If use shaders that emulate scanlines is there a way to get the shaders scanlines to display correctly for Vertical Arcade games, as when you use a CRT shader the scanlines are going horizontally across the screen where as for vertical games they should be going vertically??
It depends on the shader. Some of them are easy enough to rotate in the code, but others don’t look as good. The FBA core usually handles vertical games correctly, with the scanlines running vertically, while MAME-based cores have them running horizontally. I’m not sure exactly why that is, presumably related to MAME’s weird gigantic-framebuffer thing.
So how can shaders be rotated in code?
For Mame you can do:
-rotate 90° in MAme GUI (L2 button, Video Menu) -rotate 90°in the opposite way in Retroarch settings/Video
Hope someone will find a fix some day.