I’m using a 12.1″ 4:3 LCD screen for retropie. The screen has a resolution of 1024×768.
Initially emu’s were showing as 4:3 but not full screen. I went into the retropie menu in Emulation station and ‘retroarch/retropie configurations’ and set the ‘common/all’ config to be forced as 1024 x and 768 y
Now SNES, Megadrive etc all populate the full screen.
However this has not affected Mame(mame4allpi) or Neo-Geo so there is a large black border on the left/right of the screen.
I assume this is because the ‘all’ option is just for retroarch configs?
I went into the individual config for mame4all and neogeo and set it as 1024 x 768 y and rebooted.
there’s probably a way to resolve this for those emulators, but one alternative is to press X when launching the game and change the default emulator for both those systems to the retroarch equivalent:
mame4all-pi to lr-imame4all
gngeo to lr-fba or lr-fba-next
the compatibility and performance should be about the same. you will need the neogeo.zip in the neogeo roms folder if you haven’t already.