After a few weeks of headaches I finally managed to get RetroArch working on a Linux machine outputting a nice VGA signal to a 15khz CRT TV with switchres. Things are glorious and I’m very pleased with the results, every core I’ve tested so far is working wonderfully and resolutions are crisp and nice all around.
I have a problem with my TV, however, that I’d like to see if I can fix with RetroArch. Basically, the service menu gives me several options to adjust vertical geometry but it provides absolutely no options to handle horizontal geometry. Because of this, I have no way of adjusting the image to not be cut off on the left and right of the screen (overscan).
Some games handle this well, others not so much, so I’d like to fix it.
If I try to use a custom aspect ratio it works, but then for each core (and possible game) I have to set up the correct number of vertical lines, otherwise I lose crispiness and even get some artifacts since I don’t use bilinear filtering. Core-provided aspect ratio is working perfectly.
Since I’m using one of those super resolutions - 1920x240, 2560x224, that kind of stuff - I have plenty of pixels to go horizontally for any kind of processing, so I was thinking that maybe I could use some kind of shader to add black bars to the left and right of the image, effectively squishing it horizontally.
Is this possible? If so, which shader do I use? If not, is there another solution (other than acquiring a new TV)?