Entities
In addition to regular network messages, there are various other systems provided to handle synchronizing entity data.
Spawn Data
In general, the spawning of modded entities is handled separately, by Forge.
Note
This means that simply extending a vanilla entity class may not inherit all its behavior. You may need to implement certain vanilla behaviors yourself.
You can add extra data to the spawn packet Forge sends by implementing the following interface.
IEntityAdditionalSpawnData
If your entity has data that is needed on the client, but does not change over time, then it can be added to the entity spawn packet using this interface. #writeSpawnData
and #readSpawnData
control how the data should be encoded to/decoded from the network buffer.
Dynamic Data
Data Parameters
This is the main vanilla system for synchronizing entity data from the server to the client. As such, a number of vanilla examples are available to refer to.
Firstly, you need a EntityDataAccessor<T>
for the data you wish to keep synchronized. This should be stored as a static final
field in your entity class, obtained by calling SynchedEntityData#defineId
and passing the entity class and a serializer for that type of data. The available serializer implementations can be found as static constants within the EntityDataSerializers
class.
Warning
You should only create data parameters for your own entities, within that entity’s class. Adding parameters to entities you do not control can cause the IDs used to send that data over the network to become desynchronized, causing difficult to debug crashes.
Then, override Entity#defineSynchedData
and call this.entityData.define(...)
for each of your data parameters, passing the parameter and an initial value to use. Remember to always call the super
method first!
You can then get and set these values via your entity’s entityData
instance. Changes made will be synchronized to the client automatically.