Vector4 Renderer::traceColor(Ray ray, Scene* scene, unsigned int recDepth) {
    Vector4 color;

    IntersectionData* iData = scene->intersect(ray);

    if (iData) { // sucessful intersection test

        //shade color
        color = m_shader->shade(iData, scene);

        if (recDepth < m_recursionDepth) {

            color = color.clamp01() * (1-iData->reflectionPercentage - iData->refractionPercentage);

            //normal direction
            Vector3 n = iData->normal;

            //view direction
            Vector3 w = -ray.direction;

            //origin of refraction/reflection ray
            Vector3 o_r = iData->position;

            //any reflection?
            if (iData->reflectionPercentage) {

                //direction of reflection ray
                Vector3 d_refl = (n*(w.dot(n))*2-w);
                Ray reflRay = Ray(o_r,d_refl);
                reflRay.min_t = reflRay.epsilon_t;

                color += traceColor(reflRay,scene,recDepth+1) * iData->reflectionPercentage;
            }

            //any refraction?
            if (iData->refractionPercentage) {

                //just one object for now
                double refrFrac = scene->getRefractionIndex() / iData->refractionIndex;

                if (!iData->rayEntersObject)
                    refrFrac = 1/refrFrac;

                //angle between view and normal
                double angle = w.dot(n);

                //refraction direction
                Vector3 d_refr;
                if (angle >= asin(1/refrFrac)) { //case of total reflection
                    d_refr = (n*(w.dot(n))*2-w);
                } else {
                    d_refr = (n*w.dot(n)-w)*(refrFrac) - n*sqrt(1-refrFrac*refrFrac*(1-w.dot(n)*w.dot(n)));
                }

                double checkangle = d_refr.normalize().dot(ray.direction);

                Ray refrRay = Ray(o_r,d_refr);
                refrRay.min_t = refrRay.epsilon_t;

                color += traceColor(refrRay,scene,recDepth+1) * iData->refractionPercentage;

            }

        } else {
            color = color.clamp01();
        }
    }
    else {
        color = scene->getBackground(); // background color
    }


    // clean
    if (iData!=NULL){
        delete(iData);
    }

    return color.clamp01();
}