private Colour GetNaturalColor(Thing thing, Vector3 pos, Vector3 norm, Vector3 rd, Scene scene)
{
Colour ret = new Colour(0, 0, 0);
foreach (LightSource light in scene.Lights)
{
Vector3 ldis = light.Pos - pos;
Vector3 livec = ldis.Normalized();
double neatIsect = TestRay(new Ray(pos, livec), scene);
bool isInShadow = !((neatIsect > ldis.Length()) || (neatIsect == 0));
if (!isInShadow)
{
double illum = livec.DotProduct(norm);
Colour lcolor = illum > 0 ? illum * light.Color : new Colour(0, 0, 0);
double specular = livec.DotProduct(rd.Normalized());
Colour scolor = specular > 0 ? Math.Pow(specular, thing.Surface.Roughness) * light.Color : new Colour(0, 0, 0);
ret = ret + (thing.Surface.Diffuse(pos) * lcolor) + (thing.Surface.Specular(pos) * scolor);
}
}
return(ret);
}
public override Intersection CalculateIntersection(Ray withRay)
{
Vector3 eo = Centre - withRay.Start;
double v = eo.DotProduct(withRay.Dir);
double dist;
if (v < 0)
{
dist = 0;
}
else
{
double disc = Math.Pow(Radius, 2) - (eo.DotProduct(eo) - Math.Pow(v, 2));
dist = disc < 0 ? 0 : v - Math.Sqrt(disc);
}
if (dist == 0)
{
return(null);
}
return(new Intersection(this, withRay, dist));
}