PhongShader.cxx

   1 #include <vector>
   2
   3 #include "PhongShader.hxx"
   4 #include "Primitive.hxx"
   5 #include "Scene.hxx"
   6
   7 PhongShader::PhongShader(Scene* scene,
   8                          const Vec3f& am_c,
   9                          const Vec3f& di_c,
  10                          const Vec3f& sp_c,
  11                          float ka,
  12                          float kd,
  13                          float ks,
  14                          float ke)
  15   : Shader(scene),
  16     m_ambient_color(am_c),
  17     m_diffuse_color(di_c),
  18     m_specular_color(sp_c),
  19     m_ka(ka),
  20     m_kd(kd),
  21     m_ks(ks),
  22     m_ke(ke)
  23 {
  24 }
  25
  26 PhongShader::PhongShader()
  27   : Shader(0)
  28 {
  29 }
  30
  31 PhongShader::~PhongShader()
  32 {
  33 }
  34
  35 Vec3f
  36 PhongShader::Shade(Ray& ray)
  37 {
  38  // surface normal at hit point
  39   Vec3f N = ray.hit()->GetNormal(ray);
  40   // turn normal to front
  41   if(N.dot(ray.direction()) > 0)
  42     {
  43       N *= -1;
  44     }
  45
  46   // reflection vector
  47   Vec3f R = ray.direction() - N*2*N.dot(ray.direction());
  48   R.normalize();
  49
  50   // ambient term
  51   Vec3f color = m_ambient_color * 1.0 * m_ka;
  52
  53   // construct shadow ray
  54   Vec3f shadow_org = ray.origin()+ray.direction()*ray.t();
  55   Ray shadow_ray;
  56   shadow_ray.setOrigin(shadow_org);
  57
  58
  59   int n_area_rays = 1000;
  60   std::vector<Light*> lights = m_scene->lights();
  61   for(unsigned int i = 0; i < lights.size(); ++i)
  62     {
  63       Vec3f intensity;
  64
  65       int max_s = (lights[i]->IsArea()) ? n_area_rays : 1;
  66       Vec3f color_l(0.0f,0.0f,0.0f);
  67       for(int s = 0; s < max_s; ++s)
  68         {
  69
  70           if(lights[i]->Illuminate(shadow_ray, intensity))
  71             {
  72               // check for occluders
  73               if(m_scene->Occluded(shadow_ray))
  74                 {
  75                   continue;
  76                 }
  77
  78               float IdotN = shadow_ray.direction().dot(N);
  79               if(IdotN > 0)
  80                 {
  81                   // diffuse term
  82                   color_l += m_diffuse_color * intensity * IdotN * m_kd;
  83                 }
  84
  85               // specular term
  86               float IdotR = shadow_ray.direction().dot(R);
  87               if(IdotR > 0)
  88                 {
  89                   color_l += m_specular_color * intensity * pow(IdotR,m_ke) * m_ks;
  90                 }
  91             }
  92         }
  93       color_l /= static_cast<float>(max_s);
  94       color += color_l;
  95     }
  96   color.clamp();
  97
  98   return color;
  99 }