public double Schlick()
{
// find the cosine of the angle between the eye and normal vectors
double cos = EyeVector.DotProduct(Normal);
// total internal reflection can only occur if n1 > n2
if (N1 > N2)
{
double n = N1 / N2;
double sin2t = n * n * (1.0 - cos * cos);
if (sin2t > 1.0)
{
return(1.0);
}
// compute cosine of theta_t using trig identity
var cost = Math.Sqrt(1.0 - sin2t);
// when n1 > n2, use cos(theta_t) instead
cos = cost;
}
var r0 = Math.Pow((N1 - N2) / (N1 + N2), 2);
return(r0 + (1 - r0) * Math.Pow((1 - cos), 5));
}
/*
* Christophe Schlick, came up with an
* approximation to Fresnel’s equations that is much faster, and plenty accurate
* besides. Hurray for Schlick!
*/
internal double Schlick()
{
var cos = EyeVector.Dot(NormalVector);
if (n1 > n2)
{
var n = n1 / n2;
var sin2_t = n * n * (1.0 - cos * cos);
if (sin2_t > 1)
{
return(1.0);
}
var cos_t = Math.Sqrt(1.0 - sin2_t);
cos = cos_t;
}
var r0 = Math.Pow((n1 - n2) / (n1 + n2), 2);
return(r0 + (1 - r0) * Math.Pow(1 - cos, 5));
}
public double Schlick()
{
var cos = EyeVector.Dot(NormalVector);
if (n1 > n2)
{
var n = n1 / n2;
var sin2T = Math.Pow(n, 2) * (1.0 - Math.Pow(cos, 2));
if (sin2T > 1.0)
{
return(1.0);
}
var cosT = Math.Sqrt(1.0 - sin2T);
cos = cosT;
}
var r0 = Math.Pow((n1 - n2) / (n1 + n2), 2);
return(r0 + (1 - r0) * Math.Pow((1 - cos), 5));
}