src/game/java/net/minecraft/client/renderer/texture/Stitcher.java

package net.minecraft.client.renderer.texture;

import com.google.common.collect.ImmutableList;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import javax.annotation.Nullable;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.util.Mth;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;

@OnlyIn(Dist.CLIENT)
public class Stitcher<T extends Stitcher.Entry> {
    private static final Comparator<Stitcher.Holder<?>> HOLDER_COMPARATOR = Comparator.<Stitcher.Holder<?>, Integer>comparing(p_118201_ -> -p_118201_.height)
        .thenComparing(p_118199_ -> -p_118199_.width)
        .thenComparing(p_247945_ -> p_247945_.entry.name());
    private final int mipLevel;
    private final List<Stitcher.Holder<T>> texturesToBeStitched = new ArrayList<>();
    private final List<Stitcher.Region<T>> storage = new ArrayList<>();
    private int storageX;
    private int storageY;
    private final int maxWidth;
    private final int maxHeight;

    public Stitcher(int p_118171_, int p_118172_, int p_118173_) {
        this.mipLevel = p_118173_;
        this.maxWidth = p_118171_;
        this.maxHeight = p_118172_;
    }

    public int getWidth() {
        return this.storageX;
    }

    public int getHeight() {
        return this.storageY;
    }

    public void registerSprite(T p_249253_) {
        Stitcher.Holder<T> holder = new Stitcher.Holder<>(p_249253_, this.mipLevel);
        this.texturesToBeStitched.add(holder);
    }

    public void stitch() {
        List<Stitcher.Holder<T>> list = new ArrayList<>(this.texturesToBeStitched);
        list.sort(HOLDER_COMPARATOR);

        for (Stitcher.Holder<T> holder : list) {
            if (!this.addToStorage(holder)) {
                throw new StitcherException(holder.entry, list.stream().map(p_247946_ -> p_247946_.entry).collect(ImmutableList.toImmutableList()));
            }
        }
    }

    public void gatherSprites(Stitcher.SpriteLoader<T> p_118181_) {
        for (Stitcher.Region<T> region : this.storage) {
            region.walk(p_118181_);
        }
    }

    static int smallestFittingMinTexel(int p_118189_, int p_118190_) {
        return (p_118189_ >> p_118190_) + ((p_118189_ & (1 << p_118190_) - 1) == 0 ? 0 : 1) << p_118190_;
    }

    private boolean addToStorage(Stitcher.Holder<T> p_118179_) {
        for (Stitcher.Region<T> region : this.storage) {
            if (region.add(p_118179_)) {
                return true;
            }
        }

        return this.expand(p_118179_);
    }

    private boolean expand(Stitcher.Holder<T> p_118192_) {
        int i = Mth.smallestEncompassingPowerOfTwo(this.storageX);
        int j = Mth.smallestEncompassingPowerOfTwo(this.storageY);
        int k = Mth.smallestEncompassingPowerOfTwo(this.storageX + p_118192_.width);
        int l = Mth.smallestEncompassingPowerOfTwo(this.storageY + p_118192_.height);
        boolean flag1 = k <= this.maxWidth;
        boolean flag2 = l <= this.maxHeight;
        if (!flag1 && !flag2) {
            return false;
        } else {
            boolean flag3 = flag1 && i != k;
            boolean flag4 = flag2 && j != l;
            boolean flag;
            if (flag3 ^ flag4) {
                flag = flag3;
            } else {
                flag = flag1 && i <= j;
            }

            Stitcher.Region<T> region;
            if (flag) {
                if (this.storageY == 0) {
                    this.storageY = l;
                }

                region = new Stitcher.Region<>(this.storageX, 0, k - this.storageX, this.storageY);
                this.storageX = k;
            } else {
                region = new Stitcher.Region<>(0, this.storageY, this.storageX, l - this.storageY);
                this.storageY = l;
            }

            region.add(p_118192_);
            this.storage.add(region);
            return true;
        }
    }

    @OnlyIn(Dist.CLIENT)
    public interface Entry {
        int width();

        int height();

        ResourceLocation name();
    }

    @OnlyIn(Dist.CLIENT)
    static record Holder<T extends Stitcher.Entry>(T entry, int width, int height) {
        public Holder(T p_250261_, int p_250127_) {
            this(p_250261_, Stitcher.smallestFittingMinTexel(p_250261_.width(), p_250127_), Stitcher.smallestFittingMinTexel(p_250261_.height(), p_250127_));
        }
    }

    @OnlyIn(Dist.CLIENT)
    public static class Region<T extends Stitcher.Entry> {
        private final int originX;
        private final int originY;
        private final int width;
        private final int height;
        @Nullable
        private List<Stitcher.Region<T>> subSlots;
        @Nullable
        private Stitcher.Holder<T> holder;

        public Region(int p_118216_, int p_118217_, int p_118218_, int p_118219_) {
            this.originX = p_118216_;
            this.originY = p_118217_;
            this.width = p_118218_;
            this.height = p_118219_;
        }

        public int getX() {
            return this.originX;
        }

        public int getY() {
            return this.originY;
        }

        public boolean add(Stitcher.Holder<T> p_118222_) {
            if (this.holder != null) {
                return false;
            } else {
                int i = p_118222_.width;
                int j = p_118222_.height;
                if (i <= this.width && j <= this.height) {
                    if (i == this.width && j == this.height) {
                        this.holder = p_118222_;
                        return true;
                    } else {
                        if (this.subSlots == null) {
                            this.subSlots = new ArrayList<>(1);
                            this.subSlots.add(new Stitcher.Region<>(this.originX, this.originY, i, j));
                            int k = this.width - i;
                            int l = this.height - j;
                            if (l > 0 && k > 0) {
                                int i1 = Math.max(this.height, k);
                                int j1 = Math.max(this.width, l);
                                if (i1 >= j1) {
                                    this.subSlots.add(new Stitcher.Region<>(this.originX, this.originY + j, i, l));
                                    this.subSlots.add(new Stitcher.Region<>(this.originX + i, this.originY, k, this.height));
                                } else {
                                    this.subSlots.add(new Stitcher.Region<>(this.originX + i, this.originY, k, j));
                                    this.subSlots.add(new Stitcher.Region<>(this.originX, this.originY + j, this.width, l));
                                }
                            } else if (k == 0) {
                                this.subSlots.add(new Stitcher.Region<>(this.originX, this.originY + j, i, l));
                            } else if (l == 0) {
                                this.subSlots.add(new Stitcher.Region<>(this.originX + i, this.originY, k, j));
                            }
                        }

                        for (Stitcher.Region<T> region : this.subSlots) {
                            if (region.add(p_118222_)) {
                                return true;
                            }
                        }

                        return false;
                    }
                } else {
                    return false;
                }
            }
        }

        public void walk(Stitcher.SpriteLoader<T> p_250195_) {
            if (this.holder != null) {
                p_250195_.load(this.holder.entry, this.getX(), this.getY());
            } else if (this.subSlots != null) {
                for (Stitcher.Region<T> region : this.subSlots) {
                    region.walk(p_250195_);
                }
            }
        }

        @Override
        public String toString() {
            return "Slot{originX="
                + this.originX
                + ", originY="
                + this.originY
                + ", width="
                + this.width
                + ", height="
                + this.height
                + ", texture="
                + this.holder
                + ", subSlots="
                + this.subSlots
                + "}";
        }
    }

    @OnlyIn(Dist.CLIENT)
    public interface SpriteLoader<T extends Stitcher.Entry> {
        void load(T p_249434_, int p_118230_, int p_118231_);
    }
}