Implement multi block change packet changes

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_16_2to1_16_1/packets/WorldPackets.java

@@ -1,20 +1,28 @@
 package us.myles.ViaVersion.protocols.protocol1_16_2to1_16_1.packets;
 
+import us.myles.ViaVersion.api.PacketWrapper;
 import us.myles.ViaVersion.api.minecraft.BlockChangeRecord;
+import us.myles.ViaVersion.api.minecraft.BlockChangeRecord1_16_2;
 import us.myles.ViaVersion.api.minecraft.chunks.Chunk;
 import us.myles.ViaVersion.api.minecraft.chunks.ChunkSection;
 import us.myles.ViaVersion.api.protocol.Protocol;
 import us.myles.ViaVersion.api.remapper.PacketRemapper;
 import us.myles.ViaVersion.api.rewriters.BlockRewriter;
 import us.myles.ViaVersion.api.type.Type;
+import us.myles.ViaVersion.protocols.protocol1_16_2to1_16_1.ClientboundPackets1_16_2;
 import us.myles.ViaVersion.protocols.protocol1_16_2to1_16_1.Protocol1_16_2To1_16_1;
 import us.myles.ViaVersion.protocols.protocol1_16_2to1_16_1.types.Chunk1_16_2Type;
 import us.myles.ViaVersion.protocols.protocol1_16to1_15_2.ClientboundPackets1_16;
 import us.myles.ViaVersion.protocols.protocol1_16to1_15_2.types.Chunk1_16Type;
 import us.myles.ViaVersion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
 
+import java.util.ArrayList;
+import java.util.List;
+
 public class WorldPackets {
 
+    private static final BlockChangeRecord[] EMPTY_RECORDS = new BlockChangeRecord[0];
+
     public static void register(Protocol protocol) {
         BlockRewriter blockRewriter = new BlockRewriter(protocol, Type.POSITION1_14, Protocol1_16_2To1_16_1::getNewBlockStateId, Protocol1_16_2To1_16_1::getNewBlockId);
 
@@ -50,12 +58,33 @@ public class WorldPackets {
 
                     int chunkX = wrapper.read(Type.INT);
                     int chunkZ = wrapper.read(Type.INT);
-                    wrapper.write(Type.LONG, asLong(chunkX, 0, chunkZ)); //TODO
 
+                    long chunkPosition = 0;
+                    chunkPosition |= (chunkX & 0x3FFFFFL) << 42;
+                    chunkPosition |= (chunkZ & 0x3FFFFFL) << 20;
+
+                    List<BlockChangeRecord>[] sectionRecords = new List[16];
                     BlockChangeRecord[] blockChangeRecord = wrapper.read(Type.BLOCK_CHANGE_RECORD_ARRAY);
-                    wrapper.write(Type.VAR_LONG_BLOCK_CHANGE_RECORD_ARRAY, blockChangeRecord);
                     for (BlockChangeRecord record : blockChangeRecord) {
-                        record.setBlockId(Protocol1_16_2To1_16_1.getNewBlockId(record.getBlockId()));
+                        int chunkY = record.getY() >> 4;
+                        List<BlockChangeRecord> list = sectionRecords[chunkY];
+                        if (list == null) {
+                            sectionRecords[chunkY] = (list = new ArrayList<>());
+                        }
+
+                        // Absolute y -> relative chunk section y
+                        int blockId = Protocol1_16_2To1_16_1.getNewBlockId(record.getBlockId());
+                        list.add(new BlockChangeRecord1_16_2(record.getSectionX(), record.getSectionY(), record.getSectionZ(), blockId));
+                    }
+
+                    // Now send separate packets for the different chunk sections
+                    for (int chunkY = 0; chunkY < sectionRecords.length; chunkY++) {
+                        List<BlockChangeRecord> sectionRecord = sectionRecords[chunkY];
+                        if (sectionRecord == null) continue;
+
+                        PacketWrapper newPacket = wrapper.create(ClientboundPackets1_16_2.MULTI_BLOCK_CHANGE.ordinal());
+                        newPacket.write(Type.LONG, chunkPosition | (chunkY & 0xFFFFFL));
+                        newPacket.write(Type.VAR_LONG_BLOCK_CHANGE_RECORD_ARRAY, sectionRecord.toArray(EMPTY_RECORDS));
                     }
                 });
             }
@@ -65,26 +94,4 @@ public class WorldPackets {
         blockRewriter.registerSpawnParticle(ClientboundPackets1_16.SPAWN_PARTICLE, 3, 23, 34,
                 null, InventoryPackets::toClient, Type.FLAT_VAR_INT_ITEM, Type.DOUBLE);
     }
-
-    //TODO to chunk coordinates
-    public static int x(final long long1) {
-        return (int) (long1 >> 42);
-    }
-
-    public static int y(final long long1) {
-        return (int) (long1 << 44 >> 44);
-    }
-
-    public static int z(final long long1) {
-        return (int) (long1 << 22 >> 42);
-    }
-
-
-    public static long asLong(final int x, final int y, final int z) {
-        long long4 = 0L;
-        long4 |= (x & 0x3FFFFFL) << 42;
-        long4 |= (y & 0xFFFFFL);
-        long4 |= (z & 0x3FFFFFL) << 20;
-        return long4;
-    }
 }