/// <summary>
/// Slerp the quaternion by t.
/// </summary>
public static Quaternion3d Slerp(Quaternion3d from, Quaternion3d to, double t)
{
if (t <= 0.0)
{
return(from);
}
else if (t >= 1.0)
{
return(to);
}
else
{
double cosom = from.x * to.x + from.y * to.y + from.z * to.z + from.w * to.w;
double absCosom = Math.Abs(cosom);
double scale0;
double scale1;
if (1.0 - absCosom > DMath.EPS)
{
double omega = DMath.SafeAcos(absCosom);
double sinom = 1.0 / Math.Sin(omega);
scale0 = Math.Sin((1.0 - t) * omega) * sinom;
scale1 = Math.Sin(t * omega) * sinom;
}
else
{
scale0 = 1.0 - t;
scale1 = t;
}
Quaternion3d res = new Quaternion3d(scale0 * from.x + scale1 * to.x,
scale0 * from.y + scale1 * to.y,
scale0 * from.z + scale1 * to.z,
scale0 * from.w + scale1 * to.w);
return(res.Normalized);
}
}
/// <summary>
/// Create a rotation out of a vector.
/// </summary>
static public Matrix3x3d Rotate(Vector3d euler)
{
return(Quaternion3d.FromEuler(euler).ToMatrix3x3d());
}