public static Color ray_color(Ray r, ref Hittable_list world, int depth)
{
hit_record rec = new hit_record();
if (depth <= 0)
{
return(new Color(0, 0, 0));
}
if (world.hit(r, 0.001, Utilities.infinity, ref rec))
{
Ray scattered = new Ray();
Color attenuation = new Color();
if (rec.mat_prt.scatter(r, rec, ref attenuation, ref scattered))
{
return(attenuation * ray_color(scattered, ref world, depth - 1));
}
//Random Ray
Point3 target = rec.p + rec.normal + Vec3.random_unit_vector();
return(0.5 * ray_color(new Ray(rec.p, target - rec.p), ref world, depth - 1));
}
Vec3 unit_direction = Vec3.unit_vector(r.direction);
var t = 0.5 * (unit_direction.y() + 1.0);
return((1.0 - t) * new Color(1.0, 1.0, 1.0) + t * new Color(0.5, 0.7, 1.0));
}
public static Hittable_list random_scene()
{
Hittable_list world = new Hittable_list();
var ground_material = new Lambertian(new Color(0.5, 0.5, 0.5));
world.add(new Sphere(new Point3(0, -1000, 0), 1000, ground_material));
for (int a = -11; a < 11; a++)
{
for (int b = -11; b < 11; b++)
{
var choose_mat = Utilities.random_double();
Point3 center = new Point3(a + 0.9 * Utilities.random_double(), 0.2, b + 0.9 * Utilities.random_double());
if ((center - new Point3(4, 0.2, 0)).length() > 0.9)
{
Material sphere_material;
if (choose_mat < 0.8)
{
Color albedo = Color.random() * Color.random();
sphere_material = new Lambertian(albedo);
world.add(new Sphere(center, 0.2, sphere_material));
}
else if (choose_mat < 0.95)
{
Color albedo = Color.random(0.5, 1);
var fuzz = Utilities.random_double(0, 0.5);
sphere_material = new Metal(albedo, fuzz);
world.add(new Sphere(center, 0.2, sphere_material));
}
else
{
sphere_material = new Dielectric(1.5);
world.add(new Sphere(center, 0.2, sphere_material));
}
}
}
}
var material1 = new Dielectric(1.5);
world.add(new Sphere(new Point3(0, 1, 0), 1.0, material1));
var material2 = new Lambertian(new Color(0.4, 0.2, 0.1));
world.add(new Sphere(new Point3(-4, 1, 0), 1.0, material2));
var material3 = new Metal(new Color(0.7, 0.6, 0.5), 0.0);
world.add(new Sphere(new Point3(4, 1, 0), 1.0, material3));
return(world);
}
