How does GZDoom enumerate monitors in Linux?

[youda008]

Hello. I'm writing my own launcher of GZDoom mods and i would like to have an option to select a monitor to start GZDoom in by appending apropriate '+vid_adapter x' to the launch command.

GZDoom-monitors.png (3.06 KiB) Viewed 809 times

This works fine in Windows, but is problematic in Linux.
I wrote some code that enumerates monitors using libXrandr, but the order of the monitors in the list is different from the order that GZDoom uses for its vid_adapter command,
which means when i select the first monitor from my list and start GZDoom with +vid_adapter 1, it starts on the second monitor and vice versa.
In order for this to work, i must use the exact same way of enumerating monitors as GZDoom so that the order in my launcher matches the order in GZDoom.
Can you please explain how it works?

[_mental_]

You need take a look at SDL2 source code. GZDoom passes the value of vid_adapter CVAR to its functions as is. Also, the primary monitor should have zero index I think.

[youda008]

So i open GZDoom sources and first thing i see is

Code: Select all

	// This assumes the monitors are returned by EnumDisplayMonitors in the
	// order they're found in the Direct3D9 adapters list. Fingers crossed...

looks i'm not the only one fighting these issues

[_mental_]

Taking into account that the mentioned code is Windows-specific, it has nothing to do with display enumeration on Linux.