Color PhongMaterial::shade(const Intersection& intersection, const Scene& scene) const
{
Color intensity;
PointD3 point = intersection.hit_point;
Options options = scene.options();
if(options.diffuse_illumination || options.specular_illumination)
{
Color i_diffuse;
Color i_specular;
VectorD n = intersection.normal;
for(auto &light : scene.lights())
{
VectorD l = -1 * light->direction_at(point);
float n_dot_l = n.dot(l);
Color i_light = light->intensity(point, scene);
// === Diffuse reflection ===
if(options.diffuse_illumination)
{
if(n_dot_l > 0.0f)
{
i_diffuse = i_light * c_diffuse * n_dot_l;
}
}
// === Specular reflection ===
if(options.specular_illumination)
{
VectorD v = -1 * intersection.incident_ray.direction;
VectorD r = 2 * n_dot_l * n - l;
r.normalize();
float v_dot_r = v.dot(r);
if(v_dot_r > 0.0f)
{
i_specular = i_light * c_specular * std::pow(v_dot_r, s);
}
}
}
intensity += i_diffuse;
intensity += i_specular;
}
// === Ambient reflection ===
if(options.ambient_illumination)
{
auto ambient_light = scene.ambient_light();
if(ambient_light)
{
Color i_light = scene.ambient_light()->intensity(point, scene);
Color i_ambient = i_light * c_ambient;
intensity += i_ambient;
}
}
return intensity;
}
Color MirrorMaterial::shade(const Intersection &intersection, const Scene &scene) const
{
VectorD vec_incident = -intersection.incident_ray.direction;
if(intersection.incident_ray.recursion_depth >= scene.options().max_recursion)
{
return Color(0.0, 0.0, 0.0);
}
VectorD n = intersection.normal;
// Reflection vector
VectorD vec_r = 2 * n.dot(vec_incident) * n - vec_incident;
vec_r.normalize();
// Reflection ray
Ray ray_r(intersection.hit_point, vec_r);
ray_r.recursion_depth = intersection.incident_ray.recursion_depth + 1;
// Trace reflection ray
Color reflected_color;
Intersection reflection_hit = scene.trace(ray_r);
if(reflection_hit.exists)
{
reflected_color = reflection_hit.hit_object->material()->shade(reflection_hit, scene);
}
else
{
reflected_color = scene.background();
}
return reflected_color;
}
Color LambertMaterial::shade(const Intersection& intersection, const Scene& scene) const
{
Color intensity;
PointD3 point = intersection.hit_point;
// === Diffuse reflection ===
if(scene.options().diffuse_illumination)
{
Color intensity_diffuse;
for(auto &light : scene.lights())
{
VectorD n = intersection.normal;
VectorD l = -1.0 * light->direction_at(point);
float dot = n.dot(l);
if(dot > 0.0f)
{
intensity_diffuse += light->intensity(point, scene) * c_diffuse * dot;
}
}
intensity += intensity_diffuse;
}
// === Ambient reflection ===
if(scene.options().ambient_illumination)
{
auto ambient_light = scene.ambient_light();
if(ambient_light)
{
Color ambient_intensity = scene.ambient_light()->intensity(point, scene);
Color intensity_ambient = ambient_intensity * c_ambient;
intensity += intensity_ambient;
}
}
return intensity;
}