/*
* static private float ch5_hit_sphere(Vector3 center, float radius, Ray ray)
* {
* Vector3 oc = ray.origin() - center;
* float a = Vector3.dot(ray.direction(), ray.direction());
* float b = 2 * Vector3.dot(oc, ray.direction());
* float c = Vector3.dot(oc, oc) - radius * radius;
* float discriminant = b * b - 4 * a * c;
* if (discriminant < 0)
* return -1.0f;
* else
* return -b - (float)Math.Sqrt(discriminant) / (2 * a);
* }
*/
static private Vector3 ch5_color(Ray r, HitableList hitableList)
{
HitRecord rec = new HitRecord();
if (hitableList.hit(r, 0.0f, float.MaxValue, ref rec))
{
return(0.5f * new Vector3(rec.normal.x() + 1, rec.normal.y() + 1, rec.normal.z() + 1));
}
else
{
float t = 0.5f * (r.direction().normalized.y() + 1);
return(new Vector3(1.0f, 1.0f, 1.0f) * (1 - t) + new Vector3(0.5f, 0.7f, 1.0f) * t);
}
}
static private Vector3 ch7_color(Ray r, HitableList hitableList)
{
HitRecord rec = new HitRecord();
if (hitableList.hit(r, 0.0001f, float.MaxValue, ref rec))
{
Vector3 target = rec.p + rec.normal + Sphere.random_in_unit_sphere();
return(0.5f * ch7_color(new Ray(rec.p, target - rec.p), hitableList));
}
else
{
float t = 0.5f * (r.direction().normalized.y() + 1);
return(new Vector3(1.0f, 1.0f, 1.0f) * (1 - t) + new Vector3(0.5f, 0.7f, 1.0f) * t);
}
}
static private Vector3 ch8_color(Ray r, HitableList hitableList, int depth)
{
HitRecord rec = new HitRecord();
if (hitableList.hit(r, 0.0001f, float.MaxValue, ref rec))
{
Ray scattered = null;
Vector3 attenuation = null;
if (depth > 0 && rec.mat.scatter(r, rec, ref attenuation, ref scattered))
{
return(attenuation * ch8_color(scattered, hitableList, depth - 1));
}
else
{
return(new Vector3(0, 0, 0));
}
}
else
{
float t = 0.5f * (r.direction().normalized.y() + 1);
return(new Vector3(1.0f, 1.0f, 1.0f) * (1 - t) + new Vector3(0.5f, 0.7f, 1.0f) * t);
}
}
