double phongIlluminationAchromatic(double ambientIntensity, double diffuseIntensity, double specularIntensity,double ambientReflecCoef, double diffuseReflecCoef, double specularReflecCoef,double shininess,double kc, double kl, double kq,CVec3df pointOnSurface, CVec3df surfaceNormal, CVec3df lightPosition, CVec3df viewPoint)
{
    CVec3df s; // s is the light vector
    CVec3df v;// v is the view vector
    double d;// d is distance from point on surface to light source

    s = lightPosition - pointOnSurface;
    d = length(s);
    v = viewPoint - pointOnSurface;

    double ambientReflection = ambientIntensity * ambientReflecCoef; //the ambient Intensity
    double diffuseReflection = diffuseIntensity * diffuseReflecCoef; //the diffuse Intensity
    double specularReflection = specularIntensity * specularReflecCoef; //the specular Intensity
    double distance = kc + kl + pow(kq, 2); //distance from light source

    s.normaliseDestructive();
    v.normaliseDestructive();
    CVec3df h = s + v;
    h.normaliseDestructive();

    double diffuse = diffuseReflection * (double(s.dot(surfaceNormal)) / length(s) * length(surfaceNormal));
    double specular = specularReflection * pow(double(s.dot(h) / length(s) * length(h)), shininess);

    double result = ambientReflection + (diffuse + specular) / distance;

    return result;
}