGravityModel();
+		
+		Vec3 upVector = Vectors.grab3();
+		gm.getUp(entity.getPosition(), upVector);
+		entity.changeUpVector(upVector);
+		Vectors.release(upVector);
+		
 		if (ClientState.getInstance().getLocalPlayer().getEntity() == entity && tmp_testControls.isFlying()) {
 			return;
 		}
 
-		final float gravitationalAcceleration = tmp_testControls.useMinecraftGravity() ? MC_g : IRL_g;
-		entity.getVelocity().add(0, 0, -gravitationalAcceleration * tickLength);
+		Vec3 gravitationalAcceleration = Vectors.grab3();
+		gm.getGravity(entity.getPosition(), gravitationalAcceleration);
+		
+		gravitationalAcceleration.mul(tickLength);
+		entity.getVelocity().add(gravitationalAcceleration);
+		
+		Vectors.release(gravitationalAcceleration);
 	}
 
 	@Override

src/main/java/ru/windcorp/progressia/client/graphics/world/Selection.java

@@ -23,13 +23,13 @@ import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.client.world.WorldRender;
 import ru.windcorp.progressia.common.world.BlockRay;
-import ru.windcorp.progressia.common.world.block.BlockFace;
 import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 public class Selection {
 
 	private final Vec3i block = new Vec3i();
-	private BlockFace surface = null;
+	private AbsFace surface = null;
 	private final Vec2 pointOnSurface = new Vec2(0.5f, 0.5f);
 	private final Vec3 point = new Vec3();
 
@@ -38,10 +38,9 @@ public class Selection {
 	private BlockRay ray = new BlockRay();
 
 	public void update(WorldRender world, EntityData player) {
-		Vec3 direction = new Vec3();
 		Vec3 start = new Vec3();
+		Vec3 direction = player.getLookingAt();
 		
-		player.getLookingAtVector(direction);
 		world.getEntityRenderable(player).getViewPoint(start);
 		start.add(player.getPosition());
 
@@ -71,7 +70,7 @@ public class Selection {
 		return exists ? point : null;
 	}
 
-	public BlockFace getSurface() {
+	public AbsFace getSurface() {
 		return exists ? surface : null;
 	}
 

src/main/java/ru/windcorp/progressia/client/graphics/world/WorldRenderProgram.java

@@ -33,7 +33,7 @@ import glm.vec._4.Vec4;
 import ru.windcorp.progressia.client.graphics.backend.VertexBufferObject;
 import ru.windcorp.progressia.client.graphics.backend.shaders.attributes.*;
 import ru.windcorp.progressia.client.graphics.backend.shaders.uniforms.*;
-import ru.windcorp.progressia.client.graphics.model.Face;
+import ru.windcorp.progressia.client.graphics.model.ShapePart;
 import ru.windcorp.progressia.client.graphics.model.Shape;
 import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
 import ru.windcorp.progressia.client.graphics.model.ShapeRenderProgram;
@@ -138,12 +138,12 @@ public class WorldRenderProgram extends ShapeRenderProgram {
 	public void preprocess(Shape shape) {
 		super.preprocess(shape);
 
-		for (Face face : shape.getFaces()) {
+		for (ShapePart face : shape.getParts()) {
 			computeNormals(face);
 		}
 	}
 
-	private void computeNormals(Face face) {
+	private void computeNormals(ShapePart face) {
 		Vec3 a = Vectors.grab3();
 		Vec3 b = Vectors.grab3();
 		Vec3 c = Vectors.grab3();
@@ -183,7 +183,7 @@ public class WorldRenderProgram extends ShapeRenderProgram {
 		normal.normalize();
 	}
 
-	private void loadVertexPosition(Face face, int index, Vec3 result) {
+	private void loadVertexPosition(ShapePart face, int index, Vec3 result) {
 		ByteBuffer vertices = face.getVertices();
 		int offset = vertices.position() + index * getBytesPerVertex();
 
@@ -194,7 +194,7 @@ public class WorldRenderProgram extends ShapeRenderProgram {
 		);
 	}
 
-	private void saveVertexNormal(Face face, int index, Vec3 normal) {
+	private void saveVertexNormal(ShapePart face, int index, Vec3 normal) {
 		ByteBuffer vertices = face.getVertices();
 		int offset = vertices.position() + index * getBytesPerVertex() + (3 * Float.BYTES +
 			4 * Float.BYTES +

src/main/java/ru/windcorp/progressia/client/world/ChunkRender.java

@@ -27,25 +27,29 @@ import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
 import ru.windcorp.progressia.client.world.block.BlockRender;
 import ru.windcorp.progressia.client.world.block.BlockRenderRegistry;
 import ru.windcorp.progressia.client.world.tile.TileRender;
+import ru.windcorp.progressia.client.world.tile.TileRenderReference;
 import ru.windcorp.progressia.client.world.tile.TileRenderRegistry;
 import ru.windcorp.progressia.client.world.tile.TileRenderStack;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
-import ru.windcorp.progressia.common.world.generic.GenericChunk;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.TileDataReference;
+import ru.windcorp.progressia.common.world.TileDataStack;
+import ru.windcorp.progressia.common.world.generic.ChunkGenericRO;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
+import ru.windcorp.progressia.common.world.rels.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class ChunkRender
-	implements GenericChunk<ChunkRender, BlockRender, TileRender, TileRenderStack> {
+	implements ChunkGenericRO<BlockRender, TileRender, TileRenderStack, TileRenderReference, ChunkRender> {
 
 	private final WorldRender world;
-	private final ChunkData data;
+	private final DefaultChunkData data;
 
 	private final ChunkRenderModel model;
 
 	private final Map<TileDataStack, TileRenderStackImpl> tileRenderLists = Collections
 		.synchronizedMap(new WeakHashMap<>());
 
-	public ChunkRender(WorldRender world, ChunkData data) {
+	public ChunkRender(WorldRender world, DefaultChunkData data) {
 		this.world = world;
 		this.data = data;
 		this.model = new ChunkRenderModel(this);
@@ -56,6 +60,11 @@ public class ChunkRender
 		return getData().getPosition();
 	}
 	
+	@Override
+	public AbsFace getUp() {
+		return getData().getUp();
+	}
+
 	@Override
 	public BlockRender getBlock(Vec3i posInChunk) {
 		return BlockRenderRegistry.getInstance().get(
@@ -84,11 +93,11 @@ public class ChunkRender
 		return world;
 	}
 
-	public ChunkData getData() {
+	public DefaultChunkData getData() {
 		return data;
 	}
 
-	public synchronized void markForUpdate() {
+	public void markForUpdate() {
 		getWorld().markChunkForUpdate(getPosition());
 	}
 
@@ -101,6 +110,28 @@ public class ChunkRender
 	}
 
 	private class TileRenderStackImpl extends TileRenderStack {
+		private class TileRenderReferenceImpl implements TileRenderReference {
+			private final TileDataReference parent;
+
+			public TileRenderReferenceImpl(TileDataReference parent) {
+				this.parent = parent;
+			}
+
+			@Override
+			public TileRender get() {
+				return TileRenderRegistry.getInstance().get(parent.get().getId());
+			}
+
+			@Override
+			public int getIndex() {
+				return parent.getIndex();
+			}
+
+			@Override
+			public TileRenderStack getStack() {
+				return TileRenderStackImpl.this;
+			}
+		}
 
 		private final TileDataStack parent;
 
@@ -119,10 +150,25 @@ public class ChunkRender
 		}
 
 		@Override
-		public BlockFace getFace() {
+		public RelFace getFace() {
 			return parent.getFace();
 		}
 		
+		@Override
+		public TileRenderReference getReference(int index) {
+			return new TileRenderReferenceImpl(parent.getReference(index));
+		}
+
+		@Override
+		public int getIndexByTag(int tag) {
+			return parent.getIndexByTag(tag);
+		}
+
+		@Override
+		public int getTagByIndex(int index) {
+			return parent.getTagByIndex(index);
+		}
+
 		@Override
 		public TileRender get(int index) {
 			return TileRenderRegistry.getInstance().get(parent.get(index).getId());

src/main/java/ru/windcorp/progressia/client/world/ChunkRenderModel.java

@@ -35,8 +35,10 @@ import ru.windcorp.progressia.client.world.cro.ChunkRenderOptimizerRegistry;
 import ru.windcorp.progressia.client.world.tile.TileRender;
 import ru.windcorp.progressia.client.world.tile.TileRenderNone;
 import ru.windcorp.progressia.client.world.tile.TileRenderStack;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.generic.GenericChunks;
+import ru.windcorp.progressia.common.world.rels.AxisRotations;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class ChunkRenderModel implements Renderable {
 	
@@ -53,11 +55,15 @@ public class ChunkRenderModel implements Renderable {
 	public void render(ShapeRenderHelper renderer) {
 		if (model == null) return;
 		
+		float offset = DefaultChunkData.BLOCKS_PER_CHUNK / 2 - 0.5f;
+		
 		renderer.pushTransform().translate(
-			chunk.getX() * ChunkData.BLOCKS_PER_CHUNK,
-			chunk.getY() * ChunkData.BLOCKS_PER_CHUNK,
-			chunk.getZ() * ChunkData.BLOCKS_PER_CHUNK
-		);
+			chunk.getX() * DefaultChunkData.BLOCKS_PER_CHUNK,
+			chunk.getY() * DefaultChunkData.BLOCKS_PER_CHUNK,
+			chunk.getZ() * DefaultChunkData.BLOCKS_PER_CHUNK
+		).translate(offset, offset, offset)
+		.mul(AxisRotations.getResolutionMatrix4(chunk.getUp()))
+		.translate(-offset, -offset, -offset);
 
 		model.render(renderer);
 
@@ -71,8 +77,8 @@ public class ChunkRenderModel implements Renderable {
 		
 		optimizers.forEach(ChunkRenderOptimizer::startRender);
 		
-		chunk.forEachBiC(blockInChunk -> {
-			processBlockAndTiles(blockInChunk, sink);
+		GenericChunks.forEachBiC(relBlockInChunk -> {
+			processBlockAndTiles(relBlockInChunk, sink);
 		});
 		
 		for (ChunkRenderOptimizer optimizer : optimizers) {
@@ -96,16 +102,16 @@ public class ChunkRenderModel implements Renderable {
 		}
 	}
 
-	private void processBlockAndTiles(Vec3i blockInChunk, Builder sink) {
-		processBlock(blockInChunk, sink);
+	private void processBlockAndTiles(Vec3i relBlockInChunk, Builder sink) {
+		processBlock(relBlockInChunk, sink);
 		
-		for (BlockFace face : BlockFace.getFaces()) {
-			processTileStack(blockInChunk, face, sink);
+		for (RelFace face : RelFace.getFaces()) {
+			processTileStack(relBlockInChunk, face, sink);
 		}
 	}
 
-	private void processBlock(Vec3i blockInChunk, Builder sink) {
-		BlockRender block = chunk.getBlock(blockInChunk);
+	private void processBlock(Vec3i relBlockInChunk, Builder sink) {
+		BlockRender block = chunk.getBlockRel(relBlockInChunk);
 		
 		if (block instanceof BlockRenderNone) {
 			return;
@@ -113,48 +119,48 @@ public class ChunkRenderModel implements Renderable {
 		
 		if (block.needsOwnRenderable()) {
 			sink.addPart(
-				block.createRenderable(chunk.getData(), blockInChunk), 
-				new Mat4().identity().translate(blockInChunk.x, blockInChunk.y, blockInChunk.z)
+				block.createRenderable(chunk.getData(), relBlockInChunk), 
+				new Mat4().identity().translate(relBlockInChunk.x, relBlockInChunk.y, relBlockInChunk.z)
 			);
 		}
 		
-		processBlockWithCROs(block, blockInChunk);
+		processBlockWithCROs(block, relBlockInChunk);
 	}
 
-	private void processBlockWithCROs(BlockRender block, Vec3i blockInChunk) {
+	private void processBlockWithCROs(BlockRender block, Vec3i relBlockInChunk) {
 		for (ChunkRenderOptimizer optimizer : optimizers) {
-			optimizer.addBlock(block, blockInChunk);
+			optimizer.addBlock(block, relBlockInChunk);
 		}
 	}
 
-	private void processTileStack(Vec3i blockInChunk, BlockFace face, Builder sink) {
-		TileRenderStack trs = chunk.getTilesOrNull(blockInChunk, face);
+	private void processTileStack(Vec3i relBlockInChunk, RelFace face, Builder sink) {
+		TileRenderStack trs = chunk.getTilesOrNullRel(relBlockInChunk, face);
 		
 		if (trs == null || trs.isEmpty()) {
 			return;
 		}
 		
-		trs.forEach(tile -> processTile(tile, blockInChunk, face, sink));
+		trs.forEach(tile -> processTile(tile, relBlockInChunk, face, sink));
 	}
 
-	private void processTile(TileRender tile, Vec3i blockInChunk, BlockFace face, Builder sink) {	
+	private void processTile(TileRender tile, Vec3i relBlockInChunk, RelFace face, Builder sink) {	
 		if (tile instanceof TileRenderNone) {
 			return;
 		}
 		
 		if (tile.needsOwnRenderable()) {
 			sink.addPart(
-				tile.createRenderable(chunk.getData(), blockInChunk, face), 
-				new Mat4().identity().translate(blockInChunk.x, blockInChunk.y, blockInChunk.z)
+				tile.createRenderable(chunk.getData(), relBlockInChunk, face), 
+				new Mat4().identity().translate(relBlockInChunk.x, relBlockInChunk.y, relBlockInChunk.z)
 			);
 		}
 		
-		processTileWithCROs(tile, blockInChunk, face);
+		processTileWithCROs(tile, relBlockInChunk, face);
 	}
 
-	private void processTileWithCROs(TileRender tile, Vec3i blockInChunk, BlockFace face) {
+	private void processTileWithCROs(TileRender tile, Vec3i relBlockInChunk, RelFace face) {
 		for (ChunkRenderOptimizer optimizer : optimizers) {
-			optimizer.addTile(tile, blockInChunk, face);
+			optimizer.addTile(tile, relBlockInChunk, face);
 		}
 	}
 

src/main/java/ru/windcorp/progressia/client/world/ChunkUpdateListener.java

@@ -21,10 +21,11 @@ package ru.windcorp.progressia.client.world;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.util.VectorUtil;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.ChunkDataListener;
 import ru.windcorp.progressia.common.world.block.BlockData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 import ru.windcorp.progressia.common.world.tile.TileData;
 
 class ChunkUpdateListener implements ChunkDataListener {
@@ -36,14 +37,14 @@ class ChunkUpdateListener implements ChunkDataListener {
 	}
 
 	@Override
-	public void onChunkChanged(ChunkData chunk) {
+	public void onChunkChanged(DefaultChunkData chunk) {
 		world.getChunk(chunk).markForUpdate();
 	}
 	
 	@Override
-	public void onChunkLoaded(ChunkData chunk) {
+	public void onChunkLoaded(DefaultChunkData chunk) {
 		Vec3i cursor = new Vec3i();
-		for (BlockFace face : BlockFace.getFaces()) {
+		for (AbsFace face : AbsFace.getFaces()) {
 			cursor.set(chunk.getX(), chunk.getY(), chunk.getZ());
 			cursor.add(face.getVector());
 			world.markChunkForUpdate(cursor);
@@ -51,22 +52,22 @@ class ChunkUpdateListener implements ChunkDataListener {
 	}
 	
 	@Override
-	public void onChunkBlockChanged(ChunkData chunk, Vec3i blockInChunk, BlockData previous, BlockData current) {
+	public void onChunkBlockChanged(DefaultChunkData chunk, Vec3i blockInChunk, BlockData previous, BlockData current) {
 		onLocationChanged(chunk, blockInChunk);
 	}
 	
 	@Override
 	public void onChunkTilesChanged(
-		ChunkData chunk,
+		DefaultChunkData chunk,
 		Vec3i blockInChunk,
-		BlockFace face,
+		RelFace face,
 		TileData tile,
 		boolean wasAdded
 	) {
 		onLocationChanged(chunk, blockInChunk);
 	}
 
-	private void onLocationChanged(ChunkData chunk, Vec3i blockInChunk) {
+	private void onLocationChanged(DefaultChunkData chunk, Vec3i blockInChunk) {
 		Vec3i chunkPos = Vectors.grab3i().set(chunk.getX(), chunk.getY(), chunk.getZ());
 		
 		checkCoordinate(blockInChunk, chunkPos, VectorUtil.Axis.X);
@@ -82,7 +83,7 @@ class ChunkUpdateListener implements ChunkDataListener {
 		
 		if (block == 0) {
 			diff = -1;
-		} else if (block == ChunkData.BLOCKS_PER_CHUNK - 1) {
+		} else if (block == DefaultChunkData.BLOCKS_PER_CHUNK - 1) {
 			diff = +1;
 		} else {
 			return;

src/main/java/ru/windcorp/progressia/client/world/WorldRender.java

@@ -34,57 +34,58 @@ import ru.windcorp.progressia.client.world.block.BlockRender;
 import ru.windcorp.progressia.client.world.entity.EntityRenderRegistry;
 import ru.windcorp.progressia.client.world.entity.EntityRenderable;
 import ru.windcorp.progressia.client.world.tile.TileRender;
+import ru.windcorp.progressia.client.world.tile.TileRenderReference;
 import ru.windcorp.progressia.client.world.tile.TileRenderStack;
 import ru.windcorp.progressia.common.util.VectorUtil;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.ChunkDataListeners;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.common.world.WorldDataListener;
 import ru.windcorp.progressia.common.world.entity.EntityData;
 import ru.windcorp.progressia.common.world.generic.ChunkSet;
 import ru.windcorp.progressia.common.world.generic.ChunkSets;
-import ru.windcorp.progressia.common.world.generic.GenericWorld;
+import ru.windcorp.progressia.common.world.generic.WorldGenericRO;
 
 public class WorldRender
-	implements GenericWorld<BlockRender, TileRender, TileRenderStack, ChunkRender, EntityRenderable> {
+	implements WorldGenericRO<BlockRender, TileRender, TileRenderStack, TileRenderReference, ChunkRender, EntityRenderable> {
 
-	private final WorldData data;
+	private final DefaultWorldData data;
 	private final Client client;
 
-	private final Map<ChunkData, ChunkRender> chunks = Collections.synchronizedMap(new HashMap<>());
+	private final Map<DefaultChunkData, ChunkRender> chunks = Collections.synchronizedMap(new HashMap<>());
 	private final Map<EntityData, EntityRenderable> entityModels = Collections.synchronizedMap(new WeakHashMap<>());
 
 	private final ChunkSet chunksToUpdate = ChunkSets.newSyncHashSet();
 
-	public WorldRender(WorldData data, Client client) {
+	public WorldRender(DefaultWorldData data, Client client) {
 		this.data = data;
 		this.client = client;
 
 		data.addListener(ChunkDataListeners.createAdder(new ChunkUpdateListener(this)));
 		data.addListener(new WorldDataListener() {
 			@Override
-			public void onChunkLoaded(WorldData world, ChunkData chunk) {
+			public void onChunkLoaded(DefaultWorldData world, DefaultChunkData chunk) {
 				addChunk(chunk);
 			}
 
 			@Override
-			public void beforeChunkUnloaded(WorldData world, ChunkData chunk) {
+			public void beforeChunkUnloaded(DefaultWorldData world, DefaultChunkData chunk) {
 				removeChunk(chunk);
 			}
 		});
 	}
 
-	protected void addChunk(ChunkData chunk) {
+	protected void addChunk(DefaultChunkData chunk) {
 		chunks.put(chunk, new ChunkRender(WorldRender.this, chunk));
 		markChunkForUpdate(chunk.getPosition());
 	}
 
-	protected void removeChunk(ChunkData chunk) {
+	protected void removeChunk(DefaultChunkData chunk) {
 		chunks.remove(chunk);
 	}
 
-	public WorldData getData() {
+	public DefaultWorldData getData() {
 		return data;
 	}
 
@@ -92,7 +93,7 @@ public class WorldRender
 		return client;
 	}
 
-	public ChunkRender getChunk(ChunkData chunkData) {
+	public ChunkRender getChunk(DefaultChunkData chunkData) {
 		return chunks.get(chunkData);
 	}
 
@@ -111,6 +112,13 @@ public class WorldRender
 		return entityModels.values();
 	}
 	
+	@Override
+	public EntityRenderable getEntity(long entityId) {
+		EntityData entityData = getData().getEntity(entityId);
+		if (entityData == null) return null;
+		return getEntityRenderable(entityData);
+	}
+
 	public void render(ShapeRenderHelper renderer) {
 		updateChunks();
 

src/main/java/ru/windcorp/progressia/client/world/block/BlockRender.java

@@ -18,26 +18,19 @@
  
 package ru.windcorp.progressia.client.world.block;
 
-import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.generic.BlockGeneric;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
 
-public abstract class BlockRender extends Namespaced implements GenericBlock {
+public abstract class BlockRender extends Namespaced implements BlockGeneric {
 
 	public BlockRender(String id) {
 		super(id);
 	}
 
-	public void render(ShapeRenderHelper renderer) {
-		throw new UnsupportedOperationException(
-			"BlockRender.render() not implemented in " + this
-		);
-	}
-
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i relBlockInChunk) {
 		return null;
 	}
 

src/main/java/ru/windcorp/progressia/client/world/block/BlockRenderNone.java

@@ -21,7 +21,7 @@ package ru.windcorp.progressia.client.world.block;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.client.graphics.model.EmptyModel;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 
 public class BlockRenderNone extends BlockRender {
 
@@ -30,7 +30,7 @@ public class BlockRenderNone extends BlockRender {
 	}
 
 	@Override
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk) {
 		return EmptyModel.getInstance();
 	}
 

src/main/java/ru/windcorp/progressia/client/world/block/BlockRenderOpaqueCube.java

@@ -19,7 +19,7 @@
 package ru.windcorp.progressia.client.world.block;
 
 import ru.windcorp.progressia.client.graphics.texture.Texture;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class BlockRenderOpaqueCube extends BlockRenderTexturedCube {
 
@@ -29,8 +29,8 @@ public class BlockRenderOpaqueCube extends BlockRenderTexturedCube {
 		Texture bottomTexture,
 		Texture northTexture,
 		Texture southTexture,
-		Texture eastTexture,
-		Texture westTexture
+		Texture westTexture,
+		Texture eastTexture
 	) {
 		super(
 			id,
@@ -38,8 +38,8 @@ public class BlockRenderOpaqueCube extends BlockRenderTexturedCube {
 			bottomTexture,
 			northTexture,
 			southTexture,
-			eastTexture,
-			westTexture
+			westTexture,
+			eastTexture
 		);
 	}
 
@@ -55,8 +55,20 @@ public class BlockRenderOpaqueCube extends BlockRenderTexturedCube {
 		);
 	}
 	
+	public BlockRenderOpaqueCube(String id, Texture topTexture, Texture bottomTexture, Texture sideTexture) {
+		this(
+			id,
+			topTexture,
+			bottomTexture,
+			sideTexture,
+			sideTexture,
+			sideTexture,
+			sideTexture
+		);
+	}
+
 	@Override
-	public boolean isOpaque(BlockFace face) {
+	public boolean isOpaque(RelFace face) {
 		return true;
 	}
 

src/main/java/ru/windcorp/progressia/client/world/block/BlockRenderTexturedCube.java

@@ -18,9 +18,8 @@
  
 package ru.windcorp.progressia.client.world.block;
 
-import static ru.windcorp.progressia.common.world.block.BlockFace.*;
+import static ru.windcorp.progressia.common.world.rels.AbsFace.*;
 
-import java.util.HashMap;
 import java.util.Map;
 import java.util.function.Consumer;
 
@@ -29,22 +28,23 @@ import glm.vec._3.i.Vec3i;
 import glm.vec._4.Vec4;
 import ru.windcorp.progressia.client.graphics.Colors;
 import ru.windcorp.progressia.client.graphics.backend.Usage;
-import ru.windcorp.progressia.client.graphics.model.Face;
-import ru.windcorp.progressia.client.graphics.model.Faces;
+import ru.windcorp.progressia.client.graphics.model.ShapePart;
+import ru.windcorp.progressia.client.graphics.model.ShapeParts;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
 import ru.windcorp.progressia.client.graphics.model.Shape;
 import ru.windcorp.progressia.client.graphics.texture.Texture;
 import ru.windcorp.progressia.client.graphics.world.WorldRenderProgram;
 import ru.windcorp.progressia.client.world.cro.ChunkRenderOptimizerSurface.BlockOptimizedSurface;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public abstract class BlockRenderTexturedCube
 	extends BlockRender
 	implements BlockOptimizedSurface {
 
-	private final Map<BlockFace, Texture> textures = new HashMap<>();
+	private final Map<RelFace, Texture> textures;
 
 	public BlockRenderTexturedCube(
 		String id,
@@ -52,65 +52,59 @@ public abstract class BlockRenderTexturedCube
 		Texture bottomTexture,
 		Texture northTexture,
 		Texture southTexture,
-		Texture eastTexture,
-		Texture westTexture
+		Texture westTexture,
+		Texture eastTexture
 	) {
 		super(id);
-
-		textures.put(TOP, topTexture);
-		textures.put(BOTTOM, bottomTexture);
-		textures.put(NORTH, northTexture);
-		textures.put(SOUTH, southTexture);
-		textures.put(EAST, eastTexture);
-		textures.put(WEST, westTexture);
+		this.textures = RelFace.mapToFaces(topTexture, bottomTexture, northTexture, southTexture, westTexture, eastTexture);
 	}
 
-	public Texture getTexture(BlockFace blockFace) {
+	public Texture getTexture(RelFace blockFace) {
 		return textures.get(blockFace);
 	}
 	
-	public Vec4 getColorMultiplier(BlockFace blockFace) {
+	public Vec4 getColorMultiplier(RelFace blockFace) {
 		return Colors.WHITE;
 	}
 
 	@Override
-	public final void getFaces(
-		ChunkData chunk, Vec3i blockInChunk, BlockFace blockFace,
+	public final void getShapeParts(
+		DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
 		boolean inner,
-		Consumer<Face> output,
+		Consumer<ShapePart> output,
 		Vec3 offset
 	) {
 		output.accept(createFace(chunk, blockInChunk, blockFace, inner, offset));
 	}
 	
-	private Face createFace(
-		ChunkData chunk, Vec3i blockInChunk, BlockFace blockFace,
+	private ShapePart createFace(
+		DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
 		boolean inner,
 		Vec3 offset
 	) {
-		return Faces.createBlockFace(
+		return ShapeParts.createBlockFace(
 			WorldRenderProgram.getDefault(),
 			getTexture(blockFace),
 			getColorMultiplier(blockFace),
 			offset,
-			blockFace,
+			blockFace.resolve(AbsFace.POS_Z),
 			inner
 		);
 	}
 
 	@Override
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk) {
 		boolean opaque = isBlockOpaque();
 		
-		Face[] faces = new Face[BLOCK_FACE_COUNT + (opaque ? BLOCK_FACE_COUNT : 0)];
+		ShapePart[] faces = new ShapePart[BLOCK_FACE_COUNT + (opaque ? BLOCK_FACE_COUNT : 0)];
 		
 		for (int i = 0; i < BLOCK_FACE_COUNT; ++i) {
-			faces[i] = createFace(chunk, blockInChunk, BlockFace.getFaces().get(i), false, Vectors.ZERO_3);
+			faces[i] = createFace(chunk, blockInChunk, RelFace.getFaces().get(i), false, Vectors.ZERO_3);
 		}
 		
 		if (!opaque) {
 			for (int i = 0; i < BLOCK_FACE_COUNT; ++i) {
-				faces[i + BLOCK_FACE_COUNT] = createFace(chunk, blockInChunk, BlockFace.getFaces().get(i), true, Vectors.ZERO_3);
+				faces[i + BLOCK_FACE_COUNT] = createFace(chunk, blockInChunk, RelFace.getFaces().get(i), true, Vectors.ZERO_3);
 			}
 		}
 		

src/main/java/ru/windcorp/progressia/client/world/block/BlockRenderTransparentCube.java

@@ -19,7 +19,7 @@
 package ru.windcorp.progressia.client.world.block;
 
 import ru.windcorp.progressia.client.graphics.texture.Texture;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class BlockRenderTransparentCube extends BlockRenderTexturedCube {
 
@@ -29,8 +29,8 @@ public class BlockRenderTransparentCube extends BlockRenderTexturedCube {
 		Texture bottomTexture,
 		Texture northTexture,
 		Texture southTexture,
-		Texture eastTexture,
-		Texture westTexture
+		Texture westTexture,
+		Texture eastTexture
 	) {
 		super(
 			id,
@@ -38,8 +38,8 @@ public class BlockRenderTransparentCube extends BlockRenderTexturedCube {
 			bottomTexture,
 			northTexture,
 			southTexture,
-			eastTexture,
-			westTexture
+			westTexture,
+			eastTexture
 		);
 	}
 
@@ -55,8 +55,20 @@ public class BlockRenderTransparentCube extends BlockRenderTexturedCube {
 		);
 	}
 	
+	public BlockRenderTransparentCube(String id, Texture topTexture, Texture bottomTexture, Texture sideTexture) {
+		this(
+			id,
+			topTexture,
+			bottomTexture,
+			sideTexture,
+			sideTexture,
+			sideTexture,
+			sideTexture
+		);
+	}
+
 	@Override
-	public boolean isOpaque(BlockFace face) {
+	public boolean isOpaque(RelFace face) {
 		return false;
 	}
 

src/main/java/ru/windcorp/progressia/client/world/cro/ChunkRenderOptimizer.java

@@ -24,7 +24,7 @@ import ru.windcorp.progressia.client.world.ChunkRender;
 import ru.windcorp.progressia.client.world.block.BlockRender;
 import ru.windcorp.progressia.client.world.tile.TileRender;
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 /**
  * Chunk render optimizer (CRO) is an object that produces optimized models for
@@ -35,6 +35,12 @@ import ru.windcorp.progressia.common.world.block.BlockFace;
  * tiles. An example of a CRO is {@link ChunkRenderOptimizerSurface}: it removes
  * block surfaces and tiles that it knows cannot be seen, thus significantly
  * reducing total polygon count.
+ * <p>
+ * As with everything related to rendering chunks, CROs are interacted with
+ * using the relative local chunk coordinate system. In this coordinate system,
+ * the coordinates are the chunk coordinates relativized using the chunks's up
+ * direction. In simpler terms, coordinates are {@code [0; BLOCKS_PER_CHUNK)}
+ * and Z is always up.
  * <h3>CRO lifecycle</h3>
  * A CRO instance is created by {@link ChunkRenderOptimizerRegistry}. It may
  * then be used to work on multiple chunks sequentially. Each chunk is processed
@@ -44,7 +50,7 @@ import ru.windcorp.progressia.common.world.block.BlockFace;
  * instance.</li>
  * <li>{@link #startRender()} is invoked. The CRO must reset its state.</li>
  * <li>{@link #addBlock(BlockRender, Vec3i)} and
- * {@link #addTile(TileRender, Vec3i, BlockFace)} are invoked for each block and
+ * {@link #addTile(TileRender, Vec3i, RelFace)} are invoked for each block and
  * tile that this CRO should optimize. {@code addTile} specifies tiles in order
  * of ascension within a tile stack.</li>
  * <li>{@link #endRender()} is invoked. The CRO may perform any pending
@@ -98,12 +104,13 @@ public abstract class ChunkRenderOptimizer extends Namespaced {
 	 * method is only invoked once per block. This method is not necessarily
 	 * invoked for each block.
 	 * 
-	 * @param block        a {@link BlockRender} instance describing the block.
-	 *                     It corresponds to
-	 *                     {@code getChunk().getBlock(blockInChunk)}.
-	 * @param blockInChunk the position of the block
+	 * @param block           a {@link BlockRender} instance describing the
+	 *                        block.
+	 *                        It corresponds to
+	 *                        {@code getChunk().getBlock(blockInChunk)}.
+	 * @param relBlockInChunk the relative position of the block
 	 */
-	public abstract void addBlock(BlockRender block, Vec3i blockInChunk);
+	public abstract void addBlock(BlockRender block, Vec3i relBlockInChunk);
 
 	/**
 	 * Requests that this CRO processes the provided tile. This method may only
@@ -112,11 +119,12 @@ public abstract class ChunkRenderOptimizer extends Namespaced {
 	 * invoked for each tile. When multiple tiles in a tile stack are requested,
 	 * this method is invoked for lower tiles first.
 	 * 
-	 * @param tile         a {@link BlockRender} instance describing the tile
-	 * @param blockInChunk the position of the block that the tile belongs to
-	 * @param blockFace    the face that the tile belongs to
+	 * @param tile            a {@link BlockRender} instance describing the tile
+	 * @param relBlockInChunk the relative position of the block that the tile
+	 *                        belongs to
+	 * @param blockFace       the face that the tile belongs to
 	 */
-	public abstract void addTile(TileRender tile, Vec3i blockInChunk, BlockFace blockFace);
+	public abstract void addTile(TileRender tile, Vec3i relBlockInChunk, RelFace blockFace);
 
 	/**
 	 * Requests that the CRO assembles and outputs its model. This method may

src/main/java/ru/windcorp/progressia/client/world/cro/ChunkRenderOptimizerSurface.java

@@ -18,9 +18,9 @@
 
 package ru.windcorp.progressia.client.world.cro;
 
-import static ru.windcorp.progressia.common.world.ChunkData.BLOCKS_PER_CHUNK;
-import static ru.windcorp.progressia.common.world.block.BlockFace.BLOCK_FACE_COUNT;
-import static ru.windcorp.progressia.common.world.generic.GenericTileStack.TILES_PER_FACE;
+import static ru.windcorp.progressia.common.world.DefaultChunkData.BLOCKS_PER_CHUNK;
+import static ru.windcorp.progressia.common.world.generic.TileGenericStackRO.TILES_PER_FACE;
+import static ru.windcorp.progressia.common.world.rels.AbsFace.BLOCK_FACE_COUNT;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -29,7 +29,7 @@ import java.util.function.Consumer;
 import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.client.graphics.backend.Usage;
-import ru.windcorp.progressia.client.graphics.model.Face;
+import ru.windcorp.progressia.client.graphics.model.ShapePart;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
 import ru.windcorp.progressia.client.graphics.model.Shape;
 import ru.windcorp.progressia.client.graphics.world.WorldRenderProgram;
@@ -37,8 +37,9 @@ import ru.windcorp.progressia.client.world.ChunkRender;
 import ru.windcorp.progressia.client.world.block.BlockRender;
 import ru.windcorp.progressia.client.world.tile.TileRender;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.generic.GenericChunks;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 
@@ -52,39 +53,42 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 	private static interface OptimizedSurface {
 
 		/**
-		 * Creates and outputs a set of faces that correspond to this surface.
-		 * The coordinates of the face vertices must be in chunk coordinate
-		 * system.
+		 * Creates and outputs a set of shape parts that correspond to this
+		 * surface. The coordinates of the face vertices must be in chunk
+		 * coordinate system.
 		 * 
-		 * @param chunk        the chunk that contains the requested face
-		 * @param blockInChunk the block in chunk
-		 * @param blockFace    the requested face
-		 * @param inner        whether this face should be visible from inside
-		 *                     ({@code true}) or outside ({@code false})
-		 * @param output       a consumer that the created faces must be given
-		 *                     to
-		 * @param offset       an additional offset that must be applied to all
-		 *                     vertices
+		 * @param chunk           the chunk that contains the requested face
+		 * @param relBlockInChunk the relative block in chunk
+		 * @param blockFace       the requested face
+		 * @param inner           whether this face should be visible from
+		 *                        inside
+		 *                        ({@code true}) or outside ({@code false})
+		 * @param output          a consumer that the created shape parts must
+		 *                        be
+		 *                        given to
+		 * @param offset          an additional offset that must be applied to
+		 *                        all
+		 *                        vertices
 		 */
-		void getFaces(
-			ChunkData chunk,
-			Vec3i blockInChunk,
-			BlockFace blockFace,
+		void getShapeParts(
+			DefaultChunkData chunk,
+			Vec3i relBlockInChunk,
+			RelFace blockFace,
 			boolean inner,
-			Consumer<Face> output,
+			Consumer<ShapePart> output,
 			Vec3 offset /* kostyl 156% */
 		);
 
 		/**
 		 * Returns the opacity of the surface identified by the provided
-		 * {@link BlockFace}.
+		 * {@link RelFace}.
 		 * Opaque surfaces prevent surfaces behind them from being included in
 		 * chunk models.
 		 * 
 		 * @param blockFace the face to query
 		 * @return {@code true} iff the surface is opaque.
 		 */
-		boolean isOpaque(BlockFace blockFace);
+		boolean isOpaque(RelFace blockFace);
 	}
 
 	/**
@@ -159,29 +163,29 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 	}
 
 	@Override
-	public void addBlock(BlockRender block, Vec3i pos) {
+	public void addBlock(BlockRender block, Vec3i relBlockInChunk) {
 		if (!(block instanceof BlockOptimizedSurface))
 			return;
 
 		BlockOptimizedSurface bos = (BlockOptimizedSurface) block;
-		addBlock(pos, bos);
+		addBlock(relBlockInChunk, bos);
 	}
 
 	@Override
-	public void addTile(TileRender tile, Vec3i pos, BlockFace face) {
+	public void addTile(TileRender tile, Vec3i relBlockInChunk, RelFace face) {
 		if (!(tile instanceof TileOptimizedSurface))
 			return;
 
 		TileOptimizedSurface tos = (TileOptimizedSurface) tile;
-		addTile(pos, face, tos);
+		addTile(relBlockInChunk, face, tos);
 	}
 
-	protected void addBlock(Vec3i pos, BlockOptimizedSurface block) {
-		getBlock(pos).block = block;
+	private void addBlock(Vec3i relBlockInChunk, BlockOptimizedSurface block) {
+		getBlock(relBlockInChunk).block = block;
 	}
 
-	private void addTile(Vec3i pos, BlockFace face, TileOptimizedSurface tile) {
-		FaceInfo faceInfo = getFace(pos, face);
+	private void addTile(Vec3i relBlockInChunk, RelFace face, TileOptimizedSurface tile) {
+		FaceInfo faceInfo = getFace(relBlockInChunk, face);
 
 		int index = faceInfo.tileCount;
 		faceInfo.tileCount++;
@@ -197,63 +201,58 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 		}
 	}
 
-	protected BlockInfo getBlock(Vec3i cursor) {
-		return data[cursor.x][cursor.y][cursor.z];
+	protected BlockInfo getBlock(Vec3i relBlockInChunk) {
+		return data[relBlockInChunk.x][relBlockInChunk.y][relBlockInChunk.z];
 	}
 
-	protected FaceInfo getFace(Vec3i cursor, BlockFace face) {
-		return getBlock(cursor).faces[face.getId()];
+	protected FaceInfo getFace(Vec3i relBlockInChunk, RelFace face) {
+		return getBlock(relBlockInChunk).faces[face.getId()];
 	}
 
 	@Override
 	public Renderable endRender() {
-		Collection<Face> shapeFaces = new ArrayList<>(
+		Collection<ShapePart> shapeParts = new ArrayList<>(
 			BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK * 3
 		);
 
-		Vec3i cursor = new Vec3i();
-		Consumer<Face> consumer = shapeFaces::add;
+		Consumer<ShapePart> consumer = shapeParts::add;
 
-		for (cursor.x = 0; cursor.x < BLOCKS_PER_CHUNK; ++cursor.x) {
-			for (cursor.y = 0; cursor.y < BLOCKS_PER_CHUNK; ++cursor.y) {
-				for (cursor.z = 0; cursor.z < BLOCKS_PER_CHUNK; ++cursor.z) {
-					processInnerFaces(cursor, consumer);
-					processOuterFaces(cursor, consumer);
-				}
-			}
-		}
+		GenericChunks.forEachBiC(relBlockInChunk -> {
+			processInnerFaces(relBlockInChunk, consumer);
+			processOuterFaces(relBlockInChunk, consumer);
+		});
 
-		if (shapeFaces.isEmpty()) {
+		if (shapeParts.isEmpty()) {
 			return null;
 		}
 
 		return new Shape(
 			Usage.STATIC,
 			WorldRenderProgram.getDefault(),
-			shapeFaces.toArray(new Face[shapeFaces.size()])
+			shapeParts.toArray(new ShapePart[shapeParts.size()])
 		);
 	}
 
 	private void processOuterFaces(
-		Vec3i blockInChunk,
-		Consumer<Face> output
+		Vec3i relBlockInChunk,
+		Consumer<ShapePart> output
 	) {
-		for (BlockFace blockFace : BlockFace.getFaces()) {
-			processOuterFace(blockInChunk, blockFace, output);
+		for (RelFace blockFace : RelFace.getFaces()) {
+			processOuterFace(relBlockInChunk, blockFace, output);
 		}
 	}
 
-	private void processOuterFace(Vec3i blockInChunk, BlockFace blockFace, Consumer<Face> output) {
-		if (!shouldRenderOuterFace(blockInChunk, blockFace))
+	private void processOuterFace(Vec3i relBlockInChunk, RelFace blockFace, Consumer<ShapePart> output) {
+		if (!shouldRenderOuterFace(relBlockInChunk, blockFace))
 			return;
 
-		FaceInfo info = getFace(blockInChunk, blockFace);
+		FaceInfo info = getFace(relBlockInChunk, blockFace);
 
 		if (info.tileCount == 0 && info.block.block == null)
 			return;
 
-		Vec3 faceOrigin = new Vec3(blockInChunk.x, blockInChunk.y, blockInChunk.z);
-		Vec3 offset = new Vec3(blockFace.getFloatVector()).mul(OVERLAY_OFFSET);
+		Vec3 faceOrigin = new Vec3(relBlockInChunk.x, relBlockInChunk.y, relBlockInChunk.z);
+		Vec3 offset = new Vec3(blockFace.getRelFloatVector()).mul(OVERLAY_OFFSET);
 
 		for (
 			int layer = info.topOpaqueSurface;
@@ -264,32 +263,29 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 			if (surface == null)
 				continue; // layer may be BLOCK_LAYER, then block may be null
 
-			surface.getFaces(chunk.getData(), blockInChunk, blockFace, false, output, faceOrigin);
+			surface.getShapeParts(chunk.getData(), relBlockInChunk, blockFace, false, output, faceOrigin);
 
 			faceOrigin.add(offset);
 		}
 	}
 
-	private void processInnerFaces(
-		Vec3i blockInChunk,
-		Consumer<Face> output
-	) {
-		for (BlockFace blockFace : BlockFace.getFaces()) {
-			processInnerFace(blockInChunk, blockFace, output);
+	private void processInnerFaces(Vec3i relBlockInChunk, Consumer<ShapePart> output) {
+		for (RelFace blockFace : RelFace.getFaces()) {
+			processInnerFace(relBlockInChunk, blockFace, output);
 		}
 	}
 
-	private void processInnerFace(Vec3i blockInChunk, BlockFace blockFace, Consumer<Face> output) {
-		if (!shouldRenderInnerFace(blockInChunk, blockFace))
+	private void processInnerFace(Vec3i relBlockInChunk, RelFace blockFace, Consumer<ShapePart> output) {
+		if (!shouldRenderInnerFace(relBlockInChunk, blockFace))
 			return;
 
-		FaceInfo info = getFace(blockInChunk, blockFace);
+		FaceInfo info = getFace(relBlockInChunk, blockFace);
 
 		if (info.tileCount == 0 && info.block.block == null)
 			return;
 
-		Vec3 faceOrigin = new Vec3(blockInChunk.x, blockInChunk.y, blockInChunk.z);
-		Vec3 offset = new Vec3(blockFace.getFloatVector()).mul(OVERLAY_OFFSET);
+		Vec3 faceOrigin = new Vec3(relBlockInChunk.x, relBlockInChunk.y, relBlockInChunk.z);
+		Vec3 offset = new Vec3(blockFace.getRelFloatVector()).mul(OVERLAY_OFFSET);
 
 		for (
 			int layer = FaceInfo.BLOCK_LAYER;
@@ -300,35 +296,35 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 			if (surface == null)
 				continue; // layer may be BLOCK_LAYER, then block may be null
 
-			surface.getFaces(chunk.getData(), blockInChunk, blockFace, true, output, faceOrigin);
+			surface.getShapeParts(chunk.getData(), relBlockInChunk, blockFace, true, output, faceOrigin);
 
 			faceOrigin.add(offset);
 		}
 	}
 
-	private boolean shouldRenderOuterFace(Vec3i blockInChunk, BlockFace face) {
-		blockInChunk.add(face.getVector());
+	private boolean shouldRenderOuterFace(Vec3i relBlockInChunk, RelFace face) {
+		relBlockInChunk.add(face.getRelVector());
 		try {
-			return shouldRenderWhenFacing(blockInChunk, face);
+			return shouldRenderWhenFacing(relBlockInChunk, face);
 		} finally {
-			blockInChunk.sub(face.getVector());
+			relBlockInChunk.sub(face.getRelVector());
 		}
 	}
 
-	private boolean shouldRenderInnerFace(Vec3i blockInChunk, BlockFace face) {
-		return shouldRenderWhenFacing(blockInChunk, face);
+	private boolean shouldRenderInnerFace(Vec3i relBlockInChunk, RelFace face) {
+		return shouldRenderWhenFacing(relBlockInChunk, face);
 	}
 
-	private boolean shouldRenderWhenFacing(Vec3i blockInChunk, BlockFace face) {
-		if (chunk.containsBiC(blockInChunk)) {
-			return shouldRenderWhenFacingLocal(blockInChunk, face);
+	private boolean shouldRenderWhenFacing(Vec3i relBlockInChunk, RelFace face) {
+		if (GenericChunks.containsBiC(relBlockInChunk)) {
+			return shouldRenderWhenFacingLocal(relBlockInChunk, face);
 		} else {
-			return shouldRenderWhenFacingNeighbor(blockInChunk, face);
+			return shouldRenderWhenFacingNeighbor(relBlockInChunk, face);
 		}
 	}
 
-	private boolean shouldRenderWhenFacingLocal(Vec3i blockInChunk, BlockFace face) {
-		BlockOptimizedSurface block = getBlock(blockInChunk).block;
+	private boolean shouldRenderWhenFacingLocal(Vec3i relBlockInChunk, RelFace face) {
+		BlockOptimizedSurface block = getBlock(relBlockInChunk).block;
 
 		if (block == null) {
 			return true;
@@ -340,36 +336,37 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 		return true;
 	}
 
-	private boolean shouldRenderWhenFacingNeighbor(Vec3i blockInLocalChunk, BlockFace face) {
-		Vec3i blockInChunk = Vectors.grab3i().set(blockInLocalChunk.x, blockInLocalChunk.y, blockInLocalChunk.z);
+	private boolean shouldRenderWhenFacingNeighbor(Vec3i relBlockInLocalChunk, RelFace face) {
+		Vec3i blockInChunk = Vectors.grab3i();
+		chunk.resolve(relBlockInLocalChunk, blockInChunk);
 		Vec3i chunkPos = Vectors.grab3i().set(chunk.getX(), chunk.getY(), chunk.getZ());
 
 		try {
 			// Determine blockInChunk and chunkPos
-			if (blockInLocalChunk.x == -1) {
+			if (blockInChunk.x == -1) {
 				blockInChunk.x = BLOCKS_PER_CHUNK - 1;
 				chunkPos.x -= 1;
-			} else if (blockInLocalChunk.x == BLOCKS_PER_CHUNK) {
+			} else if (blockInChunk.x == BLOCKS_PER_CHUNK) {
 				blockInChunk.x = 0;
 				chunkPos.x += 1;
-			} else if (blockInLocalChunk.y == -1) {
+			} else if (blockInChunk.y == -1) {
 				blockInChunk.y = BLOCKS_PER_CHUNK - 1;
 				chunkPos.y -= 1;
-			} else if (blockInLocalChunk.y == BLOCKS_PER_CHUNK) {
+			} else if (blockInChunk.y == BLOCKS_PER_CHUNK) {
 				blockInChunk.y = 0;
 				chunkPos.y += 1;
-			} else if (blockInLocalChunk.z == -1) {
+			} else if (blockInChunk.z == -1) {
 				blockInChunk.z = BLOCKS_PER_CHUNK - 1;
 				chunkPos.z -= 1;
-			} else if (blockInLocalChunk.z == BLOCKS_PER_CHUNK) {
+			} else if (blockInChunk.z == BLOCKS_PER_CHUNK) {
 				blockInChunk.z = 0;
 				chunkPos.z += 1;
 			} else {
 				throw new AssertionError(
 					"Requested incorrent neighbor ("
-						+ blockInLocalChunk.x + "; "
-						+ blockInLocalChunk.y + "; "
-						+ blockInLocalChunk.z + ")"
+						+ relBlockInLocalChunk.x + "; "
+						+ relBlockInLocalChunk.y + "; "
+						+ relBlockInLocalChunk.z + ")"
 				);
 			}
 
@@ -382,8 +379,11 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 				return true;
 
 			BlockOptimizedSurface bos = (BlockOptimizedSurface) block;
-			if (!bos.isOpaque(face))
+			RelFace rotatedFace = face.rotate(this.chunk.getUp(), chunk.getUp());
+
+			if (!bos.isOpaque(rotatedFace)) {
 				return true;
+			}
 
 			return false;
 

src/main/java/ru/windcorp/progressia/client/world/entity/EntityRenderable.java

@@ -19,18 +19,45 @@
 package ru.windcorp.progressia.client.world.entity;
 
 import glm.vec._3.Vec3;
+import ru.windcorp.progressia.client.graphics.backend.GraphicsInterface;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
+import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
 import ru.windcorp.progressia.common.world.entity.EntityData;
-import ru.windcorp.progressia.common.world.generic.GenericEntity;
+import ru.windcorp.progressia.common.world.generic.EntityGeneric;
 
-public abstract class EntityRenderable implements Renderable, GenericEntity {
+public abstract class EntityRenderable implements Renderable, EntityGeneric {
 
 	private final EntityData data;
 	
+	private long stateComputedForFrame = -1;
+
 	public EntityRenderable(EntityData data) {
 		this.data = data;
 	}
 
+	/**
+	 * Updates the state of this model. This method is invoked exactly once per
+	 * renderable per frame before this entity is queried for the first time.
+	 */
+	protected void update() {
+		// Do nothing
+	}
+	
+	private void updateIfNecessary() {
+		if (stateComputedForFrame != GraphicsInterface.getFramesRendered()) {
+			update();
+			stateComputedForFrame = GraphicsInterface.getFramesRendered();
+		}
+	}
+	
+	@Override
+	public final void render(ShapeRenderHelper renderer) {
+		updateIfNecessary();
+		doRender(renderer);
+	}
+	
+	protected abstract void doRender(ShapeRenderHelper renderer);
+
 	public EntityData getData() {
 		return data;
 	}
@@ -45,7 +72,41 @@ public abstract class EntityRenderable implements Renderable, GenericEntity {
 		return getData().getId();
 	}
 	
-	public void getViewPoint(Vec3 output) {
+	@Override
+	public long getEntityId() {
+		return getData().getEntityId();
+	}
+
+	public final Vec3 getLookingAt(Vec3 output) {
+		if (output == null) output = new Vec3();
+		updateIfNecessary();
+		doGetLookingAt(output);
+		return output;
+	}
+	
+	protected void doGetLookingAt(Vec3 output) {
+		output.set(getData().getLookingAt());
+	}
+
+	public final Vec3 getUpVector(Vec3 output) {
+		if (output == null) output = new Vec3();
+		updateIfNecessary();
+		doGetUpVector(output);
+		return output;
+	}
+	
+	protected void doGetUpVector(Vec3 output) {
+		output.set(getData().getUpVector());
+	}
+
+	public final Vec3 getViewPoint(Vec3 output) {
+		if (output == null) output = new Vec3();
+		updateIfNecessary();
+		doGetViewPoint(output);
+		return output;
+	}
+	
+	protected void doGetViewPoint(Vec3 output) {
 		output.set(0, 0, 0);
 	}
 

src/main/java/ru/windcorp/progressia/client/world/entity/HumanoidModel.java

@@ -43,6 +43,7 @@ public class HumanoidModel extends NPedModel {
 
 		@Override
 		protected void applyTransform(Mat4 mat, NPedModel model) {
+			super.applyTransform(mat, model);
 			float phase = model.getWalkingFrequency() * model.getWalkingParameter() + animationOffset;
 			float value = sin(phase);
 			float amplitude = getSwingAmplitude((HumanoidModel) model) * model.getVelocityParameter();

src/main/java/ru/windcorp/progressia/client/world/entity/NPedModel.java

@@ -18,11 +18,8 @@
  
 package ru.windcorp.progressia.client.world.entity;
 
-import static java.lang.Math.atan2;
-import static java.lang.Math.min;
 import static java.lang.Math.pow;
 import static java.lang.Math.toRadians;
-import static ru.windcorp.progressia.common.util.FloatMathUtil.normalizeAngle;
 
 import glm.Glm;
 import glm.mat._4.Mat4;
@@ -32,6 +29,9 @@ import ru.windcorp.progressia.client.graphics.backend.GraphicsInterface;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
 import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
 import ru.windcorp.progressia.common.Units;
+import ru.windcorp.progressia.common.util.FloatMathUtil;
+import ru.windcorp.progressia.common.util.VectorUtil;
+import ru.windcorp.progressia.common.util.Vectors;
 import ru.windcorp.progressia.common.world.entity.EntityData;
 
 public abstract class NPedModel extends EntityRenderable {
@@ -51,29 +51,30 @@ public abstract class NPedModel extends EntityRenderable {
 			ShapeRenderHelper renderer,
 			NPedModel model
 		) {
-			renderer.pushTransform().translate(translation);
 			applyTransform(renderer.pushTransform(), model);
 			renderable.render(renderer);
 			renderer.popTransform();
-			renderer.popTransform();
 		}
 
-		protected abstract void applyTransform(Mat4 mat, NPedModel model);
+		protected void applyTransform(Mat4 mat, NPedModel model) {
+			mat.translate(getTranslation());
+		}
 
 		public Vec3 getTranslation() {
 			return translation;
 		}
+		
+		public Mat4 getTransform(Mat4 output, NPedModel model) {
+			if (output == null) output = new Mat4().identity();
+			applyTransform(output, model);
+			return output;
+		}
 	}
 
 	public static class Body extends BodyPart {
 		public Body(Renderable renderable) {
 			super(renderable, null);
 		}
-
-		@Override
-		protected void applyTransform(Mat4 mat, NPedModel model) {
-			// Do nothing
-		}
 	}
 
 	public static class Head extends BodyPart {
@@ -97,7 +98,8 @@ public abstract class NPedModel extends EntityRenderable {
 
 		@Override
 		protected void applyTransform(Mat4 mat, NPedModel model) {
-			mat.rotateZ(model.getHeadYaw()).rotateY(model.getHeadPitch());
+			super.applyTransform(mat, model);
+			mat.rotateZ(-model.getHeadYaw()).rotateY(-model.getHeadPitch());
 		}
 
 		public Vec3 getViewPoint() {
@@ -105,6 +107,8 @@ public abstract class NPedModel extends EntityRenderable {
 		}
 	}
 
+	public static boolean flag;
+
 	protected final Body body;
 	protected final Head head;
 
@@ -128,7 +132,9 @@ public abstract class NPedModel extends EntityRenderable {
 
 	private float walkingFrequency;
 
-	private float bodyYaw = Float.NaN;
+	private final Vec3 bodyLookingAt = new Vec3().set(0);
+	private final Mat4 bodyTransform = new Mat4(); 
+	
 	private float headYaw;
 	private float headPitch;
 
@@ -138,17 +144,14 @@ public abstract class NPedModel extends EntityRenderable {
 		this.head = head;
 		this.scale = scale;
 
-		evaluateAngles();
+		computeRotations();
 	}
 
 	@Override
-	public void render(ShapeRenderHelper renderer) {
-		renderer.pushTransform().scale(scale).rotateZ(bodyYaw);
+	protected void doRender(ShapeRenderHelper renderer) {
+		renderer.pushTransform().scale(scale).mul(bodyTransform);
 		renderBodyParts(renderer);
 		renderer.popTransform();
-
-		accountForVelocity();
-		evaluateAngles();
 	}
 
 	protected void renderBodyParts(ShapeRenderHelper renderer) {
@@ -156,50 +159,106 @@ public abstract class NPedModel extends EntityRenderable {
 		head.render(renderer, this);
 	}
 	
-	private void evaluateAngles() {
-		float globalYaw = normalizeAngle(getData().getYaw());
-
-		if (Float.isNaN(bodyYaw)) {
-			bodyYaw = globalYaw;
-			headYaw = 0;
-		} else {
-			headYaw = normalizeAngle(globalYaw - bodyYaw);
-
-			if (headYaw > +head.maxYaw) {
-				bodyYaw += headYaw - +head.maxYaw;
-				headYaw = +head.maxYaw;
-			} else if (headYaw < -head.maxYaw) {
-				bodyYaw += headYaw - -head.maxYaw;
-				headYaw = -head.maxYaw;
-			}
-		}
-
-		bodyYaw = normalizeAngle(bodyYaw);
-
-		headPitch = Glm.clamp(
-			getData().getPitch(),
-			-head.maxPitch,
-			head.maxPitch
-		);
+	@Override
+	protected void update() {
+		advanceTime();
+		computeRotations();
 	}
 
-	private void accountForVelocity() {
-		Vec3 horizontal = new Vec3(getData().getVelocity());
-		horizontal.z = 0;
+	private void computeRotations() {
+		if (!bodyLookingAt.any()) {
+			getData().getForwardVector(bodyLookingAt);
+			headYaw = 0;
+		} else {
+			ensureBodyLookingAtIsPerpendicularToUpVector();
+			computeDesiredHeadYaw();
+			clampHeadYawAndChangeBodyLookingAt();
+		}
+		
+		recomputeBodyTransform();
+
+		setHeadPitch();
+	}
+
+	private void ensureBodyLookingAtIsPerpendicularToUpVector() {
+		Vec3 up = getData().getUpVector();
+		if (up.dot(bodyLookingAt) > 1 - 1e-4) return;
+		
+		Vec3 tmp = Vectors.grab3();
+		
+		tmp.set(up).mul(-up.dot(bodyLookingAt)).add(bodyLookingAt);
+		
+		float tmpLength = tmp.length();
+		if (tmpLength > 1e-4) {
+			bodyLookingAt.set(tmp).div(tmpLength);
+		} else {
+			// bodyLookingAt is suddenly parallel to up vector -- PANIC! ENTERING RESCUE MODE!
+			getData().getForwardVector(bodyLookingAt);
+		}
+		
+		Vectors.release(tmp);
+	}
+
+	private void computeDesiredHeadYaw() {
+		Vec3 newDirection = getData().getForwardVector(null);
+		Vec3 oldDirection = bodyLookingAt;
+		Vec3 up = getData().getUpVector();
+		
+		headYaw = (float) VectorUtil.getAngle(oldDirection, newDirection, up);
+	}
+
+	private void clampHeadYawAndChangeBodyLookingAt() {
+		float bodyYawChange = 0;
+		
+		if (headYaw > +head.maxYaw) {
+			bodyYawChange = headYaw - +head.maxYaw;
+			headYaw = +head.maxYaw;
+		} else if (headYaw < -head.maxYaw) {
+			bodyYawChange = headYaw - -head.maxYaw;
+			headYaw = -head.maxYaw;
+		}
+		
+		if (bodyYawChange != 0) {
+			VectorUtil.rotate(bodyLookingAt, getData().getUpVector(), bodyYawChange);
+		}
+	}
+
+	private void recomputeBodyTransform() {
+		Vec3 u = getData().getUpVector();
+		Vec3 f = bodyLookingAt;
+		Vec3 s = Vectors.grab3();
+		
+		s.set(u).cross(f);
+		
+		bodyTransform.identity().set(
+			+f.x, +f.y, +f.z,    0,
+			-s.x, -s.y, -s.z,    0,
+			+u.x, +u.y, +u.z,    0,
+			   0,    0,    0,    1
+		);
+		
+		Vectors.release(s);
+	}
+
+	private void setHeadPitch() {
+		headPitch = Glm.clamp((float) getData().getPitch(), -head.maxPitch, +head.maxPitch);
+	}
+
+	private void advanceTime() {
+		Vec3 horizontal = getData().getUpVector()
+			.mul_(-getData().getUpVector().dot(getData().getVelocity()))
+			.add(getData().getVelocity());
 
 		velocity = horizontal.length();
 
-		evaluateVelocityCoeff();
+		computeVelocityParameter();
 
-		// TODO switch to world time
 		walkingParameter += velocity * GraphicsInterface.getFrameLength() * 1000;
 		
-		bodyYaw += velocityParameter * normalizeAngle(
-			(float) (atan2(horizontal.y, horizontal.x) - bodyYaw)
-		) * min(1, GraphicsInterface.getFrameLength() * 10);
+		rotateBodyWithMovement(horizontal);
 	}
 
-	private void evaluateVelocityCoeff() {
+	private void computeVelocityParameter() {
 		if (velocity > maxEffectiveVelocity) {
 			velocityParameter = 1;
 		} else {
@@ -207,17 +266,39 @@ public abstract class NPedModel extends EntityRenderable {
 		}
 	}
 
+	private void rotateBodyWithMovement(Vec3 target) {
+		if (velocityParameter == 0 || !target.any() || Glm.equals(target, bodyLookingAt)) {
+			return;
+		}
+		
+		Vec3 axis = getData().getUpVector();
+		
+		float yawDifference = FloatMathUtil.normalizeAngle(
+			(float) VectorUtil.getAngle(
+				bodyLookingAt,
+				target.normalize_(),
+				axis
+			)
+		);
+		
+		float bodyYawChange =
+			velocityParameter *
+			yawDifference *
+			(float) Math.expm1(GraphicsInterface.getFrameLength() * 10);
+		
+		VectorUtil.rotate(bodyLookingAt, axis, bodyYawChange);
+	}
+
 	@Override
-	public void getViewPoint(Vec3 output) {
+	protected void doGetViewPoint(Vec3 output) {
 		Mat4 m = new Mat4();
 		Vec4 v = new Vec4();
 
 		m.identity()
 			.scale(scale)
-			.rotateZ(bodyYaw)
-			.translate(head.getTranslation())
-			.rotateZ(headYaw)
-			.rotateY(headPitch);
+			.mul(bodyTransform);
+		
+		head.getTransform(m, this);
 
 		v.set(head.getViewPoint(), 1);
 		m.mul(v);
@@ -233,8 +314,8 @@ public abstract class NPedModel extends EntityRenderable {
 		return head;
 	}
 	
-	public float getBodyYaw() {
-		return bodyYaw;
+	public Vec3 getBodyLookingAt() {
+		return bodyLookingAt;
 	}
 
 	public float getHeadYaw() {

src/main/java/ru/windcorp/progressia/client/world/entity/QuadripedModel.java

@@ -44,6 +44,7 @@ public class QuadripedModel extends NPedModel {
 
 		@Override
 		protected void applyTransform(Mat4 mat, NPedModel model) {
+			super.applyTransform(mat, model);
 			float phase = model.getWalkingFrequency() * model.getWalkingParameter() + animationOffset;
 			float value = sin(phase);
 			float amplitude = ((QuadripedModel) model).getWalkingSwing() * model.getVelocityParameter();

src/main/java/ru/windcorp/progressia/client/world/tile/TileRender.java

@@ -18,28 +18,21 @@
  
 package ru.windcorp.progressia.client.world.tile;
 
-import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
 import ru.windcorp.progressia.client.world.cro.ChunkRenderOptimizer;
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.generic.TileGeneric;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
-public class TileRender extends Namespaced implements GenericTile {
+public class TileRender extends Namespaced implements TileGeneric {
 
 	public TileRender(String id) {
 		super(id);
 	}
 
-	public void render(ShapeRenderHelper renderer, BlockFace face) {
-		throw new UnsupportedOperationException(
-			"TileRender.render() not implemented in " + this
-		);
-	}
-
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk, BlockFace face) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk, RelFace face) {
 		return null;
 	}
 

src/main/java/ru/windcorp/progressia/client/world/tile/TileRenderNone.java

@@ -20,8 +20,8 @@ package ru.windcorp.progressia.client.world.tile;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.client.graphics.model.EmptyModel;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class TileRenderNone extends TileRender {
 
@@ -30,7 +30,7 @@ public class TileRenderNone extends TileRender {
 	}
 	
 	@Override
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk, BlockFace face) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk, RelFace face) {
 		return EmptyModel.getInstance();
 	}
 	

src/main/java/ru/windcorp/progressia/client/world/tile/TileRenderOpaqueSurface.java

@@ -19,7 +19,7 @@
 package ru.windcorp.progressia.client.world.tile;
 
 import ru.windcorp.progressia.client.graphics.texture.Texture;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class TileRenderOpaqueSurface extends TileRenderSurface {
 
@@ -28,7 +28,7 @@ public class TileRenderOpaqueSurface extends TileRenderSurface {
 	}
 
 	@Override
-	public boolean isOpaque(BlockFace face) {
+	public boolean isOpaque(RelFace face) {
 		return true;
 	}
 

src/main/java/ru/windcorp/progressia/client/world/tile/TileRenderReference.java

@@ -0,0 +1,27 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.client.world.tile;
+
+import ru.windcorp.progressia.client.world.ChunkRender;
+import ru.windcorp.progressia.client.world.block.BlockRender;
+import ru.windcorp.progressia.common.world.generic.TileGenericReferenceRO;
+
+public interface TileRenderReference
+	extends TileGenericReferenceRO<BlockRender, TileRender, TileRenderStack, TileRenderReference, ChunkRender> {
+
+}

src/main/java/ru/windcorp/progressia/client/world/tile/TileRenderStack.java

@@ -18,12 +18,15 @@
  
 package ru.windcorp.progressia.client.world.tile;
 
-import ru.windcorp.progressia.client.world.ChunkRender;
-import ru.windcorp.progressia.common.world.generic.GenericTileStack;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import java.util.AbstractList;
 
+import ru.windcorp.progressia.client.world.ChunkRender;
+import ru.windcorp.progressia.client.world.block.BlockRender;
+import ru.windcorp.progressia.common.world.TileDataStack;
+import ru.windcorp.progressia.common.world.generic.TileGenericStackRO;
 public abstract class TileRenderStack
-	extends GenericTileStack<TileRenderStack, TileRender, ChunkRender> {
+	extends AbstractList<TileRender>
+	implements TileGenericStackRO<BlockRender, TileRender, TileRenderStack, TileRenderReference, ChunkRender> {
 
 	public abstract TileDataStack getData();
 

src/main/java/ru/windcorp/progressia/client/world/tile/TileRenderSurface.java

@@ -25,16 +25,17 @@ import glm.vec._3.i.Vec3i;
 import glm.vec._4.Vec4;
 import ru.windcorp.progressia.client.graphics.Colors;
 import ru.windcorp.progressia.client.graphics.backend.Usage;
-import ru.windcorp.progressia.client.graphics.model.Face;
-import ru.windcorp.progressia.client.graphics.model.Faces;
+import ru.windcorp.progressia.client.graphics.model.ShapePart;
+import ru.windcorp.progressia.client.graphics.model.ShapeParts;
 import ru.windcorp.progressia.client.graphics.model.Shape;
 import ru.windcorp.progressia.client.graphics.model.Renderable;
 import ru.windcorp.progressia.client.graphics.texture.Texture;
 import ru.windcorp.progressia.client.graphics.world.WorldRenderProgram;
 import ru.windcorp.progressia.client.world.cro.ChunkRenderOptimizerSurface.TileOptimizedSurface;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public abstract class TileRenderSurface extends TileRender implements TileOptimizedSurface {
 
@@ -49,41 +50,41 @@ public abstract class TileRenderSurface extends TileRender implements TileOptimi
 		this(id, null);
 	}
 
-	public Texture getTexture(BlockFace blockFace) {
+	public Texture getTexture(RelFace blockFace) {
 		return texture;
 	}
 	
-	public Vec4 getColorMultiplier(BlockFace blockFace) {
+	public Vec4 getColorMultiplier(RelFace blockFace) {
 		return Colors.WHITE;
 	}
 	
 	@Override
-	public final void getFaces(
-		ChunkData chunk, Vec3i blockInChunk, BlockFace blockFace,
+	public final void getShapeParts(
+		DefaultChunkData chunk, Vec3i relBlockInChunk, RelFace blockFace,
 		boolean inner,
-		Consumer<Face> output,
+		Consumer<ShapePart> output,
 		Vec3 offset
 	) {
-		output.accept(createFace(chunk, blockInChunk, blockFace, inner, offset));
+		output.accept(createFace(chunk, relBlockInChunk, blockFace, inner, offset));
 	}
 	
-	private Face createFace(
-		ChunkData chunk, Vec3i blockInChunk, BlockFace blockFace,
+	private ShapePart createFace(
+		DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
 		boolean inner,
 		Vec3 offset
 	) {
-		return Faces.createBlockFace(
+		return ShapeParts.createBlockFace(
 			WorldRenderProgram.getDefault(),
 			getTexture(blockFace),
 			getColorMultiplier(blockFace),
 			offset,
-			blockFace,
+			blockFace.resolve(AbsFace.POS_Z),
 			inner
 		);
 	}
 
 	@Override
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk, BlockFace blockFace) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace) {
 		return new Shape(
 			Usage.STATIC,
 			WorldRenderProgram.getDefault(),

src/main/java/ru/windcorp/progressia/client/world/tile/TileRenderTransparentSurface.java

@@ -19,7 +19,7 @@
 package ru.windcorp.progressia.client.world.tile;
 
 import ru.windcorp.progressia.client.graphics.texture.Texture;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 
 public class TileRenderTransparentSurface extends TileRenderSurface {
 
@@ -28,7 +28,7 @@ public class TileRenderTransparentSurface extends TileRenderSurface {
 	}
 
 	@Override
-	public boolean isOpaque(BlockFace face) {
+	public boolean isOpaque(RelFace face) {
 		return false;
 	}
 

src/main/java/ru/windcorp/progressia/common/collision/AABBRotator.java

@@ -0,0 +1,134 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.collision;
+
+import java.util.function.Supplier;
+
+import com.google.common.collect.ImmutableList;
+
+import glm.vec._3.Vec3;
+import ru.windcorp.progressia.common.util.Vectors;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
+import ru.windcorp.progressia.common.world.rels.AxisRotations;
+
+public class AABBRotator implements AABBoid {
+	
+	private class AABBRotatorWall implements Wall {
+		
+		private final int id;
+
+		public AABBRotatorWall(int id) {
+			this.id = id;
+		}
+
+		@Override
+		public void getOrigin(Vec3 output) {
+			parent.getWall(id).getOrigin(output);
+			AxisRotations.resolve(output, upSupplier.get(), output);
+		}
+
+		@Override
+		public void getWidth(Vec3 output) {
+			parent.getWall(id).getWidth(output);
+			AxisRotations.resolve(output, upSupplier.get(), output);
+		}
+
+		@Override
+		public void getHeight(Vec3 output) {
+			parent.getWall(id).getHeight(output);
+			AxisRotations.resolve(output, upSupplier.get(), output);
+		}
+		
+	}
+	
+	private final Supplier<AbsFace> upSupplier;
+	private final Supplier<Vec3> hingeSupplier;
+	private final AABBoid parent;
+
+	private final AABBRotatorWall[] walls = new AABBRotatorWall[AbsFace.BLOCK_FACE_COUNT];
+	
+	{
+		for (int id = 0; id < walls.length; ++id) {
+			walls[id] = new AABBRotatorWall(id);
+		}
+	}
+
+	public AABBRotator(Supplier<AbsFace> upSupplier, Supplier<Vec3> hingeSupplier, AABBoid parent) {
+		this.upSupplier = upSupplier;
+		this.hingeSupplier = hingeSupplier;
+		this.parent = parent;
+	}
+
+	@Override
+	public void setOrigin(Vec3 origin) {
+		Vec3 relativeOrigin = Vectors.grab3();
+		Vec3 hinge = hingeSupplier.get();
+		
+		origin.sub(hinge, relativeOrigin);
+		AxisRotations.relativize(relativeOrigin, upSupplier.get(), relativeOrigin);
+		relativeOrigin.add(hinge);
+		
+		parent.setOrigin(relativeOrigin);
+		
+		Vectors.release(relativeOrigin);
+	}
+
+	@Override
+	public void moveOrigin(Vec3 displacement) {
+		parent.moveOrigin(displacement);
+	}
+
+	@Override
+	public void getOrigin(Vec3 output) {
+		parent.getOrigin(output);
+		Vec3 hinge = hingeSupplier.get();
+		
+		output.sub(hinge);
+		AxisRotations.resolve(output, upSupplier.get(), output);
+		output.add(hinge);
+	}
+
+	@Override
+	public void getSize(Vec3 output) {
+		parent.getSize(output);
+		AxisRotations.resolve(output, upSupplier.get(), output);
+		output.abs();
+	}
+
+	@Override
+	public Wall getWall(int faceId) {
+		return walls[faceId];
+	}
+	
+	public static CollisionModel rotate(Supplier<AbsFace> upSupplier, Supplier<Vec3> hingeSupplier, CollisionModel parent) {
+		if (parent instanceof AABBoid) {
+			return new AABBRotator(upSupplier, hingeSupplier, (AABBoid) parent);
+		} else if (parent instanceof CompoundCollisionModel) {
+			ImmutableList.Builder<CollisionModel> models = ImmutableList.builder();
+			
+			for (CollisionModel original : ((CompoundCollisionModel) parent).getModels()) {
+				models.add(rotate(upSupplier, hingeSupplier, original));
+			}
+			
+			return new CompoundCollisionModel(models.build());
+		} else {
+			throw new RuntimeException("not supported");
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/collision/AABBoid.java

@@ -19,7 +19,7 @@
 package ru.windcorp.progressia.common.collision;
 
 import glm.vec._3.Vec3;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 public interface AABBoid extends CollisionModel {
 
@@ -27,7 +27,7 @@ public interface AABBoid extends CollisionModel {
 
 	void getSize(Vec3 output);
 
-	default Wall getWall(BlockFace face) {
+	default Wall getWall(AbsFace face) {
 		return getWall(face.getId());
 	}
 

src/main/java/ru/windcorp/progressia/common/collision/TranslatedAABB.java

@@ -20,7 +20,7 @@ package ru.windcorp.progressia.common.collision;
 
 import glm.vec._3.Vec3;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 public class TranslatedAABB implements AABBoid {
 
@@ -51,7 +51,7 @@ public class TranslatedAABB implements AABBoid {
 	private AABBoid parent;
 	private final Vec3 translation = new Vec3();
 
-	private final TranslatedAABBWall[] walls = new TranslatedAABBWall[BlockFace.BLOCK_FACE_COUNT];
+	private final TranslatedAABBWall[] walls = new TranslatedAABBWall[AbsFace.BLOCK_FACE_COUNT];
 
 	{
 		for (int id = 0; id < walls.length; ++id) {

src/main/java/ru/windcorp/progressia/common/collision/WorldCollisionHelper.java

@@ -24,7 +24,7 @@ import java.util.Collection;
 import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.util.LowOverheadCache;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class WorldCollisionHelper {
 
@@ -79,7 +79,7 @@ public class WorldCollisionHelper {
 	 *                    checked against
 	 * @param maxTime     maximum collision time
 	 */
-	public void tuneToCollideable(WorldData world, Collideable collideable, float maxTime) {
+	public void tuneToCollideable(DefaultWorldData world, Collideable collideable, float maxTime) {
 		activeBlockModels.forEach(blockModelCache::release);
 		activeBlockModels.clear();
 		CollisionPathComputer.forEveryBlockInCollisionPath(

src/main/java/ru/windcorp/progressia/common/collision/colliders/AABBoidCollider.java

@@ -25,7 +25,7 @@ import ru.windcorp.progressia.common.collision.colliders.Collider.ColliderWorksp
 import ru.windcorp.progressia.common.collision.colliders.Collider.Collision;
 import ru.windcorp.progressia.common.util.Matrices;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 class AABBoidCollider {
 
@@ -50,7 +50,7 @@ class AABBoidCollider {
 		computeCollisionVelocity(collisionVelocity, obstacleBody, colliderBody);
 
 		// For every wall of collision space
-		for (int i = 0; i < BlockFace.BLOCK_FACE_COUNT; ++i) {
+		for (int i = 0; i < AbsFace.BLOCK_FACE_COUNT; ++i) {
 			Wall wall = originCollisionSpace.getWall(i);
 
 			Collision collision = computeWallCollision(
@@ -122,46 +122,51 @@ class AABBoidCollider {
 		return output;
 	}
 
+	// @formatter:off
 	/*
-	 * Here we determine whether a collision has actually happened, and if it
-	 * did, at what moment.
-	 * The basic idea is to compute the moment of collision and impact
-	 * coordinates in wall coordinate space.
-	 * Then, we can check impact coordinates to determine if we actually hit the
-	 * wall or flew by and then
-	 * check time to make sure the collision is not too far in the future and
-	 * not in the past.
+	 * Here we determine whether a collision has actually happened, and if it did, at what moment.
+	 * 
+	 * The basic idea is to compute the moment of collision and impact coordinates in wall coordinate space.
+	 * Then, we can check impact coordinates to determine if we actually hit the wall or flew by and then
+	 * check time to make sure the collision is not too far in the future and not in the past.
+	 * 
 	 * DETAILED EXPLANATION:
-	 * Consider a surface defined by an origin r_wall and two noncollinear
-	 * nonzero vectors w and h.
+	 * 
+	 * Consider a surface defined by an origin r_wall and two noncollinear nonzero vectors w and h.
 	 * Consider a line defined by an origin r_line and a nonzero vector v.
+	 * 
 	 * Then, a collision occurs if there exist x, y and t such that
-	 * ______ _
-	 * r_line + v * t
+	 *   ______   _
+	 *   r_line + v * t
+	 *   
 	 * and
-	 * ______ _ _
-	 * r_wall + w * x + h * y
-	 * describe the same location (indeed, this corresponds to a collision at
-	 * moment t0 + t
-	 * with a point on the wall with coordinates (x; y) in (w; h) coordinate
-	 * system).
+	 *   ______   _       _
+	 *   r_wall + w * x + h * y
+	 *   
+	 * describe the same location (indeed, this corresponds to a collision at moment t0 + t
+	 * with a point on the wall with coordinates (x; y) in (w; h) coordinate system).
+	 * 
 	 * Therefore,
-	 * ______ _ ______ _ _
-	 * r_line + v*t = r_wall + w*x + h*y;
-	 * _ ⎡w_x h_x -v_x⎤ ⎡x⎤ _ ______ ______
-	 * r = ⎢w_y h_y -v_y⎥ * ⎢y⎥, where r = r_line - r_wall;
-	 * ⎣w_z h_z -v_z⎦ ⎣t⎦
-	 * ⎡x⎤ ⎡w_x h_x -v_x⎤ -1 _
-	 * ⎢y⎥ = ⎢w_y h_y -v_y⎥ * r, if the matrix is invertible.
-	 * ⎣t⎦ ⎣w_z h_z -v_z⎦
+	 *   ______   _     ______   _     _
+	 *   r_line + v*t = r_wall + w*x + h*y;
+	 *   
+	 *   _   ⎡w_x  h_x  -v_x⎤   ⎡x⎤        _   ______   ______
+	 *   r = ⎢w_y  h_y  -v_y⎥ * ⎢y⎥, where r = r_line - r_wall;
+	 *       ⎣w_z  h_z  -v_z⎦   ⎣t⎦
+	 *       
+	 *   ⎡x⎤   ⎡w_x  h_x  -v_x⎤ -1   _
+	 *   ⎢y⎥ = ⎢w_y  h_y  -v_y⎥    * r, if the matrix is invertible.
+	 *   ⎣t⎦   ⎣w_z  h_z  -v_z⎦
+	 * 
 	 * Then, one only needs to ensure that:
-	 * 0 < x < 1,
-	 * 0 < y < 1, and
-	 * 0 < t < T, where T is remaining tick time.
-	 * If the matrix is not invertible or any of the conditions are not met, no
-	 * collision happened.
+	 *   0 < x < 1,
+	 *   0 < y < 1, and
+	 *   0 < t < T, where T is remaining tick time.
+	 * 
+	 * If the matrix is not invertible or any of the conditions are not met, no collision happened.
 	 * If all conditions are satisfied, then the moment of impact is t0 + t.
 	 */
+	// @formatter:on
 	private static Collision computeWallCollision(
 		Wall obstacleWall,
 		AABBoid colliderModel,

src/main/java/ru/windcorp/progressia/common/collision/colliders/Collider.java

@@ -27,7 +27,7 @@ import glm.vec._3.Vec3;
 import ru.windcorp.progressia.common.collision.*;
 import ru.windcorp.progressia.common.util.LowOverheadCache;
 import ru.windcorp.progressia.common.util.Vectors;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class Collider {
 
@@ -36,7 +36,7 @@ public class Collider {
 	/**
 	 * Dear Princess Celestia,
 	 * <p>
-	 * When {@linkplain #advanceTime(Collection, Collision, WorldData, float)
+	 * When {@linkplain #advanceTime(Collection, Collision, DefaultWorldData, float)
 	 * advancing time},
 	 * time step for all entities <em>except</em> currently colliding bodies is
 	 * the current
@@ -61,7 +61,7 @@ public class Collider {
 
 	public static void performCollisions(
 		List<? extends Collideable> colls,
-		WorldData world,
+		DefaultWorldData world,
 		float tickLength,
 		ColliderWorkspace workspace
 	) {
@@ -96,7 +96,7 @@ public class Collider {
 	private static Collision getFirstCollision(
 		List<? extends Collideable> colls,
 		float tickLength,
-		WorldData world,
+		DefaultWorldData world,
 		ColliderWorkspace workspace
 	) {
 		Collision result = null;
@@ -126,7 +126,7 @@ public class Collider {
 	private static void tuneWorldCollisionHelper(
 		Collideable coll,
 		float tickLength,
-		WorldData world,
+		DefaultWorldData world,
 		ColliderWorkspace workspace
 	) {
 		WorldCollisionHelper wch = workspace.worldCollisionHelper;
@@ -194,7 +194,7 @@ public class Collider {
 		Collision collision,
 
 		Collection<? extends Collideable> colls,
-		WorldData world,
+		DefaultWorldData world,
 		float tickLength,
 		ColliderWorkspace workspace
 	) {
@@ -212,66 +212,72 @@ public class Collider {
 		handlePhysics(collision);
 	}
 
+	// @formatter:off
 	/*
 	 * Here we compute the change in body velocities due to a collision.
+	 * 
 	 * We make the following simplifications:
-	 * 1) The bodies are perfectly rigid;
-	 * 2) The collision is perfectly inelastic
-	 * (no bouncing);
-	 * 3) The bodies are spherical;
-	 * 4) No tangential friction exists
-	 * (bodies do not experience friction when sliding against each other);
-	 * 5) Velocities are not relativistic.
+	 *   1)  The bodies are perfectly rigid;
+	 *   2)  The collision is perfectly inelastic
+	 *       (no bouncing);
+	 *   3)  The bodies are spherical;
+	 *   4)  No tangential friction exists
+	 *       (bodies do not experience friction when sliding against each other);
+	 *   5)  Velocities are not relativistic.
+	 *   
 	 * Angular momentum is ignored per 3) and 4),
-	 * e.g. when something pushes an end of a long stick, the stick does not
-	 * rotate.
+	 * e.g. when something pushes an end of a long stick, the stick does not rotate.
+	 * 
 	 * DETAILED EXPLANATION:
-	 * Two spherical (sic) bodies, a and b, experience a perfectly inelastic
-	 * collision
+	 * 
+	 * Two spherical (sic) bodies, a and b, experience a perfectly inelastic collision
 	 * along a unit vector
-	 * _ _ _ _ _
-	 * n = (w ⨯ h) / (|w ⨯ h|),
-	 * _ _
+	 *   _    _   _      _   _
+	 *   n = (w ⨯ h) / (|w ⨯ h|),
+	 *       _     _
 	 * where w and h are two noncollinear nonzero vectors on the dividing plane.
-	 * ___ ___
+	 *                                             ___  ___
 	 * Body masses and velocities are M_a, M_b and v_a, v_b, respectively.
-	 * ___ ___
+	 *                                            ___     ___
 	 * After the collision desired velocities are u_a and u_b, respectively.
-	 * _
-	 * (Notation convention: suffix 'n' denotes a vector projection onto vector
-	 * n,
+	 *                                                                          _
+	 * (Notation convention: suffix 'n' denotes a vector projection onto vector n,
 	 * and suffix 't' denotes a vector projection onto the dividing plane.)
-	 * Consider the law of conservation of momentum for axis n and the dividing
-	 * plane:
-	 * ____________ ____________ ________________
-	 * n: ⎧ p_a_before_n + p_b_before_n = p_common_after_n;
-	 * ⎨ ___________ ____________
-	 * t: ⎩ p_i_after_t = p_i_before_t for any i in {a, b}.
+	 * 
+	 * Consider the law of conservation of momentum for axis n and the dividing plane:
+	 *        ____________   ____________   ________________
+	 *   n: ⎧ p_a_before_n + p_b_before_n = p_common_after_n;
+	 *      ⎨ ___________   ____________
+	 *   t: ⎩ p_i_after_t = p_i_before_t    for any i in {a, b}.
+	 *   
 	 * Expressing all p_* in given terms:
-	 * ___ _ ___ _ ___ ___ ____ ____
-	 * n: ⎧ M_a * (v_a ⋅ n) + M_b * (v_b ⋅ n) = (M_a + M_b) * u_n, where u_n ≡
-	 * u_an = u_bn;
-	 * ⎨ ____ ___ _ ___ _
-	 * t: ⎩ u_it = v_i - n * (v_i ⋅ n) for any i in {a, b}.
+	 *               ___   _           ___   _                  ___           ___   ____   ____
+	 *   n: ⎧ M_a * (v_a ⋅ n) + M_b * (v_b ⋅ n) = (M_a + M_b) * u_n,    where u_n ≡ u_an = u_bn;
+	 *      ⎨ ____   ___   _    ___   _
+	 *   t: ⎩ u_it = v_i - n * (v_i ⋅ n)                                for any i in {a, b}.
+	 *   
 	 * Therefore:
-	 * ___ _ ___ _ ___ _
-	 * u_n = n * ( M_a/(M_a + M_b) * v_a ⋅ n + M_b/(M_a + M_b) * v_b ⋅ n );
+	 *   ___   _                       ___   _                       ___   _
+	 *   u_n = n * ( M_a/(M_a + M_b) * v_a ⋅ n  +  M_b/(M_a + M_b) * v_b ⋅ n );
+	 * 
 	 * or, equivalently,
-	 * ___ _ ___ _ ___ _
-	 * u_n = n * ( m_a * v_a ⋅ n + m_b * v_b ⋅ n ),
+	 *   ___   _           ___   _           ___   _
+	 *   u_n = n * ( m_a * v_a ⋅ n  +  m_b * v_b ⋅ n ),
+	 * 
 	 * where m_a and m_b are relative masses (see below).
+	 * 
 	 * Finally,
-	 * ___ ____ ___
-	 * u_i = u_it + u_n for any i in {a, b}.
-	 * The usage of relative masses m_i permits a convenient generalization of
-	 * the algorithm
-	 * for infinite masses, signifying masses "significantly greater" than
-	 * finite masses:
-	 * 1) If both M_a and M_b are finite, let m_i = M_i / (M_a + M_b) for any i
-	 * in {a, b}.
-	 * 2) If M_i is finite but M_j is infinite, let m_i = 0 and m_j = 1.
-	 * 3) If both M_a and M_b are infinite, let m_i = 1/2 for any i in {a, b}.
+	 *   ___   ____   ___
+	 *   u_i = u_it + u_n    for any i in {a, b}.
+	 *   
+	 * The usage of relative masses m_i permits a convenient generalization of the algorithm
+	 * for infinite masses, signifying masses "significantly greater" than finite masses:
+	 * 
+	 *   1)  If both M_a and M_b are finite,       let m_i = M_i / (M_a + M_b)    for any i in {a, b}.
+	 *   2)  If M_i is finite but M_j is infinite, let m_i = 0 and m_j = 1.
+	 *   3)  If both M_a and M_b are infinite,     let m_i = 1/2                  for any i in {a, b}.
 	 */
+	// @formatter:on
 	private static void handlePhysics(Collision collision) {
 		// Fuck JGLM
 		Vec3 n = Vectors.grab3();
@@ -355,7 +361,7 @@ public class Collider {
 	private static void advanceTime(
 		Collection<? extends Collideable> colls,
 		Collision exceptions,
-		WorldData world,
+		DefaultWorldData world,
 		float step
 	) {
 		world.advanceTime(step);

src/main/java/ru/windcorp/progressia/common/hacks/GuavaEventBusHijacker.java

@@ -29,15 +29,14 @@ import com.google.common.util.concurrent.MoreExecutors;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
 
 /**
- * This class had to be written because there is not legal way to instantiate a
- * non-async
- * {@link EventBus} with both a custom identifier and a custom exception
- * handler. Which
- * is a shame. Guava maintainers know about the issue but have rejected
- * solutions multiple
- * times <em>without a clearly stated reason</em>; looks like some dirty
- * reflection will
- * have to do.
+ * This class had to be written because there is no legal way to instantiate a
+ * non-async {@link EventBus} with both a custom identifier and a custom
+ * exception handler. Which is a shame. Guava maintainers know about the issue
+ * but have rejected solutions multiple times <em>without a clearly stated
+ * reason</em>; looks like some dirty reflection will have to do.
+ * <p>
+ * When explicitly referencing this class, please mention its usage in
+ * implementation notes because it is unreliable long-term.
  * 
  * @author javapony
  */

src/main/java/ru/windcorp/progressia/common/state/StateChange.java

@@ -16,7 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package ru.windcorp.progressia.server.world.tasks;
+package ru.windcorp.progressia.common.state;
 
 @FunctionalInterface
 public interface StateChange<T> {

src/main/java/ru/windcorp/progressia/common/util/ArrayFloatRangeMap.java

@@ -0,0 +1,225 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Objects;
+
+public class ArrayFloatRangeMap<E> implements FloatRangeMap<E> {
+
+	protected static class Node<E> implements Comparable<Node<E>> {
+		public float pos;
+		public E value;
+
+		public Node(float pos, E value) {
+			this.pos = pos;
+			this.value = value;
+		}
+
+		@Override
+		public int compareTo(Node<E> o) {
+			return Float.compare(pos, o.pos);
+		}
+	}
+
+	/*
+	 * Expects a random-access list
+	 */
+	protected final List<Node<E>> nodes;
+	protected int ranges = 0;
+	
+	protected static final int DEFAULT_CAPACITY = 16;
+
+	public ArrayFloatRangeMap(int capacity) {
+		this.nodes = new ArrayList<>(2 * capacity);
+	}
+	
+	public ArrayFloatRangeMap() {
+		this(DEFAULT_CAPACITY);
+	}
+
+	@Override
+	public int size() {
+		return this.ranges;
+	}
+
+	@Override
+	public Iterator<E> iterator() {
+		return new Iterator<E>() {
+			
+			private int nextIndex = 0;
+			
+			{
+				assert nodes.isEmpty() || nodes.get(nextIndex).value != null;
+			}
+
+			private void findNext() {
+				while (nextIndex < nodes.size()) {
+					nextIndex++;
+					Node<E> node = nodes.get(nextIndex);
+					if (node.value != null) return;
+				}
+			}
+			
+			@Override
+			public boolean hasNext() {
+				return nextIndex < nodes.size();
+			}
+			
+			@Override
+			public E next() {
+				E result = nodes.get(nextIndex).value;
+				findNext();
+				return result;
+			}
+		};
+	}
+
+	/**
+	 * Returns an index of the smallest {@link Node} larger than or exactly at
+	 * {@code position}.
+	 * 
+	 * @param position the position to look up
+	 * @return an index in the {@link #nodes} list containing the first
+	 *         {@link Node} whose {@link Node#pos} is not smaller than
+	 *         {@code position}, or {@code nodes.size()} if no such index exists
+	 */
+	protected int findCeiling(float position) {
+
+		/*
+		 * Implementation based on OpenJDK's
+		 * Collections.indexedBinarySearch(List, Comparator)
+		 */
+
+		int low = 0;
+		int high = nodes.size() - 1;
+
+		while (low <= high) {
+			int mid = (low + high) >>> 1;
+			float midVal = nodes.get(mid).pos;
+			int cmp = Float.compare(midVal, position);
+
+			if (cmp < 0)
+				low = mid + 1;
+			else if (cmp > 0)
+				high = mid - 1;
+			else
+				return mid; // key found
+		}
+		
+		return low; // the insertion point is the desired index 
+	}
+	
+	/**
+	 * Returns an index of the largest {@link Node} smaller than or exactly at
+	 * {@code position}.
+	 * 
+	 * @param position the position to look up
+	 * @return an index in the {@link #nodes} list containing the last
+	 *         {@link Node} whose {@link Node#pos} is not greater than
+	 *         {@code position}, or {@code -1} if no such index exists
+	 */
+	protected int findFloor(float position) {
+
+		/*
+		 * Implementation based on OpenJDK's
+		 * Collections.indexedBinarySearch(List, Comparator)
+		 */
+
+		int low = 0;
+		int high = nodes.size() - 1;
+
+		while (low <= high) {
+			int mid = (low + high) >>> 1;
+			float midVal = nodes.get(mid).pos;
+			int cmp = Float.compare(midVal, position);
+
+			if (cmp < 0)
+				low = mid + 1;
+			else if (cmp > 0)
+				high = mid - 1;
+			else
+				return mid; // key found
+		}
+		
+		return low - 1; // the insertion point immediately follows the desired index
+	}
+	
+	protected Node<E> getEffectiveNode(float at) {
+		int effectiveNodeIndex = findFloor(at);
+		if (effectiveNodeIndex < 0) return null;
+		return nodes.get(effectiveNodeIndex);
+	}
+	
+	@Override
+	public E get(float at) {
+		Node<E> effectiveNode = getEffectiveNode(at);
+		return effectiveNode == null ? null : effectiveNode.value;
+	}
+	
+	@Override
+	public void put(float min, float max, E element) {
+		Objects.requireNonNull(element, "element");
+		
+		if (!(max > min)) // This funky construction also deals with NaNs since NaNs always fail any comparison
+		{
+			throw new IllegalArgumentException(max + " is not greater than " + min);
+		}
+		
+		int indexOfInsertionOfMin = findCeiling(min);
+		
+		nodes.add(indexOfInsertionOfMin, new Node<E>(min, element));
+		ranges++;
+		
+		ListIterator<Node<E>> it = nodes.listIterator(indexOfInsertionOfMin + 1);
+		E elementEffectiveImmediatelyAfterInsertedRange = null;
+		
+		if (indexOfInsertionOfMin > 0) {
+			elementEffectiveImmediatelyAfterInsertedRange = nodes.get(indexOfInsertionOfMin - 1).value;
+		}
+		
+		while (it.hasNext()) {
+			Node<E> node = it.next();
+			
+			if (node.pos >= max) {
+				break;
+			}
+			
+			elementEffectiveImmediatelyAfterInsertedRange = node.value;
+			if (elementEffectiveImmediatelyAfterInsertedRange != null) {
+				// Removing an actual range
+				ranges--;
+			}
+			it.remove();
+		}
+		
+		if (max != Float.POSITIVE_INFINITY) {
+			nodes.add(indexOfInsertionOfMin + 1, new Node<E>(max, elementEffectiveImmediatelyAfterInsertedRange));
+			
+			if (elementEffectiveImmediatelyAfterInsertedRange != null) {
+				// We might have added one right back
+				ranges++;
+			}			
+		}
+		
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/util/FloatRangeMap.java

@@ -0,0 +1,36 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util;
+
+public interface FloatRangeMap<E> extends Iterable<E> {
+	
+	void put(float min, float max, E element);
+	E get(float at);
+	
+	int size();
+	
+	default boolean defines(float position) {
+		return get(position) != null;
+	}
+	
+	default E getOrDefault(float at, E def) {
+		E result = get(at);
+		return result == null ? def : result;
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/util/VectorUtil.java

@@ -20,6 +20,8 @@ package ru.windcorp.progressia.common.util;
 
 import java.util.function.Consumer;
 
+import glm.Glm;
+import glm.mat._3.Mat3;
 import glm.mat._4.Mat4;
 import glm.vec._2.Vec2;
 import glm.vec._2.d.Vec2d;
@@ -37,6 +39,40 @@ public class VectorUtil {
 		X, Y, Z, W;
 	}
 	
+	public static enum SignedAxis {
+		POS_X(Axis.X, +1),
+		NEG_X(Axis.X, -1),
+		POS_Y(Axis.Y, +1),
+		NEG_Y(Axis.Y, -1),
+		POS_Z(Axis.Z, +1),
+		NEG_Z(Axis.Z, -1),
+		POS_W(Axis.W, +1),
+		NEG_W(Axis.W, -1);
+		
+		private final Axis axis;
+		private final boolean isPositive;
+		
+		private SignedAxis(Axis axis, int sign) {
+			this.axis = axis;
+			this.isPositive = (sign == +1 ? true : false);
+		}
+		
+		/**
+		 * @return the axis
+		 */
+		public Axis getAxis() {
+			return axis;
+		}
+		
+		public boolean isPositive() {
+			return isPositive;
+		}
+		
+		public int getSign() {
+			return isPositive ? +1 : -1;
+		}
+	}
+
 	public static void iterateCuboid(
 		int x0,
 		int y0,
@@ -124,7 +160,11 @@ public class VectorUtil {
 		iterateCuboidAround(center.x, center.y, center.z, diameter, action);
 	}
 
-	public static void applyMat4(Vec3 in, Mat4 mat, Vec3 out) {
+	public static Vec3 applyMat4(Vec3 in, Mat4 mat, Vec3 out) {
+		if (out == null) {
+			out = new Vec3();
+		}
+		
 		Vec4 vec4 = Vectors.grab4();
 		vec4.set(in, 1f);
 
@@ -132,15 +172,83 @@ public class VectorUtil {
 
 		out.set(vec4.x, vec4.y, vec4.z);
 		Vectors.release(vec4);
+		
+		return out;
 	}
 
-	public static void applyMat4(Vec3 inOut, Mat4 mat) {
-		Vec4 vec4 = Vectors.grab4();
-		vec4.set(inOut, 1f);
+	public static Vec3 applyMat4(Vec3 inOut, Mat4 mat) {
+		return applyMat4(inOut, mat, inOut);
+	}
 	
-		mat.mul(vec4);
+	public static Vec3 rotate(Vec3 in, Vec3 axis, float angle, Vec3 out) {
+		if (out == null) {
+			out = new Vec3();
+		}
 		
-		inOut.set(vec4.x, vec4.y, vec4.z);
+		Mat3 mat = Matrices.grab3();
+		
+		mat.identity().rotate(angle, axis);
+		mat.mul(in, out);
+		
+		Matrices.release(mat);
+		
+		return out;
+	}
+	
+	public static Vec3 rotate(Vec3 inOut, Vec3 axis, float angle) {
+		return rotate(inOut, axis, angle, inOut);
+	}
+	
+	public static double getAngle(Vec3 from, Vec3 to, Vec3 normal) {
+		Vec3 left = Vectors.grab3();
+		
+		left.set(normal).cross(from);
+		double sign = Math.signum(left.dot(to));
+		
+		double result = (float) Math.acos(Glm.clamp(from.dot(to), -1, +1)) * sign;
+		
+		Vectors.release(left);
+		return result;
+	}
+	
+	public static Vec3 projectOnSurface(Vec3 in, Vec3 normal, Vec3 out) {
+		if (in == out) {
+			return projectOnSurface(in, normal);
+		}
+		
+		if (out == null) {
+			out = new Vec3();
+		}
+		
+		out.set(normal).mul(-normal.dot(in)).add(in);
+		
+		return out;
+	}
+	
+	public static Vec3 projectOnSurface(Vec3 inOut, Vec3 normal) {
+		Vec3 buffer = Vectors.grab3();
+		
+		projectOnSurface(inOut, normal, buffer);
+		inOut.set(buffer);
+		
+		Vectors.release(buffer);
+		
+		return inOut;
+	}
+	
+	public static Vec3 projectOnVector(Vec3 in, Vec3 vector, Vec3 out) {
+		if (out == null) {
+			out = new Vec3();
+		}
+		
+		float dot = vector.dot(in);
+		out.set(vector).mul(dot);
+		
+		return out;
+	}
+	
+	public static Vec3 projectOnVector(Vec3 inOut, Vec3 vector) {
+		return projectOnVector(inOut, vector);
 	}
 
 	public static Vec3 linearCombination(
@@ -150,6 +258,10 @@ public class VectorUtil {
 		float kb,
 		Vec3 output
 	) {
+		if (output == null) {
+			output = new Vec3();
+		}
+		
 		output.set(
 			va.x * ka + vb.x * kb,
 			va.y * ka + vb.y * kb,
@@ -167,6 +279,10 @@ public class VectorUtil {
 		float kc,
 		Vec3 output
 	) {
+		if (output == null) {
+			output = new Vec3();
+		}
+		
 		output.set(
 			va.x * ka + vb.x * kb + vc.x * kc,
 			va.y * ka + vb.y * kb + vc.y * kc,
@@ -175,6 +291,88 @@ public class VectorUtil {
 		return output;
 	}
 	
+	public static Vec3i sort(Vec3i input, Vec3i output) {
+		if (output == null) {
+			output = new Vec3i();
+		}
+		
+		int ax = input.x, ay = input.y, az = input.z;
+
+		if (ax > ay) {
+			if (ax > az) {
+				output.x = ax;
+				output.y = ay > az ? ay : az;
+				output.z = ay > az ? az : ay;
+			} else {
+				output.x = az;
+				output.y = ax;
+				output.z = ay;
+			}
+		} else {
+			if (ay > az) {
+				output.x = ay;
+				output.y = ax > az ? ax : az;
+				output.z = ax > az ? az : ax;
+			} else {
+				output.x = az;
+				output.y = ay;
+				output.z = ax;
+			}
+		}
+		
+		return output;
+	}
+	
+	public static Vec3 sort(Vec3 input, Vec3 output) {
+		if (output == null) {
+			output = new Vec3();
+		}
+		
+		float ax = input.x, ay = input.y, az = input.z;
+
+		if (ax > ay) {
+			if (ax > az) {
+				output.x = ax;
+				output.y = ay > az ? ay : az;
+				output.z = ay > az ? az : ay;
+			} else {
+				output.x = az;
+				output.y = ax;
+				output.z = ay;
+			}
+		} else {
+			if (ay > az) {
+				output.x = ay;
+				output.y = ax > az ? ax : az;
+				output.z = ax > az ? az : ax;
+			} else {
+				output.x = az;
+				output.y = ay;
+				output.z = ax;
+			}
+		}
+		
+		return output;
+	}
+	
+	public static Vec3i sortAfterAbs(Vec3i input, Vec3i output) {
+		if (output == null) {
+			output = new Vec3i();
+		}
+		
+		input.abs(output);
+		return sort(output, output);
+	}
+	
+	public static Vec3 sortAfterAbs(Vec3 input, Vec3 output) {
+		if (output == null) {
+			output = new Vec3();
+		}
+		
+		input.abs(output);
+		return sort(output, output);
+	}
+
 	public static float get(Vec2 v, Axis a) {
 		switch (a) {
 		case X:

src/main/java/ru/windcorp/progressia/common/util/crash/ReportingEventBus.java

@@ -22,11 +22,27 @@ import com.google.common.eventbus.EventBus;
 
 import ru.windcorp.progressia.common.hacks.GuavaEventBusHijacker;
 
+/**
+ * A utility for creating Guava's {@link EventBus}es that
+ * {@linkplain CrashReports report} exceptions instead of suppressing them.
+ * 
+ * @author javapony
+ */
 public class ReportingEventBus {
 
 	private ReportingEventBus() {
 	}
 
+	/**
+	 * Instantiates a new {@link EventBus} with the provided identifier that
+	 * reports any unhandled exceptions with {@link CrashReports}.
+	 * 
+	 * @param identifier the identifier of the new bus
+	 * @return the created event bus
+	 * @implNote This implementation relies on {@link GuavaEventBusHijacker} for
+	 *           creating buses with custom identifiers and uncaught exception
+	 *           handlers. It may break suddenly with a Guava update.
+	 */
 	public static EventBus create(String identifier) {
 		return GuavaEventBusHijacker.newEventBus(
 			identifier,

src/main/java/ru/windcorp/progressia/common/util/noise/discrete/DiscreteNoise.java

@@ -0,0 +1,25 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util.noise.discrete;
+
+public interface DiscreteNoise<T> {
+	
+	T get(double x, double y);
+	T get(double x, double y, double z);
+
+}

src/main/java/ru/windcorp/progressia/common/util/noise/discrete/WorleyProceduralNoise.java

@@ -0,0 +1,228 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.util.noise.discrete;
+
+import java.util.Collection;
+import com.google.common.collect.ImmutableList;
+
+public class WorleyProceduralNoise<T> implements DiscreteNoise<T> {
+
+	/*
+	 * Stolen from OpenJDK's Random implementation
+	 * *evil cackling*
+	 */
+	private static final long MULTIPLIER = 0x5DEECE66DL;
+	private static final long ADDEND = 0xBL;
+	private static final long MASK = (1L << 48) - 1;
+	private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)
+
+	private static long permute(long seed) {
+		return (seed * MULTIPLIER + ADDEND) & MASK;
+	}
+
+	private static double getDouble(long seed) {
+		final int mask26bits = (1 << 26) - 1;
+		final int mask27bits = (1 << 27) - 1;
+
+		int randomBitsX26 = (int) (seed & 0xFFFFFFFF);
+		int randomBitsX27 = (int) ((seed >>> Integer.SIZE) & 0xFFFFFFFF);
+
+		randomBitsX26 = randomBitsX26 & mask26bits;
+		randomBitsX27 = randomBitsX27 & mask27bits;
+
+		return (((long) (randomBitsX26) << 27) + randomBitsX27) * DOUBLE_UNIT;
+	}
+
+	public static class Entry<T> {
+		private final T value;
+		private final double chance;
+
+		public Entry(T value, double chance) {
+			this.value = value;
+			this.chance = chance;
+		}
+	}
+
+	public static class Builder<T> {
+
+		com.google.common.collect.ImmutableList.Builder<Entry<T>> builder = ImmutableList.builder();
+
+		public Builder<T> add(T value, double chance) {
+			builder.add(new Entry<>(value, chance));
+			return this;
+		}
+
+		public WorleyProceduralNoise<T> build(long seed) {
+			return new WorleyProceduralNoise<>(this, seed);
+		}
+
+	}
+
+	public static <T> Builder<T> builder() {
+		return new Builder<>();
+	}
+
+	private final Entry<?>[] entries;
+	private final long seed;
+
+	public WorleyProceduralNoise(Builder<T> builder, long seed) {
+		this(builder.builder.build(), seed);
+	}
+
+	public WorleyProceduralNoise(Collection<? extends Entry<? extends T>> entries, long seed) {
+		this.entries = new Entry<?>[entries.size()];
+
+		double chancesSum = 0;
+		for (Entry<? extends T> entry : entries) {
+			chancesSum += entry.chance;
+		}
+
+		int i = 0;
+		for (Entry<? extends T> entry : entries) {
+			this.entries[i] = new Entry<T>(entry.value, entry.chance / chancesSum);
+			i++;
+		}
+
+		this.seed = seed;
+	}
+
+	@Override
+	public T get(double x, double y) {
+
+		int ox = (int) x;
+		int oy = (int) y;
+
+		T closest = null;
+		double closestDistanceSq = Double.POSITIVE_INFINITY;
+
+		for (int cellX = ox - 1; cellX <= ox + 1; ++cellX) {
+			for (int cellY = oy - 1; cellY <= oy + 1; ++cellY) {
+
+				long cellSeed = permute(cellY ^ permute(cellX ^ seed));
+
+				int nodes = getNodeCount(cellSeed);
+				cellSeed = permute(cellSeed);
+
+				for (int i = 0; i < nodes; ++i) {
+
+					double nodeX = getDouble(cellSeed) + cellX;
+					cellSeed = permute(cellSeed);
+
+					double nodeY = getDouble(cellSeed) + cellY;
+					cellSeed = permute(cellSeed);
+
+					T value = getValue(getDouble(cellSeed));
+					cellSeed = permute(cellSeed);
+
+					double distanceSq = (x - nodeX) * (x - nodeX) + (y - nodeY) * (y - nodeY);
+					if (distanceSq < closestDistanceSq) {
+						closestDistanceSq = distanceSq;
+						closest = value;
+					}
+
+				}
+			}
+		}
+
+		return closest;
+
+	}
+
+	@Override
+	public T get(double x, double y, double z) {
+
+		int ox = (int) x;
+		int oy = (int) y;
+		int oz = (int) z;
+
+		T closest = null;
+		double closestDistanceSq = Double.POSITIVE_INFINITY;
+
+		for (int cellX = ox - 1; cellX <= ox + 1; ++cellX) {
+			for (int cellY = oy - 1; cellY <= oy + 1; ++cellY) {
+				for (int cellZ = oz - 1; cellZ <= oz + 1; ++cellZ) {
+
+					long cellSeed = permute(cellZ ^ permute(cellY ^ permute(cellX ^ seed)));
+
+					int nodes = getNodeCount(cellSeed);
+					cellSeed = permute(cellSeed);
+
+					for (int i = 0; i < nodes; ++i) {
+
+						double nodeX = getDouble(cellSeed) + cellX;
+						cellSeed = permute(cellSeed);
+
+						double nodeY = getDouble(cellSeed) + cellY;
+						cellSeed = permute(cellSeed);
+
+						double nodeZ = getDouble(cellSeed) + cellZ;
+						cellSeed = permute(cellSeed);
+
+						T value = getValue(getDouble(cellSeed));
+						cellSeed = permute(cellSeed);
+
+						double distanceSq = (x - nodeX) * (x - nodeX) + (y - nodeY) * (y - nodeY)
+							+ (z - nodeZ) * (z - nodeZ);
+						if (distanceSq < closestDistanceSq) {
+							closestDistanceSq = distanceSq;
+							closest = value;
+						}
+
+					}
+				}
+			}
+		}
+
+		return closest;
+
+	}
+
+	@SuppressWarnings("unchecked")
+	private T getValue(double target) {
+		int i;
+
+		for (i = 0; i < entries.length && target > entries[i].chance; ++i) {
+			target -= entries[i].chance;
+		}
+
+		return (T) entries[i].value;
+	}
+
+	private int getNodeCount(long seed) {
+		int uniform = ((int) seed) % 8;
+
+		switch (uniform) {
+		case 0:
+		case 1:
+		case 2:
+		case 3:
+			return 1;
+
+		case 4:
+		case 5:
+			return 2;
+
+		case 6:
+			return 3;
+
+		default:
+			return 4;
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/BlockRay.java

@@ -22,7 +22,7 @@ import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.util.VectorUtil;
 import ru.windcorp.progressia.common.util.VectorUtil.Axis;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 import static java.lang.Math.*;
 
@@ -34,15 +34,23 @@ public class BlockRay {
 	private float distance;
 
 	private final Vec3i block = new Vec3i();
-	private BlockFace currentFace = null;
+	private AbsFace currentFace = null;
 
 	private boolean isValid = false;
 
 	public void start(Vec3 position, Vec3 direction) {
-		if (!direction.any()) {
+		if (direction.x == 0 && direction.y == 0 && direction.z == 0) {
 			throw new IllegalArgumentException("Direction is a zero vector");
 		}
 		
+		if (Float.isNaN(direction.x) || Float.isNaN(direction.y) || Float.isNaN(direction.z)) {
+			throw new IllegalArgumentException("Direction contains NaN: " + direction);
+		}
+		
+		if (Float.isNaN(position.x) || Float.isNaN(position.y) || Float.isNaN(position.z)) {
+			throw new IllegalArgumentException("Position contains NaN: " + position);
+		}
+
 		isValid = true;
 		this.position.set(position).sub(0.5f); // Make sure lattice points are
 												// block vertices, not centers
@@ -76,15 +84,13 @@ public class BlockRay {
 			axis = Axis.Z;
 		}
 		
+		assert tMin > 0 : "tMin is not positive (" + tMin + ")";
+
 		// block.(axis) += signum(direction.(axis))
 		VectorUtil.set(block, axis, VectorUtil.get(block, axis) + (int) signum(VectorUtil.get(direction, axis)));
 
 		// position += direction * tMin
-		VectorUtil.linearCombination(position, 1, direction, tMin, position); // position
-																				// +=
-																				// direction
-																				// *
-																				// tMin
+		VectorUtil.linearCombination(position, 1, direction, tMin, position);
 		distance += tMin;
 
 		// position.(axis) = round(position.(axis))
@@ -110,18 +116,18 @@ public class BlockRay {
 		return (edge - c) / dir;
 	}
 
-	private BlockFace computeCurrentFace(Axis axis, int sign) {
+	private AbsFace computeCurrentFace(Axis axis, int sign) {
 		if (sign == 0)
 			throw new IllegalStateException("sign is zero");
 
 		switch (axis) {
 		case X:
-			return sign > 0 ? BlockFace.SOUTH : BlockFace.NORTH;
+			return sign > 0 ? AbsFace.NEG_X : AbsFace.POS_X;
 		case Y:
-			return sign > 0 ? BlockFace.EAST : BlockFace.WEST;
+			return sign > 0 ? AbsFace.NEG_Y : AbsFace.POS_Y;
 		default:
 		case Z:
-			return sign > 0 ? BlockFace.BOTTOM : BlockFace.TOP;
+			return sign > 0 ? AbsFace.NEG_Z : AbsFace.POS_Z;
 		}
 	}
 
@@ -137,7 +143,7 @@ public class BlockRay {
 		return output;
 	}
 
-	public BlockFace getCurrentFace() {
+	public AbsFace getCurrentFace() {
 		return currentFace;
 	}
 

src/main/java/ru/windcorp/progressia/common/world/ChunkData.java

@@ -1,560 +1,12 @@
-/*
- * Progressia
- * Copyright (C)  2020-2021  Wind Corporation and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
- 
 package ru.windcorp.progressia.common.world;
 
-import static ru.windcorp.progressia.common.world.block.BlockFace.*;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Objects;
-import java.util.function.BiConsumer;
-import java.util.function.Consumer;
-
-import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.util.VectorUtil;
 import ru.windcorp.progressia.common.world.block.BlockData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
-import ru.windcorp.progressia.common.world.generic.GenericChunk;
+import ru.windcorp.progressia.common.world.generic.ChunkGenericWO;
 import ru.windcorp.progressia.common.world.tile.TileData;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
-import ru.windcorp.progressia.common.world.tile.TileReference;
-import ru.windcorp.progressia.common.world.tile.TileStackIsFullException;
 
-public class ChunkData
-	implements GenericChunk<ChunkData, BlockData, TileData, TileDataStack> {
+public interface ChunkData
+	extends ChunkDataRO, ChunkGenericWO<BlockData, TileData, TileDataStack, TileDataReference, ChunkData> {
 	
-	public static final int BLOCKS_PER_CHUNK = Coordinates.CHUNK_SIZE;
-
-	private final Vec3i position = new Vec3i();
-	private final WorldData world;
-
-	private final BlockData[] blocks = new BlockData[BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK];
-
-	private final TileDataStack[] tiles = new TileDataStack[BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK *
-		BLOCK_FACE_COUNT];
-
-	private Object generationHint = null;
-
-	private final Collection<ChunkDataListener> listeners = Collections.synchronizedCollection(new ArrayList<>());
-
-	public ChunkData(Vec3i position, WorldData world) {
-		this.position.set(position.x, position.y, position.z);
-		this.world = world;
-	}
-
-	@Override
-	public Vec3i getPosition() {
-		return position;
-	}
-
-	@Override
-	public BlockData getBlock(Vec3i posInChunk) {
-		return blocks[getBlockIndex(posInChunk)];
-	}
-
-	public void setBlock(Vec3i posInChunk, BlockData block, boolean notify) {
-		BlockData previous = blocks[getBlockIndex(posInChunk)];
-		blocks[getBlockIndex(posInChunk)] = block;
-
-		if (notify) {
-			getListeners().forEach(l -> {
-				l.onChunkBlockChanged(this, posInChunk, previous, block);
-				l.onChunkChanged(this);
-			});
-		}
-	}
-
-	@Override
-	public TileDataStack getTilesOrNull(Vec3i blockInChunk, BlockFace face) {
-		return tiles[getTileIndex(blockInChunk, face)];
-	}
-
-	/**
-	 * Internal use only. Modify a list returned by
-	 * {@link #getTiles(Vec3i, BlockFace)} or
-	 * {@link #getTilesOrNull(Vec3i, BlockFace)}
-	 * to change tiles.
-	 */
-	protected void setTiles(
-		Vec3i blockInChunk,
-		BlockFace face,
-		TileDataStack tiles
-	) {
-		this.tiles[getTileIndex(blockInChunk, face)] = tiles;
-	}
-
-	@Override
-	public boolean hasTiles(Vec3i blockInChunk, BlockFace face) {
-		return getTilesOrNull(blockInChunk, face) != null;
-	}
-
-	@Override
-	public TileDataStack getTiles(Vec3i blockInChunk, BlockFace face) {
-		int index = getTileIndex(blockInChunk, face);
-
-		if (tiles[index] == null) {
-			createTileStack(blockInChunk, face);
-		}
-
-		return tiles[index];
-	}
-
-	private void createTileStack(Vec3i blockInChunk, BlockFace face) {
-		Vec3i independentBlockInChunk = conjureIndependentBlockInChunkVec3i(blockInChunk);
-		TileDataStackImpl stack = new TileDataStackImpl(independentBlockInChunk, face);
-		setTiles(blockInChunk, face, stack);
-	}
-
-	private Vec3i conjureIndependentBlockInChunkVec3i(Vec3i blockInChunk) {
-		for (int i = 0; i < BlockFace.BLOCK_FACE_COUNT; ++i) {
-			TileDataStack stack = getTilesOrNull(blockInChunk, BlockFace.getFaces().get(i));
-			if (stack instanceof TileDataStackImpl) {
-				return ((TileDataStackImpl) stack).blockInChunk;
-			}
-		}
-
-		return new Vec3i(blockInChunk);
-	}
-
-	private static int getBlockIndex(Vec3i posInChunk) {
-		checkLocalCoordinates(posInChunk);
-
-		return posInChunk.z * BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK +
-			posInChunk.y * BLOCKS_PER_CHUNK +
-			posInChunk.x;
-	}
-
-	private static int getTileIndex(Vec3i posInChunk, BlockFace face) {
-		return getBlockIndex(posInChunk) * BLOCK_FACE_COUNT +
-			face.getId();
-	}
-
-	private static void checkLocalCoordinates(Vec3i posInChunk) {
-		if (!isInBounds(posInChunk)) {
-			throw new IllegalCoordinatesException(
-				"Coordinates " + str(posInChunk) + " "
-					+ "are not legal chunk coordinates"
-			);
-		}
-	}
-
-	public static boolean isInBounds(Vec3i posInChunk) {
-		return posInChunk.x >= 0 && posInChunk.x < BLOCKS_PER_CHUNK &&
-			posInChunk.y >= 0 && posInChunk.y < BLOCKS_PER_CHUNK &&
-			posInChunk.z >= 0 && posInChunk.z < BLOCKS_PER_CHUNK;
-	}
-
-	public boolean isBorder(Vec3i blockInChunk, BlockFace face) {
-		final int min = 0, max = BLOCKS_PER_CHUNK - 1;
-		return (blockInChunk.x == min && face == SOUTH) ||
-			(blockInChunk.x == max && face == NORTH) ||
-			(blockInChunk.y == min && face == EAST) ||
-			(blockInChunk.y == max && face == WEST) ||
-			(blockInChunk.z == min && face == BOTTOM) ||
-			(blockInChunk.z == max && face == TOP);
-	}
-
-	public void forEachBlock(Consumer<Vec3i> action) {
-		VectorUtil.iterateCuboid(
-			0,
-			0,
-			0,
-			BLOCKS_PER_CHUNK,
-			BLOCKS_PER_CHUNK,
-			BLOCKS_PER_CHUNK,
-			action
-		);
-	}
-
-	public void forEachTileStack(Consumer<TileDataStack> action) {
-		forEachBlock(blockInChunk -> {
-			for (BlockFace face : BlockFace.getFaces()) {
-				TileDataStack stack = getTilesOrNull(blockInChunk, face);
-				if (stack == null)
-					continue;
-				action.accept(stack);
-			}
-		});
-	}
-
-	/**
-	 * Iterates over all tiles in this chunk.
-	 * 
-	 * @param action the action to perform. {@code TileLocation} refers to each
-	 *               tile using its primary block
-	 */
-	public void forEachTile(BiConsumer<TileDataStack, TileData> action) {
-		forEachTileStack(stack -> stack.forEach(tileData -> action.accept(stack, tileData)));
-	}
-
-	public WorldData getWorld() {
-		return world;
-	}
-
-	public Collection<ChunkDataListener> getListeners() {
-		return listeners;
-	}
-
-	public void addListener(ChunkDataListener listener) {
-		this.listeners.add(listener);
-	}
-
-	public void removeListener(ChunkDataListener listener) {
-		this.listeners.remove(listener);
-	}
-
-	private static String str(Vec3i v) {
-		return "(" + v.x + "; " + v.y + "; " + v.z + ")";
-	}
-
-	protected void onLoaded() {
-		getListeners().forEach(l -> l.onChunkLoaded(this));
-	}
-
-	protected void beforeUnloaded() {
-		getListeners().forEach(l -> l.beforeChunkUnloaded(this));
-	}
-
-	public Object getGenerationHint() {
-		return generationHint;
-	}
-
-	public void setGenerationHint(Object generationHint) {
-		this.generationHint = generationHint;
-	}
-
-	/**
-	 * Implementation of {@link TileDataStack} used internally by
-	 * {@link ChunkData} to
-	 * actually store the tiles. This is basically an array wrapper with
-	 * reporting
-	 * capabilities.
-	 * 
-	 * @author javapony
-	 */
-	private class TileDataStackImpl extends TileDataStack {
-		private class TileReferenceImpl implements TileReference {
-			private int index;
-
-			public TileReferenceImpl(int index) {
-				this.index = index;
-			}
-
-			public void incrementIndex() {
-				this.index++;
-			}
-
-			public void decrementIndex() {
-				this.index--;
-			}
-
-			public void invalidate() {
-				this.index = 0;
-			}
-
-			@Override
-			public TileData get() {
-				if (!isValid())
-					return null;
-				return TileDataStackImpl.this.get(this.index);
-			}
-
-			@Override
-			public int getIndex() {
-				return index;
-			}
-
-			@Override
-			public TileDataStack getStack() {
-				return TileDataStackImpl.this;
-			}
-
-			@Override
-			public boolean isValid() {
-				return this.index >= 0;
-			}
-		}
-
-		private final TileData[] tiles = new TileData[TILES_PER_FACE];
-		private int size = 0;
-
-		private final TileReferenceImpl[] references = new TileReferenceImpl[tiles.length];
-		private final int[] indicesByTag = new int[tiles.length];
-		private final int[] tagsByIndex = new int[tiles.length];
-
-		{
-			Arrays.fill(indicesByTag, -1);
-			Arrays.fill(tagsByIndex, -1);
-		}
-
-		/*
-		 * Potentially shared
-		 */
-		private final Vec3i blockInChunk;
-		private final BlockFace face;
-
-		public TileDataStackImpl(Vec3i blockInChunk, BlockFace face) {
-			this.blockInChunk = blockInChunk;
-			this.face = face;
-		}
-
-		@Override
-		public Vec3i getBlockInChunk(Vec3i output) {
-			if (output == null)
-				output = new Vec3i();
-			output.set(blockInChunk.x, blockInChunk.y, blockInChunk.z);
-			return output;
-		}
-
-		@Override
-		public BlockFace getFace() {
-			return face;
-		}
-
-		@Override
-		public ChunkData getChunk() {
-			return ChunkData.this;
-		}
-
-		@Override
-		public int size() {
-			return size;
-		}
-
-		@Override
-		public TileData get(int index) {
-			checkIndex(index, false);
-
-			return tiles[index];
-		}
-
-		@Override
-		public TileData set(int index, TileData tile) {
-			Objects.requireNonNull(tile, "tile");
-			TileData previous = get(index); // checks index
-
-			tiles[index] = tile;
-
-			if (references[index] != null) {
-				references[index].invalidate();
-				references[index] = null;
-			}
-
-			assert checkConsistency();
-
-			report(previous, tile);
-			return previous;
-		}
-
-		@Override
-		public void add(int index, TileData tile) {
-			Objects.requireNonNull(tile, "tile");
-			checkIndex(index, true);
-
-			if (index != size()) {
-				System.arraycopy(tiles, index + 1, tiles, index + 2, size - index);
-
-				for (int i = index; i < size; ++i) {
-					if (references[i] != null) {
-						references[i].incrementIndex();
-					}
-
-					indicesByTag[tagsByIndex[i]]++;
-				}
-
-				System.arraycopy(references, index + 1, references, index + 2, size - index);
-				System.arraycopy(tagsByIndex, index + 1, tagsByIndex, index + 2, size - index);
-			}
-
-			size++;
-			tiles[index] = tile;
-			references[index] = null;
-
-			for (int tag = 0; tag < indicesByTag.length; ++tag) {
-				if (tagsByIndex[tag] == -1) {
-					indicesByTag[tag] = index;
-					tagsByIndex[index] = tag;
-					break;
-				}
-			}
-
-			modCount++;
-			assert checkConsistency();
-
-			report(null, tile);
-		}
-
-		@Override
-		public void load(TileData tile, int tag) {
-			addFarthest(tile);
-
-			int assignedTag = getIndexByTag(tag);
-
-			if (assignedTag == tag)
-				return;
-			if (assignedTag == -1) {
-				throw new IllegalArgumentException(
-					"Tag " + tag + " already used by tile at index " + getIndexByTag(tag)
-				);
-			}
-
-			indicesByTag[tagsByIndex[size() - 1]] = -1;
-			tagsByIndex[size() - 1] = tag;
-			indicesByTag[tag] = size() - 1;
-
-			assert checkConsistency();
-		}
-
-		@Override
-		public TileData remove(int index) {
-			TileData previous = get(index); // checks index
-
-			if (references[index] != null) {
-				references[index].invalidate();
-			}
-
-			indicesByTag[tagsByIndex[index]] = -1;
-
-			if (index != size() - 1) {
-				System.arraycopy(tiles, index + 1, tiles, index, size - index - 1);
-
-				for (int i = index + 1; i < size; ++i) {
-					if (references[i] != null) {
-						references[i].decrementIndex();
-					}
-
-					indicesByTag[tagsByIndex[i]]--;
-				}
-
-				System.arraycopy(references, index + 1, references, index, size - index - 1);
-				System.arraycopy(tagsByIndex, index + 1, tagsByIndex, index, size - index - 1);
-			}
-
-			size--;
-			tiles[size] = null;
-			references[size] = null;
-			tagsByIndex[size] = -1;
-
-			modCount++;
-			assert checkConsistency();
-
-			report(previous, null);
-			return previous;
-		}
-
-		@Override
-		public TileReference getReference(int index) {
-			checkIndex(index, false);
-
-			if (references[index] == null) {
-				references[index] = new TileReferenceImpl(index);
-			}
-
-			return references[index];
-		}
-
-		@Override
-		public int getIndexByTag(int tag) {
-			return indicesByTag[tag];
-		}
-
-		@Override
-		public int getTagByIndex(int index) {
-			checkIndex(index, false);
-			return tagsByIndex[index];
-		}
-
-		@Override
-		public void clear() {
-			while (!isEmpty()) {
-				removeFarthest();
-			}
-		}
-
-		private void checkIndex(int index, boolean isSizeAllowed) {
-			if (isSizeAllowed ? (index > size()) : (index >= size()))
-				throw new IndexOutOfBoundsException("Index " + index + " is out of bounds: size is " + size);
-
-			if (index < 0)
-				throw new IndexOutOfBoundsException("Index " + index + " is out of bounds: index cannot be negative");
-
-			if (index >= TILES_PER_FACE)
-				throw new TileStackIsFullException(
-					"Index " + index + " is out of bounds: maximum tile stack size is " + TILES_PER_FACE
-				);
-		}
-
-		private void report(TileData previous, TileData current) {
-			ChunkData.this.getListeners().forEach(l -> {
-				if (previous != null) {
-					l.onChunkTilesChanged(ChunkData.this, blockInChunk, face, previous, false);
-				}
-
-				if (current != null) {
-					l.onChunkTilesChanged(ChunkData.this, blockInChunk, face, current, true);
-				}
-
-				l.onChunkChanged(ChunkData.this);
-			});
-		}
-
-		private boolean checkConsistency() {
-			int index;
-
-			for (index = 0; index < size(); ++index) {
-				if (get(index) == null)
-					throw new AssertionError("get(index) is null");
-
-				if (references[index] != null) {
-					TileReference ref = getReference(index);
-					if (ref == null)
-						throw new AssertionError("references[index] is not null but getReference(index) is");
-					if (!ref.isValid())
-						throw new AssertionError("Reference is not valid");
-					if (ref.get() != get(index))
-						throw new AssertionError("Reference points to " + (ref.get() == null ? "null" : "wrong tile"));
-					if (ref.getIndex() != index)
-						throw new AssertionError("Reference has invalid index");
-					if (ref.getStack() != this)
-						throw new AssertionError("Reference has invalid TDS");
-				}
-
-				if (index != indicesByTag[tagsByIndex[index]])
-					throw new AssertionError("Tag mapping is inconsistent");
-				if (index != getIndexByTag(getTagByIndex(index)))
-					throw new AssertionError("Tag methods are inconsistent with tag mapping");
-			}
-
-			for (; index < tiles.length; ++index) {
-				if (tiles[index] != null)
-					throw new AssertionError("Leftover tile detected");
-				if (references[index] != null)
-					throw new AssertionError("Leftover reference detected");
-				if (tagsByIndex[index] != -1)
-					throw new AssertionError("Leftover tags detected");
-			}
-
-			return true;
-		}
-
-	}
+	// currently empty
 
 }

src/main/java/ru/windcorp/progressia/common/world/ChunkDataListener.java

@@ -20,7 +20,7 @@ package ru.windcorp.progressia.common.world;
 
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.world.block.BlockData;
-import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
 import ru.windcorp.progressia.common.world.tile.TileData;
 
 public interface ChunkDataListener {
@@ -36,7 +36,7 @@ public interface ChunkDataListener {
 	 * @param previous     the previous occupant of {@code blockInChunk}
 	 * @param current      the current (new) occupant of {@code blockInChunk}
 	 */
-	default void onChunkBlockChanged(ChunkData chunk, Vec3i blockInChunk, BlockData previous, BlockData current) {
+	default void onChunkBlockChanged(DefaultChunkData chunk, Vec3i blockInChunk, BlockData previous, BlockData current) {
 	}
 
 	/**
@@ -53,9 +53,9 @@ public interface ChunkDataListener {
 	 *                     {@code false} iff the tile has been removed
 	 */
 	default void onChunkTilesChanged(
-		ChunkData chunk,
+		DefaultChunkData chunk,
 		Vec3i blockInChunk,
-		BlockFace face,
+		RelFace face,
 		TileData tile,
 		boolean wasAdded
 	) {
@@ -70,7 +70,7 @@ public interface ChunkDataListener {
 	 * 
 	 * @param chunk the chunk that has changed
 	 */
-	default void onChunkChanged(ChunkData chunk) {
+	default void onChunkChanged(DefaultChunkData chunk) {
 	}
 
 	/**
@@ -78,7 +78,7 @@ public interface ChunkDataListener {
 	 * 
 	 * @param chunk the chunk that has loaded
 	 */
-	default void onChunkLoaded(ChunkData chunk) {
+	default void onChunkLoaded(DefaultChunkData chunk) {
 	}
 
 	/**
@@ -86,7 +86,7 @@ public interface ChunkDataListener {
 	 * 
 	 * @param chunk the chunk that is going to be loaded
 	 */
-	default void beforeChunkUnloaded(ChunkData chunk) {
+	default void beforeChunkUnloaded(DefaultChunkData chunk) {
 	}
 
 }

src/main/java/ru/windcorp/progressia/common/world/ChunkDataListeners.java

@@ -28,7 +28,7 @@ public class ChunkDataListeners {
 	public static WorldDataListener createAdder(Supplier<ChunkDataListener> listenerSupplier) {
 		return new WorldDataListener() {
 			@Override
-			public void getChunkListeners(WorldData world, Vec3i chunk, Consumer<ChunkDataListener> chunkListenerSink) {
+			public void getChunkListeners(DefaultWorldData world, Vec3i chunk, Consumer<ChunkDataListener> chunkListenerSink) {
 				chunkListenerSink.accept(listenerSupplier.get());
 			}
 		};

src/main/java/ru/windcorp/progressia/common/world/ChunkDataRO.java

@@ -0,0 +1,12 @@
+package ru.windcorp.progressia.common.world;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.generic.ChunkGenericRO;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface ChunkDataRO
+	extends ChunkGenericRO<BlockData, TileData, TileDataStackRO, TileDataReferenceRO, ChunkDataRO> {
+
+	// currently empty
+
+}

src/main/java/ru/windcorp/progressia/common/world/Coordinates.java

@@ -18,7 +18,7 @@
  
 package ru.windcorp.progressia.common.world;
 
-import static ru.windcorp.progressia.common.world.ChunkData.BLOCKS_PER_CHUNK;
+import static ru.windcorp.progressia.common.world.DefaultChunkData.BLOCKS_PER_CHUNK;
 
 import glm.vec._3.i.Vec3i;
 

src/main/java/ru/windcorp/progressia/common/world/DefaultChunkData.java

@@ -0,0 +1,529 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package ru.windcorp.progressia.common.world;
+
+import static ru.windcorp.progressia.common.world.rels.BlockFace.BLOCK_FACE_COUNT;
+
+import java.util.AbstractList;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Objects;
+
+import glm.vec._3.i.Vec3i;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.generic.GenericChunks;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
+import ru.windcorp.progressia.common.world.rels.BlockFace;
+import ru.windcorp.progressia.common.world.rels.RelFace;
+import ru.windcorp.progressia.common.world.tile.TileData;
+import ru.windcorp.progressia.common.world.tile.TileStackIsFullException;
+
+/**
+ * The implementation of {@link ChunkData} used to store the actual game world.
+ * This class should be considered an implementation detail.
+ */
+public class DefaultChunkData implements ChunkData {
+
+	public static final int BLOCKS_PER_CHUNK = Coordinates.CHUNK_SIZE;
+	public static final int CHUNK_RADIUS = BLOCKS_PER_CHUNK / 2;
+
+	private final Vec3i position = new Vec3i();
+	private final DefaultWorldData world;
+
+	private final BlockData[] blocks = new BlockData[BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK];
+
+	private final TileDataStack[] tiles = new TileDataStack[BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK
+		* BLOCK_FACE_COUNT];
+
+	private final AbsFace up;
+
+	private Object generationHint = null;
+
+	private final Collection<ChunkDataListener> listeners = Collections.synchronizedCollection(new ArrayList<>());
+
+	public DefaultChunkData(Vec3i position, DefaultWorldData world) {
+		this.position.set(position.x, position.y, position.z);
+		this.world = world;
+		this.up = world.getGravityModel().getDiscreteUp(position);
+	}
+
+	@Override
+	public Vec3i getPosition() {
+		return position;
+	}
+
+	@Override
+	public AbsFace getUp() {
+		return up;
+	}
+
+	@Override
+	public BlockData getBlock(Vec3i posInChunk) {
+		return blocks[getBlockIndex(posInChunk)];
+	}
+
+	@Override
+	public void setBlock(Vec3i posInChunk, BlockData block, boolean notify) {
+		BlockData previous = blocks[getBlockIndex(posInChunk)];
+		blocks[getBlockIndex(posInChunk)] = block;
+
+		if (notify) {
+			getListeners().forEach(l -> {
+				l.onChunkBlockChanged(this, posInChunk, previous, block);
+				l.onChunkChanged(this);
+			});
+		}
+	}
+
+	@Override
+	public TileDataStack getTilesOrNull(Vec3i blockInChunk, BlockFace face) {
+		return tiles[getTileIndex(blockInChunk, face)];
+	}
+
+	/**
+	 * Internal use only. Modify a list returned by
+	 * {@link #getTiles(Vec3i, BlockFace)} or
+	 * {@link #getTilesOrNull(Vec3i, BlockFace)}
+	 * to change tiles.
+	 */
+	protected void setTiles(
+		Vec3i blockInChunk,
+		BlockFace face,
+		TileDataStack tiles
+	) {
+		this.tiles[getTileIndex(blockInChunk, face)] = tiles;
+	}
+
+	@Override
+	public boolean hasTiles(Vec3i blockInChunk, BlockFace face) {
+		return getTilesOrNull(blockInChunk, face) != null;
+	}
+
+	@Override
+	public TileDataStack getTiles(Vec3i blockInChunk, BlockFace face) {
+		int index = getTileIndex(blockInChunk, face);
+
+		if (tiles[index] == null) {
+			createTileStack(blockInChunk, face);
+		}
+
+		return tiles[index];
+	}
+
+	private void createTileStack(Vec3i blockInChunk, BlockFace face) {
+		Vec3i independentBlockInChunk = conjureIndependentBlockInChunkVec3i(blockInChunk);
+		TileDataStackImpl stack = new TileDataStackImpl(independentBlockInChunk, face);
+		setTiles(blockInChunk, face, stack);
+	}
+
+	private Vec3i conjureIndependentBlockInChunkVec3i(Vec3i blockInChunk) {
+		for (int i = 0; i < AbsFace.BLOCK_FACE_COUNT; ++i) {
+			TileDataStack stack = getTilesOrNull(blockInChunk, AbsFace.getFaces().get(i));
+			if (stack instanceof TileDataStackImpl) {
+				return ((TileDataStackImpl) stack).blockInChunk;
+			}
+		}
+
+		return new Vec3i(blockInChunk);
+	}
+
+	private static int getBlockIndex(Vec3i posInChunk) {
+		checkLocalCoordinates(posInChunk);
+
+		return posInChunk.z * BLOCKS_PER_CHUNK * BLOCKS_PER_CHUNK +
+			posInChunk.y * BLOCKS_PER_CHUNK +
+			posInChunk.x;
+	}
+
+	private int getTileIndex(Vec3i posInChunk, BlockFace face) {
+		return getBlockIndex(posInChunk) * BLOCK_FACE_COUNT +
+			face.resolve(getUp()).getId();
+	}
+
+	private static void checkLocalCoordinates(Vec3i posInChunk) {
+		if (!GenericChunks.containsBiC(posInChunk)) {
+			throw new IllegalCoordinatesException(
+				"Coordinates (" + posInChunk.x + "; " + posInChunk.y + "; " + posInChunk.z + ") "
+					+ "are not legal chunk coordinates"
+			);
+		}
+	}
+
+	public DefaultWorldData getWorld() {
+		return world;
+	}
+
+	public Collection<ChunkDataListener> getListeners() {
+		return listeners;
+	}
+
+	public void addListener(ChunkDataListener listener) {
+		this.listeners.add(listener);
+	}
+
+	public void removeListener(ChunkDataListener listener) {
+		this.listeners.remove(listener);
+	}
+
+	protected void onLoaded() {
+		getListeners().forEach(l -> l.onChunkLoaded(this));
+	}
+
+	protected void beforeUnloaded() {
+		getListeners().forEach(l -> l.beforeChunkUnloaded(this));
+	}
+
+	public Object getGenerationHint() {
+		return generationHint;
+	}
+
+	public void setGenerationHint(Object generationHint) {
+		this.generationHint = generationHint;
+	}
+
+	/**
+	 * Implementation of {@link TileDataStack} used internally by
+	 * {@link DefaultChunkData} to
+	 * actually store the tiles. This is basically an array wrapper with
+	 * reporting
+	 * capabilities.
+	 * 
+	 * @author javapony
+	 */
+	private class TileDataStackImpl extends AbstractList<TileData> implements TileDataStack {
+		private class TileDataReferenceImpl implements TileDataReference {
+			private int index;
+
+			public TileDataReferenceImpl(int index) {
+				this.index = index;
+			}
+
+			public void incrementIndex() {
+				this.index++;
+			}
+
+			public void decrementIndex() {
+				this.index--;
+			}
+
+			public void invalidate() {
+				this.index = -1;
+			}
+
+			@Override
+			public TileData get() {
+				if (!isValid())
+					return null;
+				return TileDataStackImpl.this.get(this.index);
+			}
+
+			@Override
+			public int getIndex() {
+				return index;
+			}
+
+			@Override
+			public TileDataStack getStack() {
+				return TileDataStackImpl.this;
+			}
+
+			@Override
+			public boolean isValid() {
+				return this.index >= 0;
+			}
+		}
+
+		private final TileData[] tiles = new TileData[TILES_PER_FACE];
+		private int size = 0;
+
+		private final TileDataReferenceImpl[] references = new TileDataReferenceImpl[tiles.length];
+		private final int[] indicesByTag = new int[tiles.length];
+		private final int[] tagsByIndex = new int[tiles.length];
+
+		{
+			Arrays.fill(indicesByTag, -1);
+			Arrays.fill(tagsByIndex, -1);
+		}
+
+		/*
+		 * Potentially shared
+		 */
+		private final Vec3i blockInChunk;
+		private final RelFace face;
+
+		public TileDataStackImpl(Vec3i blockInChunk, BlockFace face) {
+			this.blockInChunk = blockInChunk;
+			this.face = face.relativize(getUp());
+		}
+
+		@Override
+		public Vec3i getBlockInChunk(Vec3i output) {
+			if (output == null)
+				output = new Vec3i();
+			output.set(blockInChunk.x, blockInChunk.y, blockInChunk.z);
+			return output;
+		}
+
+		@Override
+		public RelFace getFace() {
+			return face;
+		}
+
+		@Override
+		public DefaultChunkData getChunk() {
+			return DefaultChunkData.this;
+		}
+
+		@Override
+		public int size() {
+			return size;
+		}
+
+		@Override
+		public TileData get(int index) {
+			checkIndex(index, false);
+
+			return tiles[index];
+		}
+
+		@Override
+		public TileData set(int index, TileData tile) {
+			Objects.requireNonNull(tile, "tile");
+			TileData previous = get(index); // checks index
+
+			tiles[index] = tile;
+
+			if (references[index] != null) {
+				references[index].invalidate();
+				references[index] = null;
+			}
+
+			assert checkConsistency();
+
+			report(previous, tile);
+			return previous;
+		}
+
+		@Override
+		public void add(int index, TileData tile) {
+			Objects.requireNonNull(tile, "tile");
+			checkIndex(index, true);
+
+			if (index != size()) {
+				System.arraycopy(tiles, index + 1, tiles, index + 2, size - index);
+
+				for (int i = index; i < size; ++i) {
+					if (references[i] != null) {
+						references[i].incrementIndex();
+					}
+
+					indicesByTag[tagsByIndex[i]]++;
+				}
+
+				System.arraycopy(references, index + 1, references, index + 2, size - index);
+				System.arraycopy(tagsByIndex, index + 1, tagsByIndex, index + 2, size - index);
+			}
+
+			size++;
+			tiles[index] = tile;
+			references[index] = null;
+
+			for (int tag = 0; tag < indicesByTag.length; ++tag) {
+				if (indicesByTag[tag] == -1) {
+					indicesByTag[tag] = index;
+					tagsByIndex[index] = tag;
+					break;
+				}
+			}
+
+			modCount++;
+			assert checkConsistency();
+
+			report(null, tile);
+		}
+
+		@Override
+		public void load(TileData tile, int tag) {
+			addFarthest(tile);
+
+			int assignedIndex = size() - 1;
+
+			// Skip if we already have the correct tag
+			int assignedTag = getTagByIndex(assignedIndex);
+			if (assignedTag == tag) {
+				return;
+			}
+			assert assignedTag != -1 : "Adding farthest tile resulted in -1 tag";
+
+			// Make sure we aren't trying to assign a tag already in use
+			int tileWithRequestedTag = getIndexByTag(tag);
+			if (tileWithRequestedTag != -1) {
+				throw new IllegalArgumentException(
+					"Tag " + tag + " already used by tile at index " + tileWithRequestedTag
+				);
+			}
+			assert tileWithRequestedTag != assignedIndex
+				: "tag == assignedTag yet tileWithRequestedTag != assignedIndex";
+
+			// Do the tag editing
+			indicesByTag[assignedTag] = -1; // Release assigned tag
+			tagsByIndex[assignedIndex] = tag; // Reroute assigned index to
+												// requested tag
+			indicesByTag[tag] = assignedIndex; // Claim requested tag
+			assert checkConsistency();
+		}
+
+		@Override
+		public TileData remove(int index) {
+			TileData previous = get(index); // checks index
+
+			if (references[index] != null) {
+				references[index].invalidate();
+			}
+
+			indicesByTag[tagsByIndex[index]] = -1;
+
+			if (index != size() - 1) {
+				System.arraycopy(tiles, index + 1, tiles, index, size - index - 1);
+
+				for (int i = index + 1; i < size; ++i) {
+					if (references[i] != null) {
+						references[i].decrementIndex();
+					}
+
+					indicesByTag[tagsByIndex[i]]--;
+				}
+
+				System.arraycopy(references, index + 1, references, index, size - index - 1);
+				System.arraycopy(tagsByIndex, index + 1, tagsByIndex, index, size - index - 1);
+			}
+
+			size--;
+			tiles[size] = null;
+			references[size] = null;
+			tagsByIndex[size] = -1;
+
+			modCount++;
+			assert checkConsistency();
+
+			report(previous, null);
+			return previous;
+		}
+
+		@Override
+		public TileDataReference getReference(int index) {
+			checkIndex(index, false);
+
+			if (references[index] == null) {
+				references[index] = new TileDataReferenceImpl(index);
+			}
+
+			return references[index];
+		}
+
+		@Override
+		public int getIndexByTag(int tag) {
+			return indicesByTag[tag];
+		}
+
+		@Override
+		public int getTagByIndex(int index) {
+			checkIndex(index, false);
+			return tagsByIndex[index];
+		}
+
+		@Override
+		public void clear() {
+			while (!isEmpty()) {
+				removeFarthest();
+			}
+		}
+
+		private void checkIndex(int index, boolean isSizeAllowed) {
+			if (isSizeAllowed ? (index > size()) : (index >= size()))
+				throw new IndexOutOfBoundsException("Index " + index + " is out of bounds: size is " + size);
+
+			if (index < 0)
+				throw new IndexOutOfBoundsException("Index " + index + " is out of bounds: index cannot be negative");
+
+			if (index >= TILES_PER_FACE)
+				throw new TileStackIsFullException(
+					"Index " + index + " is out of bounds: maximum tile stack size is " + TILES_PER_FACE
+				);
+		}
+
+		private void report(TileData previous, TileData current) {
+			DefaultChunkData.this.getListeners().forEach(l -> {
+				if (previous != null) {
+					l.onChunkTilesChanged(DefaultChunkData.this, blockInChunk, face, previous, false);
+				}
+
+				if (current != null) {
+					l.onChunkTilesChanged(DefaultChunkData.this, blockInChunk, face, current, true);
+				}
+
+				l.onChunkChanged(DefaultChunkData.this);
+			});
+		}
+
+		private boolean checkConsistency() {
+			int index;
+
+			for (index = 0; index < size(); ++index) {
+				if (get(index) == null)
+					throw new AssertionError("get(index) is null");
+
+				if (references[index] != null) {
+					TileDataReference ref = getReference(index);
+					if (ref == null)
+						throw new AssertionError("references[index] is not null but getReference(index) is");
+					if (!ref.isValid())
+						throw new AssertionError("Reference is not valid");
+					if (ref.get() != get(index))
+						throw new AssertionError("Reference points to " + (ref.get() == null ? "null" : "wrong tile"));
+					if (ref.getIndex() != index)
+						throw new AssertionError("Reference has invalid index");
+					if (ref.getStack() != this)
+						throw new AssertionError("Reference has invalid TDS");
+				}
+
+				if (index != indicesByTag[tagsByIndex[index]])
+					throw new AssertionError("Tag mapping is inconsistent");
+				if (index != getIndexByTag(getTagByIndex(index)))
+					throw new AssertionError("Tag methods are inconsistent with tag mapping");
+			}
+
+			for (; index < tiles.length; ++index) {
+				if (tiles[index] != null)
+					throw new AssertionError("Leftover tile detected");
+				if (references[index] != null)
+					throw new AssertionError("Leftover reference detected");
+				if (tagsByIndex[index] != -1)
+					throw new AssertionError("Leftover tags detected");
+			}
+
+			return true;
+		}
+
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/DefaultWorldData.java

@@ -0,0 +1,262 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package ru.windcorp.progressia.common.world;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Objects;
+import java.util.function.Consumer;
+
+import glm.vec._3.i.Vec3i;
+import gnu.trove.TCollections;
+import gnu.trove.map.TLongObjectMap;
+import gnu.trove.map.hash.TLongObjectHashMap;
+import gnu.trove.set.TLongSet;
+import ru.windcorp.progressia.common.collision.CollisionModel;
+import ru.windcorp.progressia.common.state.StateChange;
+import ru.windcorp.progressia.common.state.StatefulObject;
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.generic.ChunkMap;
+import ru.windcorp.progressia.common.world.generic.ChunkSet;
+import ru.windcorp.progressia.common.world.generic.EntityGeneric;
+import ru.windcorp.progressia.common.world.rels.BlockFace;
+import ru.windcorp.progressia.common.world.generic.LongBasedChunkMap;
+
+public class DefaultWorldData implements WorldData {
+
+	private final ChunkMap<DefaultChunkData> chunksByPos = new LongBasedChunkMap<>(
+		TCollections.synchronizedMap(new TLongObjectHashMap<>())
+	);
+
+	private final Collection<DefaultChunkData> chunks = Collections.unmodifiableCollection(chunksByPos.values());
+
+	private final TLongObjectMap<EntityData> entitiesById = TCollections.synchronizedMap(new TLongObjectHashMap<>());
+
+	private final Collection<EntityData> entities = Collections.unmodifiableCollection(entitiesById.valueCollection());
+
+	private GravityModel gravityModel = null;
+
+	private float time = 0;
+
+	private final Collection<WorldDataListener> listeners = Collections.synchronizedCollection(new ArrayList<>());
+
+	public DefaultWorldData() {
+
+	}
+
+	@Override
+	public DefaultChunkData getChunk(Vec3i pos) {
+		return chunksByPos.get(pos);
+	}
+	
+	@Override
+	public DefaultChunkData getChunkByBlock(Vec3i blockInWorld) {
+		return (DefaultChunkData) WorldData.super.getChunkByBlock(blockInWorld);
+	}
+
+	@Override
+	public Collection<DefaultChunkData> getChunks() {
+		return chunks;
+	}
+
+	public ChunkSet getLoadedChunks() {
+		return chunksByPos.keys();
+	}
+
+	@Override
+	public Collection<EntityData> getEntities() {
+		return entities;
+	}
+
+	@Override
+	public void forEachEntity(Consumer<? super EntityData> action) {
+		synchronized (entitiesById) { // TODO HORRIBLY MUTILATE THE CORPSE OF
+										// TROVE4J so that
+										// gnu.trove.impl.sync.SynchronizedCollection.forEach
+										// is synchronized
+			getEntities().forEach(action);
+		}
+	}
+
+	public TLongSet getLoadedEntities() {
+		return entitiesById.keySet();
+	}
+
+	private void addChunkListeners(DefaultChunkData chunk) {
+		getListeners().forEach(l -> l.getChunkListeners(this, chunk.getPosition(), chunk::addListener));
+	}
+
+	public synchronized void addChunk(DefaultChunkData chunk) {
+		addChunkListeners(chunk);
+
+		DefaultChunkData previous = chunksByPos.get(chunk);
+		if (previous != null) {
+			throw new IllegalArgumentException(
+				String.format(
+					"Chunk at (%d; %d; %d) already exists",
+					chunk.getPosition().x,
+					chunk.getPosition().y,
+					chunk.getPosition().z
+				)
+			);
+		}
+
+		chunksByPos.put(chunk, chunk);
+
+		chunk.onLoaded();
+		getListeners().forEach(l -> l.onChunkLoaded(this, chunk));
+	}
+
+	public synchronized void removeChunk(DefaultChunkData chunk) {
+		getListeners().forEach(l -> l.beforeChunkUnloaded(this, chunk));
+		chunk.beforeUnloaded();
+
+		chunksByPos.remove(chunk);
+	}
+
+	@Override
+	public void setBlock(Vec3i blockInWorld, BlockData block, boolean notify) {
+		DefaultChunkData chunk = getChunkByBlock(blockInWorld);
+		if (chunk == null)
+			throw new IllegalCoordinatesException(
+				"Coordinates "
+					+ "(" + blockInWorld.x + "; " + blockInWorld.y + "; " + blockInWorld.z + ") "
+					+ "do not belong to a loaded chunk"
+			);
+
+		chunk.setBlock(Coordinates.convertInWorldToInChunk(blockInWorld, null), block, notify);
+	}
+
+	@Override
+	public TileDataStack getTiles(Vec3i blockInWorld, BlockFace face) {
+		return WorldData.super.getTiles(blockInWorld, face);
+	}
+
+	@Override
+	public EntityData getEntity(long entityId) {
+		return entitiesById.get(entityId);
+	}
+
+	@Override
+	public void addEntity(EntityData entity) {
+		Objects.requireNonNull(entity, "entity");
+
+		EntityData previous = entitiesById.putIfAbsent(entity.getEntityId(), entity);
+
+		if (previous != null) {
+			String message = "Cannot add entity " + entity + ": ";
+
+			if (previous == entity) {
+				message += "already present";
+			} else {
+				message += "entity with the same EntityID already present (" + previous + ")";
+			}
+
+			throw new IllegalStateException(message);
+		}
+
+		getListeners().forEach(l -> l.onEntityAdded(this, entity));
+	}
+
+	@Override
+	public void removeEntity(long entityId) {
+		synchronized (entitiesById) {
+			EntityData entity = entitiesById.get(entityId);
+
+			if (entity == null) {
+				throw new IllegalArgumentException(
+					"Entity with EntityID " + EntityData.formatEntityId(entityId) + " not present"
+				);
+			} else {
+				removeEntity(entity);
+			}
+		}
+	}
+
+	@Override
+	public void removeEntity(EntityData entity) {
+		Objects.requireNonNull(entity, "entity");
+
+		getListeners().forEach(l -> l.beforeEntityRemoved(this, entity));
+		entitiesById.remove(entity.getEntityId());
+	}
+
+	@Override
+	public <SE extends StatefulObject & EntityGeneric> void changeEntity(SE entity, StateChange<SE> change) {
+		change.change(entity);
+	}
+
+	@Override
+	public float getTime() {
+		return time;
+	}
+
+	@Override
+	public void advanceTime(float change) {
+		this.time += change;
+	}
+
+	public CollisionModel getCollisionModelOfBlock(Vec3i blockInWorld) {
+		DefaultChunkData chunk = getChunkByBlock(blockInWorld);
+		if (chunk == null)
+			return null;
+
+		BlockData block = chunk.getBlock(Coordinates.convertInWorldToInChunk(blockInWorld, null));
+		if (block == null)
+			return null;
+		return block.getCollisionModel();
+	}
+
+	/**
+	 * @return the gravity model
+	 */
+	@Override
+	public GravityModel getGravityModel() {
+		return gravityModel;
+	}
+
+	/**
+	 * @param gravityModel the gravity model to set
+	 */
+	public void setGravityModel(GravityModel gravityModel) {
+		if (!chunks.isEmpty()) {
+			throw new IllegalStateException(
+				"Attempted to change gravity model to " + gravityModel + " while " + chunks.size()
+					+ " chunks were loaded"
+			);
+		}
+
+		this.gravityModel = gravityModel;
+	}
+
+	public Collection<WorldDataListener> getListeners() {
+		return listeners;
+	}
+
+	public void addListener(WorldDataListener e) {
+		listeners.add(e);
+	}
+
+	public void removeListener(WorldDataListener o) {
+		listeners.remove(o);
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/GravityModel.java

@@ -0,0 +1,230 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.world;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.util.Objects;
+
+import glm.vec._3.Vec3;
+import glm.vec._3.i.Vec3i;
+import ru.windcorp.progressia.common.util.crash.CrashReports;
+import ru.windcorp.progressia.common.util.namespaces.Namespaced;
+import ru.windcorp.progressia.common.world.rels.AbsFace;
+
+/**
+ * Gravity model specifies the gravitational acceleration field, the up
+ * direction field and the discrete up direction field.
+ * <p>
+ * A gravity model may be queried for the vector of gravitational acceleration
+ * that should affect an object. This vector is, generally speaking, a function
+ * of space: gravity in two different locations may vary. Gravity may also be a
+ * zero vector.
+ * <p>
+ * The vector of gravitational acceleration defines the up direction. Up vector
+ * is defined as the additive inverse of the normalized gravitational
+ * acceleration vector or {@code (0; 0; 0)} if there is no gravity.
+ * <p>
+ * Separately from the gravitational acceleration and the up vectors, a
+ * <em>discrete up</em> vector field is specified by a gravity model. This field
+ * is defined for each chunk uniquely and may only take the value of one of the
+ * six {@linkplain AbsFace absolute directions}. This vector specifies the
+ * rotation of blocks, tiles and other objects that may not have a
+ * non-axis-aligned direction. Discrete up vector must be specified even for
+ * chunks that have a zero or an ambiguous up direction. Although discrete up
+ * direction is not technically linked to the up direction, is it expected by
+ * the players that they generally align.
+ * 
+ * @author javapony
+ */
+public abstract class GravityModel extends Namespaced {
+
+	public GravityModel(String id) {
+		super(id);
+	}
+
+	/**
+	 * Computes the vector of gravitational acceleration at the provided
+	 * location.
+	 * 
+	 * @param pos    the position to compute gravity at
+	 * @param output a {@link Vec3} where the result is stored. May be
+	 *               {@code null}.
+	 * @return the vector of gravitational acceleration. The returned object
+	 *         will match {@code output} parameter is it is non-null.
+	 */
+	public Vec3 getGravity(Vec3 pos, Vec3 output) {
+		Objects.requireNonNull(pos, "pos");
+
+		if (output == null) {
+			output = new Vec3();
+		}
+
+		try {
+			doGetGravity(pos, output);
+		} catch (Exception e) {
+			throw CrashReports.report(e, "%s failed to compute gravity at (%d; %d; %d)", this, pos.x, pos.y, pos.z);
+		}
+
+		return output;
+	}
+
+	/**
+	 * Computes the up direction at the provided location. Up vector is defined
+	 * as the additive inverse of the normalized gravitational acceleration
+	 * vector or {@code (0; 0; 0)} if there is no gravity.
+	 * 
+	 * @param pos    the position to compute up vector at
+	 * @param output a {@link Vec3} where the result is stored. May be
+	 *               {@code null}.
+	 * @return the up vector. The returned object will match {@code output}
+	 *         parameter is it is non-null.
+	 */
+	public Vec3 getUp(Vec3 pos, Vec3 output) {
+		output = getGravity(pos, output);
+
+		if (output.any()) {
+			output.normalize().negate();
+		}
+
+		return output;
+	}
+
+	/**
+	 * Computes the discrete up vector for the chunk at the specified
+	 * coordinates.
+	 * 
+	 * @param chunkPos the coordinates of chunk to compute discrete up at
+	 * @return an {@link AbsFace} that corresponds to the up direction in the
+	 *         specified chunk. Never {@code null}.
+	 */
+	public AbsFace getDiscreteUp(Vec3i chunkPos) {
+		Objects.requireNonNull(chunkPos, "chunkPos");
+
+		final AbsFace result;
+
+		try {
+			result = doGetDiscreteUp(chunkPos);
+		} catch (Exception e) {
+			throw CrashReports.report(
+				e,
+				"%s failed to compute discrete up at (%d; %d; %d)",
+				this,
+				chunkPos.x,
+				chunkPos.y,
+				chunkPos.z
+			);
+		}
+
+		if (result == null) {
+			throw CrashReports.report(
+				null,
+				"%s has computed null as the discrete up at (%d; %d; %d). This is forbidden.",
+				this,
+				chunkPos.x,
+				chunkPos.y,
+				chunkPos.z
+			);
+		}
+
+		return result;
+	}
+
+	/**
+	 * Computes the gravitational acceleration vector at the provided location.
+	 * Actual computation of gravity is delegated to this method by the other
+	 * methods in this class.
+	 * 
+	 * @param pos    the position to compute gravity at
+	 * @param output a {@link Vec3} where the result must be stored. Never
+	 *               {@code null}.
+	 */
+	protected abstract void doGetGravity(Vec3 pos, Vec3 output);
+
+	/**
+	 * Computes the discrete up vector for the chunk at the specified
+	 * coordinates. A direction must be assigned under any circumstances. Actual
+	 * computation of discrete up is delegated to this method by the other
+	 * methods in this class.
+	 * 
+	 * @param chunkPos the coordinates of chunk to compute discrete up at
+	 * @return an {@link AbsFace} that corresponds to the up direction in the
+	 *         specified chunk. Never {@code null}.
+	 */
+	protected abstract AbsFace doGetDiscreteUp(Vec3i chunkPos);
+	
+	/**
+	 * Parses the settings from the provided {@link DataInput} and configures this object appropriately. This method will not necessarily exhaust the input.
+	 * @param input a stream to read the settings from
+	 * @throws IOException if an I/O error occurs
+	 * @throws DecodingException if the settings could not be parsed from input
+	 */
+	public void readSettings(DataInput input) throws IOException, DecodingException {
+		Objects.requireNonNull(input, "input");
+		
+		try {
+			doReadSettings(input);
+		} catch (IOException | DecodingException e) {
+			throw e;
+		} catch (Exception e) {
+			throw CrashReports.report(
+				e,
+				"%s failed to read its settings",
+				this
+			);
+		}
+	}
+	
+	/**
+	 * Encodes the settings of this model into the provided {@link DataOutput}.
+	 * @param output a stream to write the settings into
+	 * @throws IOException if an I/O error occurs
+	 */
+	public void writeSettings(DataOutput output) throws IOException {
+		Objects.requireNonNull(output, "output");
+		
+		try {
+			doWriteSettings(output);
+		} catch (IOException e) {
+			throw e;
+		} catch (Exception e) {
+			throw CrashReports.report(
+				e,
+				"%s failed to write its settings",
+				this
+			);
+		}
+	}
+	
+	/**
+	 * Parses the settings from the provided {@link DataInput} and configures this object appropriately. This method will not necessarily exhaust the input.
+	 * @param input a stream to read the settings from
+	 * @throws IOException if an I/O error occurs
+	 * @throws DecodingException if the settings could not be parsed from input
+	 */
+	protected abstract void doReadSettings(DataInput input) throws IOException, DecodingException;
+	
+	/**
+	 * Encodes the settings of this model into the provided {@link DataOutput}.
+	 * @param output a stream to write the settings into
+	 * @throws IOException if an I/O error occurs
+	 */
+	protected abstract void doWriteSettings(DataOutput output) throws IOException;
+
+}

src/main/java/ru/windcorp/progressia/common/world/GravityModelRegistry.java

@@ -0,0 +1,30 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.world;
+
+import ru.windcorp.progressia.common.util.namespaces.NamespacedFactoryRegistry;
+
+public class GravityModelRegistry extends NamespacedFactoryRegistry<GravityModel> {
+	
+	public static final GravityModelRegistry INSTANCE = new GravityModelRegistry();
+	
+	public static GravityModelRegistry getInstance() {
+		return INSTANCE;
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/PacketAffectWorld.java

@@ -26,6 +26,6 @@ public abstract class PacketAffectWorld extends Packet {
 		super(id);
 	}
 
-	public abstract void apply(WorldData world);
+	public abstract void apply(DefaultWorldData world);
 
 }

src/main/java/ru/windcorp/progressia/common/world/PacketRevokeChunk.java

@@ -53,9 +53,9 @@ public class PacketRevokeChunk extends PacketAffectChunk {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		synchronized (world) {
-			ChunkData chunk = world.getChunk(position);
+			DefaultChunkData chunk = world.getChunk(position);
 			if (chunk != null) {
 				world.removeChunk(chunk);
 			}

src/main/java/ru/windcorp/progressia/common/world/PacketSendChunk.java

@@ -41,7 +41,7 @@ public class PacketSendChunk extends PacketAffectChunk {
 		super(id);
 	}
 
-	public void set(ChunkData chunk) {
+	public void set(DefaultChunkData chunk) {
 		this.position.set(chunk.getX(), chunk.getY(), chunk.getZ());
 
 		try {
@@ -67,7 +67,7 @@ public class PacketSendChunk extends PacketAffectChunk {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		try {
 			world.addChunk(ChunkIO.load(world, position, data.getReader(), IOContext.COMMS));
 		} catch (DecodingException | IOException e) {

src/main/java/ru/windcorp/progressia/common/world/PacketSetGravityModel.java

@@ -0,0 +1,76 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.world;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import ru.windcorp.progressia.common.util.DataBuffer;
+import ru.windcorp.progressia.common.util.crash.CrashReports;
+
+public class PacketSetGravityModel extends PacketAffectWorld {
+	
+	private String gravityModelId;
+	private final DataBuffer settings = new DataBuffer();
+	
+	public PacketSetGravityModel() {
+		this("Core:SetGravityModel");
+	}
+
+	protected PacketSetGravityModel(String id) {
+		super(id);
+	}
+	
+	public void set(GravityModel model) {
+		this.gravityModelId = model.getId();
+		
+		try {
+			model.writeSettings(settings.getWriter());
+		} catch (IOException e) {
+			throw CrashReports.report(e, "%s has errored when writing its settings", model);
+		}
+	}
+
+	@Override
+	public void read(DataInput input) throws IOException, DecodingException {
+		gravityModelId = input.readUTF();
+		settings.fill(input, input.readInt());
+	}
+
+	@Override
+	public void write(DataOutput output) throws IOException {
+		output.writeUTF(gravityModelId);
+		output.writeInt(settings.getSize());
+		settings.flush(output);
+	}
+
+	@Override
+	public void apply(DefaultWorldData world) {
+		GravityModel model = GravityModelRegistry.getInstance().create(gravityModelId);
+		world.setGravityModel(model);
+		try {
+			model.readSettings(settings.getReader());
+		} catch (IOException e) {
+			throw CrashReports.report(e, "%s has errored when reading its settings", model);
+		} catch (DecodingException e) {
+			throw CrashReports.report(e, "%s has failed to parse its settings", model);
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/TileDataReference.java

@@ -0,0 +1,10 @@
+package ru.windcorp.progressia.common.world;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.generic.TileGenericReferenceWO;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface TileDataReference extends TileDataReferenceRO,
+	TileGenericReferenceWO<BlockData, TileData, TileDataStack, TileDataReference, ChunkData> {
+
+}

src/main/java/ru/windcorp/progressia/common/world/TileDataReferenceRO.java

@@ -0,0 +1,12 @@
+package ru.windcorp.progressia.common.world;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.generic.TileGenericReferenceRO;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface TileDataReferenceRO
+	extends TileGenericReferenceRO<BlockData, TileData, TileDataStackRO, TileDataReferenceRO, ChunkDataRO> {
+
+	// currently empty
+	
+}

src/main/java/ru/windcorp/progressia/common/world/TileDataStack.java

@@ -0,0 +1,25 @@
+package ru.windcorp.progressia.common.world;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.generic.TileGenericStackWO;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface TileDataStack
+	extends TileDataStackRO, TileGenericStackWO<BlockData, TileData, TileDataStack, TileDataReference, ChunkData> {
+
+	@Override
+	default boolean isFull() {
+		return TileDataStackRO.super.isFull();
+	}
+	
+	/*
+	 * Method specialization
+	 */
+	
+	@Override
+	TileDataReference getReference(int index);
+	
+	@Override
+	ChunkData getChunk();
+
+}

src/main/java/ru/windcorp/progressia/common/world/TileDataStackRO.java

@@ -0,0 +1,12 @@
+package ru.windcorp.progressia.common.world;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.generic.TileGenericStackRO;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface TileDataStackRO
+	extends TileGenericStackRO<BlockData, TileData, TileDataStackRO, TileDataReferenceRO, ChunkDataRO> {
+	
+	// currently empty
+
+}

src/main/java/ru/windcorp/progressia/common/world/WorldData.java

@@ -1,216 +1,52 @@
-/*
- * Progressia
- * Copyright (C)  2020-2021  Wind Corporation and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
- 
 package ru.windcorp.progressia.common.world;
 
-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
-import java.util.Objects;
-import java.util.function.Consumer;
 
 import glm.vec._3.i.Vec3i;
-import gnu.trove.TCollections;
-import gnu.trove.map.TLongObjectMap;
-import gnu.trove.map.hash.TLongObjectHashMap;
-import gnu.trove.set.TLongSet;
-import ru.windcorp.progressia.common.collision.CollisionModel;
 import ru.windcorp.progressia.common.world.block.BlockData;
 import ru.windcorp.progressia.common.world.entity.EntityData;
-import ru.windcorp.progressia.common.world.generic.ChunkMap;
-import ru.windcorp.progressia.common.world.generic.ChunkSet;
-import ru.windcorp.progressia.common.world.generic.GenericWorld;
-import ru.windcorp.progressia.common.world.generic.LongBasedChunkMap;
+import ru.windcorp.progressia.common.world.generic.WorldGenericWO;
+import ru.windcorp.progressia.common.world.rels.BlockFace;
 import ru.windcorp.progressia.common.world.tile.TileData;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
 
-public class WorldData
-	implements GenericWorld<BlockData, TileData, TileDataStack, ChunkData, EntityData> {
+public interface WorldData
+	extends WorldDataRO, WorldGenericWO<BlockData, TileData, TileDataStack, TileDataReference, ChunkData, EntityData> {
 
-	private final ChunkMap<ChunkData> chunksByPos = new LongBasedChunkMap<>(
-		TCollections.synchronizedMap(new TLongObjectHashMap<>())
-	);
+	@Override
+	default TileDataStack getTiles(Vec3i blockInWorld, BlockFace face) {
+		return (TileDataStack) WorldDataRO.super.getTiles(blockInWorld, face);
+	}
 
-	private final Collection<ChunkData> chunks = Collections.unmodifiableCollection(chunksByPos.values());
+	/**
+	 * Increases in-game time of this world by {@code change}. Total time is
+	 * decreased when {@code change} is negative.
+	 * 
+	 * @param change the amount of time to add to current world time. May be
+	 *               negative.
+	 * @see #getTime()
+	 */
+	void advanceTime(float change);
 	
-	private final TLongObjectMap<EntityData> entitiesById = TCollections.synchronizedMap(new TLongObjectHashMap<>());
+	/*
+	 * Method specialization
+	 */
 	
-	private final Collection<EntityData> entities = Collections.unmodifiableCollection(entitiesById.valueCollection());
+	@Override
+	ChunkData getChunk(Vec3i pos);
 	
-	private float time = 0;
+	@Override
+	Collection<? extends ChunkData> getChunks();
 	
-	private final Collection<WorldDataListener> listeners = Collections.synchronizedCollection(new ArrayList<>());
-
-	public WorldData() {
+	// TODO: rename WGRO.forEachChunk -> forEachChunkRO and define WGWO.forEachChunk
 	
+	@Override
+	default ChunkData getChunkByBlock(Vec3i blockInWorld) {
+		return (ChunkData) WorldDataRO.super.getChunkByBlock(blockInWorld);
 	}
 	
 	@Override
-	public ChunkData getChunk(Vec3i pos) {
-		return chunksByPos.get(pos);
-	}
-
-	@Override
-	public Collection<ChunkData> getChunks() {
-		return chunks;
-	}
-
-	public ChunkSet getLoadedChunks() {
-		return chunksByPos.keys();
-	}
-
-	@Override
-	public Collection<EntityData> getEntities() {
-		return entities;
-	}
-
-	@Override
-	public void forEachEntity(Consumer<? super EntityData> action) {
-		synchronized (entitiesById) { // TODO HORRIBLY MUTILATE THE CORPSE OF
-										// TROVE4J so that
-										// gnu.trove.impl.sync.SynchronizedCollection.forEach
-										// is synchronized
-			getEntities().forEach(action);
-		}
-	}
-
-	public TLongSet getLoadedEntities() {
-		return entitiesById.keySet();
-	}
-
-	private void addChunkListeners(ChunkData chunk) {
-		getListeners().forEach(l -> l.getChunkListeners(this, chunk.getPosition(), chunk::addListener));
-	}
-
-	public synchronized void addChunk(ChunkData chunk) {
-		addChunkListeners(chunk);
-
-		ChunkData previous = chunksByPos.get(chunk);
-		if (previous != null) {
-			throw new IllegalArgumentException(
-				String.format(
-					"Chunk at (%d; %d; %d) already exists",
-					chunk.getPosition().x,
-					chunk.getPosition().y,
-					chunk.getPosition().z
-				)
-			);
-		}
-
-		chunksByPos.put(chunk, chunk);
-
-		chunk.onLoaded();
-		getListeners().forEach(l -> l.onChunkLoaded(this, chunk));
-	}
-
-	public synchronized void removeChunk(ChunkData chunk) {
-		getListeners().forEach(l -> l.beforeChunkUnloaded(this, chunk));
-		chunk.beforeUnloaded();
-
-		chunksByPos.remove(chunk);
-	}
-
-	public void setBlock(Vec3i blockInWorld, BlockData block, boolean notify) {
-		ChunkData chunk = getChunkByBlock(blockInWorld);
-		if (chunk == null)
-			throw new IllegalCoordinatesException(
-				"Coordinates "
-					+ "(" + blockInWorld.x + "; " + blockInWorld.y + "; " + blockInWorld.z + ") "
-					+ "do not belong to a loaded chunk"
-			);
-
-		chunk.setBlock(Coordinates.convertInWorldToInChunk(blockInWorld, null), block, notify);
-	}
-
-	public EntityData getEntity(long entityId) {
-		return entitiesById.get(entityId);
-	}
-
-	public void addEntity(EntityData entity) {
-		Objects.requireNonNull(entity, "entity");
-
-		EntityData previous = entitiesById.putIfAbsent(entity.getEntityId(), entity);
-
-		if (previous != null) {
-			String message = "Cannot add entity " + entity + ": ";
-
-			if (previous == entity) {
-				message += "already present";
-			} else {
-				message += "entity with the same EntityID already present (" + previous + ")";
-			}
-
-			throw new IllegalStateException(message);
-		}
-
-		getListeners().forEach(l -> l.onEntityAdded(this, entity));
-	}
-
-	public void removeEntity(long entityId) {
-		synchronized (entitiesById) {
-			EntityData entity = entitiesById.get(entityId);
-
-			if (entity == null) {
-				throw new IllegalArgumentException(
-					"Entity with EntityID " + EntityData.formatEntityId(entityId) + " not present"
-				);
-			} else {
-				removeEntity(entity);
-			}
-		}
-	}
-
-	public void removeEntity(EntityData entity) {
-		Objects.requireNonNull(entity, "entity");
-
-		getListeners().forEach(l -> l.beforeEntityRemoved(this, entity));
-		entitiesById.remove(entity.getEntityId());
-	}
-
-	public float getTime() {
-		return time;
-	}
-
-	public void advanceTime(float change) {
-		this.time += change;
-	}
-
-	public CollisionModel getCollisionModelOfBlock(Vec3i blockInWorld) {
-		ChunkData chunk = getChunkByBlock(blockInWorld);
-		if (chunk == null)
-			return null;
-
-		BlockData block = chunk.getBlock(Coordinates.convertInWorldToInChunk(blockInWorld, null));
-		if (block == null)
-			return null;
-		return block.getCollisionModel();
-	}
-
-	public Collection<WorldDataListener> getListeners() {
-		return listeners;
-	}
-
-	public void addListener(WorldDataListener e) {
-		listeners.add(e);
-	}
-
-	public void removeListener(WorldDataListener o) {
-		listeners.remove(o);
+	default TileDataStack getTilesOrNull(Vec3i blockInWorld, BlockFace face) {
+		return (TileDataStack) WorldDataRO.super.getTilesOrNull(blockInWorld, face);
 	}
 
 }

src/main/java/ru/windcorp/progressia/common/world/WorldDataListener.java

@@ -26,11 +26,11 @@ import ru.windcorp.progressia.common.world.entity.EntityData;
 public interface WorldDataListener {
 
 	/**
-	 * Invoked when a new {@link ChunkData} instance is created. This method
+	 * Invoked when a new {@link DefaultChunkData} instance is created. This method
 	 * should be used to add
 	 * {@link ChunkDataListener}s to a new chunk. When listeners are added with
 	 * this method,
-	 * their {@link ChunkDataListener#onChunkLoaded(ChunkData) onChunkLoaded}
+	 * their {@link ChunkDataListener#onChunkLoaded(DefaultChunkData) onChunkLoaded}
 	 * methods will be invoked.
 	 * 
 	 * @param world             the world instance
@@ -41,7 +41,7 @@ public interface WorldDataListener {
 	 *                          {@link Consumer#accept(Object) accept} method
 	 *                          will be added to the chunk.
 	 */
-	default void getChunkListeners(WorldData world, Vec3i chunk, Consumer<ChunkDataListener> chunkListenerSink) {
+	default void getChunkListeners(DefaultWorldData world, Vec3i chunk, Consumer<ChunkDataListener> chunkListenerSink) {
 	}
 
 	/**
@@ -50,7 +50,7 @@ public interface WorldDataListener {
 	 * @param world the world instance
 	 * @param chunk the chunk that has loaded
 	 */
-	default void onChunkLoaded(WorldData world, ChunkData chunk) {
+	default void onChunkLoaded(DefaultWorldData world, DefaultChunkData chunk) {
 	}
 
 	/**
@@ -59,7 +59,7 @@ public interface WorldDataListener {
 	 * @param world the world instance
 	 * @param chunk the chunk that is going to be unloaded
 	 */
-	default void beforeChunkUnloaded(WorldData world, ChunkData chunk) {
+	default void beforeChunkUnloaded(DefaultWorldData world, DefaultChunkData chunk) {
 	}
 
 	/**
@@ -68,7 +68,7 @@ public interface WorldDataListener {
 	 * @param world  the world instance
 	 * @param entity the entity that has been added
 	 */
-	default void onEntityAdded(WorldData world, EntityData entity) {
+	default void onEntityAdded(DefaultWorldData world, EntityData entity) {
 	}
 
 	/**
@@ -77,7 +77,7 @@ public interface WorldDataListener {
 	 * @param world  the world instance
 	 * @param entity the entity that is going to be removed
 	 */
-	default void beforeEntityRemoved(WorldData world, EntityData entity) {
+	default void beforeEntityRemoved(DefaultWorldData world, EntityData entity) {
 	}
 
 }

src/main/java/ru/windcorp/progressia/common/world/WorldDataRO.java

@@ -0,0 +1,29 @@
+package ru.windcorp.progressia.common.world;
+
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.generic.WorldGenericRO;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface WorldDataRO
+	extends WorldGenericRO<BlockData, TileData, TileDataStackRO, TileDataReferenceRO, ChunkDataRO, EntityData> {
+
+	/**
+	 * Returns in-world time since creation. World time is zero before and
+	 * during first tick.
+	 * <p>
+	 * Game logic should assume that this value mostly increases uniformly.
+	 * However, it is not guaranteed that in-world time always increments.
+	 * 
+	 * @return time, in in-game seconds, since the world was created
+	 */
+	float getTime();
+
+	/**
+	 * Gets the {@link GravityModel} used by this world.
+	 * 
+	 * @return the gravity model
+	 */
+	GravityModel getGravityModel();
+
+}

src/main/java/ru/windcorp/progressia/common/world/block/BlockData.java

@@ -21,9 +21,9 @@ package ru.windcorp.progressia.common.world.block;
 import ru.windcorp.progressia.common.collision.AABB;
 import ru.windcorp.progressia.common.collision.CollisionModel;
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+import ru.windcorp.progressia.common.world.generic.BlockGeneric;
 
-public class BlockData extends Namespaced implements GenericBlock {
+public class BlockData extends Namespaced implements BlockGeneric {
 
 	public BlockData(String id) {
 		super(id);

src/main/java/ru/windcorp/progressia/common/world/block/BlockFace.java

@@ -1,177 +0,0 @@
-/*
- * Progressia
- * Copyright (C)  2020-2021  Wind Corporation and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
- 
-package ru.windcorp.progressia.common.world.block;
-
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMap;
-
-import glm.vec._3.i.Vec3i;
-
-public final class BlockFace extends BlockRelation {
-
-	public static final BlockFace TOP = new BlockFace(0, 0, +1, true, "TOP"),
-		BOTTOM = new BlockFace(0, 0, -1, false, "BOTTOM"),
-		NORTH = new BlockFace(+1, 0, 0, true, "NORTH"),
-		SOUTH = new BlockFace(-1, 0, 0, false, "SOUTH"),
-		WEST = new BlockFace(0, +1, 0, false, "WEST"),
-		EAST = new BlockFace(0, -1, 0, true, "EAST");
-
-	private static final ImmutableList<BlockFace> ALL_FACES = ImmutableList.of(TOP, BOTTOM, NORTH, SOUTH, WEST, EAST);
-
-	static {
-		link(TOP, BOTTOM);
-		link(NORTH, SOUTH);
-		link(WEST, EAST);
-	}
-
-	private static final ImmutableList<BlockFace> PRIMARY_FACES = ALL_FACES.stream().filter(BlockFace::isPrimary)
-		.collect(ImmutableList.toImmutableList());
-
-	private static final ImmutableList<BlockFace> SECONDARY_FACES = ALL_FACES.stream().filter(BlockFace::isSecondary)
-		.collect(ImmutableList.toImmutableList());
-
-	public static final int BLOCK_FACE_COUNT = ALL_FACES.size();
-	public static final int PRIMARY_BLOCK_FACE_COUNT = PRIMARY_FACES.size();
-	public static final int SECONDARY_BLOCK_FACE_COUNT = SECONDARY_FACES.size();
-
-	public static ImmutableList<BlockFace> getFaces() {
-		return ALL_FACES;
-	}
-
-	public static ImmutableList<BlockFace> getPrimaryFaces() {
-		return PRIMARY_FACES;
-	}
-
-	public static ImmutableList<BlockFace> getSecondaryFaces() {
-		return SECONDARY_FACES;
-	}
-
-	private static void link(BlockFace a, BlockFace b) {
-		a.counterFace = b;
-		b.counterFace = a;
-	}
-
-	public static <E> ImmutableMap<BlockFace, E> mapToFaces(
-		E top,
-		E bottom,
-		E north,
-		E south,
-		E east,
-		E west
-	) {
-		return ImmutableMap.<BlockFace, E>builderWithExpectedSize(6)
-			.put(TOP, top)
-			.put(BOTTOM, bottom)
-			.put(NORTH, north)
-			.put(SOUTH, south)
-			.put(EAST, east)
-			.put(WEST, west)
-			.build();
-	}
-
-	private static int nextId = 0;
-
-	private final int id;
-	private final String name;
-	private BlockFace counterFace;
-	private final boolean isPrimary;
-
-	private BlockFace(int x, int y, int z, boolean isPrimary, String name) {
-		super(x, y, z);
-		this.id = nextId++;
-		this.isPrimary = isPrimary;
-		this.name = name;
-	}
-
-	public String getName() {
-		return name;
-	}
-
-	public boolean isPrimary() {
-		return isPrimary;
-	}
-
-	public BlockFace getPrimary() {
-		if (isPrimary)
-			return this;
-		else
-			return counterFace;
-	}
-
-	public BlockFace getPrimaryAndMoveCursor(Vec3i cursor) {
-		if (isPrimary)
-			return this;
-
-		cursor.add(getVector());
-		return counterFace;
-	}
-
-	public boolean isSecondary() {
-		return !isPrimary;
-	}
-
-	public BlockFace getSecondary() {
-		if (isPrimary)
-			return counterFace;
-		else
-			return this;
-	}
-
-	public BlockFace getSecondaryAndMoveCursor(Vec3i cursor) {
-		if (!isPrimary)
-			return this;
-
-		cursor.add(getVector());
-		return counterFace;
-	}
-
-	public BlockFace getCounter() {
-		return counterFace;
-	}
-
-	public BlockFace getCounterAndMoveCursor(Vec3i cursor) {
-		cursor.add(getVector());
-		return counterFace;
-	}
-
-	public int getId() {
-		return id;
-	}
-
-	@Override
-	public float getEuclideanDistance() {
-		return 1.0f;
-	}
-
-	@Override
-	public int getChebyshevDistance() {
-		return 1;
-	}
-
-	@Override
-	public int getManhattanDistance() {
-		return 1;
-	}
-
-	@Override
-	public String toString() {
-		return getName();
-	}
-
-}

src/main/java/ru/windcorp/progressia/common/world/block/PacketSetBlock.java

@@ -24,7 +24,7 @@ import java.io.IOException;
 
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class PacketSetBlock extends PacketAffectBlock {
 
@@ -60,7 +60,7 @@ public class PacketSetBlock extends PacketAffectBlock {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		BlockData block = BlockDataRegistry.getInstance().get(getBlockId());
 		world.setBlock(getBlockInWorld(), block, true);
 	}

src/main/java/ru/windcorp/progressia/common/world/context/BlockDataContext.java

@@ -0,0 +1,62 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.world.context;
+
+import glm.vec._3.i.Vec3i;
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.generic.context.BlockGenericContextWO;
+import ru.windcorp.progressia.common.world.rels.RelFace;
+import ru.windcorp.progressia.common.world.rels.RelRelation;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface BlockDataContext
+	extends BlockGenericContextWO<BlockData, TileData, EntityData>,
+	WorldDataContext,
+	BlockDataContextRO {
+
+	/*
+	 * Subcontexting
+	 */
+	
+	@Override
+	default BlockDataContext pushRelative(int dx, int dy, int dz) {
+		return push(getLocation().add_(dx, dy, dz));
+	}
+	
+	@Override
+	default BlockDataContext pushRelative(Vec3i direction) {
+		return push(getLocation().add_(direction));
+	}
+	
+	@Override
+	default BlockDataContext pushRelative(RelRelation direction) {
+		return push(getLocation().add_(direction.getRelVector()));
+	}
+	
+	@Override
+	default TileStackDataContext push(RelFace face) {
+		return push(getLocation(), face);
+	}
+	
+	@Override
+	default TileDataContext push(RelFace face, int layer) {
+		return push(getLocation(), face, layer);
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/context/BlockDataContextRO.java

@@ -0,0 +1,61 @@
+/*
+ * Progressia
+ * Copyright (C)  2020-2021  Wind Corporation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package ru.windcorp.progressia.common.world.context;
+
+import glm.vec._3.i.Vec3i;
+import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.generic.context.BlockGenericContextRO;
+import ru.windcorp.progressia.common.world.rels.RelFace;
+import ru.windcorp.progressia.common.world.rels.RelRelation;
+import ru.windcorp.progressia.common.world.tile.TileData;
+
+public interface BlockDataContextRO
+	extends BlockGenericContextRO<BlockData, TileData, EntityData>,
+	WorldDataContextRO {
+
+	/*
+	 * Subcontexting
+	 */
+	
+	@Override
+	default BlockDataContextRO pushRelative(int dx, int dy, int dz) {
+		return push(getLocation().add_(dx, dy, dz));
+	}
+	
+	@Override
+	default BlockDataContextRO pushRelative(Vec3i direction) {
+		return push(getLocation().add_(direction));
+	}
+	
+	@Override
+	default BlockDataContextRO pushRelative(RelRelation direction) {
+		return push(getLocation().add_(direction.getRelVector()));
+	}
+	
+	@Override
+	default TileStackDataContextRO push(RelFace face) {
+		return push(getLocation(), face);
+	}
+	
+	@Override
+	default TileDataContextRO push(RelFace face, int layer) {
+		return push(getLocation(), face, layer);
+	}
+
+}