public Material(
ColorProbability diffuseProbabilities,
ColorProbability specularProbabilities,
ColorProbability refractiveProbabilities,
Probability diffuseReflectionProbability,
Probability specularReflectionProbability,
Probability refractionProbability,
BRDF brdf,
Light emmissiveLight,
RefractiveIndex refractiveIndex
)
{
DiffuseProbabilities = diffuseProbabilities;
SpecularProbabilities = specularProbabilities;
RefractiveProbabilities = refractiveProbabilities;
DiffuseReflectionProbability = diffuseReflectionProbability;
SpecularReflectionProbability = specularReflectionProbability;
RefractionProbability = refractionProbability;
BRDF = brdf;
EmmissiveLight = emmissiveLight;
RefractiveIndex = refractiveIndex;
}
public static Probability ProportionOfAdditions(ColorProbability cpa, ColorProbability cpb)
{
var aSum = cpa.Red.Value + cpa.Green.Value + cpa.Blue.Value;
var bSum = cpb.Red.Value + cpb.Green.Value + cpb.Blue.Value;
return(new Probability(aSum / (aSum + bSum)));
}
private static BRDF DiffuseBRDF(ColorProbability colorProbability)
{
return((
Light incomingLight,
UnitVector incomingVector,
UnitVector outgoingVector,
UnitVector surfaceNormal,
Point surfacePosition
) => incomingLight *colorProbability *Vector.DotProduct(outgoingVector, surfaceNormal));
}
public static Probability MaxOfAdditions(ColorProbability cpa, ColorProbability cpb)
{
var ar = cpa.Red;
var ag = cpa.Green;
var ab = cpa.Blue;
var br = cpb.Red;
var bg = cpb.Green;
var bb = cpb.Blue;
return(Probability.Max(ar + br, ag + bg, ab + bb));
}
private static BRDF SpecularBRDF(ColorProbability colorProbability)
{
return((
Light incomingLight,
UnitVector incomingVector,
UnitVector outgoingVector,
UnitVector surfaceNormal,
Point surfacePosition
) =>
{
var reflectionVector = surfaceNormal * Vector.DotProduct(surfaceNormal * 2.0, incomingVector) - incomingVector;
return incomingLight * colorProbability * Vector.DotProduct(outgoingVector, reflectionVector);
});
}
public static Material CreateDiffuseSpecular(ColorProbability diffuseProbabilities, ColorProbability specularProbabilities)
{
var drdgdb = diffuseProbabilities.SumComponents();
var srsgsb = specularProbabilities.SumComponents();
var pReflect = ColorProbability.MaxOfAdditions(diffuseProbabilities, specularProbabilities);
var pDiffuse = pReflect * drdgdb / (drdgdb + srsgsb);
return(new Material(
diffuseProbabilities,
specularProbabilities,
ColorProbability.Zero,
pDiffuse,
pReflect - pDiffuse,
Probability.Zero,
PhongBRDF(diffuseProbabilities, specularProbabilities),
Light.None,
RefractiveIndex.Vacuum
));
}
public static Material CreateRefractive(
ColorProbability specularProbabilities,
ColorProbability refractiveProbabilities,
RefractiveIndex refractiveIndex
)
{
var sr = specularProbabilities.Red;
var sg = specularProbabilities.Green;
var sb = specularProbabilities.Blue;
var rr = refractiveProbabilities.Red;
var rg = refractiveProbabilities.Green;
var rb = refractiveProbabilities.Blue;
var pReflect = ColorProbability.MaxOfAdditions(specularProbabilities, refractiveProbabilities);
var pRefract = ColorProbability.ProportionOfAdditions(specularProbabilities, refractiveProbabilities);
return(new Material(
ColorProbability.Zero, specularProbabilities, refractiveProbabilities,
Probability.Zero, pReflect, pRefract,
PhongBRDF(ColorProbability.Zero, specularProbabilities),
Light.None, refractiveIndex
));
}
private static BRDF PhongBRDF(ColorProbability diffuseProbabilities, ColorProbability specularProbabilities)
{
return(SumBRDFs(new[] { DiffuseBRDF(diffuseProbabilities), SpecularBRDF(specularProbabilities) }));
}
