X11 uses the Wayland message box code when no video system is initialized

[icculus]

So if you run SDL/test/testmessage.c, you'll notice on X11 you'll get message boxes like this...

...until you get to the last one...

...this is because, without the video subsystem initialized, we use SDL_MessageboxValidForDriver to decide what to do, but this returns SDL_TRUE immediately if the parent window is NULL.

Which means we try the Wayland code before the X11 code. And the Wayland code just spawns an instance of zenity to show a GTK+ message box.

Problem 1: we should probably choose the X11 driver here, but we definitely want Wayland if this would just end up talking to XWayland, so it's complicated.
Problem 2: SDL_MessageboxValidForDriver needs a better approach, perhaps.
Problem 3: the GTK+ dialog looks SO MUCH BETTER. I kinda feel like we should use this on X11 too, and fallback to our own code if zenity isn't available.

[flibitijibibo]

If it makes using Wayland's path on X any more enticing, it's possible to also have a KDialog path as well, as suggested in #4227. I suppose the Wayland ValidForDriver could check for any of the supported dialog subprocesses then fall back if none exist?

[weirddan455]

I did some testing on this. Regarding the problems you stated:

Problem 1: It looks like SDL does choose X11 driver first in the last stable release 2.0.20. At some point since then code in SDL_ShowMessageBox got changed so it tries Wayland first.

Problem 2: Yea, maybe it should be doing some real detection of whether X11 or Wayland is actually running.

Problem 3: I made some quick changes to SDL to use Zenity over X11 when there's an SDL window up. It works but it's not a proper modal dialog like the current X11 code is. It actually gets parented to my terminal window for some reason. Could be a problem for full screen programs especially. If the user clicks anywhere, the error message can get hidden away.

[slouken]

This is fixed in 343da85.