triangular_communicatin.cpp

/* Date : 22 Mar 2017 - Wed */

struct ContentViewer_t;
struct ContentEngine_t;
struct RenderingEngine_t;

struct Callable_t
{
   virtual void callback() = 0;
};

struct ContentEngine_t : Callable_t
{
   Callable_t *cview, *reng;

   /* function to talk to content
      engine from rendering engine  */
   void callback() { /* do something */ }

   void SetContentViewer(Callable_t *ptr) { cview=ptr; }
   void SetRenderingEngine(Callable_t *ptr) { reng=ptr; }

   void SaySomething() { /* do something */ }

   void TalkWithCView() { cview->callback(); }

   void TalkWithREng() { reng->callback(); }
};

struct RenderingEngine_t : Callable_t
{
   Callable_t *cview, *ceng;

   /* Function to talk to redering
      engine from content engine    */
   void callback() { /* do something */ }

   void SetContentEngine(Callable_t *ptr) { ceng=ptr; }
   void SetContentViewer(Callable_t *ptr) { cview=ptr; }

   void SaySomething() { /* do something */ }

   void TalkWithCView() { cview->callback(); }

   void TalkWithCEng() { ceng->callback(); }
};

struct ContentViewer_t : Callable_t
{
   ContentEngine_t ceng;
   RenderingEngine_t reng;

   void callback() { /* do something */ }

   ContentViewer_t()
   {
      reng.SetContentViewer(this);
      reng.SetContentEngine(&ceng);

      ceng.SetContentViewer(this);
      ceng.SetRenderingEngine(&reng);
   }

   void TalkWithOthers()
   {
      ceng.SaySomething();
      reng.SaySomething();
   }
};

int main()
{
   ContentViewer_t cview;
   return 0;
}