minecraft-src/net/minecraft/world/level/biome/BiomeSource.java

package net.minecraft.world.level.biome;

import com.google.common.base.Suppliers;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import com.mojang.datafixers.util.Pair;
import com.mojang.serialization.Codec;
import com.mojang.serialization.MapCodec;
import java.util.List;
import java.util.Set;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import net.minecraft.SharedConstants;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.core.Holder;
import net.minecraft.core.QuartPos;
import net.minecraft.core.registries.BuiltInRegistries;
import net.minecraft.util.Mth;
import net.minecraft.util.RandomSource;
import net.minecraft.world.level.LevelReader;
import net.minecraft.world.level.biome.Climate.Sampler;
import org.jetbrains.annotations.Nullable;

public abstract class BiomeSource implements BiomeResolver {
	public static final Codec<BiomeSource> CODEC = BuiltInRegistries.BIOME_SOURCE.byNameCodec().dispatchStable(BiomeSource::codec, Function.identity());
	private final Supplier<Set<Holder<Biome>>> possibleBiomes = Suppliers.memoize(
		() -> (Set<Holder<Biome>>)this.collectPossibleBiomes().distinct().collect(ImmutableSet.toImmutableSet())
	);

	protected BiomeSource() {
	}

	protected abstract MapCodec<? extends BiomeSource> codec();

	protected abstract Stream<Holder<Biome>> collectPossibleBiomes();

	public Set<Holder<Biome>> possibleBiomes() {
		return (Set<Holder<Biome>>)this.possibleBiomes.get();
	}

	public Set<Holder<Biome>> getBiomesWithin(int x, int y, int z, int radius, Sampler sampler) {
		int i = QuartPos.fromBlock(x - radius);
		int j = QuartPos.fromBlock(y - radius);
		int k = QuartPos.fromBlock(z - radius);
		int l = QuartPos.fromBlock(x + radius);
		int m = QuartPos.fromBlock(y + radius);
		int n = QuartPos.fromBlock(z + radius);
		int o = l - i + 1;
		int p = m - j + 1;
		int q = n - k + 1;
		Set<Holder<Biome>> set = Sets.<Holder<Biome>>newHashSet();

		for (int r = 0; r < q; r++) {
			for (int s = 0; s < o; s++) {
				for (int t = 0; t < p; t++) {
					int u = i + s;
					int v = j + t;
					int w = k + r;
					set.add(this.getNoiseBiome(u, v, w, sampler));
				}
			}
		}

		return set;
	}

	@Nullable
	public Pair<BlockPos, Holder<Biome>> findBiomeHorizontal(
		int x, int y, int z, int radius, Predicate<Holder<Biome>> biomePredicate, RandomSource random, Sampler sampler
	) {
		return this.findBiomeHorizontal(x, y, z, radius, 1, biomePredicate, random, false, sampler);
	}

	@Nullable
	public Pair<BlockPos, Holder<Biome>> findClosestBiome3d(
		BlockPos pos, int radius, int horizontalStep, int verticalStep, Predicate<Holder<Biome>> biomePredicate, Sampler sampler, LevelReader level
	) {
		Set<Holder<Biome>> set = (Set<Holder<Biome>>)this.possibleBiomes().stream().filter(biomePredicate).collect(Collectors.toUnmodifiableSet());
		if (set.isEmpty()) {
			return null;
		} else {
			int i = Math.floorDiv(radius, horizontalStep);
			int[] is = Mth.outFromOrigin(pos.getY(), level.getMinY() + 1, level.getMaxY() + 1, verticalStep).toArray();

			for (BlockPos.MutableBlockPos mutableBlockPos : BlockPos.spiralAround(BlockPos.ZERO, i, Direction.EAST, Direction.SOUTH)) {
				int j = pos.getX() + mutableBlockPos.getX() * horizontalStep;
				int k = pos.getZ() + mutableBlockPos.getZ() * horizontalStep;
				int l = QuartPos.fromBlock(j);
				int m = QuartPos.fromBlock(k);

				for (int n : is) {
					int o = QuartPos.fromBlock(n);
					Holder<Biome> holder = this.getNoiseBiome(l, o, m, sampler);
					if (set.contains(holder)) {
						return Pair.of(new BlockPos(j, n, k), holder);
					}
				}
			}

			return null;
		}
	}

	@Nullable
	public Pair<BlockPos, Holder<Biome>> findBiomeHorizontal(
		int x, int y, int z, int radius, int increment, Predicate<Holder<Biome>> biomePredicate, RandomSource random, boolean findClosest, Sampler sampler
	) {
		int i = QuartPos.fromBlock(x);
		int j = QuartPos.fromBlock(z);
		int k = QuartPos.fromBlock(radius);
		int l = QuartPos.fromBlock(y);
		Pair<BlockPos, Holder<Biome>> pair = null;
		int m = 0;
		int n = findClosest ? 0 : k;
		int o = n;

		while (o <= k) {
			for (int p = SharedConstants.debugGenerateSquareTerrainWithoutNoise ? 0 : -o; p <= o; p += increment) {
				boolean bl = Math.abs(p) == o;

				for (int q = -o; q <= o; q += increment) {
					if (findClosest) {
						boolean bl2 = Math.abs(q) == o;
						if (!bl2 && !bl) {
							continue;
						}
					}

					int r = i + q;
					int s = j + p;
					Holder<Biome> holder = this.getNoiseBiome(r, l, s, sampler);
					if (biomePredicate.test(holder)) {
						if (pair == null || random.nextInt(m + 1) == 0) {
							BlockPos blockPos = new BlockPos(QuartPos.toBlock(r), y, QuartPos.toBlock(s));
							if (findClosest) {
								return Pair.of(blockPos, holder);
							}

							pair = Pair.of(blockPos, holder);
						}

						m++;
					}
				}
			}

			o += increment;
		}

		return pair;
	}

	@Override
	public abstract Holder<Biome> getNoiseBiome(int i, int j, int k, Sampler sampler);

	public void addDebugInfo(List<String> info, BlockPos pos, Sampler sampler) {
	}
}