方块实体的数据同步

方块实体自带的数据同步是从逻辑服务端发向逻辑客户端的

• NBT处理
  • getUpdateTag：写数据（序列化）
  • load：读数据（反序列化）
• 数据包处理
  • getUpdatePacket：在方块实体更新时写数据
    • 大多数子类使用ClientboundBlockEntityDataPacket.create(this)从getUpdateTag获取数据
  • handleUpdateTag：在区块加载时读数据
    • 默认直接调用load处理
  • ...

ClientboundBlockEntityDataPacket

package net.minecraft.network.protocol.game;

public class ClientboundBlockEntityDataPacket implements Packet<ClientGamePacketListener> {
    private final BlockPos pos;
    /** Used only for vanilla block entities */
    private final BlockEntityType<?> type;
    @Nullable
    private final CompoundTag tag;

    //如果你有特殊需求可以直接使用这个方法
    public static ClientboundBlockEntityDataPacket create(BlockEntity pBlockEntity, Function<BlockEntity, CompoundTag> pTagGetter) {
       return new ClientboundBlockEntityDataPacket(pBlockEntity.getBlockPos(), pBlockEntity.getType(), pTagGetter.apply(pBlockEntity));
    }

    //这就是我们使用的方法
    public static ClientboundBlockEntityDataPacket create(BlockEntity pBlockEntity) {
       return create(pBlockEntity, BlockEntity::getUpdateTag);
    }

    private ClientboundBlockEntityDataPacket(BlockPos pPos, BlockEntityType<?> pType, CompoundTag pTag) {
       this.pos = pPos;
       this.type = pType;
       this.tag = pTag.isEmpty() ? null : pTag;
    }

    public ClientboundBlockEntityDataPacket(FriendlyByteBuf pBuffer) {
       this.pos = pBuffer.readBlockPos();
       this.type = pBuffer.readById(BuiltInRegistries.BLOCK_ENTITY_TYPE);
       this.tag = pBuffer.readNbt();
    }

    //省略
    //……
}