glm::vec3 indirect(const glm::vec3 &c, const glm::vec3 &p, const glm::vec3 &n, const Glass &glass, int iterations)
{
float ior = 1.5f;
// Calcul du rayon réfléchi
glm::vec3 direction = reflect(c,n);
glm::vec3 directionNorm = glm::normalize(direction);
Ray rayReflexion{p+directionNorm*0.1f, directionNorm};
// Calcul du rayon réfracté
glm::vec3 vecRefract;
refract(-c, n, ior, vecRefract);
Ray rayRefraction{p+vecRefract*0.1f, vecRefract};
// Calcul du coefficient reflechi/refracte
float coeff = fresnelR(-c, n, ior);
float rand = random_u();
if (rand < coeff)
{
return radiance(rayReflexion, iterations-1);
}
return radiance(rayRefraction, iterations-1) * glass.color;
//return radiance(rayReflexion, iterations-1) * coeff + radiance(rayRefraction, iterations-1) * (1- coeff);
}
// Fresnel coeficient of transmission.
// Normal point outside the surface
// ior is n0 / n1 where n0 is inside and n1 is outside
float fresnelR(const glm::vec3 i, const glm::vec3 n, const float ior)
{
if(glm::dot(n, i) < 0)
return fresnelR(i, n * -1.f, 1.f / ior);
float R0 = (ior - 1.f) / (ior + 1.f);
R0 *= R0;
return R0 + (1.f - R0) * std::pow(1.f - glm::dot(i, n), 5.f);
}
glm::vec3 indirect(const Ray &rOrigine, const Ray &rReflect, const glm::vec3 &p, const glm::vec3 & n, int countdown, const Glass &glass) {
float fresnel = fresnelR(-rOrigine.direction,n, 1.5);
glm::vec3 refracted;
bool canRefract = refract(-rOrigine.direction, n, 1.5, refracted);
Ray rRefracted{p+refracted*0.1f, refracted};
if(canRefract) {
float u = random_u();
if(u < fresnel)
return radiance(rReflect, countdown);
else
return radiance(rRefracted, countdown);
}
//return fresnel*radiance(rReflect, countdown)+(1-fresnel)*radiance(rRefracted, countdown);
else
return fresnel*radiance(rReflect, countdown);
}
