I was wondering if the light gun would work in a configuration when the monitor is mounded vertically. I am thinking about a WG U3100 which I think works with the gun. The only thing is that I plan to use the rotation of the video card (integrated intel) to rotate the monitor. In this case, the display resolution is 480x640 (not 640x480). I do not have to do any ROL or ROR in mame, just change the aspect to 3:4 instead of 4:3. But I wonder if when the light gun sends its coords in, will it send x for y and y for x. Any ideas?
I have tried using the rotation feature of my graphic card (an ArcadeVGA) and it seems to clash with MAME32, because games do not load when I setup windows to be displayed vertically. I don't know if this is an issue with ArcadeVGA only, or happen with all cards. I will try that you say about the aspect, and see if it works. Using ror, it should work, because the resolution of vertical games keep on being the same, for instance, 320x240, and not 240x320. In fact I would dare to say that vertical monitors do not exist. Actually, they are horizontal monitors, which are rotated, so that's why you see vertical scanlines. I'm sorry I cannot help with the lightgun issue, since I have never tried it with MAME.