public Ray Refract(Point3D hp, float eta)
{
var nidot = Point3D.Scalar(normal, _castedRay.dir);
var k = 1.0f - eta * eta * (1.0f - nidot * nidot);
if (k >= 0)
{
k = (float)Math.Sqrt(k);
return(Ray.BuildRay(hp, Point3D.Norm(eta * _castedRay.dir - (k + eta * nidot) * normal)));
}
else
{
return(null);
}
}
public Ray Reflect(Point3D hp)
{
return(Ray.BuildRay(hp, Point3D.Norm(_castedRay.dir - 2 * normal * Point3D.Scalar(normal, _castedRay.dir))));
}
