Cache arrays used by RenderableBoxGroup

core/src/main/java/com/seibel/distanthorizons/core/render/renderer/generic/RenderBoxArrayCache.java

@@ -0,0 +1,91 @@
+package com.seibel.distanthorizons.core.render.renderer.generic;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.RemovalNotification;
+import com.seibel.distanthorizons.core.logging.DhLoggerBuilder;
+import org.apache.logging.log4j.Logger;
+
+import java.util.concurrent.ConcurrentMap;
+
+/**
+ * @see RenderableBoxGroup
+ */
+public class RenderBoxArrayCache
+{
+	private static final Logger LOGGER = DhLoggerBuilder.getLogger();
+	
+	public static final int ARRAY_LENGTH_WIDTH = 24;
+	public static final int ARRAY_ID_WIDTH = 8;
+	
+	public static final int ARRAY_LENGTH_OFFSET = 0;
+	public static final int ARRAY_ID_OFFSET = ARRAY_LENGTH_OFFSET + ARRAY_LENGTH_WIDTH;
+	
+	public static final int ARRAY_LENGTH_MASK = (int) Math.pow(2, ARRAY_LENGTH_WIDTH) - 1;
+	public static final int ARRAY_ID_MASK = (int) Math.pow(2, ARRAY_ID_WIDTH) - 1;
+	
+	
+	private static final ConcurrentMap<Integer, float[]> FLOAT_ARRAY_BY_KEY = CacheBuilder.newBuilder()
+			// This number needs to be high enough so that
+			// the number of generic object groups won't cause array thrashing.
+			// For now 512 should be way more than needed, unless
+			// someone adds a boatload of random generic objects.
+			.maximumSize(512)
+			.removalListener((RemovalNotification<Integer, float[]> notification) -> { /* TODO log a warning if arrays start getting removed, that means we may need to re-think how the caching here works */ })
+			.build().asMap();
+	private static final ConcurrentMap<Integer, int[]> INT_ARRAY_BY_KEY = CacheBuilder.newBuilder()
+			.maximumSize(512)
+			.removalListener((RemovalNotification<Integer, int[]> notification) -> {})
+			.build().asMap();
+	
+	
+	
+	//============//
+	// get arrays //
+	//============//
+	
+	/** 
+	 * The ID parameter is to prevent returning the same array
+	 * multiple times when the same length is requested.
+	 */
+	public static float[] getCachedFloatArray(int length, int id)
+	{
+		int key = encodeKey(length, id);
+		return FLOAT_ARRAY_BY_KEY.computeIfAbsent(key, (newKey) ->
+		{
+			int newLength = getLengthFromKey(newKey);
+			return new float[newLength];
+		});
+	}
+	public static int[] getCachedIntArray(int length, int id)
+	{
+		int key = encodeKey(length, id);
+		return INT_ARRAY_BY_KEY.computeIfAbsent(key, (newKey) ->
+		{
+			int newLength = getLengthFromKey(newKey);
+			return new int[newLength];
+		});
+	}
+	
+	
+	
+	//==============//
+	// key encoding //
+	//==============//
+	
+	private static int encodeKey(int arrayLength, int id)
+	{
+		if (id > Byte.MAX_VALUE)
+		{
+			throw new IndexOutOfBoundsException("The array's ID can only be 8 bytes long.");
+		}
+		
+		int data = 0;
+		data |= (arrayLength & ARRAY_LENGTH_MASK);
+		data |= (id & ARRAY_ID_MASK) << ARRAY_ID_OFFSET;
+		return data;
+	}
+	
+	private static int getLengthFromKey(int key) { return (key & ARRAY_LENGTH_MASK); }
+	private static int getIdFromKey(int key) { return ((key >> ARRAY_ID_OFFSET) & ARRAY_ID_MASK); }
+	
+}

core/src/main/java/com/seibel/distanthorizons/core/render/renderer/generic/RenderableBoxGroup.java

@@ -24,7 +24,7 @@ public class RenderableBoxGroup
 			extends AbstractList<DhApiRenderableBox> 
 			implements IDhApiRenderableBoxGroup, Closeable
 	{
-		public final static AtomicInteger NEXT_ID_ATOMIC_INT = new AtomicInteger(0);
+		public static final AtomicInteger NEXT_ID_ATOMIC_INT = new AtomicInteger(0);
 		
 		
 		
@@ -247,9 +247,9 @@ public class RenderableBoxGroup
 			
 			
 			// transformation / scaling //
-			int[] chunkPosData = new int[boxCount * 3];
-			float[] subChunkPosData = new float[boxCount * 3];
-			float[] scalingData = new float[boxCount * 3];
+			int[] chunkPosData = RenderBoxArrayCache.getCachedIntArray(boxCount * 3, 0);
+			float[] subChunkPosData = RenderBoxArrayCache.getCachedFloatArray(boxCount * 3, 1);
+			float[] scalingData = RenderBoxArrayCache.getCachedFloatArray(boxCount * 3, 2);
 			for (int i = 0; i < boxCount; i++)
 			{
 				DhApiRenderableBox box = this.get(i);
@@ -272,8 +272,8 @@ public class RenderableBoxGroup
 			
 			
 			// colors/materials //
-			float[] colorData = new float[boxCount * 4];
-			int[] materialData = new int[boxCount];
+			float[] colorData = RenderBoxArrayCache.getCachedFloatArray(boxCount * 4, 3);
+			int[] materialData = RenderBoxArrayCache.getCachedIntArray(boxCount, 4);
 			for (int i = 0; i < boxCount; i++)
 			{
 				DhApiRenderableBox box = this.get(i);