CycleDir GetPerspectiveTriangleOrder(double3 [] pts)
{
for (int i = 0; i < pts.Length; i++)
{
double z = pts [i].z <= 0 ? 1e-5 : pts [i].z;
pts [i].xy /= z;
}
double signedArea = Math3.SignedArea2(pts [0].xy, pts [1].xy, pts [2].xy);
return(signedArea >= 0 ? CycleDir.Ccw : CycleDir.Cw);
}
