Just curious, why does it convert offscreen shots to 0,maxY instead of something more static like -1,-1 (or 0,0 if negatives aren't allowed)?
It started with 0,0 but this didn't work on some games (lethal enforcers 2, mostly, IIRC). The change happened in, err... clip from whatsnew:
0.106u12
...
Changed the coordinates where for offscreen lightgun reloading, moving
it from the upper-left to the upper-right for better compatibility.
Funny thing is the source (current, 0.107, & 0.106u12) set it to
lower-left (actually "minX, maxY"), and the documentation matches when it says "0, maxY". [shrug] Hmm... I guess the whatsnew was wrong. I wonder if the maxX, minY that matches the whatsnew is "better"?
Mame could send "-1,-1" but that's probably less compatible with more games, and might crash some.
Skimming the source, I see
maybe why current mame reload has problems: looks like mame's reload option only works on mouse 1, while most lightguns, with mame's multiple mouse & multiple lightgun support, are not mouse 1. But there's a lot going on, so I'll have to do some coding and testing to be sure.