//Check the material of the hit object and if the transparency is 0, return black.
//Return calculated refracted value is it is transparent
public Color RefractedColor(Computations c, int remaining = 1)
{
if (Utility.FE(c.rayObject.material.Transparency, 0) || remaining == 0)
{
return(Color.black);
}
//Check for infinite internal reflection
double nRatio = c.n1 / c.n2;
double cosI = Vector.Dot(c.eye, c.normal);
double sin2T = nRatio * nRatio * (1 - (cosI * cosI));
if (sin2T > 1)
{
return(Color.black);
}
double cosT = Math.Sqrt(1.0 - sin2T);
Vector direction = c.normal * (nRatio * cosI - cosT) - c.eye * nRatio;
Ray refractRay = new Ray(c.underPoint, direction);
Color refractedColor = ColorAt(refractRay, remaining - 1) *
c.rayObject.material.Transparency;
//Replace later with code for refraction calculations
return(refractedColor);
}
public Color ReflectedColor(Computations c, int remaining = 1)
{
if (remaining == 0 || Utility.FE(c.rayObject.material.Reflective, 0.0))
{
return(Color.black);
}
Ray reflectionRay = new Ray(c.overPoint, c.reflectVector);
return(ColorAt(reflectionRay, remaining - 1) * c.rayObject.material.Reflective);
}
public Color ColorAt(Ray ray, int remaining = 1)
{
List <Intersection> hits = this.Intersections(ray);
if (hits.Count == 0)
{
return(Color.black);
}
Intersection hit = this.Hit(hits);
Computations c = Computations.Prepare(hit, ray, hits);
Color finalColor = Scene.current.ShadeHit(c, remaining);
return(finalColor);
}
public double Schlick(Computations c)
{
double cos = Vector.Dot(c.eye, c.normal);
if (c.n1 > c.n2)
{
double n = c.n1 / c.n2;
double sin2T = (n * n) * (1.0 - (cos * cos));
if (sin2T > 1.0)
{
return(1.0);
}
double cosT = Math.Sqrt(1.0 - sin2T);
cos = cosT;
}
double r0 = Math.Pow((c.n1 - c.n2) / (c.n1 + c.n2), 2);
return(r0 + (1 - r0) * Math.Pow((1 - cos), 5));
}
public Color ShadeHit(Computations c, int remaining = 1)
{
if (c == null)
{
return(Color.black);
}
Color surfaceColor = new Color(0, 0, 0);
for (int i = 0; i < lights.Count; i++)
{
//Is this light in shadow?
if (c.rayObject.canReceiveShadows)
{
bool isShadow = IsShadowed(c.overPoint, lights[i]);
surfaceColor += c.rayObject.Lighting(c.point,
lights[i],
c.eye,
c.normal,
isShadow);
}
}
Color reflected = this.ReflectedColor(c, remaining);
Color refracted = this.RefractedColor(c, remaining);
if (c.rayObject.material.Reflective > 0 &&
c.rayObject.material.Transparency > 0)
{
double reflectance = this.Schlick(c);
return(surfaceColor + reflected * reflectance +
refracted * (1.0 - reflectance));
}
return(surfaceColor + reflected + refracted);
}
public static Computations Prepare(Intersection i, Ray ray, List <Intersection> xs)
{
if (i == null)
{
return(null);
}
Point temp = ray.Position(i.t);
Computations c = new Computations();
c.rayObject = i.rayObject;
c.t = i.t;
c.point = temp;
c.eye = -ray.direction.Normalize();
c.normal = i.rayObject.GetNormal(temp, i).Normalize();
c.n1 = RefractiveIndex.Vacuum;
c.n2 = RefractiveIndex.Vacuum;
if (c.normal.Dot(c.eye) < 0)
{
c.inside = true;
c.normal = -c.normal;
}
else
{
c.inside = false;
}
//Transparency Intersections algorithm
if (xs != null)
{
List <RayObject> container = new List <RayObject>();
for (int x = 0; x < xs.Count; x++)
{
if (i == xs[x])
{
if (container.Count == 0)
{
c.n1 = RefractiveIndex.Vacuum;
}
else
{
c.n1 = container.Last <RayObject>().material.RefracIndex;
}
}
if (container.Contains(xs[x].rayObject))
{
container.Remove(xs[x].rayObject);
}
else
{
container.Add(xs[x].rayObject);
}
if (i == xs[x])
{
if (container.Count == 0)
{
c.n2 = RefractiveIndex.Vacuum;
}
else
{
c.n2 = container.Last <RayObject>().material.RefracIndex;
}
break;
}
}
}
c.reflectVector = Vector.Reflect(ray.direction, c.normal);
c.overPoint = c.point + (c.normal * Constants.epsilon);
c.underPoint = c.point - (c.normal * Constants.epsilon);
return(c);
}
