TileEntities

Tile Entities are like simplified Entities, that are bound to a Block. They are used to store dynamic data, execute tick based tasks and for dynamic rendering. Some examples from vanilla Minecraft would be: handling of inventories (chests), smelting logic on furnaces, or area effects for beacons. More advanced examples exist in mods, such as quarries, sorting machines, pipes, and displays.

Creating a TileEntity

In order to create a TileEntity you need to extend the TileEntity class. It is important that your TileEntity has a default constructor, so that Minecraft can properly load it. After you’ve created your class, you need to register the TileEntity. For this you need to call

GameRegistry#registerTileEntity(Class<? extends TileEntity> tileEntityClass, ResourceLocation key)

Where the first parameter is simply your TileEntity class and the second the registry name of your TileEntity. At this point you can either choose to do it during the FMLPreInitializationEvent or during the RegistryEvent.Register<Block> event, as TileEntities don’t have their own Registry Event yet.

Attaching a TileEntity to a Block

To attach your new TileEntity to a Block you need to override 2 (two) methods within the Block class.

Block#hasTileEntity(IBlockstate state)

Block#createTileEntity(World world, IBlockState state)

Storing Data within your TileEntity

In order to save data, override the following two methods

TileEntity#writeToNBT(NBTTagCompound nbt)

TileEntity#readFromNBT(NBTTagCompound nbt)

Whenever your data changes you need to call `TileEntity#markDirty()`, otherwise the `Chunk` containing your `TileEntity` might be skipped while the world is saved.

It is important that you call the super methods!

Keeping a TileEntity through changing BlockStates

There might be situations in which you need to change your BlockState, such as with the vanilla furnace, which changes its state from lit=false to lit=true when fuel and something smeltable is inside. Achieving this is rather simple, by overriding following method

TileEntity#shouldRefresh(World world, BlockPos pos, IBlockState oldState, IBlockState newSate)

Ticking TileEntities

If you need a ticking TileEntity, for example to keep track of the progress during a smelting process, you need to add the net.minecraft.util.ITickable interface to your TileEntity. Now you can implement all your calculations within

ITickable#update()

Synchronizing the Data to the Client

There are 3 (three) ways of syncing data to the client. Synchronizing on chunk load, synchronizing on block updates and synchronizing with a custom network message.

Synchronizing on chunk load

For this you need to override

TileEntity#getUpdateTag()

TileEntity#handleUpdateTag(NBTTagCompound nbt)

Synchronizing on block update

This method is a bit more complicated, but again you just need to override 2 methods. Here is a tiny example implementation of it

@Override
public SPacketUpdateTileEntity getUpdatePacket(){
    NBTTagCompound nbtTag = new NBTTagCompound();
    //Write your data into the nbtTag
    return new SPacketUpdateTileEntity(getPos(), 1, nbtTag);
}

@Override
public void onDataPacket(NetworkManager net, SPacketUpdateTileEntity pkt){
    NBTTagCompound tag = pkt.getNbtCompound();
    //Handle your Data
}

• The position of your TileEntity.
• An ID, though it isn’t really used besides by Vanilla, therefore you can just put a 1 in there.
• An NBTTagCompound which should contain your data.

Additionally to this you now need to cause a “BlockUpdate” on the Client.

World#notifyBlockUpdate(BlockPos pos, IBlockState oldState, IBlockState newState, int flags)

Synchronizing using a custom network message

This way of synchronizing is probably the most complicated one, but is usually also the most optimized one, as you can make sure that only the data you need to be synchronized is actually synchronized. You should first check out the Networking section and especially SimpleImpl before attempting this. Once you’ve created your custom network message, you can send it to all users that have the TileEntity loaded with:

SimpleNetworkWrapper#sendToAllTracking(IMessage, NetworkRegistry.TargetPoint)