private Vec3 getColor(Ray ray)
{
double t = _sphere.GetHitTime(ray);
if (t > 0.0)
{
Vec3 N = Vec3.UnitVector(ray.PointAtParameter(t) - new Vec3(0.0, 0.0, -1.0));
return(0.5 * new Vec3(N.x + 1, N.y + 1, N.z + 1));
}
return(Background.Color(ray));
}
public static Vec3 Color(Ray ray)
{
// -1.0 < ray.Diraction < 1.0
Vec3 unitDirection = Vec3.UnitVector(ray.Direction());
// 0.0 < t < 1.0
double t = 0.5 * (unitDirection.y + 1.0);
// white -> blue
// Lerp = (1 - t) * Begin + (t * End)
return((1.0 - t) * new Vec3(1.0, 1.0, 1.0) + (t * new Vec3(0.5, 0.7, 1.0)));
}