A fine change

- Add Affine interface which combines Translate Rotate and Scale without
  directly using matrices.
- Use joml's rotateAround where applicable.
- Add Transform#transform(Pose)
- Only the ctor for PoseTransformStack is internal.

src/main/java/com/jozufozu/flywheel/lib/instance/TransformedInstance.java

@@ -32,6 +32,13 @@ public class TransformedInstance extends ColoredLitInstance implements Transform
 		return this;
 	}
 
+	@Override
+	public TransformedInstance rotateAround(Quaternionf quaternion, float x, float y, float z) {
+		this.model.rotateAround(quaternion, x, y, z);
+		this.normal.rotate(quaternion);
+		return this;
+	}
+
 	@Override
 	public TransformedInstance scale(float x, float y, float z) {
 		model.scale(x, y, z);

src/main/java/com/jozufozu/flywheel/lib/transform/Affine.java

@@ -0,0 +1,27 @@
+package com.jozufozu.flywheel.lib.transform;
+
+import org.joml.Quaternionf;
+
+import com.mojang.math.Axis;
+
+import net.minecraft.core.Direction;
+
+public interface Affine<Self extends Affine<Self>> extends Translate<Self>, Rotate<Self>, Scale<Self> {
+	default Self rotateAround(Quaternionf quaternion, float x, float y, float z) {
+		return translate(x, y, z).rotate(quaternion)
+				.translate(-x, -y, -z);
+	}
+
+	default Self rotateCentered(Quaternionf q) {
+		return rotateAround(q, CENTER, CENTER, CENTER);
+	}
+
+	default Self rotateCentered(float radians, Axis axis) {
+		return rotateCentered(axis.rotation(radians));
+	}
+
+	default Self rotateCentered(float radians, Direction axis) {
+		var step = axis.step();
+		return rotateCentered(new Quaternionf().setAngleAxis(radians, step.x(), step.y(), step.z()));
+	}
+}

src/main/java/com/jozufozu/flywheel/lib/transform/PoseTransformStack.java

@@ -12,10 +12,10 @@ import com.mojang.blaze3d.vertex.PoseStack;
  * <br>
  * Only one instance of this class should exist per {@link PoseStack}.
  */
-@ApiStatus.Internal
 public class PoseTransformStack implements TransformStack<PoseTransformStack> {
-	private final PoseStack stack;
+	public final PoseStack stack;
 
+	@ApiStatus.Internal
 	public PoseTransformStack(PoseStack stack) {
 		this.stack = stack;
 	}
@@ -26,6 +26,12 @@ public class PoseTransformStack implements TransformStack<PoseTransformStack> {
 		return this;
 	}
 
+	@Override
+	public PoseTransformStack rotateAround(Quaternionf quaternion, float x, float y, float z) {
+		stack.rotateAround(quaternion, x, y, z);
+		return this;
+	}
+
 	@Override
 	public PoseTransformStack scale(float factorX, float factorY, float factorZ) {
 		stack.scale(factorX, factorY, factorZ);

src/main/java/com/jozufozu/flywheel/lib/transform/Transform.java

@@ -2,14 +2,10 @@ package com.jozufozu.flywheel.lib.transform;
 
 import org.joml.Matrix3f;
 import org.joml.Matrix4f;
-import org.joml.Quaternionf;
 
 import com.mojang.blaze3d.vertex.PoseStack;
-import com.mojang.math.Axis;
 
-import net.minecraft.core.Direction;
-
-public interface Transform<Self extends Transform<Self>> extends Scale<Self>, Rotate<Self>, Translate<Self> {
+public interface Transform<Self extends Transform<Self>> extends Affine<Self> {
 	Self mulPose(Matrix4f pose);
 
 	Self mulNormal(Matrix3f normal);
@@ -18,23 +14,11 @@ public interface Transform<Self extends Transform<Self>> extends Scale<Self>, Ro
 		return mulPose(pose).mulNormal(normal);
 	}
 
+	default Self transform(PoseStack.Pose pose) {
+		return transform(pose.pose(), pose.normal());
+	}
+
 	default Self transform(PoseStack stack) {
-		PoseStack.Pose last = stack.last();
-		return transform(last.pose(), last.normal());
-	}
-
-	default Self rotateCentered(Quaternionf q) {
-		return center().rotate(q)
-				.uncenter();
-	}
-
-	default Self rotateCentered(float radians, Axis axis) {
-		return center().rotate(radians, axis)
-				.uncenter();
-	}
-
-	default Self rotateCentered(float radians, Direction axis) {
-		return center().rotate(radians, axis)
-				.uncenter();
+		return transform(stack.last());
 	}
 }

src/main/java/com/jozufozu/flywheel/lib/transform/Translate.java

@@ -6,6 +6,8 @@ import net.minecraft.core.Vec3i;
 import net.minecraft.world.phys.Vec3;
 
 public interface Translate<Self extends Translate<Self>> {
+	float CENTER = 0.5f;
+
 	Self translate(double x, double y, double z);
 
 	default Self translate(double v) {
@@ -57,11 +59,11 @@ public interface Translate<Self extends Translate<Self>> {
 	}
 
 	default Self center() {
-		return translate(0.5);
+		return translate(CENTER);
 	}
 
 	default Self uncenter() {
-		return translate(-0.5);
+		return translate(-CENTER);
 	}
 
 	/**