private static Lighting GetIntensity(IMaterial material, Tuple4 lightDirection, double intensity, Tuple4 eyeVector, Tuple4 pointOnSurface, Tuple4 surfaceNormal)
{
var diffuse = 0.0;
var specular = 0.0;
var cosine = Tuple4.DotProduct(lightDirection, surfaceNormal);
if (cosine >= 0)
{
diffuse = cosine * material.Diffuse;
if (material.IsShining())
{
// var reflected = Tuple4.Subtract(Tuple4.Scale(surfaceNormal, 2 * Tuple4.DotProduct(surfaceNormal, lightDirection)), lightDirection);
var reflected = Tuple4.Reflect(Tuple4.Negate(lightDirection), surfaceNormal);
var reflectedDotDir = Tuple4.DotProduct(reflected, eyeVector);
if (reflectedDotDir > 0)
{
specular = material.Specular * Math.Pow(reflectedDotDir / (reflected.Length() * eyeVector.Length()), material.Shininess);
}
}
}
return(diffuse, specular, intensity);
}