[1.15.2] world.getEntitiesWithinAABB locks world generation

[Luminaire 0]

The following is a code snippet that is my attempt to get the list of entities around a spawning entity.  I want to do this to find what animals are nearby, so I can replace the spawning entity with one of that type instead.

Unfortunately as soon as I call it, the world generation stops completely at 16%.

 

public class HandleAnimalSpawns {
    public void handleSpawns(LivingSpawnEvent.CheckSpawn event){
        Entity entity = event.getEntity();
        World world = event.getWorld().getWorld();
    
        List<LivingEntity> entities = WorldHelper.getEntitiesInRange(LivingEntity.class, 10, world, entity.getPosition());          
}

public class WorldHelper {
    public static <T extends LivingEntity> List<T> getEntitiesInRange(Class<? extends T> filterEntity, int range, World world, BlockPos pos)
    {
        AxisAlignedBB axis = new AxisAlignedBB(pos.getX() - range, pos.getY() - range, pos.getZ() - range, pos.getX() + range, pos.getY() + range, pos.getZ() + range);
        List<T> list = world.getEntitiesWithinAABB(filterEntity, axis);
        //This log entry will never get called
        LOGGER.info("Got List");
        return list;
    }
}

[Beethoven92 42]

Is your event listener actually getting called? It seems that you did not register your event handler on the event bus

[Luminaire 0]

It's definitely gets called.  I removed them to make my snippet simpler, but I added a bunch of log statements to see where it was stopping, and this statement runs:

AxisAlignedBB axis = new AxisAlignedBB(pos.getX() - range, pos.getY() - range, pos.getZ() - range, pos.getX() + range, pos.getY() + range, pos.getZ() + range);

 

It stops right after that on the 

List<T> list = world.getEntitiesWithinAABB(filterEntity, axis);

 

Here is my event subscriber, but I know it's running:

 

public class EventSubscriber {
    @SubscribeEvent
    public void checkSpawns(LivingSpawnEvent.CheckSpawn event){

        Entity entity = event.getEntity();

        if (event.getWorld().isRemote()) {
            return;
        }

        if (!(entity instanceof LivingEntity)) {
            return;
        }

        if (entity instanceof AnimalEntity){
            HandleAnimalSpawns handler = new HandleAnimalSpawns();
            handler.handleSpawns(event);
        }
    }
}

 

and to complete my example:

 

@Mod(FarmAnimals.MODID)
public class FarmAnimals {
    private static final Logger LOGGER = LogManager.getLogger();

    public static final String MODID = "luminairefarmanimals";

    public FarmAnimals(){
        MinecraftForge.EVENT_BUS.register(new EventSubscriber());

    }
}

Edited September 25 by Luminaire

[vemerion 44]

10 hours ago, Luminaire said:

It stops right after that on the 

List<T> list = world.getEntitiesWithinAABB(filterEntity, axis);

I think the problem is that you can not use getEntitiesWithinAABB() while the world is created. If you remove the second getWorld() and use the IWorld instead it will not hang, but you will not find the nearby entities at world gen (but it will work fine after that).

[diesieben07 7412]

Never (well not never, but almost never) call IWorld#getWorld. It won't do what you want.

During world gen the World is not ready yet (it's being generated after all). So if you ask for it, it waits for the worldgen to complete. But that is waiting on your event handler to complete, which is waiting for the world to load, which is waiting for the world to generate, which is waiting for your event handler to complete, which is... You see where this is going.

 

You cannot get the list of entities during world generation. When an entity spawns during world generation, it's Entity object is immediately written to NBT and that NBT data is stored (see ChunkPrimer#addEntity). There are no Entity objects to get during worldgen.

[Luminaire 0]

Thanks, well that explains why it’s locking. Maybe there is some other way to accomplish what I want. I am trying to make a mod that makes it so farm animals (cows, sheep, pigs, and chickens) will only spawn near villages. 
 

I was worried that if there are other animal mods installed, if I just denied those spawns in the village radius farm animals would be extremely rare, so I was trying to replace any non farm animal spawn near villages with farm animals, even at world creation when larger numbers of passive spawns are created.  The reason for the get in radius was so I could detect animal groups and replace them all with one type of animal. Is there possibly a way to detect when a spawn is part of a group of mobs? Or is there some other way to accomplish the spirit of what I’m trying to do, so that farm animals spawn in a good number near villages?

[Luminaire 0]

I'll just got with what's suggested, and wait until after world generation to have the spawns replaced.

[Luminaire 0]

Do you know how I find out if it's during chunk generation?

I tried event.getWorld().chunkExists(), but it always returns true