/*
 * Rendering the whole screen
 * Levels of render go from bottom to top
 */
void CApp::OnRender()
{
  CSurface::OnDraw(Surf_Display, Surf_Background, 0, 0);

  CArea::area_control.OnRender(Surf_Display,
      -CCamera::camera_control.GetX(), -CCamera::camera_control.GetY());

  ItemRenderSystem irs;
  irs.render(Surf_Display);
  RenderSystem rs;
  rs.render(Surf_Display);
  HealthSystem hps(data::FindFile("gfx/UI/Text.png").c_str(),
      data::FindFile("gfx/Status.png").c_str());
  hps.start();
  hps.render(Surf_Display);
  CHud::HUD.OnRender(Surf_Display);
  if (DebugModeOn) {
    CHud::HUD.DebugMode(Surf_Display);
  }

  SDL_Flip(Surf_Display);
}