Added Chunk#setEnableCachePacket to improve memory usage when needed

src/main/java/net/minestom/server/instance/Chunk.java

@@ -65,6 +65,7 @@ public abstract class Chunk implements Viewable, DataContainer {
     private boolean shouldGenerate;
 
     // Packet cache
+    private volatile boolean enableCachePacket;
     protected volatile boolean packetUpdated;
     private ByteBuf fullDataPacket;
 
@@ -83,6 +84,9 @@ public abstract class Chunk implements Viewable, DataContainer {
         this.chunkZ = chunkZ;
         this.shouldGenerate = shouldGenerate;
 
+        // true by default
+        this.enableCachePacket = true;
+
         if (biomes != null && biomes.length == BIOME_COUNT) {
             this.biomes = biomes;
         } else {
@@ -273,6 +277,30 @@ public abstract class Chunk implements Viewable, DataContainer {
         return shouldGenerate;
     }
 
+    /**
+     * Get if this chunk automatically cache the latest {@link ChunkDataPacket} version.
+     * <p>
+     * Retrieved with {@link #retrieveDataBuffer(Consumer)}.
+     *
+     * @return true if the chunk automatically cache the chunk packet
+     */
+    public boolean enableCachePacket() {
+        return enableCachePacket;
+    }
+
+    /**
+     * Enable or disable the automatic {@link ChunkDataPacket} caching.
+     *
+     * @param enableCachePacket true to enable to chunk packet caching
+     */
+    public synchronized void setEnableCachePacket(boolean enableCachePacket) {
+        this.enableCachePacket = enableCachePacket;
+        if (enableCachePacket && fullDataPacket != null) {
+            this.fullDataPacket.release();
+            this.fullDataPacket = null;
+        }
+    }
+
     /**
      * Get the cached data packet
      * <p>
@@ -285,7 +313,7 @@ public abstract class Chunk implements Viewable, DataContainer {
     }
 
     /**
-     * Set the cached {@link ChunkDataPacket} of this chunk
+     * Set the cached {@link ChunkDataPacket} of this chunk.
      *
      * @param fullDataPacket the new cached chunk packet
      */
@@ -313,7 +341,9 @@ public abstract class Chunk implements Viewable, DataContainer {
         if (data == null || !packetUpdated) {
             // Packet has never been wrote or is outdated, write it
             PacketWriterUtils.writeCallbackPacket(getFreshFullDataPacket(), packet -> {
-                setFullDataPacket(packet);
+                if (enableCachePacket) {
+                    setFullDataPacket(packet);
+                }
                 consumer.accept(packet);
             });
         } else {
@@ -504,7 +534,7 @@ public abstract class Chunk implements Viewable, DataContainer {
      * Get the {@link ChunkDataPacket} to update a single chunk section
      *
      * @param section the chunk section to update
-     * @return the {@link ChunkDataPacket} to update a single chunk sectionl
+     * @return the {@link ChunkDataPacket} to update a single chunk section
      */
     protected ChunkDataPacket getChunkSectionUpdatePacket(int section) {
         ChunkDataPacket chunkDataPacket = getFreshPartialDataPacket();

src/main/java/net/minestom/server/instance/DynamicChunk.java

@@ -38,8 +38,8 @@ public class DynamicChunk extends Chunk {
     protected final short[] customBlocksId = new short[CHUNK_SIZE_X * CHUNK_SIZE_Y * CHUNK_SIZE_Z];
 
     // Used to get all blocks with data (no null)
-    // Key is still chunk coord
-    protected Int2ObjectMap<Data> blocksData = new Int2ObjectOpenHashMap<>(16 * 16); // Start with the size of a single row
+    // Key is still chunk coordinates (see #getBlockIndex)
+    protected Int2ObjectMap<Data> blocksData = new Int2ObjectOpenHashMap<>();
 
     // Contains CustomBlocks' block index which are updatable
     protected IntSet updatableBlocks = new IntOpenHashSet();

src/main/java/net/minestom/server/instance/IChunkLoader.java

@@ -4,6 +4,7 @@ import net.minestom.server.utils.chunk.ChunkCallback;
 
 /**
  * Interface implemented to change the way chunks are loaded/saved.
+ * <p>
  * See {@link MinestomBasicChunkLoader} for the default implementation used in {@link InstanceContainer}.
  */
 public interface IChunkLoader {