src/game/java/net/minecraft/client/animation/KeyframeAnimations.java

package net.minecraft.client.animation;

import java.util.List;
import java.util.Optional;
import java.util.Map.Entry;
import net.minecraft.client.model.Model;
import net.minecraft.client.model.geom.ModelPart;
import net.minecraft.util.Mth;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;
import org.joml.Vector3f;

@OnlyIn(Dist.CLIENT)
public class KeyframeAnimations {
    public static void animate(Model p_362391_, AnimationDefinition p_232321_, long p_232322_, float p_232323_, Vector3f p_253861_) {
        float f = getElapsedSeconds(p_232321_, p_232322_);

        for (Entry<String, List<AnimationChannel>> entry : p_232321_.boneAnimations().entrySet()) {
            Optional<ModelPart> optional = p_362391_.getAnyDescendantWithName(entry.getKey());
            List<AnimationChannel> list = entry.getValue();
            optional.ifPresent(p_232330_ -> list.forEach(p_288241_ -> {
                    Keyframe[] akeyframe = p_288241_.keyframes();
                    int i = Math.max(0, Mth.binarySearch(0, akeyframe.length, p_232315_ -> f <= akeyframe[p_232315_].timestamp()) - 1);
                    int j = Math.min(akeyframe.length - 1, i + 1);
                    Keyframe keyframe = akeyframe[i];
                    Keyframe keyframe1 = akeyframe[j];
                    float f1 = f - keyframe.timestamp();
                    float f2;
                    if (j != i) {
                        f2 = Mth.clamp(f1 / (keyframe1.timestamp() - keyframe.timestamp()), 0.0F, 1.0F);
                    } else {
                        f2 = 0.0F;
                    }

                    keyframe1.interpolation().apply(p_253861_, f2, akeyframe, i, j, p_232323_);
                    p_288241_.target().apply(p_232330_, p_253861_);
                }));
        }
    }

    private static float getElapsedSeconds(AnimationDefinition p_232317_, long p_232318_) {
        float f = (float)p_232318_ / 1000.0F;
        return p_232317_.looping() ? f % p_232317_.lengthInSeconds() : f;
    }

    public static Vector3f posVec(float p_253691_, float p_254046_, float p_254461_) {
        return new Vector3f(p_253691_, -p_254046_, p_254461_);
    }

    public static Vector3f degreeVec(float p_254402_, float p_253917_, float p_254397_) {
        return new Vector3f(p_254402_ * (float) (Math.PI / 180.0), p_253917_ * (float) (Math.PI / 180.0), p_254397_ * (float) (Math.PI / 180.0));
    }

    public static Vector3f scaleVec(double p_253806_, double p_253647_, double p_254396_) {
        return new Vector3f((float)(p_253806_ - 1.0), (float)(p_253647_ - 1.0), (float)(p_254396_ - 1.0));
    }
}