public IEnumerable<ISect> Intersect(Ray r)
{
foreach (SceneObject obj in Things)
{
yield return obj.Intersect(r);
}
}
public override ISect Intersect(Ray ray)
{
Vector eo = Vector.Minus(Center, ray.Start);
double v = Vector.Dot(eo, ray.Dir);
double dist;
if (v < 0)
{
dist = 0;
}
else
{
double disc = Math.Pow(Radius, 2) - (Vector.Dot(eo, eo) - Math.Pow(v, 2));
dist = disc < 0 ? 0 : v - Math.Sqrt(disc);
}
if (dist == 0) return ISect.Null;
return new ISect(this, ray, dist);
}
private Color TraceRay(Ray ray, Scene scene, int depth)
{
ISect isect = MinIntersection(ray, scene);
if (ISect.IsNull(isect))
return Color.Background;
return Shade(isect, scene, depth);
}
private double TestRay(Ray ray, Scene scene)
{
ISect isect = MinIntersection(ray, scene);
if (ISect.IsNull(isect))
return 0;
return isect.Dist;
}
private ISect MinIntersection(Ray ray, Scene scene)
{
ISect min = ISect.Null;
foreach (SceneObject obj in scene.Things)
{
ISect isect = obj.Intersect(ray);
if (!ISect.IsNull(isect))
{
if (ISect.IsNull(min) || min.Dist > isect.Dist)
{
min = isect;
}
}
}
return min;
}
