t_bool dielectric(t_material *material, const t_ray *r, const t_hit_record *h, t_vec3 *attenuation, t_ray *scattered)
{
t_vec3 outward_normal;
t_vec3 reflected;
t_vec3 refracted;
float ni_over_nt;
float reflect_probe;
float cosine;
vec3_reflect(&reflected, &RAY_DIRECTION(r), &h->normal);
vec3_assign(attenuation, &material->texture.albedo);
if (vec3_dot(&RAY_DIRECTION(r), &h->normal) > 0)
{
vec3_mul_f(&outward_normal, &h->normal, -1.f);
//TODO pass idx
ni_over_nt = REF_IDX;
cosine = REF_IDX * vec3_dot(&RAY_DIRECTION(r), &h->normal) / vec3_length(&RAY_DIRECTION(r));
}
else
{
vec3_assign(&outward_normal, &h->normal);
ni_over_nt = 1.0f / REF_IDX;
cosine = - vec3_dot(&RAY_DIRECTION(r), &h->normal) / vec3_length(&RAY_DIRECTION(r));
}
if (refract(&RAY_DIRECTION(r), &outward_normal, ni_over_nt, &refracted))
reflect_probe = schlick(cosine, REF_IDX);
else
reflect_probe = 1.0f;
if (drand48() < reflect_probe)
ray_assign(scattered, &h->pos, &reflected);
else
ray_assign(scattered, &h->pos, &refracted);
return (TRUE);
}
bool Dielectric::scatter(const Ray& r_in, const HitRecord& record, vec3& attenuation, Ray& scattered) const
{
vec3 outward_normal;
vec3 reflected = reflect(r_in.direction(), record.normal);
float ni_over_nt;
attenuation = vec3(1,1,1);
vec3 refracted;
float reflect_probability;
float cosine;
if (dot(r_in.direction(), record.normal) > 0)
{
outward_normal = -record.normal;
ni_over_nt = refractive_index;
cosine = refractive_index * dot(r_in.direction(), record.normal) / r_in.direction().length();
}
else
{
outward_normal = record.normal;
ni_over_nt = 1.0f / refractive_index;
cosine = -dot(r_in.direction(), record.normal) / r_in.direction().length();
}
if (refract(r_in.direction(), outward_normal, ni_over_nt, refracted))
{
reflect_probability = schlick(cosine, refractive_index);
}
else
{
reflect_probability = 1.0f;
}
if (drand48() < reflect_probability)
{
scattered = Ray(record.point, reflected); // REFLECT vs
}
else
{
scattered = Ray(record.point, refracted); // REFRACT !!
}
return true;
}
