Update to JoinGamePacket and RespawnPacket (#1640)

* Add death location support to JoinGamePacket

src/main/java/net/minestom/server/entity/Player.java

@@ -55,6 +55,7 @@ import net.minestom.server.network.packet.server.SendablePacket;
 import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.login.LoginDisconnectPacket;
 import net.minestom.server.network.packet.server.play.*;
+import net.minestom.server.network.packet.server.play.data.DeathLocation;
 import net.minestom.server.network.player.GameProfile;
 import net.minestom.server.network.player.PlayerConnection;
 import net.minestom.server.network.player.PlayerSocketConnection;
@@ -250,10 +251,14 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
                 "minecraft:chat_type", Messenger.chatRegistry(),
                 "minecraft:dimension_type", MinecraftServer.getDimensionTypeManager().toNBT(),
                 "minecraft:worldgen/biome", MinecraftServer.getBiomeManager().toNBT()));
+
+        // TODO: Add some way to determine last death location
+        final DeathLocation deathLocation = null;
+
         final JoinGamePacket joinGamePacket = new JoinGamePacket(getEntityId(), false, gameMode, null,
                 List.of(dimensionType.getName().asString()), nbt, dimensionType.toString(), dimensionType.getName().asString(),
                 0, 0, MinecraftServer.getChunkViewDistance(), MinecraftServer.getChunkViewDistance(),
-                false, true, false, levelFlat);
+                false, true, false, levelFlat, deathLocation);
         sendPacket(joinGamePacket);
 
         // Server brand name
@@ -443,8 +448,11 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         setFireForDuration(0);
         setOnFire(false);
         refreshHealth();
+
+        // TODO: Add some way to determine last death location
+        final DeathLocation deathLocation = null;
         sendPacket(new RespawnPacket(getDimensionType().toString(), getDimensionType().getName().asString(),
-               0, gameMode, gameMode, false, levelFlat, true));
+               0, gameMode, gameMode, false, levelFlat, true, deathLocation));
 
         PlayerRespawnEvent respawnEvent = new PlayerRespawnEvent(this);
         EventDispatcher.call(respawnEvent);
@@ -968,8 +976,10 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         final PlayerInfoPacket removePlayerPacket = getRemovePlayerToList();
         final PlayerInfoPacket addPlayerPacket = getAddPlayerToList();
 
+        // TODO: Add some way to determine last death location
+        final DeathLocation deathLocation = null;
         RespawnPacket respawnPacket = new RespawnPacket(getDimensionType().toString(), getDimensionType().getName().asString(),
-                0, gameMode, gameMode, false, levelFlat, true);
+                0, gameMode, gameMode, false, levelFlat, true, deathLocation);
 
         sendPacket(removePlayerPacket);
         sendPacket(destroyEntitiesPacket);
@@ -1341,8 +1351,10 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         Check.argCondition(dimensionType.equals(getDimensionType()),
                 "The dimension needs to be different than the current one!");
         this.dimensionType = dimensionType;
+        // TODO: Add some way to determine last death location
+        final DeathLocation deathLocation = null;
         sendPacket(new RespawnPacket(dimensionType.toString(), getDimensionType().getName().asString(),
-                0, gameMode, gameMode, false, levelFlat, true));
+                0, gameMode, gameMode, false, levelFlat, true, deathLocation));
         refreshClientStateAfterRespawn();
     }
 

src/main/java/net/minestom/server/network/NetworkBuffer.java

@@ -4,6 +4,7 @@ import net.kyori.adventure.text.Component;
 import net.minestom.server.coordinate.Point;
 import net.minestom.server.entity.Entity;
 import net.minestom.server.item.ItemStack;
+import net.minestom.server.network.packet.server.play.data.DeathLocation;
 import net.minestom.server.utils.Direction;
 import net.minestom.server.utils.Either;
 import org.jetbrains.annotations.ApiStatus;
@@ -57,6 +58,7 @@ public final class NetworkBuffer {
     public static final Type<int[]> VILLAGER_DATA = NetworkBufferTypes.VILLAGER_DATA;
     public static final Type<Integer> OPT_VAR_INT = NetworkBufferTypes.OPT_VAR_INT;
     public static final Type<Entity.Pose> POSE = NetworkBufferTypes.POSE;
+    public static final Type<DeathLocation> DEATH_LOCATION = NetworkBufferTypes.DEATH_LOCATION;
 
     ByteBuffer nioBuffer;
     final boolean resizable;

src/main/java/net/minestom/server/network/NetworkBufferTypes.java

@@ -7,6 +7,7 @@ import net.minestom.server.coordinate.Vec;
 import net.minestom.server.entity.Entity;
 import net.minestom.server.item.ItemStack;
 import net.minestom.server.item.Material;
+import net.minestom.server.network.packet.server.play.data.DeathLocation;
 import net.minestom.server.utils.Direction;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.UnknownNullability;
@@ -505,6 +506,23 @@ final class NetworkBufferTypes {
                 final int ordinal = buffer.read(VAR_INT);
                 return Entity.Pose.values()[ordinal];
             });
+    static final TypeImpl<DeathLocation> DEATH_LOCATION = new TypeImpl<>(DeathLocation.class,
+            (buffer, value) -> {
+                if (value == null) {
+                    buffer.write(BOOLEAN, false);
+                } else {
+                    buffer.write(BOOLEAN, true);
+                    buffer.write(STRING, value.dimension());
+                    buffer.write(BLOCK_POSITION, value.position());
+                }
+                return -1;
+            },
+            buffer -> {
+                if (buffer.read(BOOLEAN)) {
+                    return new DeathLocation(buffer.read(STRING), buffer.read(BLOCK_POSITION));
+                }
+                return null;
+            });
 
     record TypeImpl<T>(@NotNull Class<T> type,
                        @NotNull TypeWriter<T> writer,

src/main/java/net/minestom/server/network/packet/server/play/JoinGamePacket.java

@@ -4,7 +4,9 @@ import net.minestom.server.entity.GameMode;
 import net.minestom.server.network.NetworkBuffer;
 import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.ServerPacketIdentifier;
+import net.minestom.server.network.packet.server.play.data.DeathLocation;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.List;
@@ -14,17 +16,18 @@ import static net.minestom.server.network.NetworkBuffer.*;
 public record JoinGamePacket(int entityId, boolean isHardcore, GameMode gameMode, GameMode previousGameMode,
                              List<String> worlds, NBTCompound dimensionCodec, String dimensionType, String world,
                              long hashedSeed, int maxPlayers, int viewDistance, int simulationDistance,
-                             boolean reducedDebugInfo, boolean enableRespawnScreen, boolean isDebug,
+                             boolean reducedDebugInfo, boolean enableRespawnScreen, boolean isDebug, boolean isFlat,
-                             boolean isFlat) implements ServerPacket {
+                             DeathLocation deathLocation) implements ServerPacket {
     public JoinGamePacket {
         worlds = List.copyOf(worlds);
     }
 
     public JoinGamePacket(@NotNull NetworkBuffer reader) {
-        this(reader.read(VAR_INT), reader.read(BOOLEAN), GameMode.fromId(reader.read(BYTE)), GameMode.fromId(reader.read(BYTE)),
+        this(reader.read(INT), reader.read(BOOLEAN), GameMode.fromId(reader.read(BYTE)), getNullableGameMode(reader.read(BYTE)),
                 reader.readCollection(STRING), (NBTCompound) reader.read(NBT), reader.read(STRING), reader.read(STRING),
                 reader.read(LONG), reader.read(VAR_INT), reader.read(VAR_INT), reader.read(VAR_INT),
-                reader.read(BOOLEAN), reader.read(BOOLEAN), reader.read(BOOLEAN), reader.read(BOOLEAN));
+                reader.read(BOOLEAN), reader.read(BOOLEAN), reader.read(BOOLEAN), reader.read(BOOLEAN),
+                reader.read(DEATH_LOCATION));
     }
 
     @Override
@@ -54,7 +57,7 @@ public record JoinGamePacket(int entityId, boolean isHardcore, GameMode gameMode
         //is flat
         writer.write(BOOLEAN, isFlat);
 
-        writer.write(BOOLEAN, false);
+        writer.write(DEATH_LOCATION, deathLocation);
     }
 
     @Override
@@ -62,4 +65,14 @@ public record JoinGamePacket(int entityId, boolean isHardcore, GameMode gameMode
         return ServerPacketIdentifier.JOIN_GAME;
     }
 
+    /**
+     * This method exists in lieu of a NetworkBufferType since -1 is only a
+     * valid value in this packet and changing behaviour of GameMode.fromId()
+     * to be nullable would be too big of a change. Also, game modes are often
+     * represented as other data types, including floats.
+     */
+    private static @Nullable GameMode getNullableGameMode(final byte id) {
+        return id == (byte) -1 ? null : GameMode.fromId(id);
+    }
+
 }

src/main/java/net/minestom/server/network/packet/server/play/RespawnPacket.java

@@ -4,17 +4,19 @@ import net.minestom.server.entity.GameMode;
 import net.minestom.server.network.NetworkBuffer;
 import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.ServerPacketIdentifier;
+import net.minestom.server.network.packet.server.play.data.DeathLocation;
 import org.jetbrains.annotations.NotNull;
 
 import static net.minestom.server.network.NetworkBuffer.*;
 
 public record RespawnPacket(String dimensionType, String worldName,
                             long hashedSeed, GameMode gameMode, GameMode previousGameMode,
-                            boolean isDebug, boolean isFlat, boolean copyMeta) implements ServerPacket {
+                            boolean isDebug, boolean isFlat, boolean copyMeta,
+                            DeathLocation deathLocation) implements ServerPacket {
     public RespawnPacket(@NotNull NetworkBuffer reader) {
         this(reader.read(STRING), reader.read(STRING),
-                reader.read(LONG), GameMode.values()[reader.read(BYTE)], GameMode.values()[reader.read(BYTE)],
+                reader.read(LONG), GameMode.fromId(reader.read(BYTE)), GameMode.fromId(reader.read(BYTE)),
-                reader.read(BOOLEAN), reader.read(BOOLEAN), reader.read(BOOLEAN));
+                reader.read(BOOLEAN), reader.read(BOOLEAN), reader.read(BOOLEAN), reader.read(DEATH_LOCATION));
     }
 
     @Override
@@ -27,8 +29,7 @@ public record RespawnPacket(String dimensionType, String worldName,
         writer.write(BOOLEAN, isDebug);
         writer.write(BOOLEAN, isFlat);
         writer.write(BOOLEAN, copyMeta);
-
+        writer.write(DEATH_LOCATION, deathLocation);
-        writer.write(BOOLEAN, false);
     }
 
     @Override

src/main/java/net/minestom/server/network/packet/server/play/data/DeathLocation.java

@@ -0,0 +1,8 @@
+package net.minestom.server.network.packet.server.play.data;
+
+import net.minestom.server.coordinate.Point;
+import org.jetbrains.annotations.NotNull;
+
+public record DeathLocation(@NotNull String dimension, @NotNull Point position) {
+
+}