X11/GLX - Fullscreen mode?

Question

I am trying to create a Linux application - a screensaver, in this case - and it is proving remarkably difficult to find information on the simple task of making a wind

Answer 1

Best and easier way to achieve it is to use the ICCCM Specification atom which will work for most recent Window Managers. Just use the following code:

Atom wm_state   = XInternAtom (display, "_NET_WM_STATE", true );
Atom wm_fullscreen = XInternAtom (display, "_NET_WM_STATE_FULLSCREEN", true );

XChangeProperty(display, window, wm_state, XA_ATOM, 32,
                PropModeReplace, (unsigned char *)&wm_fullscreen, 1);

Your window might be transparent, if so, just use XSetBackground() function where you need it and it's done.