As MAME now has Lua scripting capabilities, there are a lot of modifications you can make to MAME that require no compilation and can be shared externally without need to submit it to MAMEdev.
Here are a few example project ideas off the top of my head:
A highscore.dat script. If you want to get really crazy, you could have it upload/download scores to/from a website. You could run a whole service around sharing scores for tournament play or for casual play with friends, even. I've been told there's already a working script with basic score save/load on Github somewhere, but it's not crossplatform ready.
Display maps for games. This could be as small as a minimap overlay, or as big as a full screen map viewer.
Speedrunner tools: a master timer, checkpoint list, and time per checkpoint. Bonus points if you read game state and automatically update the checkpoints.
AI partner for two player games. Tired of playing Bubble Bobble alone? Write an AI! Bonus points if you can get it to teach itself as it goes.
On that note, I need to see if there's any way to possibly set up Lua with MAME to assign a whole monitor to be used for Lua display. That would allow for even more neat tricks, like displaying the game marquee.
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DIY MAME Lua projects
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Re: Hiscores with stock MAME
