/// <summary>
/// Metoda PhongAt slouzi pro vypocet odrazu svetla z povrchu materialu
/// Na zaklade predaneho objektu intersection a ray je spocitan odraz
/// Objekt je vyvzorkovan dle zadaneho poctu vzorku do vstupniho formulare
/// Dale je kontrolovan pocet pozadovanych zanoreni
/// </summary>
/// <param name="intersection"></param>
/// <param name="ray"></param>
/// <returns>Vector s barvou </returns>
private Vector PhongAt(Intersection intersection, Ray ray)
{
Vector viewVector = -ray.Direction;
Vector localNormal = (viewVector.Dot(intersection.Normal) > 0.0) ?
intersection.Normal : -intersection.Normal;
Vector localNormalEps = localNormal * Vector.EPSILON;
Vector localNormalEpsPoint = intersection.Point + localNormalEps;
Vector materialColor = intersection.Material.Color;
Vector ambientColor = (materialColor * BackgroundColor(ray.Direction)) *
AmbientPercent(localNormalEpsPoint, localNormal);
Vector totalColor = ambientColor;
foreach (Light light in Lights)
{
Vector diffuseColorSum = new Vector();
for (int n = 0; n < lightSamples; ++n)
{
Vector lightDir = (light.Shape.RandomPoint - intersection.Point).Normalized;
Ray lightRay = new Ray(localNormalEpsPoint, lightDir, Ray.InitialDepth);
Intersection lightTry = light.Shape.Intersect(lightRay);
Intersection shadowTry = NearestShape(lightRay);
if (lightTry.T < shadowTry.T)
{
double lnDot = lightDir.Dot(localNormal);
Vector lightColor = light.Shape.Material.Color;
Vector diffuseColor = (materialColor * lightColor) * lnDot;
diffuseColorSum = diffuseColorSum + diffuseColor;
}
}
totalColor = totalColor + (diffuseColorSum * (1.0 / lightSamples));
}
if (ray.Depth < maxDepth)
{
Vector reflectDir = viewVector.Reflected(localNormal).Normalized;
Ray reflectRay = new Ray(localNormalEpsPoint, reflectDir, ray.Depth + 1);
Vector reflectColor = RayTrace(reflectRay) * Reflectivity;
totalColor = totalColor + reflectColor;
}
return(totalColor);
}