Take biome data from same indexes as Mojang ("middle" of 4x4x4 areas)

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_15to1_14_4/packets/WorldPackets.java

@@ -86,19 +86,19 @@ public class WorldPackets {
                         if (chunk.isGroundUp()) {
                             int[] biomeData = chunk.getBiomeData();
                             int[] newBiomeData = new int[1024];
-                            // Now in 4x4x4 areas (x, then z, then y)
-                            // Set the x/z data
-                            int i = 0;
-                            for (int z = 1; z <= 16; z += 4) {
-                                for (int x = 1; x <= 16; x += 4) {
-                                    int biome = biomeData[(x * z) - 1];
-                                    // Extend it on the y axis
-                                    for (int y = 0; y < 1024; y += 16) {
-                                        newBiomeData[i + y] = biome;
-                                    }
-                                    i++;
+                            // Now in 4x4x4 areas - take the biome of each "middle"
+                            for (int i = 0; i < 4; ++i) {
+                                for (int j = 0; j < 4; ++j) {
+                                    int x = (j << 2) + 2;
+                                    int z = (i << 2) + 2;
+                                    int oldIndex = (z << 4 | x);
+                                    newBiomeData[i << 2 | j] = biomeData[oldIndex];
                                 }
                             }
+                            // ... and copy it to the new y layers
+                            for (int i = 1; i < 64; ++i) {
+                                System.arraycopy(newBiomeData, 0, newBiomeData, i * 16, 16);
+                            }
 
                             chunk.setBiomeData(newBiomeData);
                         }