sphere.cpp

std::pair<int,double> const Sphere::getIntersection(Ray const& input_ray, bool shadow_ray) const
{
  std::pair<int,double> pair;
    double t;
    Ray ray = input_ray;

  if(shadow_ray == false)
    ray = Ray(inv_t_matrix_*ray.origin,inv_t_matrix_*ray.dir);

    // double A = 1; (unused)
    double B = 2*(
          ray.dir[0]*(ray.origin[0]-center_[0])
           + ray.dir[1]*(ray.origin[1]-center_[1])
           + ray.dir[2]*(ray.origin[2]-center_[2]));
    double C = pow(ray.origin[0]-center_[0],2)
           + pow(ray.origin[1]-center_[1],2)
           + pow(ray.origin[2]-center_[2],2) - radius_pow2_;
    double discr = B*B-4*C;

    if(discr > 0)
    {
        t = (-B - sqrt(discr))*0.5;
        if(t > 0.00001)
          pair = std::make_pair(1,t);
        if(t < 0)
        {
            t = (-B + sqrt(discr))*0.5;
            if(t > 0.00001)
              pair = std::make_pair(1,t);
        }
        else
          pair = std::make_pair(1,t);
    }
    else
        pair = std::make_pair(0,0);

    return pair;
}
Color const Sphere::getColor(math3d::point const& intersection_point, std::shared_ptr<Scene> const& scene) const
{
  double red, green, blue;
  double dot_normal_light, dot_normal_reflection;
  math3d::point center = t_matrix_*center_;
  math3d::vector sphere_normal = math3d::vector(
                            intersection_point[0]-center[0],
                            intersection_point[1]-center[1],
                            intersection_point[2]-center[2]
                          ).normalize();
  sphere_normal = math3d::transpose(inv_t_matrix_)*sphere_normal;
  std::vector<std::shared_ptr<SFDS>> lights = scene->shadowFeeler(intersection_point);
  Color ambiance = scene->getAmbiance();
  red = ambiance[0]*material_->ka[0];
  blue = ambiance[1]*material_->ka[1];
  green = ambiance[2]*material_->ka[2];

  for(std::vector<std::shared_ptr<SFDS>>::iterator iter = lights.begin(); iter!=lights.end(); ++iter)
  {
    if((*iter)->delta != 0)
    {
      dot_normal_light = math3d::dot(sphere_normal,(*iter)->vector);
      dot_normal_reflection = math3d::dot(2*(dot_normal_light)*sphere_normal-(*iter)->vector,sphere_normal);
      if(dot_normal_light < 0) dot_normal_light = 0;
      red +=   (*iter)->delta
                * (*iter)->light->dif_[0]
                * (material_->kd[0]*dot_normal_light
                 + pow(material_->ks[0]*dot_normal_reflection,
                       material_->m));
      green += (*iter)->delta
                * (*iter)->light->dif_[1]
                * (material_->kd[1]*dot_normal_light
                 + pow(material_->ks[1]*dot_normal_reflection,
                       material_->m));
      blue +=  (*iter)->delta
                * (*iter)->light->dif_[2]
                * (material_->kd[2]*dot_normal_light
                 + pow(material_->ks[2]*dot_normal_reflection,
                       material_->m));
    }
  }
  Color color = Color(red,blue,green);
  return color;
}