// if no object is hit, draw a gradient
static Vector3 color(Ray r, Hitable world, int depth)
{
hit_record rec = new hit_record();
// see if an object is hit
if (world.hit(r, 0.001f, float.MaxValue, ref rec))
{
// shade the indicated point
Ray scattered = new Ray();
Vector3 attenuation = new Vector3();
if (depth < 50 && rec.mat.scatter(r, rec, ref attenuation, ref scattered))
{
return(attenuation * color(scattered, world, depth + 1));
}
else
{
// reached our max depth, don't render any further
return(new Vector3());
}
}
else
{
// no object hit, draw the background
Vector3 unit_dir = r.direction().unit_vector();
float t = 0.5f * (unit_dir.y() + 1.0f);
return((new Vector3(1.0f, 1.0f, 1.0f)) * (1.0f - t) + (new Vector3(0.5f, 0.7f, 1.0f) * t));
}
}
public Ray getRay(float s, float t)
{
Vector3 rd = lens_radius * Utils.random_in_unit_disk();
Vector3 offset = u * rd.x() + v * rd.y();
float time = (float)Utils.rnd.NextDouble() * (time0 - time1);
return(new Ray(origin + offset, lower_left + s * horizontal + t * vertical - origin - offset, time));
}
public bool hit(Ray r, float tmin, float tmax)
{
float t0 = Utils.fmin((_min.x() - r.origin().x()) / r.direction().x(),
(_max.x() - r.origin().x()) / r.direction().x());
float t1 = Utils.fmax((_min.x() - r.origin().x()) / r.direction().x(),
(_max.x() - r.origin().x()) / r.direction().x());
tmin = Utils.fmax(t0, tmin);
tmax = Utils.fmin(t1, tmax);
if (tmax <= tmin)
{
return(false);
}
t0 = Utils.fmin((_min.y() - r.origin().y()) / r.direction().y(),
(_max.y() - r.origin().y()) / r.direction().y());
t1 = Utils.fmax((_min.y() - r.origin().y()) / r.direction().y(),
(_max.y() - r.origin().y()) / r.direction().y());
tmin = Utils.fmax(t0, tmin);
tmax = Utils.fmin(t1, tmax);
if (tmax <= tmin)
{
return(false);
}
t0 = Utils.fmin((_min.z() - r.origin().z()) / r.direction().z(),
(_max.z() - r.origin().z()) / r.direction().z());
t1 = Utils.fmax((_min.y() - r.origin().y()) / r.direction().y(),
(_max.z() - r.origin().z()) / r.direction().z());
tmin = Utils.fmax(t0, tmin);
tmax = Utils.fmin(t1, tmax);
if (tmax <= tmin)
{
return(false);
}
return(true);
}
public override Vector3 value(float u, float v, ref Vector3 p)
{
float sins = (float)(Math.Sin(p.x() * size) * Math.Sin(p.y() * size) * Math.Sin(p.z() * size));
if (sins > 0.0f)
{
return(even.value(u, v, ref p));
}
else
{
return(odd.value(u, v, ref p));
}
}
public float noise(Vector3 p)
{
float u = p.x() - (float)Math.Floor(p.x());
float v = p.y() - (float)Math.Floor(p.y());
float w = p.z() - (float)Math.Floor(p.z());
int i = (int)Math.Floor(p.x());
int j = (int)Math.Floor(p.y());
int k = (int)Math.Floor(p.z());
Vector3[,,] c = new Vector3[2, 2, 2];
for (int di = 0; di < 2; di++)
{
for (int dj = 0; dj < 2; dj++)
{
for (int dk = 0; dk < 2; dk++)
{
c [di, dj, dk] = ran_vecs [perm_x [(i + di) & 255] ^ perm_y [(j + dj) & 255] ^ perm_z [(k + dk) & 255]];
}
}
}
return(Utils.trilinear_interpolation(c, u, v, w));
}
public static void Main(string[] args)
{
// output to a ppm file
Console.Write("P3\n" + nx + " " + ny + " " + "\n255\n");
// create the world
List <Hitable> world = new List <Hitable>();
world.Add(new Moving_Sphere(new Vector3(0.0f, 0.0f, 0.0f),
new Vector3(0.0f, 0.0f, -2.0f),
0.0f,
10.0f,
0.5f,
new Lambertian(new Const_Texture(new Vector3(0.137f, 0.467f, 1.0f)))));
world.Add(new Sphere(new Vector3(1.0f, 0.0f, -1.0f),
0.5f,
new Dielectric(1.5f)));
world.Add(new Sphere(new Vector3(1.0f, 0.0f, -1.0f),
-0.3f,
new Dielectric(1.5f)));
world.Add(new Sphere(new Vector3(-1.0f, 0.0f, -1.0f),
0.5f,
new Metal(new Noise(10.0f))));
world.Add(new Sphere(new Vector3(0.0f, -100.5f, -1.0f),
100.0f,
new Lambertian(new Marble(new Vector3(0.0f, 0.8f, 0.0f), 5.0f))));
BVH_Node tree = new BVH_Node(world, 0.0f, 10.0f);
// init the camera
Vector3 lookfrom = new Vector3(3.0f, 2.0f, 2.0f);
Vector3 lookat = new Vector3(0.0f, 0.0f, -1.0f);
float dist_to_focus = (lookfrom - lookat).length();
float apeture = 0.5f;
Camera cam = new Camera(lookfrom,
lookat,
new Vector3(0.0f, 1.0f, 0.0f),
40.0f,
(float)nx / (float)ny,
apeture,
dist_to_focus,
0.0f,
10.0f);
for (int i = ny - 1; i >= 0; i--)
{
for (int j = 0; j < nx; j++)
{
// supersampling for antialiasing
Vector3 col = new Vector3();
for (int s = 0; s < ns; s++)
{
float u = (float)(j + Utils.rnd.NextDouble()) / (float)nx;
float v = (float)(i + Utils.rnd.NextDouble()) / (float)ny;
Ray r = cam.getRay(u, v);
col += color(r, tree, 0);
}
col /= (float)ns;
// gamma correction
col = new Vector3((float)Math.Sqrt(col.x()),
(float)Math.Sqrt(col.y()),
(float)Math.Sqrt(col.z()));
// values written to file
int ir = (int)(255.99f * col.r());
int ig = (int)(255.99f * col.g());
int ib = (int)(255.99f * col.b());
Console.Write(ir + " " + ig + " " + ib + "\n");
}
}
}
public static Vector3 cross(Vector3 a, Vector3 b)
{
return(new Vector3(a.y() * b.z() - a.z() * b.y(),
-(a.x() * b.z() - a.z() * b.x()),
a.x() * b.y() - a.y() * b.x()));
}
// other operations
public static float dot(Vector3 a, Vector3 b)
{
return(a.x() * b.x() + a.y() * b.y() + a.z() * b.z());
}