Merge remote-tracking branch 'github/master' into audio

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

@@ -27,6 +27,7 @@ import ru.windcorp.progressia.client.graphics.texture.Atlases;
 import ru.windcorp.progressia.client.graphics.world.WorldRenderProgram;
 import ru.windcorp.progressia.common.resource.ResourceManager;
 import ru.windcorp.progressia.server.ServerState;
+import ru.windcorp.progressia.test.TestContent;
 
 public class ClientProxy implements Proxy {
 

src/main/java/ru/windcorp/progressia/client/comms/DefaultClientCommsListener.java

@@ -1,9 +1,6 @@
 package ru.windcorp.progressia.client.comms;
 
 import java.io.IOException;
-import java.util.Collection;
-import java.util.UUID;
-
 import ru.windcorp.progressia.client.Client;
 import ru.windcorp.progressia.client.graphics.world.EntityAnchor;
 import ru.windcorp.progressia.client.world.ChunkRender;
@@ -11,9 +8,10 @@ import ru.windcorp.progressia.common.comms.CommsListener;
 import ru.windcorp.progressia.common.comms.packets.Packet;
 import ru.windcorp.progressia.common.comms.packets.PacketSetLocalPlayer;
 import ru.windcorp.progressia.common.comms.packets.PacketWorldChange;
-import ru.windcorp.progressia.common.world.ChunkData;
 import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.entity.PacketEntityChange;
 
+// TODO refactor with no mercy
 public class DefaultClientCommsListener implements CommsListener {
 	
 	private final Client client;
@@ -29,31 +27,18 @@ public class DefaultClientCommsListener implements CommsListener {
 					getClient().getWorld().getData()
 			);
 			
+			if (!(packet instanceof PacketEntityChange)) {
 				tmp_reassembleWorld();
+			}
 		} else if (packet instanceof PacketSetLocalPlayer) {
 			setLocalPlayer((PacketSetLocalPlayer) packet);
 		}
 	}
 
 	private void setLocalPlayer(PacketSetLocalPlayer packet) {
-		UUID uuid = packet.getLocalPlayerEntityUUID();
-		
-		Collection<ChunkData> chunks =
-				getClient().getWorld().getData().getChunks();
-		
-		EntityData entity = null;
-		
-		synchronized (chunks) {
-			chunkLoop:
-			for (ChunkData chunk : chunks) {
-				for (EntityData anEntity : chunk.getEntities()) {
-					if (anEntity.getUUID().equals(uuid)) {
-						entity = anEntity;
-						break chunkLoop;
-					}
-				}
-			}
-		}
+		EntityData entity = getClient().getWorld().getData().getEntity(
+				packet.getLocalPlayerEntityId()
+		);
 		
 		if (entity == null) {
 			throw new RuntimeException("");

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

@@ -18,6 +18,7 @@
 package ru.windcorp.progressia.client.graphics.world;
 
 import static java.lang.Math.*;
+import static ru.windcorp.progressia.common.util.FloatMathUtils.*;
 
 import java.util.Collection;
 import java.util.function.Consumer;
@@ -76,12 +77,33 @@ public class Camera {
 	
 	private float fieldOfView;
 	
+	/*
+	 * Cache
+	 */
+	
+	private final Vec3 lastAnchorPosition = new Vec3();
+	private float lastAnchorYaw;
+	private float lastAnchorPitch;
+	
+	private final Mat4 lastCameraMatrix = new Mat4();
+	
+	private final Vec3 lastAnchorLookingAt = new Vec3();
+	private final Vec3 lastAnchorUp = new Vec3();
+	
+	{
+		invalidateCache();
+	}
+	
 	public Camera(float fieldOfView) {
 		setFieldOfView(fieldOfView);
 	}
 	
 	public Camera() {}
 	
+	/*
+	 * apply() and subroutines
+	 */
+
 	public void apply(WorldRenderHelper helper) {
 		SoundManager.update();
 		applyPerspective(helper);
@@ -90,6 +112,8 @@ public class Camera {
 		applyMode(helper);
 		applyDirection(helper);
 		applyPosition(helper);
+		
+		cacheCameraTransform(helper);
 	}
 
 	private void applyPerspective(WorldRenderHelper helper) {
@@ -124,22 +148,48 @@ public class Camera {
 	}
 	
 	private void applyDirection(WorldRenderHelper helper) {
+		float pitch = anchor.getCameraPitch();
+		float yaw = anchor.getCameraYaw();
+		
 		helper.pushViewTransform()
-		.rotateY(-anchor.getCameraPitch())
-		.rotateZ(-anchor.getCameraYaw());
+			.rotateY(-pitch)
+			.rotateZ(-yaw);
+		
+		this.lastAnchorYaw = yaw;
+		this.lastAnchorPitch = pitch;
+		
+		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)
+		);
 	}
 
 	private void applyPosition(WorldRenderHelper helper) {
 		Vec3 v = Vectors.grab3();
 		
 		anchor.getCameraPosition(v);
-		v.negate();
+		this.lastAnchorPosition.set(v);
 		
+		v.negate();
 		helper.pushViewTransform().translate(v);
 		
 		Vectors.release(v);
 	}
 
+	private void cacheCameraTransform(WorldRenderHelper helper) {
+		this.lastCameraMatrix.set(helper.getViewTransform());
+	}
+	
+	/*
+	 * FOV management
+	 */
+
 	private float computeFovY() {
 		float widthOverHeight = GraphicsInterface.getAspectRatio();
 		
@@ -162,6 +212,10 @@ public class Camera {
 		this.fieldOfView = fieldOfView;
 	}
 	
+	/*
+	 * Anchor management
+	 */
+	
 	public Anchor getAnchor() {
 		return anchor;
 	}
@@ -174,6 +228,7 @@ public class Camera {
 		if (anchor == null) {
 			this.anchor = null;
 			this.modes = null;
+			invalidateCache();
 			return;
 		}
 		
@@ -192,6 +247,22 @@ public class Camera {
 		this.currentModeIndex = 0;
 	}
 	
+	private void invalidateCache() {
+		this.lastAnchorPosition.set(Float.NaN);
+		this.lastAnchorYaw = Float.NaN;
+		this.lastAnchorPitch = Float.NaN;
+		
+		this.lastCameraMatrix.set(
+				Float.NaN, Float.NaN, Float.NaN, Float.NaN,
+				Float.NaN, Float.NaN, Float.NaN, Float.NaN,
+				Float.NaN, Float.NaN, Float.NaN, Float.NaN,
+				Float.NaN, Float.NaN, Float.NaN, Float.NaN
+		);
+		
+		this.lastAnchorLookingAt.set(Float.NaN);
+		this.lastAnchorUp.set(Float.NaN);
+	}
+
 	public Anchor.Mode getMode() {
 		return modes[currentModeIndex];
 	}
@@ -204,4 +275,28 @@ public class Camera {
 		}
 	}
 
+	public float getLastAnchorYaw() {
+		return lastAnchorYaw;
+	}
+
+	public float getLastAnchorPitch() {
+		return lastAnchorPitch;
+	}
+
+	public Vec3 getLastAnchorPosition() {
+		return lastAnchorPosition;
+	}
+
+	public Mat4 getLastCameraMatrix() {
+		return lastCameraMatrix;
+	}
+
+	public Vec3 getLastAnchorLookingAt() {
+		return lastAnchorLookingAt;
+	}
+
+	public Vec3 getLastAnchorUp() {
+		return lastAnchorUp;
+	}
+
 }

src/main/java/ru/windcorp/progressia/common/comms/packets/PacketSetLocalPlayer.java

@@ -1,18 +1,20 @@
 package ru.windcorp.progressia.common.comms.packets;
 
-import java.util.UUID;
-
 public class PacketSetLocalPlayer extends Packet {
 	
-	private final UUID localPlayerEntityUUID;
+	private long localPlayerEntityId;
 
-	public PacketSetLocalPlayer(UUID uuid) {
+	public PacketSetLocalPlayer(long entityId) {
 		super("Core", "SetLocalPlayer");
-		this.localPlayerEntityUUID = uuid;
+		this.localPlayerEntityId = entityId;
 	}
 	
-	public UUID getLocalPlayerEntityUUID() {
-		return localPlayerEntityUUID;
+	public long getLocalPlayerEntityId() {
+		return localPlayerEntityId;
+	}
+	
+	public void setLocalPlayerEntityId(long localPlayerEntityId) {
+		this.localPlayerEntityId = localPlayerEntityId;
 	}
 
 }

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

@@ -0,0 +1,83 @@
+package ru.windcorp.progressia.common.state;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+public abstract class AbstractStatefulObjectLayout
+extends StatefulObjectLayout {
+
+	public AbstractStatefulObjectLayout(String objectId) {
+		super(objectId);
+	}
+	
+	protected abstract int getFieldCount();
+	protected abstract StateField getField(int fieldIndex);
+
+	@Override
+	public void read(
+			StatefulObject object,
+			DataInput input,
+			IOContext context
+	) throws IOException {
+		
+		int fieldCount = getFieldCount();
+		for (int i = 0; i < fieldCount; ++i) {
+			
+			StateField field = getField(i);
+			if (context == IOContext.COMMS && field.isLocal()) continue;
+			field.read(object, input, context);
+			
+		}
+	}
+
+	@Override
+	public void write(
+			StatefulObject object,
+			DataOutput output,
+			IOContext context
+	) throws IOException {
+		
+		int fieldCount = getFieldCount();
+		for (int i = 0; i < fieldCount; ++i) {
+			
+			StateField field = getField(i);
+			if (context == IOContext.COMMS && field.isLocal()) continue;
+			field.write(object, output, context);
+			
+		}
+	}
+
+	@Override
+	public void copy(StatefulObject from, StatefulObject to) {
+		int fieldCount = getFieldCount();
+		for (int i = 0; i < fieldCount; ++i) {
+			getField(i).copy(from, to);
+		}
+	}
+
+	@Override
+	public int computeHashCode(StatefulObject object) {
+		int result = 1;
+		
+		int fieldCount = getFieldCount();
+		for (int i = 0; i < fieldCount; ++i) {
+			
+			result = 31 * result + getField(i).computeHashCode(object);
+			
+		}
+		
+		return result;
+	}
+
+	@Override
+	public boolean areEqual(StatefulObject a, StatefulObject b) {
+		int fieldCount = getFieldCount();
+		for (int i = 0; i < fieldCount; ++i) {
+			if (!getField(i).areEqual(a, b)) return false;
+		}
+		
+		return true;
+	}
+
+}

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

@@ -0,0 +1,20 @@
+package ru.windcorp.progressia.common.state;
+
+import gnu.trove.map.TIntIntMap;
+import gnu.trove.map.hash.TIntIntHashMap;
+
+public class HashMapStateStorage extends StateStorage {
+	
+	private final TIntIntMap ints = new TIntIntHashMap();
+
+	@Override
+	public int getInt(int index) {
+		return ints.get(index);
+	}
+
+	@Override
+	public void setInt(int index, int value) {
+		ints.put(index, value);
+	}
+
+}

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

@@ -0,0 +1,9 @@
+package ru.windcorp.progressia.common.state;
+
+public enum IOContext {
+	
+	COMMS,
+	SAVE,
+	INTERNAL;
+
+}

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

@@ -0,0 +1,103 @@
+package ru.windcorp.progressia.common.state;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class InspectingStatefulObjectLayout
+extends AbstractStatefulObjectLayout {
+
+	private final List<StateField> fields = new ArrayList<>();
+	
+	private final PrimitiveCounters fieldIndexCounters =
+			new PrimitiveCounters();
+	
+	public InspectingStatefulObjectLayout(String objectId) {
+		super(objectId);
+	}
+
+	@Override
+	public StateStorage createStorage() {
+		return new HashMapStateStorage();
+	}
+
+	@Override
+	protected int getFieldCount() {
+		return fields.size();
+	}
+
+	@Override
+	protected StateField getField(int fieldIndex) {
+		return fields.get(fieldIndex);
+	}
+	
+	public StatefulObjectLayout compile() {
+		return new OptimizedStatefulObjectLayout(
+				getObjectId(),
+				fields, fieldIndexCounters
+		);
+	}
+
+	private <T extends StateField> T registerField(T field) {
+		fields.add(field);
+		return field;
+	}
+	
+	@Override
+	public StateFieldBuilder getBuilder(String namespace, String name) {
+		return new InspectingStateFieldBuilder(
+				namespace, name
+		);
+	}
+	
+	private class InspectingStateFieldBuilder implements StateFieldBuilder {
+		
+		private class Int implements StateFieldBuilder.Int {
+
+			@Override
+			public IntStateField build() {
+				return registerField(new IntStateField(
+						namespace, name,
+						isLocal,
+						fieldIndexCounters.getIntsThenIncrement()
+				));
+			}
+			
+		}
+		
+		private final String namespace;
+		private final String name;
+		
+		private boolean isLocal = true;
+
+		public InspectingStateFieldBuilder(
+				String namespace, String name
+		) {
+			this.namespace = namespace;
+			this.name = name;
+		}
+
+		@Override
+		public Int ofInt() {
+			return new Int();
+		}
+		
+		@Override
+		public StateFieldBuilder setLocal(boolean isLocal) {
+			this.isLocal = isLocal;
+			return this;
+		}
+		
+		@Override
+		public void setOrdinal(int ordinal) {
+			if (ordinal != fields.size()) {
+				throw new IllegalStateException(
+						"This field is going to receive ordinal "
+								+ fields.size() + ", requested ordinal "
+								+ ordinal
+				);
+			}
+		}
+		
+	}
+
+}

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

@@ -0,0 +1,62 @@
+package ru.windcorp.progressia.common.state;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+public class IntStateField extends StateField {
+
+	public IntStateField(
+			String namespace, String name,
+			boolean isLocal,
+			int index
+	) {
+		super(namespace, name, isLocal, index);
+	}
+	
+	public int get(StatefulObject object) {
+		return object.getStorage().getInt(getIndex());
+	}
+	
+	public void setNow(StatefulObject object, int value) {
+		object.getStorage().setInt(getIndex(), value);
+	}
+	
+	public void set(StateChanger changer, int value) {
+		changer.setInt(this, value);
+	}
+
+	@Override
+	public void read(
+			StatefulObject object,
+			DataInput input,
+			IOContext context
+	) throws IOException {
+		object.getStorage().setInt(getIndex(), input.readInt());
+	}
+
+	@Override
+	public void write(
+			StatefulObject object,
+			DataOutput output,
+			IOContext context
+	) throws IOException {
+		output.writeInt(object.getStorage().getInt(getIndex()));
+	}
+
+	@Override
+	public void copy(StatefulObject from, StatefulObject to) {
+		setNow(to, get(from));
+	}
+
+	@Override
+	public int computeHashCode(StatefulObject object) {
+		return get(object);
+	}
+
+	@Override
+	public boolean areEqual(StatefulObject a, StatefulObject b) {
+		return get(a) == get(b);
+	}
+
+}

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

@@ -0,0 +1,19 @@
+package ru.windcorp.progressia.common.state;
+
+public class OptimizedStateStorage extends StateStorage {
+	
+	private final int[] ints;
+	
+	public OptimizedStateStorage(PrimitiveCounters sizes) {
+		this.ints = new int[sizes.getInts()];
+	}
+
+	public int getInt(int index) {
+		return ints[index];
+	}
+
+	public void setInt(int index, int value) {
+		ints[index] = value;
+	}
+
+}

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

@@ -0,0 +1,68 @@
+package ru.windcorp.progressia.common.state;
+
+import java.util.List;
+
+import com.google.common.collect.ImmutableList;
+
+public class OptimizedStatefulObjectLayout
+extends AbstractStatefulObjectLayout {
+
+	private final List<StateField> fields;
+	private final PrimitiveCounters sizes;
+
+	public OptimizedStatefulObjectLayout(
+			String objectId,
+			List<StateField> fields, PrimitiveCounters counters
+	) {
+		super(objectId);
+		this.fields = ImmutableList.copyOf(fields);
+		this.sizes = new PrimitiveCounters(counters);
+	}
+
+	@Override
+	protected int getFieldCount() {
+		return fields.size();
+	}
+
+	@Override
+	protected StateField getField(int fieldIndex) {
+		return fields.get(fieldIndex);
+	}
+
+	@Override
+	public StateStorage createStorage() {
+		return new OptimizedStateStorage(sizes);
+	}
+
+	@Override
+	public StateFieldBuilder getBuilder(String namespace, String name) {
+		return new RetrieverStateFieldBuilder();
+	}
+	
+	private class RetrieverStateFieldBuilder implements StateFieldBuilder {
+		
+		private StateField result;
+
+		@Override
+		public Int ofInt() {
+			return new Int() {
+				@Override
+				public IntStateField build() {
+					return (IntStateField) result;
+				}
+			};
+		}
+
+		@Override
+		public StateFieldBuilder setLocal(boolean isLocal) {
+			return this;
+		}
+
+		@Override
+		public void setOrdinal(int ordinal) {
+			this.result = fields.get(ordinal);
+		}
+
+	}
+
+}

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

@@ -0,0 +1,21 @@
+package ru.windcorp.progressia.common.state;
+
+class PrimitiveCounters {
+	
+	private int ints = 0;
+	
+	public PrimitiveCounters() {}
+	
+	public PrimitiveCounters(PrimitiveCounters copyFrom) {
+		this.ints = copyFrom.ints;
+	}
+	
+	public int getInts() {
+		return ints;
+	}
+	
+	public int getIntsThenIncrement() {
+		return this.ints++;
+	}
+
+}

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

@@ -0,0 +1,7 @@
+package ru.windcorp.progressia.common.state;
+
+public interface StateChanger {
+	
+	void setInt(IntStateField field, int value);
+
+}

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

@@ -0,0 +1,50 @@
+package ru.windcorp.progressia.common.state;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import ru.windcorp.progressia.common.util.Namespaced;
+
+public abstract class StateField extends Namespaced {
+	
+	private final boolean isLocal;
+	private final int index;
+
+	public StateField(
+			String namespace, String name,
+			boolean isLocal,
+			int index
+	) {
+		super(namespace, name);
+		this.isLocal = isLocal;
+		this.index = index;
+	}
+	
+	public boolean isLocal() {
+		return isLocal;
+	}
+	
+	protected int getIndex() {
+		return index;
+	}
+	
+	public abstract void read(
+			StatefulObject object,
+			DataInput input,
+			IOContext context
+	) throws IOException;
+	
+	public abstract void write(
+			StatefulObject object,
+			DataOutput output,
+			IOContext context
+	) throws IOException;
+	
+	public abstract void copy(StatefulObject from, StatefulObject to);
+	
+	public abstract int computeHashCode(StatefulObject object);
+	
+	public abstract boolean areEqual(StatefulObject a, StatefulObject b);
+
+}

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

@@ -0,0 +1,24 @@
+package ru.windcorp.progressia.common.state;
+
+public interface StateFieldBuilder {
+	
+	public static interface Int {
+		IntStateField build();
+	}
+	
+	Int ofInt();
+	
+	StateFieldBuilder setLocal(boolean isLocal);
+	
+	default StateFieldBuilder setLocal() {
+		return setLocal(true);
+	}
+	
+	default StateFieldBuilder setShared() {
+		return setLocal(false);
+	}
+	
+	void setOrdinal(int ordinal);
+	
+
+}

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

@@ -0,0 +1,9 @@
+package ru.windcorp.progressia.common.state;
+
+public abstract class StateStorage {
+
+	public abstract int getInt(int index);
+
+	public abstract void setInt(int index, int value);
+
+}

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

@@ -0,0 +1,224 @@
+package ru.windcorp.progressia.common.state;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.util.Objects;
+
+import ru.windcorp.progressia.common.util.Namespaced;
+
+/**
+ * An abstract class describing objects that have trackable state,
+ * such as blocks, tiles or entities. This class contains the declaration of
+ * the state mechanics
+ * (implementation of which is mostly delegated to
+ * {@link StatefulObjectLayout}).
+ * 
+ * <h1>Structure</h1>
+ * 
+ * Stateful objects are characterized by their <i>likeness</i> and <i>state</i>.
+ * <p>
+ * An object's likeness is the combination of the object's runtime class (as in
+ * {@link #getClass()}) and its ID. Objects that are "alike" share the same
+ * internal structure, represented by a common
+ * {@linkplain StatefulObjectLayout layout}. Likeness can be tested with
+ * {@link #isLike(Object)}.
+ * <p>
+ * An object's state is the combination of the values of an object's
+ * {@linkplain StateField state fields}. State fields are different from object
+ * fields as described by the Java language: not every object field is a part
+ * of its state, although state fields are usually implemented as object fields.
+ * Each state field is, in its turn, has the following characteristics:
+ * <ul>
+ * <li>ID, distinct from the ID of the stateful object to which it belongs.
+ * State field IDs are only unique within fields of one likeness.</li>
+ * <li>data type, which is one of Java primitive types or a compound (Object)
+ * type.</li>
+ * </ul>
+ */
+public abstract class StatefulObject extends Namespaced {
+	
+	private final StatefulObjectLayout layout;
+	
+	private final StateStorage storage;
+
+	public StatefulObject(
+			StatefulObjectRegistry<?> type,
+			String namespace,
+			String name
+	) {
+		super(namespace, name);
+		this.layout = type.getLayout(getId());
+		this.storage = getLayout().createStorage();
+	}
+	
+	/**
+	 * Returns the {@link StatefulObjectLayout} describing objects that are
+	 * {@linkplain #isLike(Object) "like"} this object.
+	 * You probably don't need this.
+	 * 
+	 * @return this object's field layout
+	 */
+	public StatefulObjectLayout getLayout() {
+		return layout;
+	}
+	
+	/**
+	 * Returns a {@link StateStorage} used by this object to store its state in
+	 * memory. You probably don't need this.
+	 * 
+	 * @return this object's state storage
+	 */
+	public StateStorage getStorage() {
+		return storage;
+	}
+	
+	/*
+	 * Field construction
+	 */
+	
+	/**
+	 * Used to keep track of the ordinal number of the next field to be
+	 * requested.
+	 */
+	private int fieldOrdinal = 0;
+	
+	/**
+	 * Returns a {@link StateFieldBuilder} set up to construct a field with the
+	 * specified ID.
+	 * <p>
+	 * This method must only be called from the constructor, and the same
+	 * sequence of invocations must occur during construction of each object
+	 * with the same ID.
+	 * 
+	 * @param namespace the namespace of the new field
+	 * @param name the name of the new field
+	 * 
+	 * @return a configured builder
+	 */
+	protected StateFieldBuilder field(String namespace, String name) {
+		StateFieldBuilder builder = getLayout().getBuilder(namespace, name);
+		
+		builder.setOrdinal(fieldOrdinal);
+		fieldOrdinal++;
+		
+		return builder;
+	}
+	
+	/*
+	 * IO
+	 */
+	
+	/**
+	 * Sets the state of this object according to the binary representation read
+	 * from {@code input}. If {@code context == COMMS}, the state of local
+	 * fields is unspecified after this operation.
+	 * 
+	 * @param input a {@link DataInput} that a state can be read from
+	 * @param context the context
+	 * 
+	 * @throws IOException if the state is encoded poorly or an error occurs
+	 * in {@code input}
+	 */
+	public void read(DataInput input, IOContext context) throws IOException {
+		getLayout().read(this, input, context);
+	}
+	
+	/**
+	 * Writes the binary representation of the state of this object to the
+	 * {@code output}.
+	 * 
+	 * @param output a {@link DataOutput} that a state can be written to
+	 * @param context the context
+	 * 
+	 * @throws IOException if an error occurs in {@code output}
+	 */
+	public void write(DataOutput output, IOContext context) throws IOException {
+		getLayout().write(this, output, context);
+	}
+	
+	/*
+	 * Identity operations
+	 */
+	
+	/**
+	 * Turns {@code destination} into a deep copy of this object.
+	 * <p>
+	 * Changes the provided object so that:
+	 * <ul>
+	 * <li>the provided object equals this object according to
+	 * {@link StatefulObject#equals(Object)}; and</li>
+	 * <li>the provided object is independent of this object, meaning no change
+	 * to {@code destination} can affect this object.</li>
+	 * </ul>
+	 * 
+	 * @param destination the object to copy this object into.
+	 */
+	public StatefulObject copy(StatefulObject destination) {
+		Objects.requireNonNull(destination, "destination");
+		
+		if (destination == this) {
+			throw new IllegalArgumentException(
+					"Cannot copy an object into itself"
+			);
+		}
+		
+		if (destination.getClass() != this.getClass()) {
+			throw new IllegalArgumentException(
+					"Cannot copy from " + getClass()
+					+ " (ID " + getId() + ") to " + destination.getClass()
+			);
+		}
+		
+		getLayout().copy(this, destination);
+		return destination;
+	}
+	
+	/**
+	 * @see #equals(Object)
+	 */
+	@Override
+	public int hashCode() {
+		return getLayout().computeHashCode(this);
+	}
+	
+	/**
+	 * Determines whether this object and {@code obj} have equal states.
+	 * Stateful objects are considered equal iff they are
+	 * {@linkplain #isLike(Object) "like"} and their binary representations
+	 * match exactly.
+	 * 
+	 * @param obj the object to examine
+	 * @return {@code true} if {@code obj != null} and this object is equal to
+	 * {@code obj}
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (obj == this) return true;
+		if (!this.isLike(obj)) return false;
+		
+		return getLayout().areEqual(this, (StatefulObject) obj);
+	}
+	
+	/**
+	 * Checks whether the provided object is "like" this object.
+	 * <p>
+	 * Returns {@code true} iff this object and {@code obj} have the same ID and
+	 * are instances of the same class.
+	 * 
+	 * @param obj the object to examine
+	 * @return {@code true} if {@code obj} is "like" this object
+	 */
+	public boolean isLike(Object obj) {
+		if (obj == null) return false;
+		if (obj == this) return true;
+		if (obj.getClass() != this.getClass()) return false;
+		
+		StatefulObject statefulObj = (StatefulObject) obj;
+		
+		if (statefulObj.getId().equals(this.getId())) return false;
+		
+		return true;
+	}
+	
+}

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

@@ -0,0 +1,48 @@
+package ru.windcorp.progressia.common.state;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+public abstract class StatefulObjectLayout {
+	
+	private final String objectId;
+
+	public StatefulObjectLayout(String objectId) {
+		this.objectId = objectId;
+	}
+	
+	public String getObjectId() {
+		return objectId;
+	}
+	
+	public abstract StateStorage createStorage();
+	
+	protected void checkObject(StatefulObject object) {
+		if (!object.getId().equals(getObjectId())) {
+			throw new IllegalArgumentException(
+					object.getId() + " is not " + getObjectId()
+			);
+		}
+	}
+	
+	public abstract void read(
+			StatefulObject object,
+			DataInput input,
+			IOContext context
+	) throws IOException;
+	
+	public abstract void write(
+			StatefulObject object,
+			DataOutput output,
+			IOContext context
+	) throws IOException;
+	
+	public abstract void copy(StatefulObject from, StatefulObject to);
+	
+	public abstract int computeHashCode(StatefulObject object);
+	public abstract boolean areEqual(StatefulObject a, StatefulObject b);
+	
+	public abstract StateFieldBuilder getBuilder(String namespace, String name);
+
+}

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

@@ -0,0 +1,98 @@
+package ru.windcorp.progressia.common.state;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.WeakHashMap;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import ru.windcorp.progressia.common.util.Namespaced;
+import ru.windcorp.progressia.common.util.NamespacedRegistry;
+
+/**
+ * Registry-like object for identification of various {@link StatefulObject}
+ * types, such as blocks vs tiles. This object stores and manages various
+ * {@linkplain StatefulObjectLayout layouts}.
+ */
+public class StatefulObjectRegistry<T extends StatefulObject> {
+	
+	@FunctionalInterface
+	public static interface Factory<T> {
+		/**
+		 * Initializes a new, independent instance of the stateful object.
+		 * @return the created object
+		 */
+		T build();
+	}
+	
+	protected static class Type<T> extends Namespaced {
+
+		private final Factory<T> factory;
+		
+		private final AtomicBoolean isRegistered = new AtomicBoolean(false);
+		
+		public Type(String namespace, String name, Factory<T> factory) {
+			super(namespace, name);
+			this.factory = factory;
+		}
+
+		public T build() {
+			return factory.build();
+		}
+		
+		public AtomicBoolean getRegistrationFlag() {
+			return isRegistered;
+		}
+		
+	}
+	
+	private final NamespacedRegistry<Type<T>> registry =
+			new NamespacedRegistry<Type<T>>() {
+				@Override
+				public void register(Type<T> element) {
+					super.register(element);
+					StatefulObjectRegistry.this.register(element);
+				};
+			};
+	
+	private final Map<String, StatefulObjectLayout> layouts =
+			Collections.synchronizedMap(new WeakHashMap<>());
+	
+	public StatefulObjectLayout getLayout(String id) {
+		StatefulObjectLayout layout = layouts.get(id);
+		
+		if (layout == null) {
+			throw new IllegalArgumentException(
+					"ID " + id + " has not been registered"
+			);
+		}
+		
+		return layout;
+	}
+
+	protected void register(Type<T> type) {
+		if (!type.getRegistrationFlag().compareAndSet(false, true)) {
+			throw new IllegalStateException(
+					"ID " + type.getId() + " is already registered"
+			);
+		}
+		
+		InspectingStatefulObjectLayout inspector =
+				new InspectingStatefulObjectLayout(type.getId());
+		
+		layouts.put(type.getId(), inspector);
+		
+		// During initialization inspector collects necessary data
+		type.build();
+		
+		layouts.put(type.getId(), inspector.compile());
+	}
+	
+	public T create(String id) {
+		return registry.get(id).build();
+	}
+	
+	public void register(String namespace, String name, Factory<T> factory) {
+		registry.register(new Type<>(namespace, name, factory));
+	}
+
+}

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

@@ -17,6 +17,9 @@
  *******************************************************************************/
 package ru.windcorp.progressia.common.util;
 
+import glm.vec._2.i.Vec2i;
+import glm.vec._3.i.Vec3i;
+
 public class CoordinatePacker {
 	
 	private static final int BITS_3_INTS_INTO_LONG;
@@ -53,6 +56,10 @@ public class CoordinatePacker {
 				((c & MASK_3_INTS_INTO_LONG) << (0 * BITS_3_INTS_INTO_LONG));
 	}
 	
+	public static long pack3IntsIntoLong(Vec3i v) {
+		return pack3IntsIntoLong(v.x, v.y, v.z);
+	}
+	
 	public static int unpack3IntsFromLong(long packed, int index) {
 		if (index < 0 || index >= 3) {
 			throw new IllegalArgumentException("Invalid index " + index);
@@ -72,12 +79,26 @@ public class CoordinatePacker {
 		return result;
 	}
 	
+	public static Vec3i unpack3IntsFromLong(long packed, Vec3i output) {
+		output.set(
+				unpack3IntsFromLong(packed, 0),
+				unpack3IntsFromLong(packed, 1),
+				unpack3IntsFromLong(packed, 2)
+		);
+		
+		return output;
+	}
+	
 	public static long pack2IntsIntoLong(int a, int b) {
 		return
 				((a & MASK_2_INTS_INTO_LONG) << (1 * BITS_2_INTS_INTO_LONG)) |
 				((b & MASK_2_INTS_INTO_LONG) << (0 * BITS_2_INTS_INTO_LONG));
 	}
 	
+	public static long pack2IntsIntoLong(Vec2i v) {
+		return pack2IntsIntoLong(v.x, v.y);
+	}
+	
 	public static int unpack2IntsFromLong(long packed, int index) {
 		if (index < 0 || index >= 2) {
 			throw new IllegalArgumentException("Invalid index " + index);
@@ -91,4 +112,13 @@ public class CoordinatePacker {
 		return result;
 	}
 	
+	public static Vec2i unpack2IntsFromLong(long packed, Vec2i output) {
+		output.set(
+				unpack2IntsFromLong(packed, 0),
+				unpack2IntsFromLong(packed, 1)
+		);
+		
+		return output;
+	}
+
 }

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

@@ -0,0 +1,121 @@
+package ru.windcorp.progressia.common.util;
+
+import java.io.DataInput;
+import java.io.DataInputStream;
+import java.io.DataOutput;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import gnu.trove.list.array.TByteArrayList;
+
+public class DataBuffer {
+	
+	private static final int DEFAULT_CAPACITY = 1024;
+	private static final int TRANSFER_BUFFER_SIZE = 1024;
+
+	private final TByteArrayList buffer;
+	
+	private final byte[] transferBuffer = new byte[TRANSFER_BUFFER_SIZE];
+	
+	private int position;
+	
+	private final DataInput reader = new DataInputStream(
+			new InputStream() {
+				@Override
+				public int read() throws IOException {
+					if (position >= buffer.size()) return -1;
+					int result = buffer.getQuick(position);
+					++position;
+					return result;
+				}
+			}
+	);
+	
+	private final DataOutput writer = new DataOutputStream(
+			new OutputStream() {		
+				@Override
+				public void write(int b) throws IOException {
+					buffer.add((byte) b);
+				}
+			}
+	);
+	
+	public DataBuffer(int capacity) {
+		this.buffer = new TByteArrayList(capacity);
+	}
+	
+	public DataBuffer() {
+		this(DEFAULT_CAPACITY);
+	}
+	
+	public DataBuffer(DataBuffer copyFrom) {
+		this.buffer = new TByteArrayList(copyFrom.buffer);
+	}
+	
+	public DataInput getReader() {
+		position = 0;
+		return reader;
+	}
+	
+	public DataOutput getWriter() {
+		buffer.resetQuick();
+		return writer;
+	}
+
+	public int getSize() {
+		return buffer.size();
+	}
+	
+	public void fill(DataInput source, int length) throws IOException {
+		buffer.resetQuick();
+		buffer.ensureCapacity(length);
+		
+		while (length > 0) {
+			int currentLength = Math.min(transferBuffer.length, length);
+			
+			source.readFully(transferBuffer, 0, currentLength);
+			buffer.add(transferBuffer, 0, currentLength);
+			
+			length -= currentLength;
+		}
+	}
+	
+	public void flush(DataOutput sink) throws IOException {
+		int position = 0;
+		int length = buffer.size();
+		
+		while (position < length) {
+			int currentLength = Math.min(
+					transferBuffer.length,
+					length - position
+			);
+			
+			buffer.toArray(transferBuffer, position, 0, currentLength);
+			sink.write(transferBuffer, 0, currentLength);
+			
+			length -= currentLength;
+		}
+	}
+
+	@Override
+	public int hashCode() {
+		return buffer.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		DataBuffer other = (DataBuffer) obj;
+		if (!buffer.equals(other.buffer))
+			return false;
+		return true;
+	}
+
+}

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

@@ -14,6 +14,18 @@ public class FloatMathUtils {
 		return a - 2*PI_F * floor((a + PI_F) / (2*PI_F));
 	}
 	
+	public static float sin(float x) {
+		return (float) Math.sin(x);
+	}
+	
+	public static float cos(float x) {
+		return (float) Math.cos(x);
+	}
+	
+	public static float tan(float x) {
+		return (float) Math.tan(x);
+	}
+	
 	private FloatMathUtils() {}
 
 }

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

@@ -6,6 +6,8 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.logging.log4j.LogManager;
+
 import com.google.errorprone.annotations.DoNotCall;
 
 public class NamespacedRegistry<E extends Namespaced>
@@ -15,6 +17,7 @@ implements Map<String, E> {
 			Collections.synchronizedMap(new HashMap<>());
 	
 	public void register(E element) {
+		LogManager.getLogger(getClass()).debug("Registering " + element.getId());
 		backingMap.put(element.getId(), element);
 	}
 	

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

@@ -0,0 +1,46 @@
+package ru.windcorp.progressia.common.util;
+
+import java.util.Objects;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+
+public class NamespacedUtil {
+	
+	public static final char SEPARATOR = ':';
+	public static final int MAX_PART_LENGTH = 127;
+	public static final int MAX_TOTAL_LENGTH = MAX_PART_LENGTH * 2 + 1;
+	
+	private static final String PART_REGEX = "^[A-Z][a-zA-Z0-9]{2,}$";
+	
+	private static final Predicate<String> PART_CHECKER =
+			Pattern.compile(PART_REGEX).asPredicate();
+	
+	public static String getId(String namespace, String name) {
+		checkPart(namespace, "Namespace");
+		checkPart(name, "Name");
+		
+		return namespace + SEPARATOR + name;
+	}
+	
+	private static void checkPart(String data, String name) {
+		Objects.requireNonNull(data, name);
+		
+		if (data.length() > MAX_PART_LENGTH) {
+			throw new IllegalArgumentException(
+					name + " \"" + data + "\" is too long. "
+							+ "Expected at most " + MAX_PART_LENGTH
+							+ " characters"
+			);
+		}
+		
+		if (!PART_CHECKER.test(name)) {
+			throw new IllegalArgumentException(
+					name + " \"" + data + "\" is invalid. "
+							+ "Allowed is: " + PART_REGEX
+			);
+		}
+	}
+	
+	private NamespacedUtil() {}
+
+}

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

@@ -22,7 +22,6 @@ import static ru.windcorp.progressia.common.world.block.BlockFace.*;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.UUID;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
@@ -39,6 +38,7 @@ import ru.windcorp.progressia.common.world.block.BlockData;
 import ru.windcorp.progressia.common.world.block.BlockDataRegistry;
 import ru.windcorp.progressia.common.world.block.BlockFace;
 import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.entity.EntityDataRegistry;
 import ru.windcorp.progressia.common.world.tile.TileData;
 import ru.windcorp.progressia.common.world.tile.TileDataRegistry;
 
@@ -132,13 +132,18 @@ public class ChunkData {
 			}
 		}
 		
-		EntityData javapony = new EntityData("Test", "Javapony");
-		javapony.setUUID(UUID.nameUUIDFromBytes(new byte[] {42}));
+		EntityData javapony = EntityDataRegistry.getInstance().create("Test:Javapony");
+		javapony.setEntityId(0x42);
 		javapony.setPosition(new Vec3(-6, -6, 20));
 		javapony.setDirection(new Vec2(
 				(float) Math.toRadians(40), (float) Math.toRadians(45)
 		));
 		getEntities().add(javapony);
+		
+		EntityData statie = EntityDataRegistry.getInstance().create("Test:Statie");
+		statie.setEntityId(0xDEADBEEF);
+		statie.setPosition(new Vec3(0, 15, 16));
+		getEntities().add(statie);
 	}
 
 	public BlockData getBlock(Vec3i posInChunk) {

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

@@ -21,28 +21,59 @@ import java.util.Collection;
 import java.util.Collections;
 
 import glm.vec._3.i.Vec3i;
+import gnu.trove.impl.sync.TSynchronizedLongObjectMap;
 import gnu.trove.map.TLongObjectMap;
 import gnu.trove.map.hash.TLongObjectHashMap;
 import ru.windcorp.progressia.common.util.CoordinatePacker;
 import ru.windcorp.progressia.common.util.Vectors;
+import ru.windcorp.progressia.common.world.entity.EntityData;
 
 public class WorldData {
 
-	private final TLongObjectMap<ChunkData> chunks = new TLongObjectHashMap<>();
+	private final TLongObjectMap<ChunkData> chunksByPos =
+			new TSynchronizedLongObjectMap<>(new TLongObjectHashMap<>(), this);
+	
+	private final Collection<ChunkData> chunks =
+			Collections.unmodifiableCollection(chunksByPos.valueCollection());
+	
+	private final TLongObjectMap<EntityData> entitiesById =
+			new TSynchronizedLongObjectMap<>(new TLongObjectHashMap<>(), this);
+	
+	private final Collection<EntityData> entities =
+			Collections.unmodifiableCollection(entitiesById.valueCollection());
 	
 	public WorldData() {
 		final int size = 1;
 		
 		for (int x = -(size / 2); x <= (size / 2); ++x) {
 			for (int y = -(size / 2); y <= (size / 2); ++y) {
-				chunks.put(CoordinatePacker.pack3IntsIntoLong(x, y, 0), new ChunkData(x, y, 0, this));
+				addChunk(new ChunkData(x, y, 0, this));
 			}
 		}
 	}
 	
+	private synchronized void addChunk(ChunkData chunk) {
+		chunksByPos.put(getChunkKey(chunk), chunk);
+		
+		chunk.forEachEntity(entity ->
+			entitiesById.put(entity.getEntityId(), entity)
+		);
+	}
+	
+//	private synchronized void removeChunk(ChunkData chunk) {
+//		chunksByPos.remove(getChunkKey(chunk));
+//		
+//		chunk.forEachEntity(entity ->
+//			entitiesById.remove(entity.getEntityId())
+//		);
+//	}
+	
+	private static long getChunkKey(ChunkData chunk) {
+		return CoordinatePacker.pack3IntsIntoLong(chunk.getPosition());
+	}
+	
 	public ChunkData getChunk(Vec3i pos) {
-		long key = CoordinatePacker.pack3IntsIntoLong(pos.x, pos.y, pos.z);
-		return chunks.get(key);
+		return chunksByPos.get(CoordinatePacker.pack3IntsIntoLong(pos));
 	}
 	
 	public ChunkData getChunkByBlock(Vec3i blockInWorld) {
@@ -54,7 +85,15 @@ public class WorldData {
 	}
 	
 	public Collection<ChunkData> getChunks() {
-		return Collections.unmodifiableCollection(chunks.valueCollection());
+		return chunks;
+	}
+	
+	public EntityData getEntity(long entityId) {
+		return entitiesById.get(entityId);
+	}
+	
+	public Collection<EntityData> getEntities() {
+		return entities;
 	}
 	
 }

src/main/java/ru/windcorp/progressia/common/world/entity/EntityData.java

@@ -1,22 +1,22 @@
 package ru.windcorp.progressia.common.world.entity;
 
-import java.util.UUID;
-
 import glm.vec._2.Vec2;
 import glm.vec._3.Vec3;
-import ru.windcorp.progressia.common.util.Namespaced;
+import ru.windcorp.progressia.common.state.StatefulObject;
 
-public class EntityData extends Namespaced {
+public class EntityData extends StatefulObject {
 	
 	private final Vec3 position = new Vec3();
 	private final Vec3 velocity = new Vec3();
 	
 	private final Vec2 direction = new Vec2();
 	
-	private UUID uuid;
+	private long entityId;
+	
+	private double age = 0;
 
 	public EntityData(String namespace, String name) {
-		super(namespace, name);
+		super(EntityDataRegistry.getInstance(), namespace, name);
 	}
 	
 	public Vec3 getPosition() {
@@ -51,12 +51,24 @@ public class EntityData extends Namespaced {
 		return getDirection().y;
 	}
 	
-	public UUID getUUID() {
-		return uuid;
+	public long getEntityId() {
+		return entityId;
 	}
 	
-	public void setUUID(UUID uuid) {
-		this.uuid = uuid;
+	public void setEntityId(long entityId) {
+		this.entityId = entityId;
+	}
+	
+	public double getAge() {
+		return age;
+	}
+	
+	public void setAge(double age) {
+		this.age = age;
+	}
+	
+	public void incrementAge(double increment) {
+		this.age += increment;
 	}
 
 }

src/main/java/ru/windcorp/progressia/common/world/entity/EntityDataRegistry.java

@@ -1,8 +1,8 @@
 package ru.windcorp.progressia.common.world.entity;
 
-import ru.windcorp.progressia.common.util.NamespacedRegistry;
+import ru.windcorp.progressia.common.state.StatefulObjectRegistry;
 
-public class EntityDataRegistry extends NamespacedRegistry<EntityData> {
+public class EntityDataRegistry extends StatefulObjectRegistry<EntityData> {
 	
 	private static final EntityDataRegistry INSTANCE = new EntityDataRegistry();
 	
@@ -10,4 +10,8 @@ public class EntityDataRegistry extends NamespacedRegistry<EntityData> {
 		return INSTANCE;
 	}
 	
+	public void register(String namespace, String name) {
+		super.register(namespace, name, () -> new EntityData(namespace, name));
+	}
+
 }

src/main/java/ru/windcorp/progressia/common/world/entity/PacketEntityChange.java

@@ -0,0 +1,60 @@
+package ru.windcorp.progressia.common.world.entity;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+import ru.windcorp.progressia.common.comms.packets.PacketWorldChange;
+import ru.windcorp.progressia.common.state.IOContext;
+import ru.windcorp.progressia.common.util.DataBuffer;
+import ru.windcorp.progressia.common.world.WorldData;
+
+public class PacketEntityChange extends PacketWorldChange {
+	
+	private long entityId;
+	private final DataBuffer buffer = new DataBuffer();
+
+	public PacketEntityChange() {
+		super("Core", "EntityChange");
+	}
+	
+	public long getEntityId() {
+		return entityId;
+	}
+	
+	public void setEntityId(long entityId) {
+		this.entityId = entityId;
+	}
+	
+	public DataBuffer getBuffer() {
+		return buffer;
+	}
+
+	public DataInput getReader() {
+		return buffer.getReader();
+	}
+
+	public DataOutput getWriter() {
+		return buffer.getWriter();
+	}
+
+	@Override
+	public void apply(WorldData world) {
+		EntityData entity = world.getEntity(getEntityId());
+		
+		if (entity == null) {
+			throw new RuntimeException(
+					"Entity with ID " + getEntityId() + " not found"
+			);
+		}
+		
+		try {
+			entity.read(getReader(), IOContext.COMMS);
+		} catch (IOException e) {
+			throw new RuntimeException(
+					"Entity could not be read", e
+			);
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/server/ServerThread.java

@@ -4,6 +4,8 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
+import org.apache.logging.log4j.LogManager;
+
 import ru.windcorp.progressia.server.world.Ticker;
 
 public class ServerThread implements Runnable {
@@ -50,8 +52,12 @@ public class ServerThread implements Runnable {
 	
 	@Override
 	public void run() {
+		try {
 			server.tick();
 			ticker.run();
+		} catch (Exception e) {
+			LogManager.getLogger(getClass()).error("Got an exception in server thread", e);
+		}
 	}
 	
 	public Server getServer() {

src/main/java/ru/windcorp/progressia/server/comms/ClientManager.java

@@ -4,7 +4,6 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import glm.vec._3.i.Vec3i;
 import gnu.trove.TCollections;
 import gnu.trove.map.TIntObjectMap;
 import gnu.trove.map.hash.TIntObjectHashMap;
@@ -39,10 +38,7 @@ public class ClientManager {
 		
 		client.addListener(new DefaultServerCommsListener(this, client));
 		
-		client.sendPacket(new PacketSetLocalPlayer(
-				server.getWorld().getData().getChunk(new Vec3i(0, 0, 0))
-				.getEntities().get(0).getUUID()
-		));
+		client.sendPacket(new PacketSetLocalPlayer(0x42));
 	}
 	
 	public void disconnectClient(Client client) {

src/main/java/ru/windcorp/progressia/server/world/Changer.java

@@ -3,14 +3,22 @@ package ru.windcorp.progressia.server.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.entity.EntityData;
 import ru.windcorp.progressia.common.world.tile.TileData;
 
 public interface Changer {
 	
+	@FunctionalInterface
+	public static interface Change<T> {
+		void change(T object);
+	}
+
 	void setBlock(Vec3i pos, BlockData block);
 
 	void addTile(Vec3i block, BlockFace face, TileData tile);
 
 	void removeTile(Vec3i block, BlockFace face, TileData tile);
 	
+	<T extends EntityData> void changeEntity(T entity, Change<T> change);
+
 }

src/main/java/ru/windcorp/progressia/server/world/ImplementedChangeTracker.java

@@ -1,5 +1,6 @@
 package ru.windcorp.progressia.server.world;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
@@ -7,25 +8,28 @@ import java.util.Objects;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.comms.packets.Packet;
 import ru.windcorp.progressia.common.comms.packets.PacketWorldChange;
+import ru.windcorp.progressia.common.state.IOContext;
 import ru.windcorp.progressia.common.util.LowOverheadCache;
 import ru.windcorp.progressia.common.util.Vectors;
 import ru.windcorp.progressia.common.world.Coordinates;
 import ru.windcorp.progressia.common.world.WorldData;
 import ru.windcorp.progressia.common.world.block.BlockData;
 import ru.windcorp.progressia.common.world.block.BlockFace;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.common.world.entity.PacketEntityChange;
 import ru.windcorp.progressia.common.world.tile.TileData;
 import ru.windcorp.progressia.server.Server;
 
 public class ImplementedChangeTracker implements Changer {
 	
-	public static interface Change {
+	public static interface ChangeImplementation {
 		void applyOnServer(WorldData world);
 		Packet asPacket();
 	}
 	
 	private static class SetBlock
 	extends PacketWorldChange
-	implements Change {
+	implements ChangeImplementation {
 
 		private final Vec3i position = new Vec3i();
 		private BlockData block;
@@ -63,7 +67,7 @@ public class ImplementedChangeTracker implements Changer {
 	
 	private static class AddOrRemoveTile
 	extends PacketWorldChange
-	implements Change {
+	implements ChangeImplementation {
 		
 		private final Vec3i position = new Vec3i();
 		private BlockFace face;
@@ -115,7 +119,45 @@ public class ImplementedChangeTracker implements Changer {
 		
 	}
 	
-	private final List<Change> changes = new ArrayList<>(1024);
+	private static class ChangeEntity implements ChangeImplementation {
+		
+		private EntityData entity;
+		private Change<?> change;
+		
+		private final PacketEntityChange packet = new PacketEntityChange();
+
+		public <T extends EntityData> void set(T entity, Change<T> change) {
+			this.entity = entity;
+			this.change = change;
+			
+			packet.setEntityId(entity.getEntityId());
+			try {
+				entity.write(packet.getWriter(), IOContext.COMMS);
+			} catch (IOException e) {
+				throw new RuntimeException(e);
+			}
+		}
+
+		@SuppressWarnings("unchecked")
+		@Override
+		public void applyOnServer(WorldData world) {
+			((Change<EntityData>) change).change(entity);
+			
+			try {
+				entity.write(packet.getWriter(), IOContext.COMMS);
+			} catch (IOException e) {
+				throw new RuntimeException("Entity could not be written", e);
+			}
+		}
+
+		@Override
+		public Packet asPacket() {
+			return packet;
+		}
+		
+	}
+
+	private final List<ChangeImplementation> changes = new ArrayList<>(1024);
 	
 	private final LowOverheadCache<SetBlock> setBlockCache =
 			new LowOverheadCache<>(SetBlock::new);
@@ -123,6 +165,9 @@ public class ImplementedChangeTracker implements Changer {
 	private final LowOverheadCache<AddOrRemoveTile> addOrRemoveTileCache =
 			new LowOverheadCache<>(AddOrRemoveTile::new);
 	
+	private final LowOverheadCache<ChangeEntity> changeEntityCache =
+			new LowOverheadCache<>(ChangeEntity::new);
+	
 	@Override
 	public void setBlock(Vec3i pos, BlockData block) {
 		SetBlock change = setBlockCache.grab();
@@ -144,12 +189,34 @@ public class ImplementedChangeTracker implements Changer {
 		changes.add(change);
 	}
 	
+	@Override
+	public <T extends EntityData> void changeEntity(
+			T entity, Change<T> change
+	) {
+		ChangeEntity changeRecord = changeEntityCache.grab();
+		changeRecord.set(entity, change);
+		changes.add(changeRecord);
+	}
+	
 	public void applyChanges(Server server) {
 		changes.forEach(c -> c.applyOnServer(server.getWorld().getData()));
-		changes.stream().map(Change::asPacket).filter(Objects::nonNull).forEach(
+		changes.stream().map(ChangeImplementation::asPacket).filter(Objects::nonNull).forEach(
 				server.getClientManager()::broadcastGamePacket
 		);
+		changes.forEach(this::release);
 		changes.clear();
 	}
 	
+	private void release(ChangeImplementation c) {
+		if (c instanceof SetBlock) {
+			setBlockCache.release((SetBlock) c);
+		} else if (c instanceof AddOrRemoveTile) {
+			addOrRemoveTileCache.release((AddOrRemoveTile) c);
+		} else if (c instanceof ChangeEntity) {
+			changeEntityCache.release((ChangeEntity) c);
+		} else {
+			throw new IllegalArgumentException("Could not find cache for " + c);
+		}
+	}
+
 }

src/main/java/ru/windcorp/progressia/server/world/Ticker.java

@@ -2,6 +2,8 @@ package ru.windcorp.progressia.server.world;
 
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.block.TickableBlock;
+import ru.windcorp.progressia.server.world.entity.EntityLogic;
+import ru.windcorp.progressia.server.world.entity.EntityLogicRegistry;
 import ru.windcorp.progressia.server.world.tile.TickableTile;
 
 public class Ticker implements Runnable {
@@ -36,12 +38,32 @@ public class Ticker implements Runnable {
 		blockContext.setServer(server);
 		tileContext.setServer(server);
 		
+		blockContext.setChunk(chunk);
+		tileContext.setChunk(chunk);
+		
 		tickRegularTickers(chunk, blockContext, tileContext);
 		tickRandomBlocks(chunk, blockContext, tileContext);
 		
+		tickEntities(chunk, blockContext);
+		
 		flushChanges(chunk);
 	}
 
+	private void tickEntities(
+			ChunkLogic chunk,
+			MutableChunkTickContext tickContext
+	) {
+		// TODO this is ugly
+		
+		chunk.getData().getEntities().forEach(entity -> {
+			EntityLogic logic = EntityLogicRegistry.getInstance().get(
+					entity.getId()
+			);
+			
+			logic.tick(entity, tickContext, tracker);
+		});
+	}
+
 	private void tickRegularTickers(
 			ChunkLogic chunk,
 			MutableBlockTickContext blockContext,

src/main/java/ru/windcorp/progressia/server/world/entity/EntityLogic.java

@@ -1,6 +1,9 @@
 package ru.windcorp.progressia.server.world.entity;
 
 import ru.windcorp.progressia.common.util.Namespaced;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.server.world.Changer;
+import ru.windcorp.progressia.server.world.TickContext;
 
 public class EntityLogic extends Namespaced {
 
@@ -8,4 +11,8 @@ public class EntityLogic extends Namespaced {
 		super(namespace, name);
 	}
 	
+	public void tick(EntityData entity, TickContext context, Changer changer) {
+		entity.incrementAge(context.getTickLength());
+	}
+
 }

src/main/java/ru/windcorp/progressia/test/TestContent.java

@@ -1,4 +1,4 @@
-package ru.windcorp.progressia.client;
+package ru.windcorp.progressia.test;
 
 import static ru.windcorp.progressia.client.world.block.BlockRenderRegistry.getBlockTexture;
 import static ru.windcorp.progressia.client.world.tile.TileRenderRegistry.getTileTexture;
@@ -12,6 +12,7 @@ import ru.windcorp.progressia.client.world.block.*;
 import ru.windcorp.progressia.client.world.entity.*;
 import ru.windcorp.progressia.client.world.tile.*;
 import ru.windcorp.progressia.common.comms.controls.*;
+import ru.windcorp.progressia.common.state.StatefulObjectRegistry.Factory;
 import ru.windcorp.progressia.common.world.ChunkData;
 import ru.windcorp.progressia.common.world.block.*;
 import ru.windcorp.progressia.common.world.entity.*;
@@ -77,9 +78,13 @@ public class TestContent {
 	}
 
 	private static void registerEntities() {
-		register(new EntityData("Test", "Javapony"));
+		registerEntityData("Test", "Javapony");
 		register(new TestEntityRenderJavapony());
 		register(new EntityLogic("Test", "Javapony"));
+		
+		register("Test", "Statie", TestEntityDataStatie::new);
+		register(new TestEntityRenderStatie());
+		register(new TestEntityLogicStatie());
 	}
 
 	private static void regsiterControls() {
@@ -112,8 +117,17 @@ public class TestContent {
 		TileDataRegistry.getInstance().register(x);
 	}
 	
-	private static void register(EntityData x) {
-		EntityDataRegistry.getInstance().register(x);
+	private static void register(
+			String namespace, String name,
+			Factory<EntityData> factory
+	) {
+		EntityDataRegistry.getInstance().register(namespace, name, factory);
+	}
+	
+	private static void registerEntityData(
+			String namespace, String name
+	) {
+		EntityDataRegistry.getInstance().register(namespace, name);
 	}
 	
 	private static void register(BlockRender x) {

src/main/java/ru/windcorp/progressia/test/TestEntityDataStatie.java

@@ -0,0 +1,24 @@
+package ru.windcorp.progressia.test;
+
+import ru.windcorp.progressia.common.state.IntStateField;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+
+public class TestEntityDataStatie extends EntityData {
+	
+	private final IntStateField size =
+			field("Test", "Size").setShared().ofInt().build();
+
+	public TestEntityDataStatie() {
+		super("Test", "Statie");
+		setSizeNow(16);
+	}
+	
+	public int getSize() {
+		return size.get(this);
+	}
+	
+	public void setSizeNow(int size) {
+		this.size.setNow(this, size);
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/TestEntityLogicStatie.java

@@ -0,0 +1,24 @@
+package ru.windcorp.progressia.test;
+
+import ru.windcorp.progressia.common.world.entity.EntityData;
+import ru.windcorp.progressia.server.world.Changer;
+import ru.windcorp.progressia.server.world.TickContext;
+import ru.windcorp.progressia.server.world.entity.EntityLogic;
+
+public class TestEntityLogicStatie extends EntityLogic {
+	
+	public TestEntityLogicStatie() {
+		super("Test", "Statie");
+	}
+	
+	@Override
+	public void tick(EntityData entity, TickContext context, Changer changer) {
+		super.tick(entity, context, changer);
+		
+		TestEntityDataStatie statie = (TestEntityDataStatie) entity;
+		
+		int size = (int) (18 + 6 * Math.sin(entity.getAge()));
+		changer.changeEntity(statie, e -> e.setSizeNow(size));
+	}
+
+}

src/main/java/ru/windcorp/progressia/test/TestEntityRenderJavapony.java

@@ -1,4 +1,4 @@
-package ru.windcorp.progressia.client;
+package ru.windcorp.progressia.test;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -320,7 +320,7 @@ public class TestEntityRenderJavapony extends EntityRender {
 				
 				new QuadripedModel.Body(body),
 				new QuadripedModel.Head(
-						head, new Vec3(12, 0, 20), 60, 45, new Vec3(16, 0, 20)
+						head, new Vec3(12, 0, 20), 120, 45, new Vec3(16, 0, 20)
 				),
 				new QuadripedModel.Leg(
 						leftForeLeg, new Vec3(  6, +8.1f, -16), 0.0f

src/main/java/ru/windcorp/progressia/test/TestEntityRenderStatie.java

@@ -0,0 +1,42 @@
+package ru.windcorp.progressia.test;
+
+import ru.windcorp.progressia.client.graphics.model.Renderable;
+import ru.windcorp.progressia.client.graphics.model.ShapeRenderHelper;
+import ru.windcorp.progressia.client.graphics.model.Shapes;
+import ru.windcorp.progressia.client.graphics.texture.Texture;
+import ru.windcorp.progressia.client.graphics.world.WorldRenderProgram;
+import ru.windcorp.progressia.client.world.entity.EntityRender;
+import ru.windcorp.progressia.client.world.entity.EntityRenderable;
+import ru.windcorp.progressia.common.world.entity.EntityData;
+
+public class TestEntityRenderStatie extends EntityRender {
+	
+	private final Renderable cube =
+			new Shapes.PppBuilder(
+					WorldRenderProgram.getDefault(),
+					(Texture) null
+			)
+			.setColorMultiplier(1, 1, 0)
+			.create();
+
+	public TestEntityRenderStatie() {
+		super("Test", "Statie");
+	}
+
+	@Override
+	public EntityRenderable createRenderable(EntityData entity) {
+		return new EntityRenderable(entity) {
+			@Override
+			public void render(ShapeRenderHelper renderer) {
+				renderer.pushTransform().scale(
+						((TestEntityDataStatie) entity).getSize() / 24.0f
+				);
+				
+				cube.render(renderer);
+				
+				renderer.popTransform();
+			}
+		};
+	}
+
+}