/// <summary>
/// the _source vector will rotate to point at the _target vector
/// </summary>
/// <param name="_source"></param>
/// <param name="_target"></param>
/// <returns></returns>
public static Quaternion RotateFromTo(Vector3 _source, Vector3 _target)
{
_source.Normalize();
_target.Normalize();
Quaternion q = GenericMaths.QuaternionFromAngleAxis(Vector3.Cross(_source, _target).normalized, GenericMaths.VectorsAngle(_source, _target));
return(Quaternion.Inverse(q));
}
/// <summary>
/// Prepare the solver and solve the IK problem analytically with specific axis of rotation
/// (the chain must contain 2 joints, no more and no less)
/// </summary>
/// <param name="_hingeChain">the chain</param>
/// <param name="_direction">direction of the player</param>
/// <param name="_axis">axis of rotation for the 2nd joint (the Hinge joint)</param>
public void SolveAnalytically(RootIK.Chain _hingeChain, Vector3 _direction, Vector3 _axis)
{
if (_hingeChain.joints.Count > 3)
{
return;
}
if (_hingeChain.iterations <= 0)
{
return;
}
if (_hingeChain.joints.Count <= 0)
{
return;
}
//calculate bone length;
upperLength = Vector3.Distance(_hingeChain.joints[0].transform.position, _hingeChain.joints[1].transform.position);
lowerLength = Vector3.Distance(_hingeChain.joints[1].transform.position, _hingeChain.joints[2].transform.position);
systemLength = Vector3.Distance(_hingeChain.joints[0].transform.position, _hingeChain.GetIKPosition());
//lowerjoint 1DOF
float _angle = GenericMaths.Formula(upperLength, lowerLength, systemLength) + Mathf.PI * Mathf.Rad2Deg;
if (_axis == Vector3.zero)
{
_axis = Vector3.Cross(RootIK.TransformVector(Vector3.up, _hingeChain.joints[1].transform.rotation), _direction);
}
else
{
_axis = Vector3.Cross(RootIK.TransformVector(_axis, _hingeChain.joints[1].transform.rotation), _direction);
}
Quaternion _src = _hingeChain.joints[1].transform.rotation;
Quaternion _t = GenericMaths.QuaternionFromAngleAxis(_axis, _angle + Mathf.Acos(Mathf.Clamp(_src.w, -1f, 1f)) * 10f);
Quaternion _finalRot = Quaternion.Lerp(Quaternion.identity, _t, _hingeChain.weight);
_hingeChain.joints[1].transform.rotation = GenericMaths.ApplyQuaternion(_finalRot, _src);
//Upperjoint 3DOF
Vector3 _v1 = _hingeChain.GetIKPosition() - _hingeChain.joints[0].transform.position;
Vector3 _v2 = _hingeChain.joints[2].transform.position - _hingeChain.joints[0].transform.position;
Quaternion _src2 = _hingeChain.joints[0].transform.rotation;
Quaternion _t2 = RootIK.RotateFromTo(_v2, _v1);
Quaternion _finalRot2 = Quaternion.Lerp(Quaternion.identity, _t2, _hingeChain.weight);
_hingeChain.joints[0].transform.rotation = GenericMaths.ApplyQuaternion(Quaternion.Inverse(_finalRot2), _src2);
//foot 6DOF
_hingeChain.GetEndEffector().rotation = _hingeChain.GetIKRotation();
}