Still working on Contexts. Introduced a billion interfaces. WIP.

*takes a deep breath
- Renamed Generic world structure interfaces to the following scheme:

      {Block,Tile,Chunk,World}Generic{,Stack,Reference}{RO,WO}
      (e.g. GenericWritableChunk -> ChunkGenericWO)

    - RO is Read Only, WO is Write Only
- Generic writable interfaces no longer extend their read-only
counterparts (thus Write Only)
- TileGenericStack{RO,WO} are now interfaces; AbstractList is only
introduced by final implementations
- TileGenericReferenceRO now has a WO counterpart
- Fixed compilation issues with the previous commit
- Declared some additional functionality for Generic interfaces
- Old ChunkData and WorldData renamed to DefaultChunkData and
DefaultWorldData
  - Now considered to be an implementation detail; references will be
minimized
- Introduced TileDataStack{,RO}, TileDataReference{,RO}, ChunkData{,RO},
WorldData{,RO} interfaces
  - Suffix -RO indicates Read Only, no suffix means read-write
  - To be used in place of DefaultChunk and DefaultWorld
  - Designed to support wrappers and "fake" implementations
  - May need some refinement (fix return/parameter types, ...)
- Surface world generator is now implemented poorly (WIP)
- Should compile. May work fine. Unless Java inheritance rules have
screwed me over.

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/world/ChunkRender.java

@@ -30,26 +30,26 @@ 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.DefaultChunkData;
-import ru.windcorp.progressia.common.world.generic.GenericChunk;
+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;
-import ru.windcorp.progressia.common.world.tile.TileDataReference;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
 
 public class ChunkRender
-	implements GenericChunk<BlockRender, TileRender, TileRenderStack, TileRenderReference, ChunkRender> {
+	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);
@@ -93,7 +93,7 @@ public class ChunkRender
 		return world;
 	}
 
-	public ChunkData getData() {
+	public DefaultChunkData getData() {
 		return data;
 	}
 

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

@@ -35,7 +35,7 @@ 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.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;
@@ -55,12 +55,12 @@ public class ChunkRenderModel implements Renderable {
 	public void render(ShapeRenderHelper renderer) {
 		if (model == null) return;
 		
-		float offset = ChunkData.BLOCKS_PER_CHUNK / 2 - 0.5f;
+		float offset = DefaultChunkData.BLOCKS_PER_CHUNK / 2 - 0.5f;
 		
 		renderer.pushTransform().translate(
-			chunk.getX() * ChunkData.BLOCKS_PER_CHUNK,
+			chunk.getX() * DefaultChunkData.BLOCKS_PER_CHUNK,
-			chunk.getY() * ChunkData.BLOCKS_PER_CHUNK,
+			chunk.getY() * DefaultChunkData.BLOCKS_PER_CHUNK,
-			chunk.getZ() * ChunkData.BLOCKS_PER_CHUNK
+			chunk.getZ() * DefaultChunkData.BLOCKS_PER_CHUNK
 		).translate(offset, offset, offset)
 		.mul(AxisRotations.getResolutionMatrix4(chunk.getUp()))
 		.translate(-offset, -offset, -offset);

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

@@ -21,7 +21,7 @@ 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.rels.AbsFace;
@@ -37,12 +37,12 @@ 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 (AbsFace face : AbsFace.getFaces()) {
 			cursor.set(chunk.getX(), chunk.getY(), chunk.getZ());
@@ -52,13 +52,13 @@ 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,
 		RelFace face,
 		TileData tile,
@@ -67,7 +67,7 @@ class ChunkUpdateListener implements ChunkDataListener {
 		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);
@@ -83,7 +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

@@ -38,54 +38,54 @@ 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, TileRenderReference, 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;
 	}
 
@@ -93,7 +93,7 @@ public class WorldRender
 		return client;
 	}
 
-	public ChunkRender getChunk(ChunkData chunkData) {
+	public ChunkRender getChunk(DefaultChunkData chunkData) {
 		return chunks.get(chunkData);
 	}
 

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

@@ -19,18 +19,18 @@
 package ru.windcorp.progressia.client.world.block;
 
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+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 Renderable createRenderable(ChunkData chunk, Vec3i relBlockInChunk) {
+	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/BlockRenderTexturedCube.java

@@ -36,7 +36,7 @@ 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.DefaultChunkData;
 import ru.windcorp.progressia.common.world.rels.AbsFace;
 import ru.windcorp.progressia.common.world.rels.RelFace;
 
@@ -69,7 +69,7 @@ public abstract class BlockRenderTexturedCube
 
 	@Override
 	public final void getShapeParts(
-		ChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
+		DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
 		boolean inner,
 		Consumer<ShapePart> output,
 		Vec3 offset
@@ -78,7 +78,7 @@ public abstract class BlockRenderTexturedCube
 	}
 	
 	private ShapePart createFace(
-		ChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
+		DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
 		boolean inner,
 		Vec3 offset
 	) {
@@ -93,7 +93,7 @@ public abstract class BlockRenderTexturedCube
 	}
 
 	@Override
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk) {
 		boolean opaque = isBlockOpaque();
 		
 		ShapePart[] faces = new ShapePart[BLOCK_FACE_COUNT + (opaque ? BLOCK_FACE_COUNT : 0)];

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

@@ -18,8 +18,8 @@
 
 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.DefaultChunkData.BLOCKS_PER_CHUNK;
-import static ru.windcorp.progressia.common.world.generic.GenericTileStack.TILES_PER_FACE;
+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;
@@ -37,7 +37,7 @@ 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.Vectors;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.generic.GenericChunks;
 import ru.windcorp.progressia.common.world.rels.RelFace;
 
@@ -71,7 +71,7 @@ public class ChunkRenderOptimizerSurface extends ChunkRenderOptimizer {
 		 *                        vertices
 		 */
 		void getShapeParts(
-			ChunkData chunk,
+			DefaultChunkData chunk,
 			Vec3i relBlockInChunk,
 			RelFace blockFace,
 			boolean inner,

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

@@ -23,9 +23,9 @@ 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.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;
 	

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

@@ -22,17 +22,17 @@ 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.DefaultChunkData;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
+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 Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk, RelFace face) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk, RelFace face) {
 		return null;
 	}
 

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

@@ -20,7 +20,7 @@ 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.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, RelFace face) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk, RelFace face) {
 		return EmptyModel.getInstance();
 	}
 	

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

@@ -19,9 +19,9 @@ 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.GenericTileReference;
+import ru.windcorp.progressia.common.world.generic.TileGenericReferenceRO;
 
 public interface TileRenderReference
-	extends GenericTileReference<BlockRender, TileRender, TileRenderStack, TileRenderReference, ChunkRender> {
+	extends TileGenericReferenceRO<BlockRender, TileRender, TileRenderStack, TileRenderReference, ChunkRender> {
 
 }

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

@@ -18,13 +18,15 @@
  
 package ru.windcorp.progressia.client.world.tile;
 
+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.generic.GenericTileStack;
+import ru.windcorp.progressia.common.world.TileDataStack;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import ru.windcorp.progressia.common.world.generic.TileGenericStackRO;
-
 public abstract class TileRenderStack
-	extends GenericTileStack<BlockRender, TileRender, TileRenderStack, TileRenderReference, 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

@@ -33,7 +33,7 @@ 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.DefaultChunkData;
 import ru.windcorp.progressia.common.world.rels.AbsFace;
 import ru.windcorp.progressia.common.world.rels.RelFace;
 
@@ -60,7 +60,7 @@ public abstract class TileRenderSurface extends TileRender implements TileOptimi
 	
 	@Override
 	public final void getShapeParts(
-		ChunkData chunk, Vec3i relBlockInChunk, RelFace blockFace,
+		DefaultChunkData chunk, Vec3i relBlockInChunk, RelFace blockFace,
 		boolean inner,
 		Consumer<ShapePart> output,
 		Vec3 offset
@@ -69,7 +69,7 @@ public abstract class TileRenderSurface extends TileRender implements TileOptimi
 	}
 	
 	private ShapePart createFace(
-		ChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
+		DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace,
 		boolean inner,
 		Vec3 offset
 	) {
@@ -84,7 +84,7 @@ public abstract class TileRenderSurface extends TileRender implements TileOptimi
 	}
 
 	@Override
-	public Renderable createRenderable(ChunkData chunk, Vec3i blockInChunk, RelFace blockFace) {
+	public Renderable createRenderable(DefaultChunkData chunk, Vec3i blockInChunk, RelFace blockFace) {
 		return new Shape(
 			Usage.STATIC,
 			WorldRenderProgram.getDefault(),

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/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
 	) {
@@ -361,7 +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/state/StateChange.java

@@ -16,12 +16,9 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package ru.windcorp.progressia.common.world.tile;
+package ru.windcorp.progressia.common.state;
-
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockData;
-import ru.windcorp.progressia.common.world.generic.GenericTileReference;
-
-public interface TileDataReference extends GenericTileReference<BlockData, TileData, TileDataStack, TileDataReference, ChunkData> {
 
+@FunctionalInterface
+public interface StateChange<T> {
+	void change(T object);
 }

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

@@ -1,527 +1,14 @@
-/*
- * 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.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.generic.ChunkGenericWO;
-import ru.windcorp.progressia.common.world.generic.GenericWritableChunk;
-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.TileDataReference;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
-import ru.windcorp.progressia.common.world.tile.TileStackIsFullException;
 
-public class ChunkData
+public interface ChunkData extends ChunkDataRO, ChunkGenericWO<BlockData, TileData, TileDataStack, TileDataReference, ChunkData> {
-	implements GenericWritableChunk<BlockData, TileData, TileDataStack, TileDataReference, ChunkData> {
 	
-	public static final int BLOCKS_PER_CHUNK = Coordinates.CHUNK_SIZE;
+//	@Override
-	public static final int CHUNK_RADIUS = BLOCKS_PER_CHUNK / 2;
+//	default TileDataStack getTiles(Vec3i blockInChunk, BlockFace face) {
-
+//		return null;
-	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 final AbsFace up;
-
-	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;
-		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 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);
-	}
-
-	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 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 = 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 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 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 (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) {
-			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) {
-					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/ChunkDataListener.java

@@ -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) {
 	}
 
 	/**
@@ -53,7 +53,7 @@ public interface ChunkDataListener {
 	 *                     {@code false} iff the tile has been removed
 	 */
 	default void onChunkTilesChanged(
-		ChunkData chunk,
+		DefaultChunkData chunk,
 		Vec3i blockInChunk,
 		RelFace face,
 		TileData tile,
@@ -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 +1,525 @@
+/*
+ * 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;
+
+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 = 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 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/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

@@ -61,7 +61,7 @@ public class PacketSetGravityModel extends PacketAffectWorld {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		GravityModel model = GravityModelRegistry.getInstance().create(gravityModelId);
 		world.setGravityModel(model);
 		try {

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

@@ -1,245 +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.WorldGenericWO;
-import ru.windcorp.progressia.common.world.generic.ChunkSet;
+import ru.windcorp.progressia.common.world.rels.BlockFace;
-import ru.windcorp.progressia.common.world.generic.GenericWritableWorld;
-import ru.windcorp.progressia.common.world.generic.LongBasedChunkMap;
 import ru.windcorp.progressia.common.world.tile.TileData;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
-import ru.windcorp.progressia.common.world.tile.TileDataReference;
 
-public class WorldData
+public interface WorldData
-	implements GenericWritableWorld<BlockData, TileData, TileDataStack, TileDataReference, ChunkData, EntityData> {
+	extends WorldDataRO, WorldGenericWO<BlockData, TileData, TileDataStack, TileDataReference, ChunkData, EntityData> {
-
-	private final ChunkMap<ChunkData> chunksByPos = new LongBasedChunkMap<>(
-		TCollections.synchronizedMap(new TLongObjectHashMap<>())
-	);
-
-	private final Collection<ChunkData> 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 WorldData() {
-
-	}
 
 	@Override
-	public ChunkData getChunk(Vec3i pos) {
+	default TileDataStack getTiles(Vec3i blockInWorld, BlockFace face) {
-		return chunksByPos.get(pos);
+		return (TileDataStack) WorldDataRO.super.getTiles(blockInWorld, face);
-	}
-
-	@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);
-	}
-
-	@Override
-	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);
-	}
-
-	@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());
-	}
-
-	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();
 	}
 
 	/**
-	 * @return the gravity model
+	 * 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()
 	 */
-	public GravityModel getGravityModel() {
+	void advanceTime(float change);
-		return gravityModel;
-	}
 	
-	/**
+	/*
-	 * @param gravityModel the gravity model to set
+	 * Method specialization
 	 */
-	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;
+	@Override
+	ChunkData getChunk(Vec3i pos);
+	
+	@Override
+	Collection<? extends ChunkData> getChunks();
+	
+	// TODO: rename WGRO.forEachChunk -> forEachChunkRO and define WGWO.forEachChunk
+	
+	@Override
+	default ChunkData getChunkByBlock(Vec3i blockInWorld) {
+		return (ChunkData) WorldDataRO.super.getChunkByBlock(blockInWorld);
 	}
 	
-	public Collection<WorldDataListener> getListeners() {
+	@Override
-		return listeners;
+	default TileDataStack getTilesOrNull(Vec3i blockInWorld, BlockFace face) {
-	}
+		return (TileDataStack) WorldDataRO.super.getTilesOrNull(blockInWorld, face);
-
-	public void addListener(WorldDataListener e) {
-		listeners.add(e);
-	}
-
-	public void removeListener(WorldDataListener o) {
-		listeners.remove(o);
 	}
 
 }

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/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/entity/EntityData.java

@@ -32,10 +32,10 @@ import ru.windcorp.progressia.common.collision.CollisionModel;
 import ru.windcorp.progressia.common.state.IOContext;
 import ru.windcorp.progressia.common.state.StatefulObject;
 import ru.windcorp.progressia.common.util.Matrices;
-import ru.windcorp.progressia.common.world.generic.GenericEntity;
+import ru.windcorp.progressia.common.world.generic.EntityGeneric;
 import ru.windcorp.progressia.common.world.rels.AbsFace;
 
-public class EntityData extends StatefulObject implements Collideable, GenericEntity {
+public class EntityData extends StatefulObject implements Collideable, EntityGeneric {
 
 	private final Vec3 position = new Vec3();
 	private final Vec3 velocity = new Vec3();

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

@@ -24,7 +24,7 @@ import java.io.IOException;
 
 import ru.windcorp.progressia.common.world.DecodingException;
 import ru.windcorp.progressia.common.world.PacketAffectWorld;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class PacketAffectEntity extends PacketAffectWorld {
 
@@ -53,7 +53,7 @@ public class PacketAffectEntity extends PacketAffectWorld {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		world.removeEntity(this.entityId);
 	}
 

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

@@ -26,7 +26,7 @@ import ru.windcorp.progressia.common.state.IOContext;
 import ru.windcorp.progressia.common.util.DataBuffer;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class PacketChangeEntity extends PacketAffectEntity {
 
@@ -68,7 +68,7 @@ public class PacketChangeEntity extends PacketAffectEntity {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		EntityData entity = world.getEntity(getEntityId());
 
 		if (entity == null) {

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

@@ -23,7 +23,7 @@ import java.io.DataOutput;
 import java.io.IOException;
 
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class PacketRevokeEntity extends PacketAffectEntity {
 
@@ -51,7 +51,7 @@ public class PacketRevokeEntity extends PacketAffectEntity {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		world.removeEntity(getEntityId());
 	}
 

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

@@ -26,7 +26,7 @@ import ru.windcorp.progressia.common.state.IOContext;
 import ru.windcorp.progressia.common.util.DataBuffer;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class PacketSendEntity extends PacketAffectEntity {
 
@@ -85,7 +85,7 @@ public class PacketSendEntity extends PacketAffectEntity {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		EntityData entity = EntityDataRegistry.getInstance().create(getEntityTypeId());
 
 		entity.setEntityId(getEntityId());

src/main/java/ru/windcorp/progressia/common/world/generic/BlockGeneric.java

@@ -18,7 +18,7 @@
  
 package ru.windcorp.progressia.common.world.generic;
 
-public interface GenericBlock {
+public interface BlockGeneric {
 
 	String getId();
 

src/main/java/ru/windcorp/progressia/common/world/generic/ChunkGenericRO.java

@@ -32,37 +32,37 @@ import ru.windcorp.progressia.common.world.rels.BlockFace;
 
 /**
  * An unmodifiable chunk representation. Per default, it is usually one of
- * {@link ru.windcorp.progressia.common.world.ChunkData ChunkData},
+ * {@link ru.windcorp.progressia.common.world.DefaultChunkData ChunkData},
  * {@link ru.windcorp.progressia.client.world.ChunkRender ChunkRender} or
  * {@link ru.windcorp.progressia.server.world.ChunkLogic ChunkLogic}, but this
  * interface may be implemented differently for various reasons.
  * <p>
- * A generic chunk contains {@linkplain GenericBlock blocks} and
+ * A generic chunk contains {@linkplain BlockGeneric blocks} and
- * {@linkplain GenericTileStack tile stacks} and is characterized by its
+ * {@linkplain TileGenericStackRO tile stacks} and is characterized by its
  * location. It also bears a discrete up direction. Note that no
- * {@linkplain GenericWorld world} object is directly accessible through this
+ * {@linkplain WorldGenericRO world} object is directly accessible through this
  * interface.
  * <p>
  * This interface defines the most common methods for examining a chunk and
  * implements many of them as default methods. It also contains several static
  * methods useful when dealing with chunks. {@code GenericChunk} does not
- * provide a way to modify a chunk; use {@link GenericWritableChunk} methods
+ * provide a way to modify a chunk; use {@link ChunkGenericWO} methods
  * when applicable.
  * 
  * @param <Self> a reference to itself (required to properly reference a
- *               {@link GenericTileStack})
+ *               {@link TileGenericStackRO})
  * @param <B>    block type
  * @param <T>    tile type
  * @param <TS>   tile stack type
  * @author javapony
  */
 // @formatter:off
-public interface GenericChunk<
+public interface ChunkGenericRO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
-	TR extends GenericTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
-	C  extends GenericChunk         <B, T, TS, TR, C>
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>
 > {
 // @formatter:on
 

src/main/java/ru/windcorp/progressia/common/world/generic/ChunkGenericWO.java

@@ -0,0 +1,37 @@
+/*
+ * 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.generic;
+
+import glm.vec._3.i.Vec3i;
+import ru.windcorp.progressia.common.world.rels.BlockFace;
+
+// @formatter:off
+public interface ChunkGenericWO<
+	B  extends BlockGeneric,
+	T  extends TileGeneric,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>
+> {
+// @formatter:on
+
+	void setBlock(Vec3i posInChunk, B block, boolean notify);
+
+	TS getTiles(Vec3i blockInChunk, BlockFace face);
+
+}

src/main/java/ru/windcorp/progressia/common/world/generic/ChunkMap.java

@@ -77,27 +77,27 @@ public interface ChunkMap<V> {
 	// TODO implement (int, int, int) and GenericChunk versions of all of the
 	// above
 
-	default boolean containsChunk(GenericChunk<?, ?, ?, ?, ?> chunk) {
+	default boolean containsChunk(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 		return containsKey(chunk.getPosition());
 	}
 
-	default V get(GenericChunk<?, ?, ?, ?, ?> chunk) {
+	default V get(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 		return get(chunk.getPosition());
 	}
 
-	default V put(GenericChunk<?, ?, ?, ?, ?> chunk, V obj) {
+	default V put(ChunkGenericRO<?, ?, ?, ?, ?> chunk, V obj) {
 		return put(chunk.getPosition(), obj);
 	}
 
-	default V remove(GenericChunk<?, ?, ?, ?, ?> chunk) {
+	default V remove(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 		return remove(chunk.getPosition());
 	}
 
-	default V getOrDefault(GenericChunk<?, ?, ?, ?, ?> chunk, V def) {
+	default V getOrDefault(ChunkGenericRO<?, ?, ?, ?, ?> chunk, V def) {
 		return containsChunk(chunk) ? def : get(chunk);
 	}
 
-	default <C extends GenericChunk<?, ?, ?, ?, C>> V compute(
+	default <C extends ChunkGenericRO<?, ?, ?, ?, C>> V compute(
 		C chunk,
 		BiFunction<? super C, ? super V, ? extends V> remappingFunction
 	) {
@@ -128,8 +128,8 @@ public interface ChunkMap<V> {
 
 	void forEach(BiConsumer<? super Vec3i, ? super V> action);
 
-	default <C extends GenericChunk<?, ?, ?, ?, C>> void forEachIn(
+	default <C extends ChunkGenericRO<?, ?, ?, ?, C>> void forEachIn(
-		GenericWorld<?, ?, ?, ?, C, ?> world,
+		WorldGenericRO<?, ?, ?, ?, C, ?> world,
 		BiConsumer<? super C, ? super V> action
 	) {
 		forEach((pos, value) -> {

src/main/java/ru/windcorp/progressia/common/world/generic/ChunkMaps.java

@@ -174,42 +174,42 @@ public class ChunkMaps {
 		}
 
 		@Override
-		public boolean containsChunk(GenericChunk<?, ?, ?, ?, ?> chunk) {
+		public boolean containsChunk(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 			synchronized (mutex) {
 				return parent.containsChunk(chunk);
 			}
 		}
 
 		@Override
-		public V get(GenericChunk<?, ?, ?, ?, ?> chunk) {
+		public V get(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 			synchronized (mutex) {
 				return parent.get(chunk);
 			}
 		}
 
 		@Override
-		public V put(GenericChunk<?, ?, ?, ?, ?> chunk, V obj) {
+		public V put(ChunkGenericRO<?, ?, ?, ?, ?> chunk, V obj) {
 			synchronized (mutex) {
 				return parent.put(chunk, obj);
 			}
 		}
 
 		@Override
-		public V remove(GenericChunk<?, ?, ?, ?, ?> chunk) {
+		public V remove(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 			synchronized (mutex) {
 				return parent.remove(chunk);
 			}
 		}
 
 		@Override
-		public V getOrDefault(GenericChunk<?, ?, ?, ?, ?> chunk, V def) {
+		public V getOrDefault(ChunkGenericRO<?, ?, ?, ?, ?> chunk, V def) {
 			synchronized (mutex) {
 				return parent.getOrDefault(chunk, def);
 			}
 		}
 
 		@Override
-		public <C extends GenericChunk<?, ?, ?, ?, C>> V compute(
+		public <C extends ChunkGenericRO<?, ?, ?, ?, C>> V compute(
 			C chunk,
 			BiFunction<? super C, ? super V, ? extends V> remappingFunction
 		) {
@@ -247,8 +247,8 @@ public class ChunkMaps {
 		}
 
 		@Override
-		public <C extends GenericChunk<?, ?, ?, ?, C>> void forEachIn(
+		public <C extends ChunkGenericRO<?, ?, ?, ?, C>> void forEachIn(
-			GenericWorld<?, ?, ?, ?, C, ?> world,
+			WorldGenericRO<?, ?, ?, ?, C, ?> world,
 			BiConsumer<? super C, ? super V> action
 		) {
 			synchronized (mutex) {

src/main/java/ru/windcorp/progressia/common/world/generic/ChunkSet.java

@@ -78,20 +78,20 @@ public interface ChunkSet extends Iterable<Vec3i> {
 		return result;
 	}
 
-	default boolean contains(GenericChunk<?, ?, ?, ?, ?> chunk) {
+	default boolean contains(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 		return contains(chunk.getPosition());
 	}
 
-	default boolean add(GenericChunk<?, ?, ?, ?, ?> chunk) {
+	default boolean add(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 		return add(chunk.getPosition());
 	}
 
-	default boolean remove(GenericChunk<?, ?, ?, ?, ?> chunk) {
+	default boolean remove(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 		return remove(chunk.getPosition());
 	}
 
-	default <C extends GenericChunk<?, ?, ?, ?, C>> void forEachIn(
+	default <C extends ChunkGenericRO<?, ?, ?, ?, C>> void forEachIn(
-		GenericWorld<?, ?, ?, ?, C, ?> world,
+		WorldGenericRO<?, ?, ?, ?, C, ?> world,
 		Consumer<? super C> action
 	) {
 		forEach(position -> {
@@ -210,7 +210,7 @@ public interface ChunkSet extends Iterable<Vec3i> {
 		}
 	}
 
-	default boolean containsAllChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+	default boolean containsAllChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 		boolean[] hasMissing = new boolean[] { false };
 
 		chunks.forEach(c -> {
@@ -222,7 +222,7 @@ public interface ChunkSet extends Iterable<Vec3i> {
 		return hasMissing[0];
 	}
 
-	default boolean containsAnyChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+	default boolean containsAnyChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 		boolean[] hasPresent = new boolean[] { false };
 
 		chunks.forEach(c -> {
@@ -234,11 +234,11 @@ public interface ChunkSet extends Iterable<Vec3i> {
 		return hasPresent[0];
 	}
 
-	default void addAllChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+	default void addAllChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 		chunks.forEach(this::add);
 	}
 
-	default void removeAllChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+	default void removeAllChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 		chunks.forEach(this::remove);
 	}
 

src/main/java/ru/windcorp/progressia/common/world/generic/ChunkSets.java

@@ -198,29 +198,29 @@ public class ChunkSets {
 		}
 
 		@Override
-		public boolean contains(GenericChunk<?, ?, ?, ?, ?> chunk) {
+		public boolean contains(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 			synchronized (mutex) {
 				return parent.contains(chunk);
 			}
 		}
 
 		@Override
-		public boolean add(GenericChunk<?, ?, ?, ?, ?> chunk) {
+		public boolean add(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 			synchronized (mutex) {
 				return parent.add(chunk);
 			}
 		}
 
 		@Override
-		public boolean remove(GenericChunk<?, ?, ?, ?, ?> chunk) {
+		public boolean remove(ChunkGenericRO<?, ?, ?, ?, ?> chunk) {
 			synchronized (mutex) {
 				return parent.remove(chunk);
 			}
 		}
 
 		@Override
-		public <C extends GenericChunk<?, ?, ?, ?, C>> void forEachIn(
+		public <C extends ChunkGenericRO<?, ?, ?, ?, C>> void forEachIn(
-			GenericWorld<?, ?, ?, ?, C, ?> world,
+			WorldGenericRO<?, ?, ?, ?, C, ?> world,
 			Consumer<? super C> action
 		) {
 			synchronized (mutex) {
@@ -320,28 +320,28 @@ public class ChunkSets {
 		}
 
 		@Override
-		public boolean containsAllChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+		public boolean containsAllChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 			synchronized (mutex) {
 				return parent.containsAllChunks(chunks);
 			}
 		}
 
 		@Override
-		public boolean containsAnyChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+		public boolean containsAnyChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 			synchronized (mutex) {
 				return parent.containsAnyChunks(chunks);
 			}
 		}
 
 		@Override
-		public void addAllChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+		public void addAllChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 			synchronized (mutex) {
 				parent.addAllChunks(chunks);
 			}
 		}
 
 		@Override
-		public void removeAllChunks(Iterable<? extends GenericChunk<?, ?, ?, ?, ?>> chunks) {
+		public void removeAllChunks(Iterable<? extends ChunkGenericRO<?, ?, ?, ?, ?>> chunks) {
 			synchronized (mutex) {
 				parent.removeAllChunks(chunks);
 			}

src/main/java/ru/windcorp/progressia/common/world/generic/EntityGeneric.java

@@ -22,7 +22,7 @@ import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.world.Coordinates;
 
-public interface GenericEntity {
+public interface EntityGeneric {
 
 	String getId();
 	

src/main/java/ru/windcorp/progressia/common/world/generic/GenericChunks.java

@@ -34,7 +34,7 @@ public class GenericChunks {
 			output = new Vec3i();
 		}
 
-		final int offset = GenericChunk.BLOCKS_PER_CHUNK - 1;
+		final int offset = ChunkGenericRO.BLOCKS_PER_CHUNK - 1;
 
 		output.set(relativeCoords.x, relativeCoords.y, relativeCoords.z);
 		output.mul(2).sub(offset);
@@ -51,7 +51,7 @@ public class GenericChunks {
 			output = new Vec3i();
 		}
 
-		final int offset = GenericChunk.BLOCKS_PER_CHUNK - 1;
+		final int offset = ChunkGenericRO.BLOCKS_PER_CHUNK - 1;
 
 		output.set(absoluteCoords.x, absoluteCoords.y, absoluteCoords.z);
 		output.mul(2).sub(offset);
@@ -73,7 +73,7 @@ public class GenericChunks {
 		return hits;
 	}
 	
-	static boolean testBiC(Vec3i blockInWorld, GenericChunk<?, ?, ?, ?, ?> chunk, Predicate<Vec3i> test) {
+	static boolean testBiC(Vec3i blockInWorld, ChunkGenericRO<?, ?, ?, ?, ?> chunk, Predicate<Vec3i> test) {
 		Vec3i v = Vectors.grab3i();
 
 		v = Coordinates.getInWorld(chunk.getPosition(), Vectors.ZERO_3i, v);
@@ -87,9 +87,9 @@ public class GenericChunks {
 	}
 
 	public static boolean containsBiC(Vec3i blockInChunk) {
-		return blockInChunk.x >= 0 && blockInChunk.x < GenericChunk.BLOCKS_PER_CHUNK &&
+		return blockInChunk.x >= 0 && blockInChunk.x < ChunkGenericRO.BLOCKS_PER_CHUNK &&
-			blockInChunk.y >= 0 && blockInChunk.y < GenericChunk.BLOCKS_PER_CHUNK &&
+			blockInChunk.y >= 0 && blockInChunk.y < ChunkGenericRO.BLOCKS_PER_CHUNK &&
-			blockInChunk.z >= 0 && blockInChunk.z < GenericChunk.BLOCKS_PER_CHUNK;
+			blockInChunk.z >= 0 && blockInChunk.z < ChunkGenericRO.BLOCKS_PER_CHUNK;
 	}
 
 	public static boolean isSurfaceBiC(Vec3i blockInChunk) {
@@ -109,9 +109,9 @@ public class GenericChunks {
 			0,
 			0,
 			0,
-			GenericChunk.BLOCKS_PER_CHUNK,
+			ChunkGenericRO.BLOCKS_PER_CHUNK,
-			GenericChunk.BLOCKS_PER_CHUNK,
+			ChunkGenericRO.BLOCKS_PER_CHUNK,
-			GenericChunk.BLOCKS_PER_CHUNK,
+			ChunkGenericRO.BLOCKS_PER_CHUNK,
 			action
 		);
 	}

src/main/java/ru/windcorp/progressia/common/world/generic/GenericWritableChunk.java

@@ -1,43 +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.generic;
-
-import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.util.Vectors;
-
-// @formatter:off
-public interface GenericWritableChunk<
-	B  extends GenericBlock,
-	T  extends GenericTile,
-	TS extends GenericWritableTileStack <B, T, TS, TR, C>,
-	TR extends GenericTileReference     <B, T, TS, TR, C>,
-	C  extends GenericWritableChunk     <B, T, TS, TR, C>
->
-	extends GenericChunk<B, T, TS, TR, C> {
-// @formatter:on
-
-	void setBlock(Vec3i posInChunk, B block, boolean notify);
-
-	default void setBlockRel(Vec3i relativeBlockInChunk, B block, boolean notify) {
-		Vec3i absoluteBlockInChunk = Vectors.grab3i();
-		resolve(relativeBlockInChunk, absoluteBlockInChunk);
-		setBlock(absoluteBlockInChunk, block, notify);
-		Vectors.release(absoluteBlockInChunk);
-	}
-
-}

src/main/java/ru/windcorp/progressia/common/world/generic/LongBasedChunkSet.java

@@ -45,7 +45,7 @@ public class LongBasedChunkSet implements ChunkSet {
 		addAll(copyFrom);
 	}
 
-	public LongBasedChunkSet(TLongSet impl, GenericWorld<?, ?, ?, ?, ?, ?> copyFrom) {
+	public LongBasedChunkSet(TLongSet impl, WorldGenericRO<?, ?, ?, ?, ?, ?> copyFrom) {
 		this(impl);
 		addAllChunks(copyFrom.getChunks());
 	}

src/main/java/ru/windcorp/progressia/common/world/generic/TileGeneric.java

@@ -18,7 +18,7 @@
  
 package ru.windcorp.progressia.common.world.generic;
 
-public interface GenericTile {
+public interface TileGeneric {
 
 	String getId();
 

src/main/java/ru/windcorp/progressia/common/world/generic/TileGenericReferenceRO.java

@@ -0,0 +1,50 @@
+/*
+ * 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.generic;
+
+// @formatter:off
+public interface TileGenericReferenceRO<
+	B  extends BlockGeneric,
+	T  extends TileGeneric,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>
+> {
+// @formatter:on
+
+	T get();
+
+	int getIndex();
+
+	TS getStack();
+
+	default boolean isValid() {
+		return get() != null;
+	}
+	
+	default int getTag() {
+		TS tileStack = getStack();
+		if (tileStack == null) {
+			return -1;
+		} else {
+			return tileStack.getTagByIndex(getIndex());
+		}
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/generic/TileGenericReferenceWO.java

@@ -19,23 +19,15 @@
 package ru.windcorp.progressia.common.world.generic;
 
 // @formatter:off
-public interface GenericTileReference<
+public interface TileGenericReferenceWO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
-	TR extends GenericTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
-	C  extends GenericChunk         <B, T, TS, TR, C>
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>
 > {
 // @formatter:on
 	
-	T get();
+	// currently empty
-
-	int getIndex();
-
-	TS getStack();
-
-	default boolean isValid() {
-		return get() != null;
-	}
 
 }

src/main/java/ru/windcorp/progressia/common/world/generic/TileGenericStackRO.java

@@ -18,7 +18,7 @@
  
 package ru.windcorp.progressia.common.world.generic;
 
-import java.util.AbstractList;
+import java.util.List;
 import java.util.Objects;
 import java.util.RandomAccess;
 import java.util.function.Consumer;
@@ -28,13 +28,13 @@ import ru.windcorp.progressia.common.world.Coordinates;
 import ru.windcorp.progressia.common.world.rels.RelFace;
 
 // @formatter:off
-public abstract class GenericTileStack<
+public interface TileGenericStackRO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
-	TR extends GenericTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
-	C  extends GenericChunk         <B, T, TS, TR, C>
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>
-> extends AbstractList<T> implements RandomAccess {
+> extends List<T>, RandomAccess {
 // @formatter:on
 
 	public static interface TSConsumer<T> {
@@ -43,36 +43,36 @@ public abstract class GenericTileStack<
 
 	public static final int TILES_PER_FACE = 8;
 
-	public abstract Vec3i getBlockInChunk(Vec3i output);
+	Vec3i getBlockInChunk(Vec3i output);
 
-	public abstract C getChunk();
+	C getChunk();
 
-	public abstract RelFace getFace();
+	RelFace getFace();
 
-	public abstract TR getReference(int index);
+	TR getReference(int index);
 
-	public abstract int getIndexByTag(int tag);
+	int getIndexByTag(int tag);
 
-	public abstract int getTagByIndex(int index);
+	int getTagByIndex(int index);
 
-	public Vec3i getBlockInWorld(Vec3i output) {
+	default Vec3i getBlockInWorld(Vec3i output) {
 		// This is safe
 		return Coordinates.getInWorld(getChunk().getPosition(), getBlockInChunk(output), output);
 	}
 
-	public boolean isFull() {
+	default boolean isFull() {
 		return size() >= TILES_PER_FACE;
 	}
 
-	public T getClosest() {
+	default T getClosest() {
 		return get(0);
 	}
 
-	public T getFarthest() {
+	default T getFarthest() {
 		return get(size() - 1);
 	}
 
-	public void forEach(TSConsumer<T> action) {
+	default void forEach(TSConsumer<T> action) {
 		Objects.requireNonNull(action, "action");
 		for (int i = 0; i < size(); ++i) {
 			action.accept(i, get(i));
@@ -80,14 +80,14 @@ public abstract class GenericTileStack<
 	}
 
 	@Override
-	public void forEach(Consumer<? super T> action) {
+	default void forEach(Consumer<? super T> action) {
 		Objects.requireNonNull(action, "action");
 		for (int i = 0; i < size(); ++i) {
 			action.accept(get(i));
 		}
 	}
 
-	public T findClosest(String id) {
+	default T findClosest(String id) {
 		Objects.requireNonNull(id, "id");
 
 		for (int i = 0; i < size(); ++i) {
@@ -100,7 +100,7 @@ public abstract class GenericTileStack<
 		return null;
 	}
 
-	public T findFarthest(String id) {
+	default T findFarthest(String id) {
 		Objects.requireNonNull(id, "id");
 
 		for (int i = 0; i < size(); ++i) {
@@ -113,11 +113,11 @@ public abstract class GenericTileStack<
 		return null;
 	}
 
-	public boolean contains(String id) {
+	default boolean contains(String id) {
 		return findClosest(id) != null;
 	}
 
-	public B getHost() {
+	default B getHost() {
 		return getChunk().getBlock(getBlockInChunk(null));
 	}
 

src/main/java/ru/windcorp/progressia/common/world/generic/TileGenericStackWO.java

@@ -18,15 +18,18 @@
 
 package ru.windcorp.progressia.common.world.generic;
 
+import java.util.List;
+import java.util.RandomAccess;
+
 // @formatter:off
-public abstract class GenericWritableTileStack<
+public interface TileGenericStackWO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericWritableTileStack<B, T, TS, TR, C>,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
-	TR extends GenericTileReference<B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
-	C  extends GenericWritableChunk<B, T, TS, TR, C>
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>
 >
-	extends GenericTileStack<B, T, TS, TR, C> {
+	extends List<T>, RandomAccess {
 // @formatter:on
 
 	/**
@@ -45,7 +48,7 @@ public abstract class GenericWritableTileStack<
 	 * make sure to override it in subclass
 	 */
 	@Override
-	public abstract void add(int index, T tile);
+	void add(int index, T tile);
 
 	/**
 	 * Adds the specified tile at the end of this stack assigning it the
@@ -59,7 +62,7 @@ public abstract class GenericWritableTileStack<
 	 *                                  with the
 	 *                                  provided tag
 	 */
-	public abstract void load(T tile, int tag);
+	void load(T tile, int tag);
 
 	/**
 	 * Replaces the tile at the specified position in this stack with the
@@ -74,7 +77,7 @@ public abstract class GenericWritableTileStack<
 	 * make sure to override it in subclass
 	 */
 	@Override
-	public abstract T set(int index, T tile);
+	T set(int index, T tile);
 
 	/**
 	 * Removes the tile at the specified position in this list. Shifts any
@@ -91,20 +94,22 @@ public abstract class GenericWritableTileStack<
 	 * make sure to override it in subclass
 	 */
 	@Override
-	public abstract T remove(int index);
+	T remove(int index);
 
 	/*
 	 * Aliases and overloads
 	 */
 
-	public void addClosest(T tile) {
+	default void addClosest(T tile) {
 		add(0, tile);
 	}
 
-	public void addFarthest(T tile) {
+	default void addFarthest(T tile) {
 		add(size(), tile);
 	}
 	
+	boolean isFull();
+
 	/**
 	 * Attempts to {@link #add(int, TileData) add} the provided {@code tile}
 	 * at {@code index}. If the stack is {@linkplain #isFull() full}, does
@@ -114,45 +119,45 @@ public abstract class GenericWritableTileStack<
 	 * @param tile  the tile to try to add
 	 * @return {@code true} iff this stack has changed
 	 */
-	public boolean offer(int index, T tile) {
+	default boolean offer(int index, T tile) {
 		if (isFull())
 			return false;
 		add(index, tile);
 		return true;
 	}
 
-	public boolean offerClosest(T tile) {
+	default boolean offerClosest(T tile) {
 		return offer(0, tile);
 	}
 
-	public boolean offerFarthest(T tile) {
+	default boolean offerFarthest(T tile) {
 		return offer(size(), tile);
 	}
 
-	public T removeClosest() {
+	default T removeClosest() {
 		return remove(0);
 	}
 
-	public T removeFarthest() {
+	default T removeFarthest() {
 		return remove(size() - 1);
 	}
 
-	public T poll(int index) {
+	default T poll(int index) {
 		if (size() <= index)
 			return null;
 		return remove(index);
 	}
 
-	public T pollClosest() {
+	default T pollClosest() {
 		return poll(0);
 	}
 
-	public T pollFarthest() {
+	default T pollFarthest() {
 		return poll(size() - 1);
 	}
 
 	@Override
-	public boolean add(T tile) {
+	default boolean add(T tile) {
 		addFarthest(tile);
 		return true;
 	}

src/main/java/ru/windcorp/progressia/common/world/generic/WorldGenericRO.java

@@ -30,17 +30,17 @@ import ru.windcorp.progressia.common.world.rels.AbsFace;
 import ru.windcorp.progressia.common.world.rels.BlockFace;
 
 // @formatter:off
-public interface GenericWorld<
+public interface WorldGenericRO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
-	TR extends GenericTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
-	C  extends GenericChunk         <B, T, TS, TR, C>,
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
 > {
 // @formatter:on	
 
-	Collection<C> getChunks();
+	Collection<? extends C> getChunks();
 
 	C getChunk(Vec3i pos);
 
@@ -131,6 +131,15 @@ public interface GenericWorld<
 		return stack.get(layer);
 	}
 
+	/**
+	 * Determines whether the specified position has a tile.
+	 * 
+	 * @return {@code true} iff the tile exists
+	 */
+	default boolean hasTile(Vec3i location, BlockFace face, int layer) {
+		return hasTile(location, face, layer);
+	}
+
 	default boolean isChunkLoaded(Vec3i chunkPos) {
 		return getChunk(chunkPos) != null;
 	}

src/main/java/ru/windcorp/progressia/common/world/generic/WorldGenericWO.java

@@ -18,21 +18,24 @@
 package ru.windcorp.progressia.common.world.generic;
 
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.world.block.BlockData;
+import ru.windcorp.progressia.common.state.StateChange;
+import ru.windcorp.progressia.common.state.StatefulObject;
+import ru.windcorp.progressia.common.world.rels.BlockFace;
 
 //@formatter:off
-public interface GenericWritableWorld<
+public interface WorldGenericWO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericWritableTileStack <B, T, TS, TR, C>,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
-	TR extends GenericTileReference     <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
-	C  extends GenericWritableChunk     <B, T, TS, TR, C>,
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
->
+> {
-	extends GenericWorld<B, T, TS, TR, C, E> {
 //@formatter:on
 
-	void setBlock(Vec3i blockInWorld, BlockData block, boolean notify);
+	void setBlock(Vec3i blockInWorld, B block, boolean notify);
+
+	TS getTiles(Vec3i blockInWorld, BlockFace face);
 
 	void addEntity(E entity);
 
@@ -42,4 +45,13 @@ public interface GenericWritableWorld<
 		removeEntity(entity.getEntityId());
 	}
 
+	/**
+	 * Requests that the specified change is applied to the given entity. The
+	 * {@code change} object provided may be stored until the change is applied.
+	 * 
+	 * @param entity the entity to change
+	 * @param change the change to apply
+	 */
+	<SE extends StatefulObject & EntityGeneric> void changeEntity(SE entity, StateChange<SE> change);
+
 }

src/main/java/ru/windcorp/progressia/common/world/generic/context/BlockFaceGenericContextRO.java

@@ -18,13 +18,7 @@
 package ru.windcorp.progressia.common.world.generic.context;
 
 import ru.windcorp.progressia.common.world.context.Context;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+import ru.windcorp.progressia.common.world.generic.*;
-import ru.windcorp.progressia.common.world.generic.GenericROChunk;
-import ru.windcorp.progressia.common.world.generic.GenericEntity;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
-import ru.windcorp.progressia.common.world.generic.GenericROTileReference;
-import ru.windcorp.progressia.common.world.generic.GenericROTileStack;
-import ru.windcorp.progressia.common.world.rels.RelFace;
 
 /**
  * A {@link Context} referencing a world with a block location and a block face
@@ -32,23 +26,16 @@ import ru.windcorp.progressia.common.world.rels.RelFace;
  * not actually exist.
  */
 //@formatter:off
-public interface GenericROBlockFaceContext<
+public interface BlockFaceGenericContextRO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericROTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
-	C  extends GenericROChunk         <B, T, TS, TR, C>,
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends GenericROBlockContext<B, T, TS, TR, C, E> {
+> extends WorldContexts.BlockFace, BlockGenericContextRO<B, T, TS, TR, C, E> {
 //@formatter:on
 
-	/**
-	 * Returns the face relevant to this context.
-	 * 
-	 * @return the block face
-	 */
-	RelFace getFace();
-
 	/**
 	 * Gets the tile stack at the relevant position.
 	 * 

src/main/java/ru/windcorp/progressia/common/world/generic/context/BlockFaceGenericContextWO.java

@@ -28,14 +28,14 @@ import ru.windcorp.progressia.common.world.generic.*;
  * stack may or may not actually exist.
  */
 //@formatter:off
-public interface GenericRWBlockFaceContext<
+public interface BlockFaceGenericContextWO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericRWTileStack <B, T, TS, TR, C>,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference     <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
-	C  extends GenericRWChunk     <B, T, TS, TR, C>,
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends GenericRWBlockContext<B, T, TS, TR, C, E>, GenericROBlockFaceContext<B, T, TS, TR, C, E> {
+> extends WorldContexts.BlockFace, BlockGenericContextWO<B, T, TS, TR, C, E> {
 //@formatter:on
 
 	/**
@@ -63,16 +63,4 @@ public interface GenericRWBlockFaceContext<
 		removeTile(getLocation(), getFace(), tag);
 	}
 
-	/**
-	 * Requests that the referenced tile is removed from the specified tile
-	 * stack. If the tile could not be found at the time of application this
-	 * method fails silently. The location and the face of the block are implied
-	 * by the context.
-	 * 
-	 * @param tileReference a reference to the tile
-	 */
-	default void removeTile(TR tileReference) {
-		removeTile(getLocation(), getFace(), tileReference.getTag());
-	}
-
 }

src/main/java/ru/windcorp/progressia/common/world/generic/context/BlockGenericContextRO.java

@@ -17,14 +17,8 @@
  */
 package ru.windcorp.progressia.common.world.generic.context;
 
-import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.world.context.Context;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+import ru.windcorp.progressia.common.world.generic.*;
-import ru.windcorp.progressia.common.world.generic.GenericROChunk;
-import ru.windcorp.progressia.common.world.generic.GenericEntity;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
-import ru.windcorp.progressia.common.world.generic.GenericROTileReference;
-import ru.windcorp.progressia.common.world.generic.GenericROTileStack;
 import ru.windcorp.progressia.common.world.rels.BlockFace;
 
 /**
@@ -32,29 +26,16 @@ import ru.windcorp.progressia.common.world.rels.BlockFace;
  * location may or may not be loaded.
  */
 //@formatter:off
-public interface GenericROBlockContext<
+public interface BlockGenericContextRO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericROTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
-	C  extends GenericROChunk         <B, T, TS, TR, C>,
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends GenericROWorldContext<B, T, TS, TR, C, E> {
+> extends WorldContexts.Block, WorldGenericContextRO<B, T, TS, TR, C, E> {
 //@formatter:on
 
-	/**
-	 * Returns the location of the block.
-	 * <p>
-	 * The coordinate system in use is not specified, but it is consistent
-	 * across all methods of this context.
-	 * <p>
-	 * The object returned by this method must not be modified. It is only valid
-	 * while the context is {@linkplain valid}.
-	 * 
-	 * @return a vector describing the block's position
-	 */
-	Vec3i getLocation();
-
 	/**
 	 * Determines whether the location relevant to this context is currently
 	 * loaded.

src/main/java/ru/windcorp/progressia/common/world/generic/context/BlockGenericContextWO.java

@@ -28,14 +28,14 @@ import ru.windcorp.progressia.common.world.rels.BlockFace;
  * {@link #isImmediate()}. The location may or may not be loaded.
  */
 //@formatter:off
-public interface GenericRWBlockContext<
+public interface BlockGenericContextWO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericRWTileStack <B, T, TS, TR, C>,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference     <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
-	C  extends GenericRWChunk     <B, T, TS, TR, C>,
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends GenericRWWorldContext<B, T, TS, TR, C, E>, GenericROBlockContext<B, T, TS, TR, C, E> {
+> extends WorldContexts.Block, WorldGenericContextWO<B, T, TS, TR, C, E> {
 //@formatter:on
 
 	/**
@@ -76,17 +76,4 @@ public interface GenericRWBlockContext<
 		removeTile(getLocation(), face, tag);
 	}
 
-	/**
-	 * Requests that the referenced tile is removed from the specified tile
-	 * stack. If the tile could not be found at the time of application this
-	 * method fails silently. The location of the block is implied by the
-	 * context.
-	 * 
-	 * @param face          the of the block to remove the tile from
-	 * @param tileReference a reference to the tile
-	 */
-	default void removeTile(BlockFace face, TR tileReference) {
-		removeTile(getLocation(), face, tileReference.getTag());
-	}
-
 }

src/main/java/ru/windcorp/progressia/common/world/generic/context/TileGenericContextRO.java

@@ -18,12 +18,7 @@
 package ru.windcorp.progressia.common.world.generic.context;
 
 import ru.windcorp.progressia.common.world.context.Context;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+import ru.windcorp.progressia.common.world.generic.*;
-import ru.windcorp.progressia.common.world.generic.GenericROChunk;
-import ru.windcorp.progressia.common.world.generic.GenericEntity;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
-import ru.windcorp.progressia.common.world.generic.GenericROTileReference;
-import ru.windcorp.progressia.common.world.generic.GenericROTileStack;
 
 /**
  * A {@link Context} referencing a world with a block location, a block face and
@@ -31,23 +26,16 @@ import ru.windcorp.progressia.common.world.generic.GenericROTileStack;
  * or may not actually exist.
  */
 //@formatter:off
-public interface GenericROTileContext<
+public interface TileGenericContextRO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericROTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
-	C  extends GenericROChunk         <B, T, TS, TR, C>,
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends GenericROBlockFaceContext<B, T, TS, TR, C, E> {
+> extends WorldContexts.Tile, BlockFaceGenericContextRO<B, T, TS, TR, C, E> {
 //@formatter:on
 
-	/**
-	 * Returns the tile layer relevant to this context.
-	 * 
-	 * @return the tile layer
-	 */
-	int getLayer();
-
 	/**
 	 * Determines whether the location relevant to this context has a tile.
 	 * 
@@ -67,12 +55,7 @@ public interface GenericROTileContext<
 		return getTile(getLocation(), getFace(), getLayer());
 	}
 
-	/**
+	@Override
-	 * Gets the tag of the tile at the relevant position.
-	 * 
-	 * @return the tag of the tile or {@code -1} if the location is not loaded
-	 *         or the tile does not exist
-	 */
 	default int getTag() {
 		TS tileStack = getTilesOrNull();
 		if (tileStack == null) {
@@ -82,4 +65,23 @@ public interface GenericROTileContext<
 		return tileStack.getTagByIndex(getLayer());
 	}
 
+	/**
+	 * Gets the {@link TileGenericReferenceRO TileReference} to the relevant
+	 * tile.
+	 * 
+	 * @return the reference to the tile relevant to this context or
+	 *         {@code null} if the location is not loaded or the tile does not
+	 *         exist
+	 *         
+	 * @see TileGenericStackRO#getReference(int)
+	 */
+	default TR getTileReference() {
+		TS tileStack = getTilesOrNull();
+		if (tileStack == null) {
+			return null;
+		}
+
+		return tileStack.getReference(getLayer());
+	}
+
 }

src/main/java/ru/windcorp/progressia/common/world/generic/context/TileGenericContextWO.java

@@ -28,14 +28,14 @@ import ru.windcorp.progressia.common.world.generic.*;
  * The tile may or may not actually exist.
  */
 //@formatter:off
-public interface GenericRWTileContext<
+public interface TileGenericContextWO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericRWTileStack <B, T, TS, TR, C>,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference     <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
-	C  extends GenericRWChunk     <B, T, TS, TR, C>,
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends GenericRWBlockFaceContext<B, T, TS, TR, C, E>, GenericROTileContext<B, T, TS, TR, C, E> {
+> extends WorldContexts.Tile, BlockFaceGenericContextWO<B, T, TS, TR, C, E> {
 //@formatter:on
 
 	/**

src/main/java/ru/windcorp/progressia/common/world/generic/context/WorldContexts.java

@@ -0,0 +1,127 @@
+/*
+ * 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.generic.context;
+
+import glm.vec._3.i.Vec3i;
+import ru.windcorp.progressia.common.world.context.Context;
+import ru.windcorp.progressia.common.world.rels.RelFace;
+
+/**
+ * This class defines several {@link Context} subinterfaces that are further
+ * extended by Generic contexts. These interfaces declare methods for
+ * determining which location is "relevant" to the context. Since they are not
+ * Java generics they can safely be extended more than once.
+ * <p>
+ * Do not reuse these interfaces outside the Generic contexts' package; consider
+ * them to be an implementation detail.
+ * 
+ * @author javapony
+ *
+ */
+class WorldContexts {
+
+	/**
+	 * A {@link Context} with a world instance. This interface should not be
+	 * implemented directly; see {@link WorldGenericContextRO} or
+	 * {@link WorldGenericContextWO}.
+	 * 
+	 * @author javapony
+	 *
+	 */
+	public static interface World extends Context {
+
+		// currently empty
+
+	}
+
+	/**
+	 * A {@link Context} with a world instance and a block location. This interface
+	 * should not be implemented directly; see {@link BlockGenericContextRO} or
+	 * {@link BlockGenericContextWO}.
+	 * 
+	 * @author javapony
+	 *
+	 */
+	public static interface Block extends World {
+
+		/**
+		 * Returns the location of the block.
+		 * <p>
+		 * The coordinate system in use is not specified, but it is consistent across
+		 * all methods of this context.
+		 * <p>
+		 * The object returned by this method must not be modified. It is only valid
+		 * while the context is {@linkplain valid}.
+		 * 
+		 * @return a vector describing the block's position
+		 */
+		Vec3i getLocation();
+
+	}
+
+	/**
+	 * A {@link Context} with a world instance, a block location and a block face
+	 * (block side). This interface should not be implemented directly; see
+	 * {@link BlockFaceGenericContextRO} or {@link BlockFaceGenericContextWO}.
+	 * 
+	 * @author javapony
+	 *
+	 */
+	public static interface BlockFace extends Block {
+
+		/**
+		 * Returns the face relevant to this context.
+		 * 
+		 * @return the block face
+		 */
+		RelFace getFace();
+
+	}
+
+	/**
+	 * A {@link Context} with a world instance, a block location, a block face
+	 * (block side) and a tile layer. This interface should not be implemented
+	 * directly; see {@link TileGenericContextRO} or {@link TileGenericContextWO}.
+	 * 
+	 * @author javapony
+	 *
+	 */
+	public static interface Tile extends BlockFace {
+
+		/**
+		 * Returns the tile layer relevant to this context.
+		 * 
+		 * @return the tile layer
+		 */
+		int getLayer();
+
+		/**
+		 * Gets the tag of the tile at the relevant position.
+		 * 
+		 * @return the tag of the tile or {@code -1} if the location is not loaded
+		 *         or the tile does not exist
+		 */
+		int getTag();
+
+	}
+
+	WorldContexts() {
+	}
+
+}

src/main/java/ru/windcorp/progressia/common/world/generic/context/WorldGenericContextRO.java

@@ -18,26 +18,20 @@
 package ru.windcorp.progressia.common.world.generic.context;
 
 import ru.windcorp.progressia.common.world.context.Context;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+import ru.windcorp.progressia.common.world.generic.*;
-import ru.windcorp.progressia.common.world.generic.GenericROChunk;
-import ru.windcorp.progressia.common.world.generic.GenericEntity;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
-import ru.windcorp.progressia.common.world.generic.GenericROTileReference;
-import ru.windcorp.progressia.common.world.generic.GenericROTileStack;
-import ru.windcorp.progressia.common.world.generic.GenericROWorld;
 
 /**
  * A {@link Context} with a world instance.
  */
 // @formatter:off
-public interface GenericROWorldContext<
+public interface WorldGenericContextRO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericROTileStack     <B, T, TS, TR, C>,
+	TS extends TileGenericStackRO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceRO <B, T, TS, TR, C>,
-	C  extends GenericROChunk         <B, T, TS, TR, C>,
+	C  extends ChunkGenericRO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends Context, GenericROWorld<B, T, TS, TR, C, E> {
+> extends WorldContexts.World, WorldGenericRO<B, T, TS, TR, C, E> {
 // @formatter:on
 	
 	// currently empty

src/main/java/ru/windcorp/progressia/common/world/generic/context/WorldGenericContextWO.java

@@ -30,14 +30,14 @@ import ru.windcorp.progressia.common.world.rels.BlockFace;
  * may not be immediate, see {@link #isImmediate()}.
  */
 // @formatter:off
-public interface GenericRWWorldContext<
+public interface WorldGenericContextWO<
-	B  extends GenericBlock,
+	B  extends BlockGeneric,
-	T  extends GenericTile,
+	T  extends TileGeneric,
-	TS extends GenericRWTileStack <B, T, TS, TR, C>,
+	TS extends TileGenericStackWO     <B, T, TS, TR, C>,
-	TR extends GenericROTileReference     <B, T, TS, TR, C>,
+	TR extends TileGenericReferenceWO <B, T, TS, TR, C>,
-	C  extends GenericRWChunk     <B, T, TS, TR, C>,
+	C  extends ChunkGenericWO         <B, T, TS, TR, C>,
-	E  extends GenericEntity
+	E  extends EntityGeneric
-> extends GenericROWorldContext<B, T, TS, TR, C, E>, GenericRWWorld<B, T, TS, TR, C, E> {
+> extends WorldContexts.World, WorldGenericWO<B, T, TS, TR, C, E> {
 // @formatter:on
 
 	/**
@@ -92,17 +92,20 @@ public interface GenericRWWorldContext<
 	void removeTile(Vec3i location, BlockFace face, int tag);
 
 	/**
-	 * Requests that the referenced tile is removed from the specified tile
+	 * Requests that the referenced tile is removed from its tile stack. If the
-	 * stack. If the tile could not be found at the time of application this
+	 * tile could not be found at the time of application this method fails
-	 * method fails silently.
+	 * silently.
 	 * 
-	 * @param location      the location of the block from which the tile is to
-	 *                      be removed
-	 * @param face          the of the block to remove the tile from
 	 * @param tileReference a reference to the tile
 	 */
-	default void removeTile(Vec3i location, BlockFace face, TR tileReference) {
+	default void removeTile(TileGenericReferenceRO<?, ?, ?, ?, ?> tileReference) {
-		removeTile(location, face, tileReference.getTag());
+		TileGenericStackRO<?, ?, ?, ?, ?> tileStack = tileReference.getStack();
+
+		if (tileStack == null) {
+			return;
+		}
+
+		removeTile(tileStack.getBlockInWorld(null), tileStack.getFace(), tileReference.getTag());
 	}
 
 	/**
@@ -123,7 +126,7 @@ public interface GenericRWWorldContext<
 	 * 
 	 * @param entityId the ID of the entity to remove
 	 * @see #isImmediate()
-	 * @see #removeEntity(GenericEntity)
+	 * @see #removeEntity(EntityGeneric)
 	 */
 	@Override
 	void removeEntity(long entityId);
@@ -140,12 +143,13 @@ public interface GenericRWWorldContext<
 	void removeEntity(E entity);
 
 	/**
-	 * Requests that the specified change is applied to the given entity. The {@code change} object provided may be stored until the change is applied.
+	 * Requests that the specified change is applied to the given entity. The
+	 * {@code change} object provided may be stored until the change is applied.
 	 * 
 	 * @param entity the entity to change
 	 * @param change the change to apply
 	 */
 	@Override
-	<SE extends StatefulObject & GenericEntity> void changeEntity(SE entity, StateChange<SE> change);
+	<SE extends StatefulObject & EntityGeneric> void changeEntity(SE entity, StateChange<SE> change);
 
 }

src/main/java/ru/windcorp/progressia/common/world/io/ChunkCodec.java

@@ -25,9 +25,9 @@ import java.io.IOException;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.state.IOContext;
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public abstract class ChunkCodec extends Namespaced {
 
@@ -46,12 +46,12 @@ public abstract class ChunkCodec extends Namespaced {
 		return signature;
 	}
 
-	public abstract ChunkData decode(WorldData world, Vec3i position, DataInputStream input, IOContext context)
+	public abstract DefaultChunkData decode(DefaultWorldData world, Vec3i position, DataInputStream input, IOContext context)
 		throws DecodingException,
 		IOException;
 
-	public abstract boolean shouldEncode(ChunkData chunk, IOContext context);
+	public abstract boolean shouldEncode(DefaultChunkData chunk, IOContext context);
 
-	public abstract void encode(ChunkData chunk, DataOutputStream output, IOContext context) throws IOException;
+	public abstract void encode(DefaultChunkData chunk, DataOutputStream output, IOContext context) throws IOException;
 
 }

src/main/java/ru/windcorp/progressia/common/world/io/ChunkIO.java

@@ -31,16 +31,16 @@ import gnu.trove.map.TByteObjectMap;
 import gnu.trove.map.hash.TByteObjectHashMap;
 import ru.windcorp.progressia.common.state.IOContext;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class ChunkIO {
 
 	private static final TByteObjectMap<ChunkCodec> CODECS_BY_ID = new TByteObjectHashMap<>();
 	private static final List<ChunkCodec> CODECS_BY_PRIORITY = new ArrayList<>();
 
-	public static ChunkData load(WorldData world, Vec3i position, DataInputStream data, IOContext context)
+	public static DefaultChunkData load(DefaultWorldData world, Vec3i position, DataInputStream data, IOContext context)
 		throws DecodingException,
 		IOException {
 		if (CODECS_BY_ID.isEmpty())
@@ -73,7 +73,7 @@ public class ChunkIO {
 		}
 	}
 
-	public static void save(ChunkData chunk, DataOutputStream output, IOContext context)
+	public static void save(DefaultChunkData chunk, DataOutputStream output, IOContext context)
 		throws IOException {
 		ChunkCodec codec = getCodec(chunk, context);
 
@@ -100,7 +100,7 @@ public class ChunkIO {
 		return CODECS_BY_ID.get(signature);
 	}
 
-	public static ChunkCodec getCodec(ChunkData chunk, IOContext context) {
+	public static ChunkCodec getCodec(DefaultChunkData chunk, IOContext context) {
 		for (ChunkCodec codec : CODECS_BY_PRIORITY) {
 			if (codec.shouldEncode(chunk, context)) {
 				return codec;

src/main/java/ru/windcorp/progressia/common/world/tile/PacketAddTile.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;
 import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 public class PacketAddTile extends PacketAffectTile {
@@ -61,7 +61,7 @@ public class PacketAddTile extends PacketAffectTile {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		TileData tile = TileDataRegistry.getInstance().get(getTileId());
 		world.getTiles(getBlockInWorld(), getFace()).add(tile);
 	}

src/main/java/ru/windcorp/progressia/common/world/tile/PacketRemoveTile.java

@@ -25,7 +25,8 @@ import java.io.IOException;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
+import ru.windcorp.progressia.common.world.TileDataStack;
 import ru.windcorp.progressia.common.world.rels.AbsFace;
 
 public class PacketRemoveTile extends PacketAffectTile {
@@ -54,7 +55,7 @@ public class PacketRemoveTile extends PacketAffectTile {
 	}
 
 	@Override
-	public void apply(WorldData world) {
+	public void apply(DefaultWorldData world) {
 		TileDataStack stack = world.getTiles(getBlockInWorld(), getFace());
 
 		int index = stack.getIndexByTag(getTag());

src/main/java/ru/windcorp/progressia/common/world/tile/TileData.java

@@ -19,9 +19,9 @@
 package ru.windcorp.progressia.common.world.tile;
 
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
+import ru.windcorp.progressia.common.world.generic.TileGeneric;
 
-public class TileData extends Namespaced implements GenericTile {
+public class TileData extends Namespaced implements TileGeneric {
 
 	public TileData(String id) {
 		super(id);

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

@@ -1,28 +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.tile;
-
-import ru.windcorp.progressia.common.world.ChunkData;
-import ru.windcorp.progressia.common.world.block.BlockData;
-import ru.windcorp.progressia.common.world.generic.GenericWritableTileStack;
-
-public abstract class TileDataStack
-	extends GenericWritableTileStack<BlockData, TileData, TileDataStack, TileDataReference, ChunkData> {
-
-}

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

@@ -22,7 +22,7 @@ import java.util.function.Consumer;
 
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.Units;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.Coordinates;
 import ru.windcorp.progressia.common.world.PlayerData;
 import ru.windcorp.progressia.common.world.entity.EntityData;
@@ -55,7 +55,7 @@ public class Player extends PlayerData implements ChunkLoader {
 		Coordinates.convertInWorldToChunk(start, start);
 
 		Vec3i cursor = new Vec3i();
-		float radius = getServer().getLoadDistance(this) / Units.get(ChunkData.BLOCKS_PER_CHUNK, "m");
+		float radius = getServer().getLoadDistance(this) / Units.get(DefaultChunkData.BLOCKS_PER_CHUNK, "m");
 
 		float radiusSq = radius * radius;
 		int iRadius = (int) Math.ceil(radius);

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

@@ -28,7 +28,7 @@ import ru.windcorp.jputil.functions.ThrowingRunnable;
 import ru.windcorp.progressia.common.Units;
 import ru.windcorp.progressia.common.util.TaskQueue;
 import ru.windcorp.progressia.common.util.crash.ReportingEventBus;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.server.comms.ClientManager;
 import ru.windcorp.progressia.server.events.ServerEvent;
 import ru.windcorp.progressia.server.management.load.ChunkRequestDaemon;
@@ -68,7 +68,7 @@ public class Server {
 
 	private final TickingSettings tickingSettings = new TickingSettings();
 
-	public Server(WorldData world) {
+	public Server(DefaultWorldData world) {
 		this.world = new WorldLogic(
 			world,
 			this,

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

@@ -18,7 +18,7 @@
  
 package ru.windcorp.progressia.server;
 
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 
 public class ServerState {
 
@@ -33,7 +33,7 @@ public class ServerState {
 	}
 
 	public static void startServer() {
-		Server server = new Server(new WorldData());
+		Server server = new Server(new DefaultWorldData());
 		setInstance(server);
 		server.start();
 	}

src/main/java/ru/windcorp/progressia/server/management/load/ChunkManager.java

@@ -18,10 +18,10 @@
 package ru.windcorp.progressia.server.management.load;
 
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.PacketRevokeChunk;
 import ru.windcorp.progressia.common.world.PacketSendChunk;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.server.Player;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.test.TestWorldDiskIO;
@@ -113,9 +113,9 @@ public class ChunkManager {
 			return LoadResult.ALREADY_LOADED;
 		}
 
-		WorldData world = getServer().getWorld().getData();
+		DefaultWorldData world = getServer().getWorld().getData();
 
-		ChunkData chunk = TestWorldDiskIO.tryToLoad(chunkPos, world, getServer());
+		DefaultChunkData chunk = TestWorldDiskIO.tryToLoad(chunkPos, world, getServer());
 		if (chunk != null) {
 			world.addChunk(chunk);
 			return LoadResult.LOADED_FROM_DISK;
@@ -133,8 +133,8 @@ public class ChunkManager {
 	 *         this method
 	 */
 	public boolean unloadChunk(Vec3i chunkPos) {
-		WorldData world = getServer().getWorld().getData();
+		DefaultWorldData world = getServer().getWorld().getData();
-		ChunkData chunk = world.getChunk(chunkPos);
+		DefaultChunkData chunk = world.getChunk(chunkPos);
 
 		if (chunk == null) {
 			return false;
@@ -147,7 +147,7 @@ public class ChunkManager {
 	}
 
 	public void sendChunk(Player player, Vec3i chunkPos) {
-		ChunkData chunk = getServer().getWorld().getData().getChunk(chunkPos);
+		DefaultChunkData chunk = getServer().getWorld().getData().getChunk(chunkPos);
 
 		if (chunk == null) {
 			throw new IllegalStateException(
@@ -180,7 +180,7 @@ public class ChunkManager {
 
 	/**
 	 * Checks whether or not the chunk at the specified location is loaded. A
-	 * loaded chunk is accessible through the server's {@link WorldData} object.
+	 * loaded chunk is accessible through the server's {@link DefaultWorldData} object.
 	 * 
 	 * @param chunkPos the position of the chunk
 	 * @return {@code true} iff the chunk is loaded

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

@@ -26,14 +26,14 @@ import java.util.WeakHashMap;
 import java.util.function.BiConsumer;
 
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.Coordinates;
-import ru.windcorp.progressia.common.world.generic.GenericChunk;
+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;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import ru.windcorp.progressia.common.world.TileDataStack;
-import ru.windcorp.progressia.common.world.tile.TileDataReference;
+import ru.windcorp.progressia.common.world.TileDataReference;
 import ru.windcorp.progressia.server.world.block.BlockLogic;
 import ru.windcorp.progressia.server.world.block.BlockLogicRegistry;
 import ru.windcorp.progressia.server.world.block.TickableBlock;
@@ -45,10 +45,10 @@ import ru.windcorp.progressia.server.world.tile.TileLogicReference;
 import ru.windcorp.progressia.server.world.tile.TileLogicRegistry;
 import ru.windcorp.progressia.server.world.tile.TileLogicStack;
 
-public class ChunkLogic implements GenericChunk<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic> {
+public class ChunkLogic implements ChunkGenericRO<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic> {
 
 	private final WorldLogic world;
-	private final ChunkData data;
+	private final DefaultChunkData data;
 
 	private final Collection<Vec3i> tickingBlocks = new ArrayList<>();
 	private final Collection<TileDataReference> tickingTiles = new ArrayList<>();
@@ -58,7 +58,7 @@ public class ChunkLogic implements GenericChunk<BlockLogic, TileLogic, TileLogic
 	private final Map<TileDataStack, TileLogicStackImpl> tileLogicLists = Collections
 		.synchronizedMap(new WeakHashMap<>());
 
-	public ChunkLogic(WorldLogic world, ChunkData data) {
+	public ChunkLogic(WorldLogic world, DefaultChunkData data) {
 		this.world = world;
 		this.data = data;
 
@@ -103,7 +103,7 @@ public class ChunkLogic implements GenericChunk<BlockLogic, TileLogic, TileLogic
 		return world;
 	}
 
-	public ChunkData getData() {
+	public DefaultChunkData getData() {
 		return data;
 	}
 

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

@@ -21,7 +21,7 @@ package ru.windcorp.progressia.server.world;
 import java.util.function.Consumer;
 
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.generic.GenericChunks;
 import ru.windcorp.progressia.common.world.rels.AbsFace;
 import ru.windcorp.progressia.server.world.block.BlockTickContext;
@@ -34,7 +34,7 @@ public interface ChunkTickContext extends TickContext {
 		return getWorld().getChunk(getChunk());
 	}
 
-	default ChunkData getChunkData() {
+	default DefaultChunkData getChunkData() {
 		ChunkLogic chunkLogic = getChunkLogic();
 		return chunkLogic == null ? null : chunkLogic.getData();
 	}

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

@@ -20,7 +20,7 @@ package ru.windcorp.progressia.server.world;
 
 import java.util.Random;
 
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.tasks.WorldAccessor;
 
@@ -42,7 +42,7 @@ public interface TickContext {
 		return getServer().getAdHocRandom();
 	}
 
-	default WorldData getWorldData() {
+	default DefaultWorldData getWorldData() {
 		return getWorld().getData();
 	}
 

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

@@ -23,13 +23,13 @@ import java.util.function.Consumer;
 import java.util.function.Function;
 
 import glm.vec._3.i.Vec3i;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.Coordinates;
-import ru.windcorp.progressia.common.world.generic.GenericTileStack;
+import ru.windcorp.progressia.common.world.generic.TileGenericStackRO;
 import ru.windcorp.progressia.common.world.rels.BlockFace;
 import ru.windcorp.progressia.common.world.rels.RelFace;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import ru.windcorp.progressia.common.world.TileDataStack;
-import ru.windcorp.progressia.common.world.tile.TileDataReference;
+import ru.windcorp.progressia.common.world.TileDataReference;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.block.BlockTickContext;
 import ru.windcorp.progressia.server.world.tile.TSTickContext;
@@ -109,9 +109,9 @@ public abstract class TickContextMutable implements BlockTickContext, TSTickCont
 
 			Block withBlock(Vec3i blockInWorld);
 
-			TileStack withTS(GenericTileStack<?, ?, ?, ?, ?> tileStack);
+			TileStack withTS(TileGenericStackRO<?, ?, ?, ?, ?> tileStack);
 
-			default Builder.Chunk withChunk(ChunkData chunk) {
+			default Builder.Chunk withChunk(DefaultChunkData chunk) {
 				Objects.requireNonNull(chunk, "chunk");
 				return withChunk(chunk.getPosition());
 			}
@@ -259,7 +259,7 @@ public abstract class TickContextMutable implements BlockTickContext, TSTickCont
 		}
 
 		@Override
-		public TileStack withTS(GenericTileStack<?, ?, ?, ?, ?> tileStack) {
+		public TileStack withTS(TileGenericStackRO<?, ?, ?, ?, ?> tileStack) {
 			Objects.requireNonNull(tileStack, "tileStack");
 
 			return withBlock(
@@ -324,7 +324,7 @@ public abstract class TickContextMutable implements BlockTickContext, TSTickCont
 			final int minX = Coordinates.getInWorld(chunk.x, 0);
 			final int minY = Coordinates.getInWorld(chunk.y, 0);
 			final int minZ = Coordinates.getInWorld(chunk.z, 0);
-			final int size = ChunkData.BLOCKS_PER_CHUNK;
+			final int size = DefaultChunkData.BLOCKS_PER_CHUNK;
 
 			for (v.x = minX; v.x < minX + size; ++v.x) {
 				for (v.y = minY; v.y < minY + size; ++v.y) {

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

@@ -19,7 +19,7 @@
 package ru.windcorp.progressia.server.world;
 
 import glm.vec._3.i.Vec3i;
-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.Coordinates;
 import ru.windcorp.progressia.common.world.block.BlockData;
@@ -37,7 +37,7 @@ public class UpdateTriggerer implements ChunkDataListener {
 
 	@Override
 	public void onChunkBlockChanged(
-		ChunkData chunk,
+		DefaultChunkData chunk,
 		Vec3i blockInChunk,
 		BlockData previous,
 		BlockData current
@@ -47,7 +47,7 @@ public class UpdateTriggerer implements ChunkDataListener {
 
 	@Override
 	public void onChunkTilesChanged(
-		ChunkData chunk,
+		DefaultChunkData chunk,
 		Vec3i blockInChunk,
 		RelFace face,
 		TileData tile,

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

@@ -25,12 +25,12 @@ import java.util.Map;
 import glm.Glm;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
-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.GenericWorld;
+import ru.windcorp.progressia.common.world.generic.WorldGenericRO;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.block.BlockLogic;
 import ru.windcorp.progressia.server.world.generation.WorldGenerator;
@@ -41,20 +41,20 @@ import ru.windcorp.progressia.server.world.tile.TileLogicReference;
 import ru.windcorp.progressia.server.world.tile.TileLogicStack;
 
 public class WorldLogic
-	implements GenericWorld<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic, EntityData
+	implements WorldGenericRO<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic, EntityData
 	// not using EntityLogic because it is stateless
 > {
 
-	private final WorldData data;
+	private final DefaultWorldData data;
 	private final Server server;
 
 	private final WorldGenerator generator;
 
-	private final Map<ChunkData, ChunkLogic> chunks = new HashMap<>();
+	private final Map<DefaultChunkData, ChunkLogic> chunks = new HashMap<>();
 
 	private final Evaluation tickEntitiesTask = new TickEntitiesTask();
 
-	public WorldLogic(WorldData data, Server server, WorldGenerator generator) {
+	public WorldLogic(DefaultWorldData data, Server server, WorldGenerator generator) {
 		this.data = data;
 		this.server = server;
 		
@@ -63,12 +63,12 @@ public class WorldLogic
 
 		data.addListener(new WorldDataListener() {
 			@Override
-			public void onChunkLoaded(WorldData world, ChunkData chunk) {
+			public void onChunkLoaded(DefaultWorldData world, DefaultChunkData chunk) {
 				chunks.put(chunk, new ChunkLogic(WorldLogic.this, chunk));
 			}
 
 			@Override
-			public void beforeChunkUnloaded(WorldData world, ChunkData chunk) {
+			public void beforeChunkUnloaded(DefaultWorldData world, DefaultChunkData chunk) {
 				chunks.remove(chunk);
 			}
 		});
@@ -104,7 +104,7 @@ public class WorldLogic
 		return server;
 	}
 
-	public WorldData getData() {
+	public DefaultWorldData getData() {
 		return data;
 	}
 
@@ -112,8 +112,8 @@ public class WorldLogic
 		return generator;
 	}
 
-	public ChunkData generate(Vec3i chunkPos) {
+	public DefaultChunkData generate(Vec3i chunkPos) {
-		ChunkData chunk = getGenerator().generate(chunkPos);
+		DefaultChunkData chunk = getGenerator().generate(chunkPos);
 		
 		if (!Glm.equals(chunkPos, chunk.getPosition())) {
 			throw CrashReports.report(null, "Generator %s has generated a chunk at (%d; %d; %d) when requested to generate a chunk at (%d; %d; %d)",
@@ -147,7 +147,7 @@ public class WorldLogic
 		return chunk;
 	}
 
-	public ChunkLogic getChunk(ChunkData chunkData) {
+	public ChunkLogic getChunk(DefaultChunkData chunkData) {
 		return chunks.get(chunkData);
 	}
 

src/main/java/ru/windcorp/progressia/server/world/block/BlockLogic.java

@@ -19,10 +19,10 @@
 package ru.windcorp.progressia.server.world.block;
 
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.generic.GenericBlock;
+import ru.windcorp.progressia.common.world.generic.BlockGeneric;
 import ru.windcorp.progressia.common.world.rels.RelFace;
 
-public class BlockLogic extends Namespaced implements GenericBlock {
+public class BlockLogic extends Namespaced implements BlockGeneric {
 
 	public BlockLogic(String id) {
 		super(id);

src/main/java/ru/windcorp/progressia/server/world/generation/AbstractWorldGenerator.java

@@ -23,11 +23,11 @@ import java.io.DataOutputStream;
 import java.io.IOException;
 import java.util.Objects;
 
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.DecodingException;
 import ru.windcorp.progressia.common.world.GravityModel;
 import ru.windcorp.progressia.common.world.GravityModelRegistry;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.WorldLogic;
 
@@ -71,11 +71,11 @@ public abstract class AbstractWorldGenerator<H> extends WorldGenerator {
 
 	protected abstract boolean checkIsChunkReady(H hint);
 
-	protected H getHint(ChunkData chunk) {
+	protected H getHint(DefaultChunkData chunk) {
 		return hintClass.cast(chunk.getGenerationHint());
 	}
 
-	protected void setHint(ChunkData chunk, H hint) {
+	protected void setHint(DefaultChunkData chunk, H hint) {
 		chunk.setGenerationHint(hint);
 	}
 	
@@ -95,7 +95,7 @@ public abstract class AbstractWorldGenerator<H> extends WorldGenerator {
 	}
 	
 	@Override
-	public WorldData getWorldData() {
+	public DefaultWorldData getWorldData() {
 		return server.getWorld().getData();
 	}
 

src/main/java/ru/windcorp/progressia/server/world/generation/WorldGenerator.java

@@ -25,10 +25,10 @@ import java.io.IOException;
 import glm.vec._3.Vec3;
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.DecodingException;
 import ru.windcorp.progressia.common.world.GravityModel;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.WorldLogic;
 
@@ -39,7 +39,7 @@ public abstract class WorldGenerator extends Namespaced {
 		// package-private constructor; extend AbstractWorldGeneration
 	}
 
-	public abstract ChunkData generate(Vec3i chunkPos);
+	public abstract DefaultChunkData generate(Vec3i chunkPos);
 
 	public abstract Object readGenerationHint(DataInputStream input) throws IOException, DecodingException;
 
@@ -53,6 +53,6 @@ public abstract class WorldGenerator extends Namespaced {
 	
 	public abstract Server getServer();
 	public abstract WorldLogic getWorldLogic();
-	public abstract WorldData getWorldData();
+	public abstract DefaultWorldData getWorldData();
 
 }

src/main/java/ru/windcorp/progressia/server/world/tasks/TickChunk.java

@@ -27,9 +27,9 @@ import com.google.common.collect.ImmutableList;
 
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.util.FloatMathUtil;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.rels.AbsFace;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import ru.windcorp.progressia.common.world.TileDataStack;
 import ru.windcorp.progressia.server.Server;
 import ru.windcorp.progressia.server.world.ChunkLogic;
 import ru.windcorp.progressia.server.world.TickContextMutable;
@@ -40,13 +40,13 @@ import ru.windcorp.progressia.server.world.ticking.TickingPolicy;
 import ru.windcorp.progressia.server.world.tile.TSTickContext;
 import ru.windcorp.progressia.server.world.tile.TickableTile;
 import ru.windcorp.progressia.server.world.tile.TileLogic;
-import static ru.windcorp.progressia.common.world.ChunkData.BLOCKS_PER_CHUNK;
+import static ru.windcorp.progressia.common.world.DefaultChunkData.BLOCKS_PER_CHUNK;
 
 public class TickChunk extends Evaluation {
 
-	private static final int CHUNK_VOLUME = ChunkData.BLOCKS_PER_CHUNK *
+	private static final int CHUNK_VOLUME = DefaultChunkData.BLOCKS_PER_CHUNK *
-		ChunkData.BLOCKS_PER_CHUNK *
+		DefaultChunkData.BLOCKS_PER_CHUNK *
-		ChunkData.BLOCKS_PER_CHUNK;
+		DefaultChunkData.BLOCKS_PER_CHUNK;
 
 	private final List<Consumer<Server>> randomTickMethods;
 

src/main/java/ru/windcorp/progressia/server/world/ticking/TickerCoordinator.java

@@ -34,7 +34,7 @@ import com.google.common.collect.ImmutableList;
 
 import ru.windcorp.progressia.common.Units;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
-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.ChunkDataListeners;
 import ru.windcorp.progressia.server.Server;
@@ -105,7 +105,7 @@ public class TickerCoordinator {
 
 		server.getWorld().getData().addListener(ChunkDataListeners.createAdder(new ChunkDataListener() {
 			@Override
-			public void onChunkChanged(ChunkData chunk) {
+			public void onChunkChanged(DefaultChunkData chunk) {
 				if (!canChange.get()) {
 					throw CrashReports.report(null, "A change has been detected during evaluation phase");
 				}

src/main/java/ru/windcorp/progressia/server/world/tile/TSTickContext.java

@@ -22,9 +22,9 @@ import java.util.Objects;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.rels.RelFace;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import ru.windcorp.progressia.common.world.TileDataStack;
 import ru.windcorp.progressia.server.world.ChunkLogic;
 import ru.windcorp.progressia.server.world.TickContextMutable;
 import ru.windcorp.progressia.server.world.block.BlockTickContext;
@@ -54,7 +54,7 @@ public interface TSTickContext extends BlockTickContext {
 	}
 
 	default TileDataStack getTDSOrNull() {
-		ChunkData chunkData = getChunkData();
+		DefaultChunkData chunkData = getChunkData();
 		if (chunkData == null)
 			return null;
 

src/main/java/ru/windcorp/progressia/server/world/tile/TileLogic.java

@@ -19,10 +19,10 @@
 package ru.windcorp.progressia.server.world.tile;
 
 import ru.windcorp.progressia.common.util.namespaces.Namespaced;
-import ru.windcorp.progressia.common.world.generic.GenericTile;
+import ru.windcorp.progressia.common.world.generic.TileGeneric;
 import ru.windcorp.progressia.common.world.rels.RelFace;
 
-public class TileLogic extends Namespaced implements GenericTile {
+public class TileLogic extends Namespaced implements TileGeneric {
 
 	public TileLogic(String id) {
 		super(id);

src/main/java/ru/windcorp/progressia/server/world/tile/TileLogicReference.java

@@ -17,11 +17,11 @@
  */
 package ru.windcorp.progressia.server.world.tile;
 
-import ru.windcorp.progressia.common.world.generic.GenericTileReference;
+import ru.windcorp.progressia.common.world.generic.TileGenericReferenceRO;
 import ru.windcorp.progressia.server.world.ChunkLogic;
 import ru.windcorp.progressia.server.world.block.BlockLogic;
 
 public interface TileLogicReference
-	extends GenericTileReference<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic> {
+	extends TileGenericReferenceRO<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic> {
 
 }

src/main/java/ru/windcorp/progressia/server/world/tile/TileLogicStack.java

@@ -18,13 +18,16 @@
  
 package ru.windcorp.progressia.server.world.tile;
 
-import ru.windcorp.progressia.common.world.generic.GenericTileStack;
+import java.util.AbstractList;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+
+import ru.windcorp.progressia.common.world.TileDataStack;
+import ru.windcorp.progressia.common.world.generic.TileGenericStackRO;
 import ru.windcorp.progressia.server.world.ChunkLogic;
 import ru.windcorp.progressia.server.world.block.BlockLogic;
 
 public abstract class TileLogicStack
-	extends GenericTileStack<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic> {
+	extends AbstractList<TileLogic>
+	implements TileGenericStackRO<BlockLogic, TileLogic, TileLogicStack, TileLogicReference, ChunkLogic> {
 
 	public abstract TileDataStack getData();
 

src/main/java/ru/windcorp/progressia/server/world/tile/TileTickContext.java

@@ -19,8 +19,8 @@
 package ru.windcorp.progressia.server.world.tile;
 
 import ru.windcorp.progressia.common.world.tile.TileData;
-import ru.windcorp.progressia.common.world.tile.TileDataStack;
+import ru.windcorp.progressia.common.world.TileDataStack;
-import ru.windcorp.progressia.common.world.tile.TileDataReference;
+import ru.windcorp.progressia.common.world.TileDataReference;
 
 public interface TileTickContext extends TSTickContext {
 

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

@@ -33,9 +33,9 @@ import gnu.trove.map.TObjectIntMap;
 import gnu.trove.map.hash.TObjectIntHashMap;
 import ru.windcorp.jputil.functions.ThrowingConsumer;
 import ru.windcorp.progressia.common.state.IOContext;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.common.world.block.BlockData;
 import ru.windcorp.progressia.common.world.block.BlockDataRegistry;
 import ru.windcorp.progressia.common.world.generic.GenericChunks;
@@ -76,7 +76,7 @@ public class TestChunkCodec extends ChunkCodec {
 	}
 
 	@Override
-	public boolean shouldEncode(ChunkData chunk, IOContext context) {
+	public boolean shouldEncode(DefaultChunkData chunk, IOContext context) {
 		return true;
 	}
 
@@ -85,13 +85,13 @@ public class TestChunkCodec extends ChunkCodec {
 	 */
 
 	@Override
-	public ChunkData decode(WorldData world, Vec3i position, DataInputStream input, IOContext context)
+	public DefaultChunkData decode(DefaultWorldData world, Vec3i position, DataInputStream input, IOContext context)
 		throws DecodingException,
 		IOException {
 		BlockData[] blockPalette = readBlockPalette(input);
 		TileData[] tilePalette = readTilePalette(input);
 
-		ChunkData chunk = new ChunkData(position, world);
+		DefaultChunkData chunk = new DefaultChunkData(position, world);
 		
 		readBlocks(input, blockPalette, chunk);
 		readTiles(input, tilePalette, chunk);
@@ -121,7 +121,7 @@ public class TestChunkCodec extends ChunkCodec {
 		return palette;
 	}
 
-	private void readBlocks(DataInput input, BlockData[] blockPalette, ChunkData chunk) throws IOException {
+	private void readBlocks(DataInput input, BlockData[] blockPalette, DefaultChunkData chunk) throws IOException {
 		try {
 			GenericChunks.forEachBiC(guard(v -> {
 				chunk.setBlock(v, blockPalette[input.readInt()], false);
@@ -131,7 +131,7 @@ public class TestChunkCodec extends ChunkCodec {
 		}
 	}
 
-	private void readTiles(DataInput input, TileData[] tilePalette, ChunkData chunk) throws IOException {
+	private void readTiles(DataInput input, TileData[] tilePalette, DefaultChunkData chunk) throws IOException {
 		Vec3i bic = new Vec3i();
 
 		while (true) {
@@ -157,7 +157,7 @@ public class TestChunkCodec extends ChunkCodec {
 	 */
 
 	@Override
-	public void encode(ChunkData chunk, DataOutputStream output, IOContext context) throws IOException {
+	public void encode(DefaultChunkData chunk, DataOutputStream output, IOContext context) throws IOException {
 		Palette<BlockData> blockPalette = createBlockPalette(chunk);
 		Palette<TileData> tilePalette = createTilePalette(chunk);
 
@@ -168,13 +168,13 @@ public class TestChunkCodec extends ChunkCodec {
 		writeTiles(chunk, tilePalette, output);
 	}
 
-	private Palette<BlockData> createBlockPalette(ChunkData chunk) {
+	private Palette<BlockData> createBlockPalette(DefaultChunkData chunk) {
 		Palette<BlockData> blockPalette = new Palette<>();
 		GenericChunks.forEachBiC(v -> blockPalette.add(chunk.getBlock(v)));
 		return blockPalette;
 	}
 
-	private Palette<TileData> createTilePalette(ChunkData chunk) {
+	private Palette<TileData> createTilePalette(DefaultChunkData chunk) {
 		Palette<TileData> tilePalette = new Palette<>();
 		chunk.forEachTile((ts, t) -> tilePalette.add(t));
 		return tilePalette;
@@ -196,7 +196,7 @@ public class TestChunkCodec extends ChunkCodec {
 		}
 	}
 
-	private void writeBlocks(ChunkData chunk, Palette<BlockData> blockPalette, DataOutput output) throws IOException {
+	private void writeBlocks(DefaultChunkData chunk, Palette<BlockData> blockPalette, DataOutput output) throws IOException {
 		try {
 			GenericChunks.forEachBiC(guard(v -> {
 				output.writeInt(blockPalette.getNid(chunk.getBlock(v)));
@@ -206,7 +206,7 @@ public class TestChunkCodec extends ChunkCodec {
 		}
 	}
 
-	private void writeTiles(ChunkData chunk, Palette<TileData> tilePalette, DataOutput output) throws IOException {
+	private void writeTiles(DefaultChunkData chunk, Palette<TileData> tilePalette, DataOutput output) throws IOException {
 		Vec3i bic = new Vec3i();
 
 		try {

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

@@ -34,9 +34,9 @@ import org.apache.logging.log4j.Logger;
 
 import glm.vec._3.i.Vec3i;
 import ru.windcorp.progressia.common.state.IOContext;
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.DecodingException;
-import ru.windcorp.progressia.common.world.WorldData;
+import ru.windcorp.progressia.common.world.DefaultWorldData;
 import ru.windcorp.progressia.common.world.io.ChunkIO;
 import ru.windcorp.progressia.server.Server;
 
@@ -47,7 +47,7 @@ public class TestWorldDiskIO {
 
 	private static final boolean ENABLE = false;
 
-	public static void saveChunk(ChunkData chunk, Server server) {
+	public static void saveChunk(DefaultChunkData chunk, Server server) {
 		if (!ENABLE)
 			return;
 
@@ -83,12 +83,12 @@ public class TestWorldDiskIO {
 		}
 	}
 
-	private static void writeGenerationHint(ChunkData chunk, DataOutputStream output, Server server)
+	private static void writeGenerationHint(DefaultChunkData chunk, DataOutputStream output, Server server)
 		throws IOException {
 		server.getWorld().getGenerator().writeGenerationHint(output, chunk.getGenerationHint());
 	}
 
-	public static ChunkData tryToLoad(Vec3i chunkPos, WorldData world, Server server) {
+	public static DefaultChunkData tryToLoad(Vec3i chunkPos, DefaultWorldData world, Server server) {
 		if (!ENABLE)
 			return null;
 
@@ -113,7 +113,7 @@ public class TestWorldDiskIO {
 		}
 
 		try {
-			ChunkData result = load(path, chunkPos, world, server);
+			DefaultChunkData result = load(path, chunkPos, world, server);
 
 			LOG.debug(
 				"Loaded {} {} {}",
@@ -135,7 +135,7 @@ public class TestWorldDiskIO {
 		}
 	}
 
-	private static ChunkData load(Path path, Vec3i chunkPos, WorldData world, Server server)
+	private static DefaultChunkData load(Path path, Vec3i chunkPos, DefaultWorldData world, Server server)
 		throws IOException,
 		DecodingException {
 		try (
@@ -143,13 +143,13 @@ public class TestWorldDiskIO {
 				new InflaterInputStream(new BufferedInputStream(Files.newInputStream(path)))
 			)
 		) {
-			ChunkData chunk = ChunkIO.load(world, chunkPos, input, IOContext.SAVE);
+			DefaultChunkData chunk = ChunkIO.load(world, chunkPos, input, IOContext.SAVE);
 			readGenerationHint(chunk, input, server);
 			return chunk;
 		}
 	}
 
-	private static void readGenerationHint(ChunkData chunk, DataInputStream input, Server server)
+	private static void readGenerationHint(DefaultChunkData chunk, DataInputStream input, Server server)
 		throws IOException,
 		DecodingException {
 		chunk.setGenerationHint(server.getWorld().getGenerator().readGenerationHint(input));

src/main/java/ru/windcorp/progressia/test/gen/TerrainLayer.java

@@ -19,12 +19,12 @@ package ru.windcorp.progressia.test.gen;
 
 import java.util.Random;
 
-import ru.windcorp.progressia.common.world.ChunkData;
+import ru.windcorp.progressia.common.world.DefaultChunkData;
 import ru.windcorp.progressia.common.world.block.BlockData;
 
 @FunctionalInterface
 public interface TerrainLayer {
 
-	BlockData get(float north, float west, float depth, Random random, ChunkData chunk);
+	BlockData get(float north, float west, float depth, Random random, DefaultChunkData chunk);
 	
 }