private IEnumerable <ISect> Intersections(Ray ray, Scene scene)
{
List <ISect> ret = new List <ISect>();
// loop over every thing in the scene
foreach (SceneObject t in scene.Things)
{
// see if the thing intersects with the ray
ISect intersect = t.Intersect(ray);
// if it does...
if (intersect != null)
{
// ... add it to our list (ordered by distance, ascending)
bool added = false;
for (int i = 0; i < ret.Count; i++)
{
if (ret[i].Dist > intersect.Dist)
{
ret.Insert(i, intersect);
added = true;
break;
}
}
if (!added)
{
// add as last element in the list
ret.Add(intersect);
}
}
}
return(ret);
}
private Color TraceRay(Ray ray, Scene scene, int depth)
{
IEnumerable <ISect> isects = Intersections(ray, scene);
ISect isect = isects.FirstOrDefault();
if (isect == null)
{
return(Color.Background);
}
return(Shade(isect, scene, depth));
}
private double TestRay(Ray ray, Scene scene)
{
IEnumerable <ISect> isects = Intersections(ray, scene);
ISect isect = isects.FirstOrDefault();
if (isect == null)
{
return(0);
}
return(isect.Dist);
}
private Color Shade(ISect isect, Scene scene, int depth)
{
Vector d = isect.Ray.Dir;
Vector pos = Vector.Plus(Vector.Times(isect.Dist, isect.Ray.Dir), isect.Ray.Start);
Vector normal = isect.Thing.Normal(pos);
Vector reflectDir = Vector.Minus(d, Vector.Times(2 * Vector.Dot(normal, d), normal));
Color ret = Color.DefaultColor;
ret = Color.Plus(ret, GetNaturalColor(isect.Thing, pos, normal, reflectDir, scene));
if (depth >= MaxDepth)
{
return(Color.Plus(ret, Color.Make(.5, .5, .5)));
}
return(Color.Plus(ret, GetReflectionColor(isect.Thing, Vector.Plus(pos, Vector.Times(.001, reflectDir)), normal, reflectDir, scene, depth)));
}
