MotionCapture/Assets/Models/RotationNode.cs

using UnityEngine;

namespace Models
{
    public struct RotationNode
    {
        public readonly HumanBodyBones UnityName;
        public Quaternion PreviousRotation;
        public Quaternion Rotation;

        public Quaternion CalculateRotate => PreviousRotation * Quaternion.Inverse(Rotation);

        public RotationNode(HumanBodyBones humanBodyBone, Quaternion previousRotation, Quaternion rotation)
        {
            UnityName = humanBodyBone;
            PreviousRotation = previousRotation;
            Rotation = rotation;
        }

        public RotationNode(RotationNode node, PoseLandmark begin, PoseLandmark end)
        {
            UnityName = node.UnityName;
            PreviousRotation = node.Rotation;

            var forward = end.Position - begin.Position;
            Rotation = Quaternion.LookRotation(forward);
        }
    }
}