internal static Scene SphereScene (int level, Vector center, double radius)
{
Sphere sphere = new Sphere (center, radius);
if (level == 1) {
return sphere;
} else {
Group scene = new Group (new Sphere (center, 3.0 * radius));
scene.Add (sphere);
double rn = 3.0 * radius / Math.Sqrt (12.0);
for (int dz = -1; dz <= 1; dz += 2) {
for (int dx = -1; dx <= 1; dx += 2) {
Vector c2 = new Vector (
center.x - dx * rn
, center.y + rn
, center.z - dz * rn
);
scene.Add (SphereScene (level - 1, c2, radius / 2.0));
}
}
return scene;
}
}
// Normally we'd use double.Epsilon
public static void Main (String[] args, ILog ilog)
{
int n = 0;
if (args.Length > 0)
n = Int32.Parse (args [0]);
Scene scene = Scene.SphereScene (levels, new Vector (0.0, -1.0, 0.0), 1.0);
ilog.InfoFormat ("P5");
ilog.InfoFormat ("{0} {1}", n, n);
ilog.InfoFormat ("255");
Stream stream = Stream.Null;
byte[] temp = new byte[1];
for (int y = n - 1; y >= 0; --y) {
for (int x = 0; x < n; ++x) {
double greyscale = 0.0;
for (int dx = 0; dx < ss; ++dx) {
for (int dy = 0; dy < ss; ++dy) {
Vector v = new Vector (
x + dx / (double)ss - n / 2.0
, y + dy / (double)ss - n / 2.0
, n);
Ray ray = new Ray (new Vector (0.0, 0.0, -4.0), v.Normalized ());
greyscale += scene.TraceRay (ray,
new Vector (-1.0, -3.0, 2.0).Normalized ());
}
}
temp [0] = (byte)(0.5 + 255.0 * greyscale / (ss * ss));
stream.Write (temp, 0, 1);
}
}
}
internal double TraceRay (Ray ray, Vector light)
{
IntersectionPoint p = Intersect (ray,
new IntersectionPoint (
double.PositiveInfinity, new Vector (0.0, 0.0, 0.0)));
if (double.IsInfinity (p.distance))
return 0.0;
double greyscale = -(p.normal * light);
if (greyscale <= 0.0)
return 0.0;
Vector o = ray.origin +
(p.distance * ray.direction) + (Epsilon * p.normal);
Ray shadowRay = new Ray (o, new Vector (0.0, 0.0, 0.0) - light);
IntersectionPoint shadowp = Intersect (shadowRay,
new IntersectionPoint (double.PositiveInfinity, p.normal));
return double.IsInfinity (shadowp.distance) ? greyscale : 0.0;
}
internal IntersectionPoint (double distance, Vector normal)
{
_distance = distance;
_normal = normal;
}
internal Ray (Vector origin, Vector direction)
{
_origin = origin;
_direction = direction;
}
internal Sphere (Vector center, double radius)
{
this.center = center;
this.radius = radius;
}
