[SOLVED] Sync non-player entity -- how to id proper entity[1.12.1]

[aw_wolfe]

I feel I'm missing something easy, so apologies ahead of time.

I am trying to sync data from the server to client of an entity (not a tile-entity or playerEntity).  In the MessageHandler I have the message object and MessageContext .

 

For tileEntities, you can use the blockpos and dimension passed into the message object to find the correct tileEntity.

For players, you can use the MessageContext ctx.getServerHandler().player to identify the proper player to pass the information to.

public class PacketRequestUpdateMagicEntity implements IMessage{
	private int dimension;
	private UUID	entityMagicUuid;
	
	
	public PacketRequestUpdateMagicEntity(int dimension,UUID em){
		this.dimension=dimension;
		this.entityMagicUuid=em;
	}
	
	public PacketRequestUpdateMagicEntity(EntityMagic em){
		this.dimension=em.world.provider.getDimension();
		this.entityMagicUuid=em.getUniqueID();
		
	}
	
	public PacketRequestUpdateMagicEntity(){
		
	}
	
	@Override
	public void fromBytes(ByteBuf buf) {
		this.dimension=buf.readInt();
		long least=buf.readLong();
		long most=buf.readLong();
		this.entityMagicUuid=new UUID(most,least);
	}

	@Override
	public void toBytes(ByteBuf buf) {
		buf.writeInt(dimension);
		buf.writeLong(entityMagicUuid.getLeastSignificantBits());
		buf.writeLong(entityMagicUuid.getMostSignificantBits());
	}

	
	public static class Handler implements IMessageHandler<PacketRequestUpdateMagicEntity, PacketUpdateMagicEntity>{

		@Override
		public PacketUpdateMagicEntity onMessage(PacketRequestUpdateMagicEntity message, MessageContext ctx) {
		
			System.out.println("REquest update");
			try{
				if(message.entityMagicUuid!=null){
					System.out.println("looking for entity with:"+message.entityMagicUuid.toString());
				}
			World world=FMLCommonHandler.instance().getMinecraftServerInstance().getWorld(message.dimension);
			EntityMagic em=(EntityMagic)FMLCommonHandler.instance().getMinecraftServerInstance().getEntityFromUuid(message.entityMagicUuid);
			
				if(em!=null){
					System.out.println("Entity Magic is not null");
					return new PacketUpdateMagicEntity(em);
				}
			
			}
			catch(Exception e){
				System.out.println("PacketRequestUpdateEntityMagic:Handler:Exception:"+e.toString());
			}
			return null;
		}
		
	}
}

 

For a nonplayer entity, I am trying to use the UUID from Entity.getPersistentID() passed into the message object.

The problem is that the UUID on the client and server are NOT matching. To test, I spawn a single instance of the entity and get different UUID in the output.

 

//from EntityMagic

@Override
protected void entityInit() {
	System.out.println("persistant id:"+this.getPersistentID());
	System.out.println("enitty id:"+this.getEntityId());
}

from the server I get: uuid:091146a6-36df-4b42-9637-43442687e9ff with entity id:285

 

from the client I get:8587a3ea-6816-4e35-b011-08fd968dd7aa with entity id:286

 

I thought the UUIDs should match on the client and server, if correct, then why am I seeing them differently from the entityInit?

If the UUIDs won't match, how should I find the proper entity on the client ?  Am I doing something dumb(likely)? 

 

 

Thanks,

Tony

 

Edited June 1, 2018 by aw_wolfe
solved

[Draco18s]

PersistentID is for saving to disk. getEntityID() is the network ID

[aw_wolfe]

Thanks for the clarification on the UUID and entityID.  However, my entityIDs are not matching either.  Server: 285 and on the client: 286 . 

[aw_wolfe]

Spawning:

From server side of item click (for testing) using a 'helper function in the entity class file.

///Item testing class
@Override
	public EnumActionResult onItemUseFirst(EntityPlayer player, World world, BlockPos pos, EnumFacing side, float hitX,
			float hitY, float hitZ, EnumHand hand) {
		System.out.println("scroll first use");
		if(!world.isRemote){
			System.out.println("not remote, trying to create magic");
			
		//	just testing creating magic
		 
			EntityMagic em=EntityMagic.spawn(world, player.getPositionVector(), 200, player, true, EnumParticleTypes.SPELL);
			System.out.println("Created entity with:"+em.getUniqueID().toString());
		 
			
		}
		
		return super.onItemUseFirst(player, world, pos, side, hitX, hitY, hitZ, hand);
	}

//ENtity class

public static EntityMagic spawn(World worldIn,Vec3d pos,int tduration,EntityLivingBase caster,boolean track_caster,EnumParticleTypes pt){
		EntityMagic eeb=new EntityMagic(worldIn,tduration);
		eeb.tick_duration=tduration;
		eeb.caster=caster;
		eeb.track_caster=track_caster;
		eeb.particleType=pt;
		eeb.setLocationAndAngles(pos.x, pos.y, pos.z, 0, 0);
		eeb.setData();
		worldIn.spawnEntity(eeb);
		
		
		System.out.println("spawn:Tick duration:"+eeb.tick_duration);
		
		
		return eeb;
	}

 

My thought on my mod is to have an entity used to create a magic effect, client side just does particle rendering, and server side dealt with performing the effect on other entities/etc. The combination of durations/effects/levels was going to be very large, so rather than create a different entity for each type, I thought I'd create a single entity that would act differently depending on params passed in when created.  Starting with the tick_duration (entity kills self after so long).  The problem was that on the server it works, but the instantiation on the client is the default parameters (in this case tick duration is 100...instead of the 200 passed in from the click action).  Same is true, which makes sense, since the spawn action creates a generic version on the client, the server gets the proper parameters.  So, they are out of sync from the beginning.  I put a request from the client to the server, so that it would ask for updated data immediately after creation.

 

I don't know why the entityids are 1 off.  Creating multiple entities always produces the same result...server x, client x+1.  I don't think this is reliable nor supposed to be that way. So don't want to depend on that to get the entity on the client side.

[aw_wolfe]

awesome. working.

 

1) used entityID instead of UUID

2) send update from server after spawn...instead of requesting update from entityInit. The ids matched after the constructor finished on the client. So the debug output from the entityInit function wasn't valid yet.

 

fyi: agreed, setData not a great name. Trying some debuggin stuff, was used to package class members into a nbttagcompound for syncing and saving/loading.