private static Vec3f Color(Ray r, HitableList world, int depth, Random drand)
{
HitRecord record = new HitRecord();
if (world.Hit(r, 0.0001f, float.MaxValue, ref record))
{
Ray scattered = new Ray();
Vec3f attenuation = Vec3f.Zero;
if (depth < 50 && record.Material.Scatter(r, record, out attenuation, out scattered, drand))
{
return(attenuation * Color(scattered, world, depth + 1, drand));
}
else
{
return(Vec3f.Zero);
}
}
else
{
Vec3f unit_direction = r.Direction.GetNormal();
float t = 0.5f * (unit_direction.Y + 1.0f);
return((1.0f - t) * Vec3f.One + t * (new Vec3f(0.5f, 0.7f, 1.0f)));
}
}
public static HitableList RandomScene(Random drand)
{
int n = 500;
var world = new HitableList();
world.Add(new Sphere(new Vec3f(0, -1000f, 0), 1000, new Lambertian(new Vec3f(0.5f, 0.5f, 0.5f))));
int i = 1;
for (int a = -11; a < 11; a++)
{
for (int b = -11; b < 11; b++)
{
float choose_mat = (float)drand.NextDouble();
var center = new Vec3f(a + 0.9f * (float)drand.NextDouble(), 0.2f, b + 0.9f * (float)drand.NextDouble());
if ((center - new Vec3f(4f, 0.2f, 0)).GetLength() > 0.9f)
{
if (choose_mat < 0.8f) // diffuse
{
world.Add(new Sphere(center, 0.2f, new Lambertian(new Vec3f((float)drand.NextDouble() * (float)drand.NextDouble(),
(float)drand.NextDouble() * (float)drand.NextDouble(), (float)drand.NextDouble() * (float)drand.NextDouble()))));
}
else if (choose_mat < 0.95f) // metal
{
var o = new Vec3f(
0.5f * (1f + (float)drand.NextDouble()),
0.5f * (1f + (float)drand.NextDouble()),
0.5f * (1f + (float)drand.NextDouble())
);
world.Add(new Sphere(center, 0.2f, new Metal(o, 0.5f * (float)drand.NextDouble())));
}
else // glass
{
world.Add(new Sphere(center, 0.2f, new Dielectric(1.5f)));
}
}
}
}
world.Add(new Sphere(Vec3f.UnitY, 1.0f, new Dielectric(1.5f)));
world.Add(new Sphere(new Vec3f(-4f, 1f, 0), 1.0f, new Lambertian(new Vec3f(0.4f, 0.2f, 0.1f))));
world.Add(new Sphere(new Vec3f(4f, 1f, 0), 1.0f, new Metal(new Vec3f(0.7f, 0.6f, 0.5f), 0.0f)));
return(world);
}