The only thing you can't simulate with the change is the "missing spoke" and "missed read of a spoke/gap" errors, AFAIK.
Adding the optical to the yoke, OTOH, might feel closer to the original sensitivity / angle turned than from the POT side (for reasons of deadzone, progressive/logrithmic scaling, early max, etc, which differents from wheel to wheel, and driver to driver settings).
U_rebel-
I assume this should work in the other direction? That is - swapping an optical spinner where mame expects a paddle control? For instance - if I want to play 4 person Warlords (which I believe was analog (pot) paddles) with 4 optical spinners - would the source edit work OK? I know this will have to be a mame analog+ or advmame application due to the 4 axes...
Mame is great at relative device to absolute game inputs (as with Warlords, or star wars with a trackball). So no need to edit the source. (I doubt you would notice any difference with the change, and with it you couldn't use absolute devices.)
The reason is it's really, really easy to go from a relative device's input (spinner) and use it to simulate an absolute input (POTs). And mame does this fine. It's almost as 'easy' to go the other way, but there's two totally different ways to do it.
I'll use arkanoid, a spinner, an analog joystick, and a POT spinner in this example. You can translate the absolute to relative in two ways: "distance from center" and "change from last". The POT spinner would work
exactly like a normal spinner (assumeing linear POT, no software deadzone, scaling, curving, etc) with the "change from last" method (it turns the absolute into relative by software). However, the analog joystick would probably be best with the "distance from center" method, as the distance from center would determine the speed the paddle moves. "Change from last" might work for a zero or weak spring analog joystick for some people, though.
FWIW, games like super sprint and pole position probably would do better with "distance from center" with PC steering wheels (270 degree) even though the game play would be somewhat different than the original.
With that said, mame could get good absolute to relative input play if the user could choose which way it's translated. More work I never got around to.
