src/rcrt/bxdf/Phong.cpp

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#include "Phong.h"

#include <cmath>

namespace rcrt
{

Phong::Phong(const RGBColor& Kd, const RGBColor& Ks, const float& e)
:BXDF(Ks*(e+2)/(2*M_PI), Kd/M_PI, 0, BXDFType(REFLECTIVE)),n(e)
{
}

Phong::~Phong()
{
}

RGBColor Phong::eval(const Vec3D& wOut, const Vec3D& wInc, const Vec3D& normal) const
{       
        return kd + evalSpecular(wOut,wInc,normal);
}

RGBColor Phong::evalDiffuse(const Vec3D& wOut, const Vec3D& wInc, const Vec3D& normal) const
{
        return kd;
}

RGBColor Phong::evalSpecular(const Vec3D& wOut, const Vec3D& wInc, const Vec3D& normal) const
{
        Vec3D refl(wInc.reflect(normal));

        float angle = refl * wOut;
        if (angle >= 1.0) {//clamp
                angle = 1.0;
        }
        return ks * powf(angle, n);
}


bool Phong::specular() const
{
        return true;
}

bool Phong::glossy() const
{
        return true;
}

bool Phong::diffuse() const
{
        return true;
}

bool Phong::fresnel() const
{
        return false;
}

float Phong::pdf(const Vec3D& wOut, const Vec3D& wInc, const Vec3D& normal) const
{
        float cosO = wOut * normal;
        if(cosO < 0) return 0;
        Vec3D refl(wInc.reflect(normal));
        float angle = refl * wOut;
        return (n+1)/(2*M_PI)*powf(angle,n);
}

}

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