So I've got a custom entity set up and it works just fine when spawned with an egg. I then wanted to have it spawn naturally, so I went and added a spawn to the entity registry of my mob's class (and to its placement registry), and gave it a set of biomes to spawn in. However, WorldEntitySpawner gets a nullptr here with the entity:

 

 

Anyone know why this could be?

Edited July 23, 20205 yr by k-off

Still can't figure this out for the life of me, I also tried adding the mob to the list of biomes and still nothing, the same crash.

So you have an entry in EntitySpawnPlacementRegistry and you've added a SpawnListEntry in the biomes to spawn in? I have no idea what this is:

3 hours ago, k-off said:

so I went and added a spawn to the entity registry of my mob's class

It always nice if you can show code and an error log rather than showing us where the error is.

 

I also don't even see where this class is which leads me to believe that this is an outdated version based on the variable names.

 

So, update to at least the LTS 1.15.2 if you want support.

 

 

35 minutes ago, ChampionAsh5357 said:

So you have an entry in EntitySpawnPlacementRegistry and you've added a SpawnListEntry in the biomes to spawn in? I have no idea what this is:

It always nice if you can show code and an error log rather than showing us where the error is.

 

I also don't even see where this class is which leads me to believe that this is an outdated version based on the variable names.

 

So, update to at least the LTS 1.15.2 if you want support.

 

 

worldentityspawner is a 1.14.4 class (also in previous versions as well but i digress) fyi

 

Anyway the exact error isn't very helpful, it's just a standard nullptr exception which is what i was talking about above:

Quote

java.lang.NullPointerException: Exception ticking world
    at net.minecraft.world.WorldEntitySpawner.findChunksForSpawning(WorldEntitySpawner.java:154)
    at net.minecraft.world.WorldServer.tick(WorldServer.java:212)
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:831)
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:743)
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:192)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:592)
    at java.lang.Thread.run(Thread.java:748)

and worldentityspawner is that class I showed above.

Quote

So you have an entry in EntitySpawnPlacementRegistry and you've added a SpawnListEntry in the biomes to spawn in? I have no idea what this is:

Using forgeregistries I tried doing this which I found on another post here:

	public static void spawnMobs() {

		ForgeRegistries.BIOMES.getValues().stream()
          		//This is just some randsom filtering but do whatever you want her, or dont filter at all 
          		//if you want your entity to appear anywhere.
				.filter(biome -> biome.getRegistryName().toString().equals("minecraft:mushroom_fields")
						|| biome.getRegistryName().toString().equals("minecraft:mushroom_fields_field_shore"))
				
          		//this is the main dish
				.forEach(biome -> {
					biome.getSpawns(EntityClassification.<depends on what you want>)
                      		//min and max refer to number of entities in a group.
							.add(new SpawnListEntry(<static reference to your entity>, <weight>, <min>, <max>));
				});

	}

 

 

I just went and tested this with a Vanilla mob, and it works just fine. Hmm.

Edited July 23, 20205 yr by k-off

42 minutes ago, k-off said:

worldentityspawner is a 1.14.4 class (also in previous versions as well but i digress) fyi

I meant that section within the method in the class. I still don't find it since its called from an entity type.

 

42 minutes ago, k-off said:

net.minecraft.world.WorldServer.tick(WorldServer.java:212)

Also, as much as you tell me this is 1.14.4, WorldServer was renamed to ServerWorld and WorldEntitySpawner was moved to a different package in that version making your statement a lie.

 

Just for a bit more research, this line of code was referenced in at latest 1.13.2. There are things known as EntityTypes now.

 

So once again. 1.13.2 is not supported on this forum. Update to at least LTS if you want support on your code.

24 minutes ago, ChampionAsh5357 said:

I meant that section within the method in the class. I still don't find it since its called from an entity type.

 

Also, as much as you tell me this is 1.14.4, WorldServer was renamed to ServerWorld and WorldEntitySpawner was moved to a different package in that version making your statement a lie.

 

Just for a bit more research, this line of code was referenced in at latest 1.13.2. There are things known as EntityTypes now.

 

So once again. 1.13.2 is not supported on this forum. Update to at least LTS if you want support on your code.

Yeah that's fair, life moves on and so do minecraft forge versions 👍 This thread should be locked then.

 

For anyone with a similar problem in the future, I wasn't registering the entity correctly (make sure you're registering stuff that's supposed to happen in pre vs post, etc) and resolving that fixed it.