SPIGOT-2620: Add Player#sendBlockChanges()

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-server/nms-patches/net/minecraft/network/protocol/game/PacketPlayOutMultiBlockChange.patch

@@ -1,6 +1,6 @@
 --- a/net/minecraft/network/protocol/game/PacketPlayOutMultiBlockChange.java
 +++ b/net/minecraft/network/protocol/game/PacketPlayOutMultiBlockChange.java
-@@ -32,7 +32,7 @@
+@@ -32,11 +32,20 @@
              short short0 = (Short) shortiterator.next();
  
              this.positions[j] = short0;
@@ -9,3 +9,16 @@
          }
  
      }
+ 
++    // CraftBukkit start - Add constructor
++    public PacketPlayOutMultiBlockChange(SectionPosition sectionposition, ShortSet shortset, IBlockData[] states, boolean flag) {
++        this.sectionPos = sectionposition;
++        this.suppressLightUpdates = flag;
++        this.positions = shortset.toShortArray();
++        this.states = states;
++    }
++    // CraftBukkit end
++
+     public PacketPlayOutMultiBlockChange(PacketDataSerializer packetdataserializer) {
+         this.sectionPos = SectionPosition.of(packetdataserializer.readLong());
+         this.suppressLightUpdates = packetdataserializer.readBoolean();

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -6,6 +6,8 @@ import com.google.common.io.BaseEncoding;
 import com.mojang.authlib.GameProfile;
 import com.mojang.datafixers.util.Pair;
 import io.netty.buffer.Unpooled;
+import it.unimi.dsi.fastutil.shorts.ShortArraySet;
+import it.unimi.dsi.fastutil.shorts.ShortSet;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.lang.ref.WeakReference;
@@ -28,6 +30,7 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import net.minecraft.advancements.AdvancementProgress;
 import net.minecraft.core.BlockPosition;
+import net.minecraft.core.SectionPosition;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.network.PacketDataSerializer;
 import net.minecraft.network.chat.ChatMessageContent;
@@ -51,6 +54,7 @@ import net.minecraft.network.protocol.game.PacketPlayOutEntitySound;
 import net.minecraft.network.protocol.game.PacketPlayOutExperience;
 import net.minecraft.network.protocol.game.PacketPlayOutGameStateChange;
 import net.minecraft.network.protocol.game.PacketPlayOutMap;
+import net.minecraft.network.protocol.game.PacketPlayOutMultiBlockChange;
 import net.minecraft.network.protocol.game.PacketPlayOutNamedSoundEffect;
 import net.minecraft.network.protocol.game.PacketPlayOutPlayerInfo;
 import net.minecraft.network.protocol.game.PacketPlayOutPlayerListHeaderFooter;
@@ -79,6 +83,7 @@ import net.minecraft.world.item.EnumColor;
 import net.minecraft.world.level.EnumGamemode;
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.entity.TileEntitySign;
+import net.minecraft.world.level.block.state.IBlockData;
 import net.minecraft.world.level.border.IWorldBorderListener;
 import net.minecraft.world.level.saveddata.maps.MapIcon;
 import net.minecraft.world.level.saveddata.maps.WorldMap;
@@ -101,6 +106,7 @@ import org.bukkit.Statistic;
 import org.bukkit.WeatherType;
 import org.bukkit.WorldBorder;
 import org.bukkit.block.Block;
+import org.bukkit.block.BlockState;
 import org.bukkit.block.Sign;
 import org.bukkit.block.data.BlockData;
 import org.bukkit.configuration.serialization.DelegateDeserialization;
@@ -118,6 +124,7 @@ import org.bukkit.craftbukkit.CraftWorld;
 import org.bukkit.craftbukkit.CraftWorldBorder;
 import org.bukkit.craftbukkit.advancement.CraftAdvancement;
 import org.bukkit.craftbukkit.advancement.CraftAdvancementProgress;
+import org.bukkit.craftbukkit.block.CraftBlockState;
 import org.bukkit.craftbukkit.block.CraftSign;
 import org.bukkit.craftbukkit.block.data.CraftBlockData;
 import org.bukkit.craftbukkit.conversations.ConversationTracker;
@@ -613,6 +620,44 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         getHandle().connection.send(packet);
     }
 
+    @Override
+    public void sendBlockChanges(Collection<BlockState> blocks, boolean suppressLightUpdates) {
+        Preconditions.checkArgument(blocks != null, "blocks must not be null");
+
+        if (getHandle().connection == null || blocks.isEmpty()) {
+            return;
+        }
+
+        Map<SectionPosition, ChunkSectionChanges> changes = new HashMap<>();
+        for (BlockState state : blocks) {
+            CraftBlockState cstate = (CraftBlockState) state;
+            BlockPosition blockPosition = cstate.getPosition();
+
+            // The coordinates of the chunk section in which the block is located, aka chunk x, y, and z
+            SectionPosition sectionPosition = SectionPosition.of(blockPosition);
+
+            // Push the block change position and block data to the final change map
+            ChunkSectionChanges sectionChanges = changes.computeIfAbsent(sectionPosition, (ignore) -> new ChunkSectionChanges());
+
+            sectionChanges.positions().add(SectionPosition.sectionRelativePos(blockPosition));
+            sectionChanges.blockData().add(cstate.getHandle());
+        }
+
+        // Construct the packets using the data allocated above and send then to the players
+        for (Map.Entry<SectionPosition, ChunkSectionChanges> entry : changes.entrySet()) {
+            ChunkSectionChanges chunkChanges = entry.getValue();
+            PacketPlayOutMultiBlockChange packet = new PacketPlayOutMultiBlockChange(entry.getKey(), chunkChanges.positions(), chunkChanges.blockData().toArray(IBlockData[]::new), suppressLightUpdates);
+            getHandle().connection.send(packet);
+        }
+    }
+
+    private record ChunkSectionChanges(ShortSet positions, List<IBlockData> blockData) {
+
+        public ChunkSectionChanges() {
+            this(new ShortArraySet(), new ArrayList<>());
+        }
+    }
+
     @Override
     public void sendBlockDamage(Location loc, float progress) {
         Preconditions.checkArgument(loc != null, "loc must not be null");