public static Vector3 random_in_unit_sphere()
{
Vector3 p = new Vector3();
do
{
p = 2.0f * new Vector3((float)rnd.NextDouble(), (float)rnd.NextDouble(), (float)rnd.NextDouble())
- new Vector3(1.0f, 1.0f, 1.0f);
} while(Vector3.dot(p, p) >= 1.0f);
p = p.unit_vector();
return(p);
}
public static bool refract(Vector3 v, Vector3 n, float ni_over_nt, ref Vector3 refracted)
{
Vector3 uv = v.unit_vector();
Vector3 un = n.unit_vector();
float dt = Vector3.dot(uv, un);
float discriminant = 1.0f - ni_over_nt * ni_over_nt * (1.0f - dt * dt);
// decide whether to reflect or refract
if (discriminant > 0.0f)
{
refracted = ni_over_nt * (uv - un * dt) - un * (float)Math.Sqrt(discriminant);
return(true);
}
else
{
return(false);
}
}