How to create a game loop with xlib

Question

I am trying to create a game loop for an xlib window, but I cannot manage to paint the window correctly. Right now I am creating a window with XCreateSimpleWindow(...), and

Answer 1

The reason you are not seeing anything is because you are neglecting the X event loop. All you do is sending data to the X server, but there is no way for the X server to communicate back.

You must set up a loop where XEvents are read from the queue and dispatched c.q. processed. Something like:

XEvent event;
while (XPending (m_display))
{
  XNextEvent (m_display, &event);
  if (XFilterEvent (&event, None))
  {
    continue;
  }
  switch (event.type)
  {
     case KeyPress:
       ..
     case ButtonPress:
       ..
     case Expose:
       ..
     case MapNotify:
       ..
     // etc
  }
}

This can be combined with your endless loop, though.

But yes, painting pixel by pixel is extremely slow. I don't even want to calculate the protocol overhead... :P