public override Color area_light_shade(ref Shade sr)
{
Phong phongMat = new Phong();
phongMat.set_ka(0.5f);
phongMat.set_kd(1.0f);
phongMat.set_ks(0.8f);
phongMat.set_exp(10.0f);
phongMat.set_cd(new Color(1, 1, 0, 1));
phongMat.set_cs(Constants.white);
Color L = phongMat.area_light_shade(ref sr);
Vector3 wo = -sr.ray.direction;
Vector3 wi = Vector3.zero;
float pdf = 0;
Color fr = glossy_specular_brdf.sample_f(ref sr, ref wo, ref wi, ref pdf);
Ray reflected_ray = new Ray(sr.hit_point, wi);
L += fr * sr.w.tracer_ptr.trace_ray(reflected_ray, sr.depth + 1) * Vector3.Dot(sr.normal, wi) / pdf;
return(L);
}
