public Tuple ReflectedColor(Precomputation comp, int remaining)
{
if (comp.Object.Material.Reflective == 0 || remaining <= 0)
{
return(new Tuple(0, 0, 0, 0));
}
Ray reflectRay = new Ray(comp.OverPoint, comp.ReflectVector);
Tuple colour = ColourAt(this, reflectRay, remaining - 1);
return(colour * comp.Object.Material.Reflective);
}
public static Tuple ColourAt(World world, Ray ray, int remaining)
{
Intersection[] worldIntersections = IntersectWorld(world, ray);
Intersection hit = Intersect.Hit(worldIntersections);
if (hit != null)
{
Precomputation comps = Intersect.PrepareComputations(hit, ray);
return(ShadeHit(world, comps, remaining));
}
else
{
return(new Tuple(0, 0, 0, 0));
}
}
public static Tuple ShadeHit(World world, Precomputation comps, int remaining)
{
bool shadowed = IsShadowed(world, comps.OverPoint);
Tuple Colour = Material.Lighting(comps.Object.Material, comps.Object, world.SceneLight, comps.OverPoint, comps.EyeVector, comps.NormalVector, shadowed);
Tuple reflectedColor = world.ReflectedColor(comps, remaining);
Tuple refractedColor = RefractedColor(world, comps, remaining);
Material m = comps.Object.Material;
if (m.Reflective > 0f && m.Transparency > 0f)
{
float reflectance = Schlick(comps);
return(Colour + reflectedColor * reflectance + refractedColor * (1 - reflectance));
}
else
{
return(Colour + reflectedColor + refractedColor);
}
}
public static float Schlick(Precomputation comp)
{
float cos = comp.EyeVector.Dot(comp.NormalVector);
if (comp.n1 > comp.n2)
{
float ratio = comp.n1 / comp.n2;
float sin2_t = ratio * ratio * (1.0f - (cos * cos));
if (sin2_t > 1.0)
{
return(1.0f);
}
float cos_t = MathF.Sqrt(1.0f - sin2_t);
cos = cos_t;
}
float r0 = ((comp.n1 - comp.n2) / (comp.n1 + comp.n2)) * ((comp.n1 - comp.n2) / (comp.n1 + comp.n2));
return(r0 + (1 - r0) * MathF.Pow((1 - cos), 5));
}
public static Tuple RefractedColor(World world, Precomputation comp, int remaining)
{
if (comp.Object.Material.Transparency == 0 || remaining == 0)
{
return(new Tuple(0, 0, 0));
}
float n_ratio = comp.n1 / comp.n2;
float cos_i = comp.EyeVector.Dot(comp.NormalVector);
float sin2_t = (n_ratio * n_ratio) * (1 - (cos_i * cos_i));
if (sin2_t > 1)
{
return(new Tuple(0, 0, 0));
}
float cos_t = MathF.Sqrt(1.0f - sin2_t);
Tuple direction = comp.NormalVector * (n_ratio * cos_i - cos_t) - comp.EyeVector * n_ratio;
Ray refract_ray = new Ray(comp.UnderPoint, direction);
return(ColourAt(world, refract_ray, remaining - 1) * comp.Object.Material.Transparency);
}
public static Precomputation PrepareComputations(Intersection i, Ray ray, Intersection[] optionalXS = null)
{
if (optionalXS == null)
{
optionalXS = new Intersection[1];
optionalXS[0] = i;
}
List <Shape> containers = new List <Shape>();
Precomputation comp = new Precomputation();
for (int index = 0; index < optionalXS.Length; index++)
{
if (optionalXS[index] == i)
{
if (containers.Count == 0)
{
comp.n1 = 1.0f;
}
else
{
comp.n1 = containers[containers.Count - 1].Material.Refractive_index;
}
}
if (containers.Contains(optionalXS[index].Object))
{
containers.Remove(optionalXS[index].Object);
}
else
{
containers.Add(optionalXS[index].Object);
}
if (optionalXS[index] == i)
{
if (containers.Count == 0)
{
comp.n2 = 1.0f;
}
else
{
comp.n2 = containers[containers.Count - 1].Material.Refractive_index;
}
break;
}
}
//Precomputation comp = new Precomputation();
comp.T_Value = i.T_Value;
comp.T_Value_Tuple = i.T_Value_Tuple;
comp.Object = i.Object;
comp.Point = ray.Position(comp.T_Value_Tuple);
comp.EyeVector = -ray.Direction;
comp.NormalVector = Shape.NormalAt(comp.Object, comp.Point);
if (comp.NormalVector.Dot(comp.EyeVector) < 0)
{
comp.Inside = true;
comp.NormalVector = -comp.NormalVector;
}
else
{
comp.Inside = false;
}
comp.OverPoint = comp.Point + (comp.NormalVector * Arithmetic.EPSILON);
comp.UnderPoint = comp.Point - (comp.NormalVector * Arithmetic.EPSILON);
comp.ReflectVector = Tuple.Reflect(ray.Direction, comp.NormalVector);
return(comp);
}
