Support multiple nested monitors

[maboesanman]

It would be pretty powerful to support exposing multiple nested monitors for applications which produce two game windows, such as cemu (with the separate gamepad view option enabled). Having gamescope run independently for both views, and running its upscaling would be useful, but as far as I know you can't just run two copies of gamescope as it is now to support this use case.

The arguments could look something like this:

• -w, -h, and -r become aliases for -w0, -h0, and -r0
• -wn, -hn, and -rn (for example -w1, -h1, and -r1 for n = 1) specify the dimensions of the additional monitors
• analogous -W and -H options

If the argument syntax becomes too unwieldily perhaps there could be a config file that specifies some sort of selector for what game window gets assigned to what output window.

Maybe there is another approach to this which somehow allows gamescope to be composed with itself? Maybe a "pass through" argument where gamescope exposes the system's monitors to the game, followed by the gamescope monitor. That way two gamescope sessions could be created by simply running gamescope [args] -- gamescope [args] --pass-through -- %command%

Because this use case is pretty niche the ergonomics of a feature like this might not be particularly important.

[BackThrowTheBaguetteBrawler]

i was thinking about trying to run a tiling wayland compositor like sway from within gamescope, would this be possible? It is normally possible to run sway inside a window

[jediflamaster]

This would also be useful for any game that supports multiple displays. This is actually not too uncommon in RTS games, such as supreme commander.