// class declaration
/// Cache implementation. input_t must implement "void update(bool)" and "facevertices_t& face_vertices()"
template <typename input_t> class catmull_clark_cache_implementation
{
 public:
  catmull_clark_cache_implementation(input_t& Input, int Levels);
  ~catmull_clark_cache_implementation();

  /// update point positions
  void update(bool all = false);

  /// Get the number of levels
  const unsigned long levels() const
  {
   return m_levels;
  }
  /// draw the result using opengl
  void draw();
  
 private:
  input_t& m_input;
  int m_levels;
  typedef std::map<valid_point*, border_root_t*> inner_bordermap_t;
  typedef std::map<valid_point*, inner_bordermap_t*> bordermap_t;
  typedef std::map<valid_point*, patch_corner*> cornermap_t;
  bordermap_t m_borders;
  std::vector<point_array*> m_patch_parents;
  std::vector<border_parent_t*> m_border_parents;
  cornermap_t m_patch_corners;

  // get or create the border line with given start and end points
  border_root_t* get_border(valid_point* Start, valid_point* End);

  // only retrieve the border from the map
  border_root_t* retrieve_border(valid_point* Start, valid_point* End, bool recurse = true);

  // generate cache up to level
  void generate(int level);

  // get the patch_corner associated with the Point
  patch_corner* get_patch_corner(valid_point* Point);
};

// definition
template <typename T> void libk3dmesh::detail::catmull_clark_cache_implementation<T>::draw( )
{
 k3d::gl::store_attributes attributes;
 glEnable(GL_LIGHTING);
 glColor3d(0.8, 0.8, 1);

 glFrontFace(GL_CW);
 glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);

 glDisable(GL_CULL_FACE);

 glEnable(GL_POLYGON_OFFSET_FILL);
 glPolygonOffset(1.0, 1.0);
 for (facevertices_t::iterator face = m_input.face_vertices().begin(); face != m_input.face_vertices().end(); ++face)
  (*face)->draw(m_levels-1);
}