I am currently in the process of porting a mod to 1.18.2 an it contains a partially buried structure.

The Structure is supposed to contain some Top-Blocks(in plains grass, in the desert sand, on mushroom island mycelium).

In 1.16 I got the Top-Block of the Biome, but it looks like that isn't possible anymore.

@Override
protected void handleDataMarker(String function, BlockPos pos, ServerLevelAccessor worldIn, Random rand, BoundingBox boundingBox) {
	case "top_block":
		worldIn.setBlock(pos, genWorld.getBiome(pos).value().getGenerationSettings().getSurfaceBuilderConfig().getTopMaterial(), Block.UPDATE_CLIENTS);
		break;
}

 

It's not something I know a lot about.

This link tries to explain the change in 1.18: https://github.com/TheForsakenFurby/Surface-Rules-Guide-Minecraft-JE-1.18/blob/main/Guide.md

 

Here's the vanilla overworld config (for the latest 1.20 snapshot at time of writing):

https://github.com/misode/mcmeta/blob/9d422bf8fe4824657260721682e5527ef608ce67/data/minecraft/worldgen/noise_settings/overworld.json#LL386C2-L386C2

 

From what I understand, they are only available when the chunk generator uses the NoiseGenerationSettings and only to carvers.

So you shouldn't really rely on them being available. e.g. if somebody changes their overworld to "flat" you won't have any data.

 

The way mojang do this kind of thing is to have different structures based on the biome. e.g. see the different villages.

https://github.com/misode/mcmeta/tree/data/data/minecraft/structures/village

 

If you still want to try to figue out how to get hold of the data, I would start with

NoisedBasedChunkGenerator.topMaterial()

but notice that method is deprecated in 1.18.2 and doesn't exist in 1.19.4 (the CarvingContext and SurfaceSystem methods still exist but are also deprecated).

Yea, I checked it out and it doesn’t seem to be viable anymore. My current Plan is to check the area beforehand and save whatever Blocks there are in a variable.