src/game/java/net/minecraft/client/renderer/chunk/VisibilitySet.java

package net.minecraft.client.renderer.chunk;

import java.util.BitSet;
import java.util.Set;
import net.minecraft.core.Direction;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;

@OnlyIn(Dist.CLIENT)
public class VisibilitySet {
    private static final int FACINGS = Direction.values().length;
    private final BitSet data = new BitSet(FACINGS * FACINGS);

    public void add(Set<Direction> p_112991_) {
        for (Direction direction : p_112991_) {
            for (Direction direction1 : p_112991_) {
                this.set(direction, direction1, true);
            }
        }
    }

    public void set(Direction p_112987_, Direction p_112988_, boolean p_112989_) {
        this.data.set(p_112987_.ordinal() + p_112988_.ordinal() * FACINGS, p_112989_);
        this.data.set(p_112988_.ordinal() + p_112987_.ordinal() * FACINGS, p_112989_);
    }

    public void setAll(boolean p_112993_) {
        this.data.set(0, this.data.size(), p_112993_);
    }

    public boolean visibilityBetween(Direction p_112984_, Direction p_112985_) {
        return this.data.get(p_112984_.ordinal() + p_112985_.ordinal() * FACINGS);
    }

    @Override
    public String toString() {
        StringBuilder stringbuilder = new StringBuilder();
        stringbuilder.append(' ');

        for (Direction direction : Direction.values()) {
            stringbuilder.append(' ').append(direction.toString().toUpperCase().charAt(0));
        }

        stringbuilder.append('\n');

        for (Direction direction2 : Direction.values()) {
            stringbuilder.append(direction2.toString().toUpperCase().charAt(0));

            for (Direction direction1 : Direction.values()) {
                if (direction2 == direction1) {
                    stringbuilder.append("  ");
                } else {
                    boolean flag = this.visibilityBetween(direction2, direction1);
                    stringbuilder.append(' ').append((char)(flag ? 'Y' : 'n'));
                }
            }

            stringbuilder.append('\n');
        }

        return stringbuilder.toString();
    }
}