PhongShader.cxx

   1 #include "PhongShader.hxx"
   2 #include "Primitive.hxx"
   3
   4 PhongShader::PhongShader(Scene* scene,
   5                          const Vec3f& am_c,
   6                          const Vec3f& di_c,
   7                          const Vec3f& sp_c,
   8                          float ka,
   9                          float kd,
  10                          float ks,
  11                          float ke)
  12   : Shader(scene),
  13     m_ambient_color(am_c),
  14     m_diffuse_color(di_c),
  15     m_specular_color(sp_c),
  16     m_ka(ka),
  17     m_kd(kd),
  18     m_ks(ks),
  19     m_ke(ke)
  20 {
  21 }
  22
  23 PhongShader::PhongShader()
  24   : Shader(0)
  25 {
  26 }
  27
  28 PhongShader::~PhongShader()
  29 {
  30 }
  31
  32 Vec3f
  33 PhongShader::Shade(Ray& ray)
  34 {
  35   // surface normal at hit point of object
  36   Vec3f normal = ray.hit()->GetNormal(ray);
  37   // turn to front if angle > 90°
  38   if(normal.dot(ray.direction()) < 0) {
  39     normal = normal * -1;
  40   }
  41   // direction of reflection
  42   Vec3f refl_dir = ray.direction() - normal * 2 * normal.dot(ray.direction());
  43   refl_dir.normalize();
  44
  45   // ambient color term
  46   Vec3f amb_color = m_ambient_color * m_ka;
  47
  48   Vec3f intensity, light_dir;
  49
  50   // diffuse and specular color for each light source
  51   Vec3f diff_sum;
  52   Vec3f spec_sum;
  53   for(std::vector<Light*>::iterator it = m_scene->m_lights.begin();
  54     it != m_scene->m_lights.end(); it++) {
  55     Ray light_ray;
  56     (*it)->Illuminate(light_ray, intensity);
  57     diff_sum += intensity * light_ray.direction().dot(normal);
  58     Vec3f view_dir = ray.direction()*-1; // direction from hitpoint to viewer
  59     spec_sum += intensity * pow(fmax(view_dir.dot(refl_dir),0), m_ke);
  60   }
  61   Vec3f diff_color = m_diffuse_color * m_kd * diff_sum;
  62   Vec3f spec_color = m_specular_color * m_ks * spec_sum;
  63
  64   return amb_color + diff_color + spec_color;
  65 }