minecraft-src/net/minecraft/world/level/block/SnowLayerBlock.java

package net.minecraft.world.level.block;

import com.mojang.serialization.MapCodec;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.tags.BlockTags;
import net.minecraft.util.RandomSource;
import net.minecraft.world.item.context.BlockPlaceContext;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.LevelReader;
import net.minecraft.world.level.LightLayer;
import net.minecraft.world.level.ScheduledTickAccess;
import net.minecraft.world.level.block.state.BlockBehaviour;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.block.state.StateDefinition.Builder;
import net.minecraft.world.level.block.state.properties.BlockStateProperties;
import net.minecraft.world.level.block.state.properties.IntegerProperty;
import net.minecraft.world.level.pathfinder.PathComputationType;
import net.minecraft.world.phys.shapes.CollisionContext;
import net.minecraft.world.phys.shapes.VoxelShape;
import org.jetbrains.annotations.Nullable;

public class SnowLayerBlock extends Block {
	public static final MapCodec<SnowLayerBlock> CODEC = simpleCodec(SnowLayerBlock::new);
	public static final int MAX_HEIGHT = 8;
	public static final IntegerProperty LAYERS = BlockStateProperties.LAYERS;
	private static final VoxelShape[] SHAPES = Block.boxes(8, i -> Block.column(16.0, 0.0, i * 2));
	public static final int HEIGHT_IMPASSABLE = 5;

	@Override
	public MapCodec<SnowLayerBlock> codec() {
		return CODEC;
	}

	protected SnowLayerBlock(BlockBehaviour.Properties properties) {
		super(properties);
		this.registerDefaultState(this.stateDefinition.any().setValue(LAYERS, 1));
	}

	@Override
	protected boolean isPathfindable(BlockState state, PathComputationType pathComputationType) {
		return pathComputationType == PathComputationType.LAND ? (Integer)state.getValue(LAYERS) < 5 : false;
	}

	@Override
	protected VoxelShape getShape(BlockState state, BlockGetter level, BlockPos pos, CollisionContext context) {
		return SHAPES[state.getValue(LAYERS)];
	}

	@Override
	protected VoxelShape getCollisionShape(BlockState state, BlockGetter level, BlockPos pos, CollisionContext context) {
		return SHAPES[state.getValue(LAYERS) - 1];
	}

	@Override
	protected VoxelShape getBlockSupportShape(BlockState state, BlockGetter level, BlockPos pos) {
		return SHAPES[state.getValue(LAYERS)];
	}

	@Override
	protected VoxelShape getVisualShape(BlockState state, BlockGetter level, BlockPos pos, CollisionContext context) {
		return SHAPES[state.getValue(LAYERS)];
	}

	@Override
	protected boolean useShapeForLightOcclusion(BlockState state) {
		return true;
	}

	@Override
	protected float getShadeBrightness(BlockState state, BlockGetter level, BlockPos pos) {
		return state.getValue(LAYERS) == 8 ? 0.2F : 1.0F;
	}

	@Override
	protected boolean canSurvive(BlockState state, LevelReader level, BlockPos pos) {
		BlockState blockState = level.getBlockState(pos.below());
		if (blockState.is(BlockTags.SNOW_LAYER_CANNOT_SURVIVE_ON)) {
			return false;
		} else {
			return blockState.is(BlockTags.SNOW_LAYER_CAN_SURVIVE_ON)
				? true
				: Block.isFaceFull(blockState.getCollisionShape(level, pos.below()), Direction.UP) || blockState.is(this) && (Integer)blockState.getValue(LAYERS) == 8;
		}
	}

	@Override
	protected BlockState updateShape(
		BlockState state,
		LevelReader level,
		ScheduledTickAccess scheduledTickAccess,
		BlockPos pos,
		Direction direction,
		BlockPos neighborPos,
		BlockState neighborState,
		RandomSource random
	) {
		return !state.canSurvive(level, pos)
			? Blocks.AIR.defaultBlockState()
			: super.updateShape(state, level, scheduledTickAccess, pos, direction, neighborPos, neighborState, random);
	}

	@Override
	protected void randomTick(BlockState state, ServerLevel level, BlockPos pos, RandomSource random) {
		if (level.getBrightness(LightLayer.BLOCK, pos) > 11) {
			dropResources(state, level, pos);
			level.removeBlock(pos, false);
		}
	}

	@Override
	protected boolean canBeReplaced(BlockState state, BlockPlaceContext useContext) {
		int i = (Integer)state.getValue(LAYERS);
		if (!useContext.getItemInHand().is(this.asItem()) || i >= 8) {
			return i == 1;
		} else {
			return useContext.replacingClickedOnBlock() ? useContext.getClickedFace() == Direction.UP : true;
		}
	}

	@Nullable
	@Override
	public BlockState getStateForPlacement(BlockPlaceContext context) {
		BlockState blockState = context.getLevel().getBlockState(context.getClickedPos());
		if (blockState.is(this)) {
			int i = (Integer)blockState.getValue(LAYERS);
			return blockState.setValue(LAYERS, Math.min(8, i + 1));
		} else {
			return super.getStateForPlacement(context);
		}
	}

	@Override
	protected void createBlockStateDefinition(Builder<Block, BlockState> builder) {
		builder.add(LAYERS);
	}
}