Using OpenGL Optimizer with FLTK

OptimizerWindow Class Definition

To use OpenGL Optimizer with FLTK you'll need to create a subclass of Fl_Gl_Widget that includes several state variables:

class OptimizerWindow : public Fl_Gl_Window {
  csContext *context_; // Initialized to 0 and set by draw()...
  csDrawAction *draw_action_; // Draw action...
  csGroup *scene_; // Scene to draw...
  csCamara *camera_; // Viewport for scene...

  void draw();

public:
  OptimizerWindow(int X, int Y, int W, int H, const char *L)
    : Fl_Gl_Window(X, Y, W, H, L) {
      context_ = (csContext *)0;
      draw_action_ = (csDrawAction *)0;
      scene_ = (csGroup *)0;
      camera_ = (csCamera *)0;
    }

  void scene(csGroup *g) { scene_ = g; redraw(); }

  void camera(csCamera *c) {
    camera_ = c;
    if (context_) {
      draw_action_->setCamera(camera_);
      camera_->draw(draw_action_);
      redraw();
    }
  }
};

The camera() Method

The camera() method sets the camera (projection and viewpoint) to use when drawing the scene. The scene is redrawn after this call.

The draw() Method

The draw() method performs the needed initialization and does the actual drawing:

void OptimizerWindow::draw() {
  if (!context_) {
    // This is the first time we've been asked to draw; create the
    // Optimizer context for the scene...

#ifdef WIN32
    context_ = new csContext((HDC)fl_getHDC());
    context_->ref();
    context_->makeCurrent((HDC)fl_getHDC());
#else
    context_ = new csContext(fl_display, fl_visual);
    context_->ref();
    context_->makeCurrent(fl_display, fl_window);
#endif // WIN32

    ... perform other context setup as desired ...    

    // Then create the draw action to handle drawing things...

    draw_action_ = new csDrawAction;
    if (camera_) {
      draw_action_->setCamera(camera_);
      camera_->draw(draw_action_);
    }
  } else {
#ifdef WIN32
    context_->makeCurrent((HDC)fl_getHDC());
#else
    context_->makeCurrent(fl_display, fl_window);
#endif // WIN32
  }

  if (!valid()) {
    // Update the viewport for this context...
    context_->setViewport(0, 0, w(), h());
  }

  // Clear the window...

  context_->clear(csContext::COLOR_CLEAR | csContext::DEPTH_CLEAR,
                  0.0f,		// Red
		  0.0f,		// Green
		  0.0f,		// Blue
		  1.0f);	// Alpha

  // Then draw the scene (if any)...

  if (scene_)
    draw_action_->apply(scene_);
}

The scene() Method

The scene() method sets the scene to be drawn. The scene is a collection of 3D objects in a csGroup. The scene is redrawn after this call.