public Color ColorAt(Ray r, int remaining)
{
List <Intersection> xs = IntersectWorld(r);
Intersection i = Intersection.Hit(xs);
if (i is null)
{
return(new Color(0, 0, 0));
}
else
{
Computations comps = Computations.PrepareComputations(i, r, xs);
return(ShadeHit(comps, remaining));
}
}
public static double Schlick(Computations comps)
{
double cos = Tuple.Dot(comps.eyev, comps.normalv);
if (comps.n1 > comps.n2)
{
double n = comps.n1 / comps.n2;
double sin2T = Math.Pow(n, 2.0) * (1.0 - Math.Pow(cos, 2.0));
if (sin2T > 1.0)
{
return(1.0);
}
double cosT = Math.Sqrt(1.0 - sin2T);
cos = cosT;
}
double r0 = Math.Pow(((comps.n1 - comps.n2) / (comps.n1 + comps.n2)), 2.0);
return(r0 + (1 - r0) * Math.Pow((1 - cos), 5.0));
}
// Possibly change lighting call point -> overpoint to fix checkboard pattern
public Color ShadeHit(Computations comps, int remaining)
{
bool shadowed = IsShadowedFromAllLights(comps.overPoint);
Color surfaceColor = new Color(0, 0, 0);
foreach (Light lt in Lights)
{
surfaceColor += comps.shape.Material.Lighting(comps.shape, lt, comps.overPoint, comps.eyev, comps.normalv, shadowed);
}
Color reflectedColor = ReflectedColor(comps, remaining);
Color refractedColor = RefractedColor(comps, remaining);
Material material = comps.shape.Material;
if (material.Reflectivity > 0 && material.Transparency > 0)
{
double reflectance = Intersection.Schlick(comps);
return(surfaceColor + reflectedColor * reflectance + refractedColor * (1.0 - reflectance));
}
return(surfaceColor + reflectedColor + refractedColor);
}
public static Computations PrepareComputations(Intersection i, Ray r, List <Intersection> xs = null)
{
if (xs is null)
{
xs = new List <Intersection>();
xs.Add(i);
}
Computations comps = new Computations();
comps.t = i.T;
comps.shape = i.S;
comps.point = r.Position(comps.t);
comps.eyev = -r.Direction;
comps.normalv = comps.shape.NormalAt(comps.point, i);
if (Tuple.Dot(comps.normalv, comps.eyev) < 0)
{
comps.inside = true;
comps.normalv = -comps.normalv;
}
else
{
comps.inside = false;
}
comps.reflectv = Tuple.Reflect(r.Direction, comps.normalv);
comps.overPoint = comps.point + comps.normalv * Globals.EPSILON;
comps.underPoint = comps.point - comps.normalv * Globals.EPSILON;
List <Shape> containers = new List <Shape>();
foreach (Intersection j in xs)
{
if (Globals.EqualityOfDouble(j.T, i.T) && j.S == i.S)
{
if (containers.Count == 0)
{
comps.n1 = 1.0;
}
else
{
comps.n1 = containers[containers.Count - 1].Material.RefractiveIndex;
}
}
if (containers.Contains(j.S))
{
containers.Remove(j.S);
}
else
{
containers.Add(j.S);
}
if (Globals.EqualityOfDouble(j.T, i.T) && j.S == i.S)
{
if (containers.Count == 0)
{
comps.n2 = 1.0;
}
else
{
comps.n2 = containers[containers.Count - 1].Material.RefractiveIndex;
}
break;
}
}
return(comps);
}
