Code/net/minecraft/world/level/levelgen/feature/BasaltColumnsFeature.java

package net.minecraft.world.level.levelgen.feature;

import com.google.common.collect.ImmutableList;
import com.mojang.serialization.Codec;
import javax.annotation.Nullable;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.util.RandomSource;
import net.minecraft.world.level.LevelAccessor;
import net.minecraft.world.level.WorldGenLevel;
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.levelgen.feature.configurations.ColumnFeatureConfiguration;

public class BasaltColumnsFeature extends Feature<ColumnFeatureConfiguration> {
    private static final ImmutableList<Block> CANNOT_PLACE_ON = ImmutableList.of(
        Blocks.LAVA,
        Blocks.BEDROCK,
        Blocks.MAGMA_BLOCK,
        Blocks.SOUL_SAND,
        Blocks.NETHER_BRICKS,
        Blocks.NETHER_BRICK_FENCE,
        Blocks.NETHER_BRICK_STAIRS,
        Blocks.NETHER_WART,
        Blocks.CHEST,
        Blocks.SPAWNER
    );
    private static final int CLUSTERED_REACH = 5;
    private static final int CLUSTERED_SIZE = 50;
    private static final int UNCLUSTERED_REACH = 8;
    private static final int UNCLUSTERED_SIZE = 15;

    public BasaltColumnsFeature(Codec<ColumnFeatureConfiguration> p_65153_) {
        super(p_65153_);
    }

    @Override
    public boolean place(FeaturePlaceContext<ColumnFeatureConfiguration> p_159444_) {
        int i = p_159444_.chunkGenerator().getSeaLevel();
        BlockPos blockpos = p_159444_.origin();
        WorldGenLevel worldgenlevel = p_159444_.level();
        RandomSource randomsource = p_159444_.random();
        ColumnFeatureConfiguration columnfeatureconfiguration = p_159444_.config();
        if (!canPlaceAt(worldgenlevel, i, blockpos.mutable())) {
            return false;
        } else {
            int j = columnfeatureconfiguration.height().sample(randomsource);
            boolean flag = randomsource.nextFloat() < 0.9F;
            int k = Math.min(j, flag ? 5 : 8);
            int l = flag ? 50 : 15;
            boolean flag1 = false;

            for (BlockPos blockpos1 : BlockPos.randomBetweenClosed(
                randomsource,
                l,
                blockpos.getX() - k,
                blockpos.getY(),
                blockpos.getZ() - k,
                blockpos.getX() + k,
                blockpos.getY(),
                blockpos.getZ() + k
            )) {
                int i1 = j - blockpos1.distManhattan(blockpos);
                if (i1 >= 0) {
                    flag1 |= this.placeColumn(worldgenlevel, i, blockpos1, i1, columnfeatureconfiguration.reach().sample(randomsource));
                }
            }

            return flag1;
        }
    }

    private boolean placeColumn(LevelAccessor p_65168_, int p_65169_, BlockPos p_65170_, int p_65171_, int p_65172_) {
        boolean flag = false;

        for (BlockPos blockpos : BlockPos.betweenClosed(
            p_65170_.getX() - p_65172_,
            p_65170_.getY(),
            p_65170_.getZ() - p_65172_,
            p_65170_.getX() + p_65172_,
            p_65170_.getY(),
            p_65170_.getZ() + p_65172_
        )) {
            int i = blockpos.distManhattan(p_65170_);
            BlockPos blockpos1 = isAirOrLavaOcean(p_65168_, p_65169_, blockpos)
                ? findSurface(p_65168_, p_65169_, blockpos.mutable(), i)
                : findAir(p_65168_, blockpos.mutable(), i);
            if (blockpos1 != null) {
                int j = p_65171_ - i / 2;

                for (BlockPos.MutableBlockPos blockpos$mutableblockpos = blockpos1.mutable(); j >= 0; j--) {
                    if (isAirOrLavaOcean(p_65168_, p_65169_, blockpos$mutableblockpos)) {
                        this.setBlock(p_65168_, blockpos$mutableblockpos, Blocks.BASALT.defaultBlockState());
                        blockpos$mutableblockpos.move(Direction.UP);
                        flag = true;
                    } else {
                        if (!p_65168_.getBlockState(blockpos$mutableblockpos).is(Blocks.BASALT)) {
                            break;
                        }

                        blockpos$mutableblockpos.move(Direction.UP);
                    }
                }
            }
        }

        return flag;
    }

    @Nullable
    private static BlockPos findSurface(LevelAccessor p_65159_, int p_65160_, BlockPos.MutableBlockPos p_65161_, int p_65162_) {
        while (p_65161_.getY() > p_65159_.getMinY() + 1 && p_65162_ > 0) {
            p_65162_--;
            if (canPlaceAt(p_65159_, p_65160_, p_65161_)) {
                return p_65161_;
            }

            p_65161_.move(Direction.DOWN);
        }

        return null;
    }

    private static boolean canPlaceAt(LevelAccessor p_65155_, int p_65156_, BlockPos.MutableBlockPos p_65157_) {
        if (!isAirOrLavaOcean(p_65155_, p_65156_, p_65157_)) {
            return false;
        } else {
            BlockState blockstate = p_65155_.getBlockState(p_65157_.move(Direction.DOWN));
            p_65157_.move(Direction.UP);
            return !blockstate.isAir() && !CANNOT_PLACE_ON.contains(blockstate.getBlock());
        }
    }

    @Nullable
    private static BlockPos findAir(LevelAccessor p_65174_, BlockPos.MutableBlockPos p_65175_, int p_65176_) {
        while (p_65175_.getY() <= p_65174_.getMaxY() && p_65176_ > 0) {
            p_65176_--;
            BlockState blockstate = p_65174_.getBlockState(p_65175_);
            if (CANNOT_PLACE_ON.contains(blockstate.getBlock())) {
                return null;
            }

            if (blockstate.isAir()) {
                return p_65175_;
            }

            p_65175_.move(Direction.UP);
        }

        return null;
    }

    private static boolean isAirOrLavaOcean(LevelAccessor p_65164_, int p_65165_, BlockPos p_65166_) {
        BlockState blockstate = p_65164_.getBlockState(p_65166_);
        return blockstate.isAir() || blockstate.is(Blocks.LAVA) && p_65166_.getY() <= p_65165_;
    }
}