Fix ChunkDataVersion issues with third party applications

chunky/src/java/se/llbit/chunky/world/Chunk.java

@@ -17,6 +17,7 @@
 package se.llbit.chunky.world;
 
 import se.llbit.chunky.block.minecraft.Air;
+import it.unimi.dsi.fastutil.ints.IntIntImmutablePair;
 import se.llbit.chunky.block.Block;
 import se.llbit.chunky.block.minecraft.Lava;
 import se.llbit.chunky.block.minecraft.Water;
@@ -179,7 +180,8 @@ public synchronized boolean loadChunk(@NotNull Mutable<ChunkData> chunkData, int
 
     surfaceTimestamp = dataTimestamp;
     version = chunkVersion(data);
-    chunkData.set(this.dimension.createChunkData(chunkData.get(), data.get(DATAVERSION).intValue()));
+    IntIntImmutablePair chunkBounds = inclusiveChunkBounds(data);
+    chunkData.set(this.dimension.createChunkData(chunkData.get(), chunkBounds.leftInt(), chunkBounds.rightInt()));
     loadSurface(data, chunkData.get(), yMin, yMax);
     biomesTimestamp = dataTimestamp;
 
@@ -461,8 +463,11 @@ public synchronized void getChunkData(@NotNull Mutable<ChunkData> reuseChunkData
     Tag data = tagFromMap(dataMap);
 
     int dataVersion = data.get(DATAVERSION).intValue();
+
+    IntIntImmutablePair chunkBounds = inclusiveChunkBounds(data);
+
     if(reuseChunkData.get() == null || reuseChunkData.get() instanceof EmptyChunkData) {
-      reuseChunkData.set(dimension.createChunkData(reuseChunkData.get(), dataVersion));
+      reuseChunkData.set(dimension.createChunkData(reuseChunkData.get(), chunkBounds.leftInt(), chunkBounds.rightInt()));
     } else {
       reuseChunkData.get().clear();
     }
@@ -510,6 +515,28 @@ public synchronized void getChunkData(@NotNull Mutable<ChunkData> reuseChunkData
     }
   }
 
+  /**
+   * @return The min and max blockY for a given section array
+   */
+  private IntIntImmutablePair inclusiveChunkBounds(Tag chunkData) {
+    Tag sections = getTagFromNames(chunkData, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
+    int minSectionY = Integer.MAX_VALUE;
+    int maxSectionY = Integer.MIN_VALUE;
+    if (sections.isList()) {
+      for (SpecificTag section : sections.asList()) {
+        byte sectionY = (byte) section.get("Y").byteValue();
+        if (sectionY < minSectionY) {
+          minSectionY = sectionY;
+        }
+        if (sectionY > maxSectionY) {
+          maxSectionY = sectionY;
+        }
+      }
+    }
+
+    return new IntIntImmutablePair(minSectionY << 4, (maxSectionY << 4) + 15);
+  }
+
   /**
    * @return Integer index into a chunk YXZ array
    */

chunky/src/java/se/llbit/chunky/world/CubicDimension.java

@@ -36,7 +36,7 @@ public synchronized File getRegionDirectory() {
   }
 
   @Override
-  public ChunkData createChunkData(ChunkData chunkData, int chunkVersion) {
+  public ChunkData createChunkData(ChunkData chunkData, int minY, int maxY) {
     if (chunkData instanceof GenericChunkData) {
       return chunkData;
     }

chunky/src/java/se/llbit/chunky/world/Dimension.java

@@ -100,18 +100,18 @@ public synchronized Chunk getChunk(ChunkPosition pos) {
    * Returns a ChunkData instance that is compatible with the given chunk version.
    * The provided ChunkData instance may or may not be re-used.
    */
-  public ChunkData createChunkData(@Nullable ChunkData chunkData, int chunkVersion) {
-    if(chunkVersion >= World.VERSION_21W06A) {
-      if(chunkData instanceof GenericChunkData) {
-        return chunkData;
-      }
-      return new GenericChunkData();
-    } else {
-      if(chunkData instanceof SimpleChunkData) {
+  public ChunkData createChunkData(@Nullable ChunkData chunkData, int minY, int maxY) {
+    if (minY >= 0 && maxY <= 255) {
+      if (chunkData instanceof SimpleChunkData) {
         return chunkData;
       }
       return new SimpleChunkData();
     }
+
+    if (chunkData instanceof GenericChunkData) {
+      return chunkData;
+    }
+    return new GenericChunkData();
   }
 
   public Region createRegion(RegionPosition pos) {

chunky/src/java/se/llbit/chunky/world/ImposterCubicChunk.java

@@ -67,7 +67,7 @@ public synchronized boolean loadChunk(@NotNull Mutable<ChunkData> mutableChunkDa
     }
 
     surfaceTimestamp = dataTimestamp;
-    mutableChunkData.set(this.dimension.createChunkData(mutableChunkData.get(), 0)); //chunk version ignored for cubic worlds
+    mutableChunkData.set(this.dimension.createChunkData(mutableChunkData.get(), Integer.MIN_VALUE, Integer.MAX_VALUE));
     ChunkData chunkData = mutableChunkData.get();
     loadSurfaceCubic(data, chunkData, yMin, yMax);
     biomes = IconLayer.UNKNOWN;
@@ -170,7 +170,7 @@ public synchronized void getChunkData(@NotNull Mutable<ChunkData> reuseChunkData
     request.add(LEVEL_TILEENTITIES);
     Map<Integer, Map<String, Tag>> data = getCubeTags(request);
     if(reuseChunkData.get() == null || reuseChunkData.get() instanceof EmptyChunkData) {
-      reuseChunkData.set(dimension.createChunkData(reuseChunkData.get(), 0));
+      reuseChunkData.set(dimension.createChunkData(reuseChunkData.get(), Integer.MIN_VALUE, Integer.MAX_VALUE));
     } else {
       reuseChunkData.get().clear();
     }