/// <summary>
///
/// </summary>
/// <param name="time"></param>
/// <param name="quatA"></param>
/// <param name="quatB"></param>
/// <param name="useShortestPath"></param>
/// <returns></returns>
public static OpenTK.Quaternion Slerp(Real time, OpenTK.Quaternion quatA, OpenTK.Quaternion quatB, bool useShortestPath)
{
Real cos = quatA.Dot(quatB);
Real angle = (Real)Utility.ACos(cos);
if (Utility.Abs(angle) < EPSILON)
{
return(quatA);
}
Real sin = Utility.Sin(angle);
Real inverseSin = 1.0f / sin;
Real coeff0 = Utility.Sin((1.0f - time) * angle) * inverseSin;
Real coeff1 = Utility.Sin(time * angle) * inverseSin;
OpenTK.Quaternion result;
if (cos < 0.0f && useShortestPath)
{
coeff0 = -coeff0;
// taking the complement requires renormalisation
OpenTK.Quaternion t = coeff0 * quatA + coeff1 * quatB;
t.Normalize();
result = t;
}
else
{
result = (coeff0 * quatA + coeff1 * quatB);
}
return(result);
}
/// <param name="shortestPath"></param>
public static OpenTK.Quaternion Nlerp(Real fT, OpenTK.Quaternion rkP, OpenTK.Quaternion rkQ, bool shortestPath)
{
OpenTK.Quaternion result;
Real fCos = rkP.Dot(rkQ);
if (fCos < 0.0f && shortestPath)
{
result = rkP + fT * ((OpenTK.Quaternion.Invert(rkQ)) - rkP);
}
else
{
result = rkP + fT * (rkQ - rkP);
}
result.Normalize();
return(result);
}