minecraft-src/com/mojang/blaze3d/vertex/PoseStack.java

package com.mojang.blaze3d.vertex;

import com.mojang.math.MatrixUtil;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.world.phys.Vec3;
import org.joml.Matrix3f;
import org.joml.Matrix4f;
import org.joml.Matrix4fc;
import org.joml.Quaternionfc;
import org.joml.Vector3f;
import org.joml.Vector3fc;

@Environment(EnvType.CLIENT)
public class PoseStack {
	private final List<PoseStack.Pose> poses = new ArrayList(16);
	private int lastIndex;

	public PoseStack() {
		this.poses.add(new PoseStack.Pose());
	}

	public void translate(double x, double y, double z) {
		this.translate((float)x, (float)y, (float)z);
	}

	public void translate(float x, float y, float z) {
		this.last().translate(x, y, z);
	}

	public void translate(Vec3 vector) {
		this.translate(vector.x, vector.y, vector.z);
	}

	public void scale(float x, float y, float z) {
		this.last().scale(x, y, z);
	}

	public void mulPose(Quaternionfc pose) {
		this.last().rotate(pose);
	}

	public void rotateAround(Quaternionfc quaternion, float x, float y, float z) {
		this.last().rotateAround(quaternion, x, y, z);
	}

	public void pushPose() {
		PoseStack.Pose pose = this.last();
		this.lastIndex++;
		if (this.lastIndex >= this.poses.size()) {
			this.poses.add(pose.copy());
		} else {
			((PoseStack.Pose)this.poses.get(this.lastIndex)).set(pose);
		}
	}

	public void popPose() {
		if (this.lastIndex == 0) {
			throw new NoSuchElementException();
		} else {
			this.lastIndex--;
		}
	}

	public PoseStack.Pose last() {
		return (PoseStack.Pose)this.poses.get(this.lastIndex);
	}

	public boolean isEmpty() {
		return this.lastIndex == 0;
	}

	public void setIdentity() {
		this.last().setIdentity();
	}

	public void mulPose(Matrix4fc pose) {
		this.last().mulPose(pose);
	}

	@Environment(EnvType.CLIENT)
	public static final class Pose {
		private final Matrix4f pose = new Matrix4f();
		private final Matrix3f normal = new Matrix3f();
		private boolean trustedNormals = true;

		private void computeNormalMatrix() {
			this.normal.set(this.pose).invert().transpose();
			this.trustedNormals = false;
		}

		void set(PoseStack.Pose pose) {
			this.pose.set(pose.pose);
			this.normal.set(pose.normal);
			this.trustedNormals = pose.trustedNormals;
		}

		public Matrix4f pose() {
			return this.pose;
		}

		public Matrix3f normal() {
			return this.normal;
		}

		public Vector3f transformNormal(Vector3fc pos, Vector3f destination) {
			return this.transformNormal(pos.x(), pos.y(), pos.z(), destination);
		}

		public Vector3f transformNormal(float x, float y, float z, Vector3f destination) {
			Vector3f vector3f = this.normal.transform(x, y, z, destination);
			return this.trustedNormals ? vector3f : vector3f.normalize();
		}

		public Matrix4f translate(float x, float y, float z) {
			return this.pose.translate(x, y, z);
		}

		public void scale(float x, float y, float z) {
			this.pose.scale(x, y, z);
			if (Math.abs(x) == Math.abs(y) && Math.abs(y) == Math.abs(z)) {
				if (x < 0.0F || y < 0.0F || z < 0.0F) {
					this.normal.scale(Math.signum(x), Math.signum(y), Math.signum(z));
				}
			} else {
				this.normal.scale(1.0F / x, 1.0F / y, 1.0F / z);
				this.trustedNormals = false;
			}
		}

		public void rotate(Quaternionfc pose) {
			this.pose.rotate(pose);
			this.normal.rotate(pose);
		}

		public void rotateAround(Quaternionfc pose, float x, float y, float z) {
			this.pose.rotateAround(pose, x, y, z);
			this.normal.rotate(pose);
		}

		public void setIdentity() {
			this.pose.identity();
			this.normal.identity();
			this.trustedNormals = true;
		}

		public void mulPose(Matrix4fc pose) {
			this.pose.mul(pose);
			if (!MatrixUtil.isPureTranslation(pose)) {
				if (MatrixUtil.isOrthonormal(pose)) {
					this.normal.mul(new Matrix3f(pose));
				} else {
					this.computeNormalMatrix();
				}
			}
		}

		public PoseStack.Pose copy() {
			PoseStack.Pose pose = new PoseStack.Pose();
			pose.set(this);
			return pose;
		}
	}
}