public bool IsShadowed(RTObject obj, Computations comps, Point lightPosition, Point point)
{
bool isShadowed = false;
var v = new Vector(lightPosition - point);
var distance = v.Magnitude;
var direction = v.Normalize;
var r = new Ray(point, direction);
var intersections = Intersect(r);
var h = intersections.Hit;
if ((h != null) && (h.t < distance) && (h.t > MathHelper.Epsilon))
{
var dN = obj is Triangle?direction.Dot(comps.NormalVector) : -1;
if (!obj.Equals(h.Object) && h.Object.HasShadow && (dN <= 0))
{
isShadowed = true;
}
}
return(isShadowed);
}
public double IntensityAt(RTObject obj, Computations comps, World w)
{
if (w.IsShadowed(obj, comps, Position, comps.OverPoint))
{
return(0.0);
}
return(1.0);
}
public Color ReflectedColor(Computations comps, int remaining = 5)
{
if (remaining <= 0)
{
return(Color.Black);
}
if (comps.Object.Material.Reflective.IsEqual(0.0))
{
return(Color.Black);
}
var reflectRay = new Ray(comps.OverPoint, comps.ReflectVector);
var color = ColorAt(reflectRay, remaining - 1);
return(color * comps.Object.Material.Reflective);
}
public double IntensityAt(RTObject obj, Computations comps, World w)
{
var total = 0.0;
for (int v = 0; v < VSteps; v++)
{
for (int u = 0; u < USteps; u++)
{
var lightPosition = PointOnLight(u, v);
if (!w.IsShadowed(obj, comps, lightPosition, comps.OverPoint))
{
total += 1.0;
}
}
}
return(total / Samples);
}
public Color ShadeHit(RTObject obj, Computations comps, int remaining = 5)
{
var surface = Color.Black;
double intensity = 0.0;
int count = 0;
foreach (var light in Lights)
{
count++;
intensity = light.IntensityAt(obj, comps, this);
surface = surface +
comps.Object.Material.Lighting(
obj,
light,
comps.OverPoint,
comps.EyeVector,
comps.NormalVector,
intensity);
}
if (count > 0)
{
surface = surface / count;
}
var reflected = ReflectedColor(comps, remaining);
var refracted = RefractedColor(comps, remaining);
var material = comps.Object.Material;
if ((material.Reflective > 0) && (material.Transparency > 0))
{
var reflectance = comps.Schlick;
return(surface + reflected * reflectance + refracted * (1 - reflectance));
}
return(surface + reflected + refracted);
}
public Color RefractedColor(Computations comps, int remaining)
{
if ((remaining <= 0) || comps.Object.Material.Transparency.IsEqual(0.0))
{
return(Color.Black);
}
var nRatio = comps.N1 / comps.N2;
var cosI = comps.EyeVector.Dot(comps.NormalVector);
var sin2T = nRatio * nRatio * (1 - cosI * cosI);
if (sin2T > 1.0)
{
return(Color.Black);
}
var cosT = Math.Sqrt(1.0 - sin2T);
var direction = new Vector(comps.NormalVector * (nRatio * cosI - cosT) - comps.EyeVector * nRatio);
var refractRay = new Ray(comps.UnderPoint, direction);
var color = ColorAt(refractRay, remaining - 1) * comps.Object.Material.Transparency;
return(color);
}
