Prints out pre- and post- quaternion values from Unity's Humanoid Avatar

VRMChecker.cs

// MIT License

// Copyright (c) 2021 Lyuma <xn.lyuma@gmail.com> and lox9973

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using UnityEngine;
using UnityEditor;

public class VRMChecker : MonoBehaviour
{
	static string tos(int f) {
		return (f < 0 ? "-" : "+") + (f < 0 ? -f : f);
	}
	static string tos(float f) {
		return (f < 0.0f ? "-" : "+") + string.Format("{0,1:#0.00000}", Mathf.Abs(f));
	}
	static string tos(Quaternion q) {
		return "[" + tos(q.x) + "," + tos(q.y) + "," + tos(q.z) + "," + tos(q.w) + "]";
	}

	static string tos(Vector3Int v) {
		return "[" + tos(v.x) + "," + tos(v.y) + "," + tos(v.z) + "]";
	}

	static string tos(Vector3 v) {
		return "[" + tos(v.x) + "," + tos(v.y) + "," + tos(v.z) + "]";
	}

	[MenuItem("Tools/Lyuma Test: Orient Along Unity Bones")]
	static void OrientAlongUnityBones() {
		var selectedObject = Selection.activeGameObject;
		if (selectedObject == null || selectedObject.GetComponent<Animator>() == null || !selectedObject.GetComponent<Animator>().isHuman) {
			Debug.LogError("Please select an a object with a humanoid Animator component");
			return;
		}
		var anim = selectedObject.GetComponent<Animator>();
		var avatar = anim.avatar;
		string s = "[ // " + anim.gameObject.name + "\n";
		for (int i = 0; i < HumanTrait.BoneCount; i++) {
			HumanBodyBones humanBone = (HumanBodyBones)i;
			Transform bone = anim.GetBoneTransform(humanBone);
			if (bone == null) {
				continue;
			}
			// tip == bone.position + bone.rotation * postQ * Vector3.right * limit.axisLength
			Quaternion postQ = (Quaternion)GetPostRotation.Invoke(avatar, new object[]{humanBone});
			// bone.localRotation * postQ == preQ * SwingTwist(sign * degrees)
			Quaternion preQ  = (Quaternion)GetPreRotation.Invoke(avatar, new object[]{humanBone});
			// abs(sign) != 1 is possible for custom limit range
			Vector3 sign  = GetLimitSignFull(avatar, humanBone);
			s += ("[" + tos(preQ) + "," +
			 "" + tos(postQ) + "," +
			 "" + tos(Vector3Int.RoundToInt(sign)) + "], // Bone " + i + ": " + humanBone.ToString() + "\n");
		}
		s += "]; // preQ, postQ, axisSign\n";
		Debug.Log(s);
	}


	// Following code is by lox9973, from:
	// https://gitlab.com/lox9973/shadermotion/-/blob/master/Script/Common/HumanAxes.cs

	static Vector3 GetLimitSignFull(Avatar avatar, HumanBodyBones humanBone) {
		var sign = Vector3.zero;
		for(var b = humanBone; (int)b >= 0; ) {
			var s = (Vector3)GetLimitSign.Invoke(avatar, new object[]{b});
			for(int i=0; i<3; i++)
				if(HumanTrait.MuscleFromBone((int)b, i) < 0)
					s[i] = 0;
				else if(sign[i] == 0)
					sign[i] = s[i];

			if(s.x*s.y*s.z != 0) {
				for(int i=0; i<3 && (sign.x*sign.y*sign.z) != (s.x*s.y*s.z); i++)
					if(HumanTrait.MuscleFromBone((int)humanBone, i) < 0)
						sign[i] *= -1;
				return sign;
			}

			b = b == HumanBodyBones.LeftShoulder  ? HumanBodyBones.LeftUpperArm :
				b == HumanBodyBones.RightShoulder ? HumanBodyBones.RightUpperArm :
				(HumanBodyBones)HumanTrait.GetParentBone((int)b);
		}
		return new Vector3(1, 1, 1);
	}

	static readonly MethodInfo GetPreRotation  = typeof(Avatar).GetMethod("GetPreRotation", BindingFlags.NonPublic | BindingFlags.Instance);
	static readonly MethodInfo GetPostRotation = typeof(Avatar).GetMethod("GetPostRotation", BindingFlags.NonPublic | BindingFlags.Instance);
	static readonly MethodInfo GetLimitSign    = typeof(Avatar).GetMethod("GetLimitSign", BindingFlags.NonPublic | BindingFlags.Instance);
}