@8bit_astronaut Hello,
i downloaded thoses shaders and extract them in recalbox/share/system/shaders
GLSLP= shader preset (generally several passes some kind of "shader loading profile")
GLSL= shader file.
and modify this line in= /recalbox/share/system/recalbox.conf
Set gpslp shader for all emulators (prefer shadersets above).
Absolute path (string) global.shaders=/recalbox/share/system/shaders/hq2x.glslp
At this point; ingame you can test them (see shortcut in retroarch config).
That set up recalbox to ask retroarch to use hq2xl.glsl shader with all libretro emulators. (exept fba)