public override double2 GetTexCoord(IntersectData data)
{
double3 n = GetNormal(data);
n = ModelMatrix.Transform(n);
double asin = Math.Asin(n.y);
double ty = (asin + Math.PI / 2) / Math.PI;
double atan = Math.Atan2(n.z, n.x);
double tx = (atan + Math.PI) / (2 * Math.PI);
double2 t = new double2(tx, ty);
// Scaling
//t.x *= 0.5;
//t.y *= 1;
return(t);
}