minecraft-src/net/minecraft/world/level/chunk/LevelChunkSection.java

package net.minecraft.world.level.chunk;

import java.util.function.Predicate;
import net.minecraft.core.Holder;
import net.minecraft.core.Registry;
import net.minecraft.network.FriendlyByteBuf;
import net.minecraft.world.level.biome.Biome;
import net.minecraft.world.level.biome.BiomeResolver;
import net.minecraft.world.level.biome.Biomes;
import net.minecraft.world.level.biome.Climate.Sampler;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.material.FluidState;

public class LevelChunkSection {
	public static final int SECTION_WIDTH = 16;
	public static final int SECTION_HEIGHT = 16;
	public static final int SECTION_SIZE = 4096;
	public static final int BIOME_CONTAINER_BITS = 2;
	private short nonEmptyBlockCount;
	private short tickingBlockCount;
	private short tickingFluidCount;
	private final PalettedContainer<BlockState> states;
	private PalettedContainerRO<Holder<Biome>> biomes;

	private LevelChunkSection(LevelChunkSection section) {
		this.nonEmptyBlockCount = section.nonEmptyBlockCount;
		this.tickingBlockCount = section.tickingBlockCount;
		this.tickingFluidCount = section.tickingFluidCount;
		this.states = section.states.copy();
		this.biomes = section.biomes.copy();
	}

	public LevelChunkSection(PalettedContainer<BlockState> states, PalettedContainerRO<Holder<Biome>> biomes) {
		this.states = states;
		this.biomes = biomes;
		this.recalcBlockCounts();
	}

	public LevelChunkSection(Registry<Biome> biomeRegistry) {
		this.states = new PalettedContainer<>(Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES);
		this.biomes = new PalettedContainer<>(biomeRegistry.asHolderIdMap(), biomeRegistry.getOrThrow(Biomes.PLAINS), PalettedContainer.Strategy.SECTION_BIOMES);
	}

	public BlockState getBlockState(int x, int y, int z) {
		return this.states.get(x, y, z);
	}

	public FluidState getFluidState(int x, int y, int z) {
		return this.states.get(x, y, z).getFluidState();
	}

	public void acquire() {
		this.states.acquire();
	}

	public void release() {
		this.states.release();
	}

	public BlockState setBlockState(int x, int y, int z, BlockState state) {
		return this.setBlockState(x, y, z, state, true);
	}

	public BlockState setBlockState(int x, int y, int z, BlockState state, boolean useLocks) {
		BlockState blockState;
		if (useLocks) {
			blockState = this.states.getAndSet(x, y, z, state);
		} else {
			blockState = this.states.getAndSetUnchecked(x, y, z, state);
		}

		FluidState fluidState = blockState.getFluidState();
		FluidState fluidState2 = state.getFluidState();
		if (!blockState.isAir()) {
			this.nonEmptyBlockCount--;
			if (blockState.isRandomlyTicking()) {
				this.tickingBlockCount--;
			}
		}

		if (!fluidState.isEmpty()) {
			this.tickingFluidCount--;
		}

		if (!state.isAir()) {
			this.nonEmptyBlockCount++;
			if (state.isRandomlyTicking()) {
				this.tickingBlockCount++;
			}
		}

		if (!fluidState2.isEmpty()) {
			this.tickingFluidCount++;
		}

		return blockState;
	}

	/**
	 * @return {@code true} if this section consists only of air-like blocks.
	 */
	public boolean hasOnlyAir() {
		return this.nonEmptyBlockCount == 0;
	}

	public boolean isRandomlyTicking() {
		return this.isRandomlyTickingBlocks() || this.isRandomlyTickingFluids();
	}

	/**
	 * @return {@code true} if this section has any blocks that require random ticks.
	 */
	public boolean isRandomlyTickingBlocks() {
		return this.tickingBlockCount > 0;
	}

	/**
	 * @return {@code true} if this section has any fluids that require random ticks.
	 */
	public boolean isRandomlyTickingFluids() {
		return this.tickingFluidCount > 0;
	}

	public void recalcBlockCounts() {
		class BlockCounter implements PalettedContainer.CountConsumer<BlockState> {
			public int nonEmptyBlockCount;
			public int tickingBlockCount;
			public int tickingFluidCount;

			public void accept(BlockState blockState, int i) {
				FluidState fluidState = blockState.getFluidState();
				if (!blockState.isAir()) {
					this.nonEmptyBlockCount += i;
					if (blockState.isRandomlyTicking()) {
						this.tickingBlockCount += i;
					}
				}

				if (!fluidState.isEmpty()) {
					this.nonEmptyBlockCount += i;
					if (fluidState.isRandomlyTicking()) {
						this.tickingFluidCount += i;
					}
				}
			}
		}

		BlockCounter lv = new BlockCounter();
		this.states.count(lv);
		this.nonEmptyBlockCount = (short)lv.nonEmptyBlockCount;
		this.tickingBlockCount = (short)lv.tickingBlockCount;
		this.tickingFluidCount = (short)lv.tickingFluidCount;
	}

	public PalettedContainer<BlockState> getStates() {
		return this.states;
	}

	public PalettedContainerRO<Holder<Biome>> getBiomes() {
		return this.biomes;
	}

	public void read(FriendlyByteBuf buffer) {
		this.nonEmptyBlockCount = buffer.readShort();
		this.states.read(buffer);
		PalettedContainer<Holder<Biome>> palettedContainer = this.biomes.recreate();
		palettedContainer.read(buffer);
		this.biomes = palettedContainer;
	}

	public void readBiomes(FriendlyByteBuf buffer) {
		PalettedContainer<Holder<Biome>> palettedContainer = this.biomes.recreate();
		palettedContainer.read(buffer);
		this.biomes = palettedContainer;
	}

	public void write(FriendlyByteBuf buffer) {
		buffer.writeShort(this.nonEmptyBlockCount);
		this.states.write(buffer);
		this.biomes.write(buffer);
	}

	public int getSerializedSize() {
		return 2 + this.states.getSerializedSize() + this.biomes.getSerializedSize();
	}

	/**
	 * @return {@code true} if this section has any states matching the given predicate. As the internal representation uses a {@link net.minecraft.world.level.chunk.Palette}, this is more efficient than looping through every position in the section, or indeed the chunk.
	 */
	public boolean maybeHas(Predicate<BlockState> predicate) {
		return this.states.maybeHas(predicate);
	}

	public Holder<Biome> getNoiseBiome(int x, int y, int z) {
		return this.biomes.get(x, y, z);
	}

	public void fillBiomesFromNoise(BiomeResolver biomeResolver, Sampler climateSampler, int x, int y, int z) {
		PalettedContainer<Holder<Biome>> palettedContainer = this.biomes.recreate();
		int i = 4;

		for (int j = 0; j < 4; j++) {
			for (int k = 0; k < 4; k++) {
				for (int l = 0; l < 4; l++) {
					palettedContainer.getAndSetUnchecked(j, k, l, biomeResolver.getNoiseBiome(x + j, y + k, z + l, climateSampler));
				}
			}
		}

		this.biomes = palettedContainer;
	}

	public LevelChunkSection copy() {
		return new LevelChunkSection(this);
	}
}