RegionGenerator.java

package me.hydos.naclmon.world.gen;

import me.hydos.naclmon.world.NaclmonBiomes;
import me.hydos.naclmon.world.gen.noise.IslandRegionNoise;
import me.hydos.naclmon.world.gen.noise.OpenSimplexNoise;
import net.minecraft.core.Holder;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.util.RandomSource;
import net.minecraft.world.level.biome.Biome;
import net.minecraft.world.level.chunk.ChunkAccess;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class RegionGenerator {
    private final Holder<Biome> ocean;
    private final OpenSimplexNoise oceanNoise;
    private final IslandRegionNoise islandNoise;
    private final int seaLevel;
    private final RegionBiomeSource biomeSource;

    public RegionGenerator(RandomSource random, RegionBiomeSource biomeSource, Holder<Biome> ocean, int seaLevel) {
        this.biomeSource = biomeSource;
        this.ocean = ocean;
        this.seaLevel = seaLevel;
        this.oceanNoise = new OpenSimplexNoise(random);
        this.islandNoise = new IslandRegionNoise(random);
    }

    public int getHeightAt(int x, int z, ChunkAccess chunk) {
        var biomes = getSurroundingBiomeWeights(x, z);
        var combinedHeight = 0;
        var heightsCombined = 0;

        for (var entry : biomes.entrySet()) {
            var sample = oceanNoise.sample(x * 0.0001, z * 0.0001) * 3;
            var biome = entry.getKey();

            if (NaclmonBiomes.ISLAND_FOREST.equals(biome)) sample += islandNoise.sampleForest(x, z);
            if (NaclmonBiomes.ISLAND_CLEARING.equals(biome)) sample += islandNoise.sampleClearing(x, z);

            var heightOffset = isChunkOcean(chunk) ? -30 : -10;
            var overallHeight = (int) (seaLevel + heightOffset + sample);

            combinedHeight += overallHeight * entry.getValue();
            heightsCombined += entry.getValue();
        }

        return combinedHeight / heightsCombined;
    }

    private Map<ResourceLocation, Integer> getSurroundingBiomeWeights(int x, int z) {
        var biomeDistribution = new ConcurrentHashMap<ResourceLocation, Integer>();

        for (var checkX = -3; checkX < 3; checkX += 3) {

            for (var checkZ = -3; checkZ < 3; checkZ += 3) {
                var biome = biomeSource.getNoiseBiome(x + checkX, 0, z + checkZ, null).unwrapKey().orElseThrow().location();
                biomeDistribution.putIfAbsent(biome, 0);
                biomeDistribution.put(biome, biomeDistribution.get(biome) + 1);
            }
        }

        return biomeDistribution;
    }

    private boolean isChunkOcean(ChunkAccess chunk) {
        var oceanId = this.ocean.unwrapKey().orElseThrow();
        var chunkX = ((chunk.getPos().x) << 4);
        var chunkZ = ((chunk.getPos().z) << 4);

        for (var checkX = 0; checkX < 16; checkX++) {
            for (var checkZ = 0; checkZ < 16; checkZ++) {
                var isOcean = chunk.getNoiseBiome(chunkX + checkX, 0, chunkZ + checkZ).is(oceanId);
                if (isOcean) return true;
            }
        }

        return false;
    }
}