/// <summary>
/// Set if a point is in the right/left of a vector
/// return true if the OB is right of OA
/// </summary>
/// <param name="orig"></param>
/// <param name="A"></param>
/// <param name="B"></param>
/// <returns></returns>
public static Boolean SideTest(IVertex<float> orig, IVertex<float> A, IVertex<float> B)
{
//// check if the node acceptable
IVertex<float> a = A.Copy();
a.Subtract(ref orig);
IVertex<float> b = B.Copy();
b.Subtract(ref orig);
#if true
a.Normalize();
b.Normalize();
double cross = a.X * b.Y - a.Y * b.X;
#else
double cross = Math.Atan2(b.Y, b.X) - Math.Atan2(a.Y, a.X);
cross += (cross + Math.PI <= 0.00001) ? 2 * Math.PI : 0;
cross -= (cross - Math.PI >= -0.00001) ? 2 * Math.PI : 0;
#endif
return cross < -0.0001;
}