VanillaChunkBiomeContainer.java

package net.minecraft.world.level.chunk;

import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.core.IdMap;
import net.minecraft.core.QuartPos;
import net.minecraft.util.Mth;
import net.minecraft.world.level.ChunkPos;
import net.minecraft.world.level.LevelHeightAccessor;
import net.minecraft.world.level.biome.Biome;
import net.minecraft.world.level.biome.BiomeManager;
import net.minecraft.world.level.biome.BiomeSource;
import net.minecraft.world.level.dimension.DimensionType;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.jetbrains.annotations.Nullable;

public class ChunkBiomeContainer implements BiomeManager.NoiseBiomeSource {
   private static final Logger LOGGER = LogManager.getLogger();
   private static final int WIDTH_BITS = Mth.ceillog2(16) - 2;
   private static final int HORIZONTAL_MASK;
   public static final int MAX_SIZE;
   private final IdMap<Biome> biomeRegistry;
   private final Biome[] biomes;
   private final int quartMinY;
   private final int quartHeight;

   protected ChunkBiomeContainer(IdMap<Biome> idMap, LevelHeightAccessor levelHeightAccessor, Biome[] biomes) {
      this.biomeRegistry = idMap;
      this.biomes = biomes;
      this.quartMinY = QuartPos.fromBlock(levelHeightAccessor.getMinBuildHeight());
      this.quartHeight = QuartPos.fromBlock(levelHeightAccessor.getHeight()) - 1;
   }

   @Environment(EnvType.CLIENT)
   public ChunkBiomeContainer(IdMap<Biome> idMap, LevelHeightAccessor levelHeightAccessor, int[] is) {
      this(idMap, levelHeightAccessor, new Biome[is.length]);

      for(int i = 0; i < this.biomes.length; ++i) {
         int j = is[i];
         Biome biome = (Biome)idMap.byId(j);
         if (biome == null) {
            LOGGER.warn("Received invalid biome id: {}", j);
            this.biomes[i] = (Biome)idMap.byId(0);
         } else {
            this.biomes[i] = biome;
         }
      }

   }

   public ChunkBiomeContainer(IdMap<Biome> idMap, LevelHeightAccessor levelHeightAccessor, ChunkPos chunkPos, BiomeSource biomeSource) {
      this(idMap, levelHeightAccessor, chunkPos, biomeSource, (int[])null);
   }

   public ChunkBiomeContainer(IdMap<Biome> idMap, LevelHeightAccessor levelHeightAccessor, ChunkPos chunkPos, BiomeSource biomeSource, @Nullable int[] is) {
      this(idMap, levelHeightAccessor, new Biome[(1 << WIDTH_BITS + WIDTH_BITS) * ceilDiv(levelHeightAccessor.getHeight(), 4)]);
      int i = QuartPos.fromBlock(chunkPos.getMinBlockX());
      int j = this.quartMinY;
      int k = QuartPos.fromBlock(chunkPos.getMinBlockZ());
      int l;
      if (is != null) {
         for(l = 0; l < is.length; ++l) {
            this.biomes[l] = (Biome)idMap.byId(is[l]);
            if (this.biomes[l] == null) {
               this.biomes[l] = biomeForIndex(biomeSource, i, j, k, l);
            }
         }
      } else {
         for(l = 0; l < this.biomes.length; ++l) {
            this.biomes[l] = biomeForIndex(biomeSource, i, j, k, l);
         }
      }

   }

   private static int ceilDiv(int i, int j) {
      return (i + j - 1) / j;
   }

   private static Biome biomeForIndex(BiomeSource biomeSource, int i, int j, int k, int l) {
      int m = l & HORIZONTAL_MASK;
      int n = l >> WIDTH_BITS + WIDTH_BITS;
      int o = l >> WIDTH_BITS & HORIZONTAL_MASK;
      return biomeSource.getNoiseBiome(i + m, j + n, k + o);
   }

   public int[] writeBiomes() {
      int[] is = new int[this.biomes.length];

      for(int i = 0; i < this.biomes.length; ++i) {
         is[i] = this.biomeRegistry.getId(this.biomes[i]);
      }

      return is;
   }

   public Biome getNoiseBiome(int biomeX, int biomeY, int biomeZ) {
      int i = biomeX & HORIZONTAL_MASK;
      int j = Mth.clamp(biomeY - this.quartMinY, 0, this.quartHeight);
      int k = biomeZ & HORIZONTAL_MASK;
      return this.biomes[j << WIDTH_BITS + WIDTH_BITS | k << WIDTH_BITS | i];
   }

   static {
      HORIZONTAL_MASK = (1 << WIDTH_BITS) - 1;
      MAX_SIZE = 1 << WIDTH_BITS + WIDTH_BITS + DimensionType.BITS_FOR_Y - 2;
   }
}