I need to turn on the 'OpenGL-SPECIFIC OPTION' 'gl_glsl' in sdlmame to get hardware rendering working (without this my fglrx setup gives zoomed/black & white/pixelated garbage on the screen).
Is there a way to feed the sdlmame binary extra arbitrary arguments (namely -gl_glsl) from the gui?
At the moment, no.
The framework is there for options, but I just haven't yet gotten around to adding support for the OpenGL options.
Knowing that this causes issues will make it a priority for the next release.
Can you raise a bug/feature request for me to track against?