What's the best way of waiting a finite a mount of time for an expose event on X, then waking up and doing a redraw, even if not expose event has been received? The purpose is to have an opengl animation running at sometimes where at others I simply want to redraw if needed. Here is my code as I have it now, check below for pseudo-code of what I'm looking for:
do {
XNextEvent(dpy, &event);
switch(event.type) {
...
case Expose:
need_redraw = True;
break;
}
} while(XPending(dpy)); /* loop to compress events */
if ( need_redraw )
{
// do redraw
}
And this is a pseudo-example of what I would like:
bool animation_enabled = true;
XPostTimeoutEventEvery( 0.3 ); // <-- X will send a "Timeout"
// event each 0.3 seconds.
do {
XNextEvent(dpy, &event);
switch(event.type) {
...
case Expose:
// Redraw if it is required
need_redraw = True;
break;
// -- here --
case Timeout:
// Otherwise, after 0.3 seconds, redraw anyway if
// the animation is running
if ( animation_enabled )
{
need_redraw = True;
}
break;
}
} while(XPending(dpy)); /* loop to compress events */
if ( need_redraw )
{
// do redraw
// potentially change "animation_enabled" value
}
Just use a regular system timer; if a desired event doesn't arrive in time, just do whatever you want to do.
X is not an application framework, it's a display protocol. Timers are outside (of that) scope of X11.