I've been trying to get this to work for ages, but it baffles me. I'm running Linux with the AMDGPU-PRO drivers. They work great, and I don't suspect it's their fault.
Edit: From the saiarcot895 repository.
Linux Mint 19 (Ubuntu 18.04 based)
FlightGear version: 2018.3.1
SimGear version: 2018.3.1
OSG version: 3.2.3
PLIB version: 185
I have 3 monitors that are automatically bound together, apparently by AMDGPU when I read the Xorg.log, into one large framebuffer - 4720x1050.
The only way to get fgfs to span all three monitors is to start it windowed, and then drag the corners of the window until they span all of the monitors. This also seems to be what is keeping me from configuring proper cameras for the three monitors, so I get a distorted view on the side monitors. I have not been able to get it to respect any of the configuration files that set up multiple viewports.
I would have thought launching fgfs --geometry 4720x1050 would fill the framebuffer - no, it fills the middle monitor, windowed, with a top bar from the window manager. How about with --enable-fullscreen? That fills the middle monitor as well, without the window manager frame. If I use the window manager controls I can send the fullscreen image to whichever monitor I want with the "move to monitor 1" etc. commands.
Feeding a value smaller than the monitor to --geometry is respected, like 640x480, and gets me a small window.
How do I get it to fill the entire framebuffer and not respect the monitor boundaries?