09208: apple2gs: Multiple games unplayable in MAME

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
09208	Gameplay	Major	Always	2 days ago	1 day ago

Tester	Python	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10/11 (64-bit)
Status [?]	Acknowledged			Driver	apple/apple2gs.cpp
Version	0.277	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	09208: apple2gs: Multiple games unplayable in MAME
Description	Ive been working with qkumba to identify IIGS games not working in MAME and some other MAME regressions. The following sits in between an issue resulting in games being unplayable and a feature request so qkumba suggested I create this issue report. There are some games (Aaargh!, Skate or Die, Rush Hour, Mini Prix, Magic Johnson's Basketball) that are not playable when using a joystick in MAME. There may be some more but as I am only halfway through the letter "S" on my setting IIGS games up in MAME thats all ive found so far. The issue is that the joystick emulation is continually dragging to the bottom right. Some of the above listed games can be played via the keyboard instead of joystick which means you can avoid the issue for player 1 but also means that 2 player is not possible. Others are joystick only and therefore are unplayable in MAME. The majority of games do not have this issue and play absolutely fine as things are now in MAME. KEGS\GSPort\GSPlus solve this by having a "TRIM" feature in the joystick setting menu that simulates the TRIM pots that some IIGS joysticks had (https://appletothecore.me/files/ch_products_appleii_joystick.php as an example) I know that as part of the joystick hardware TRIM settings are technically not part of the IIGS emulation and therefore maybe out of scope but without it these games have to use KEGS based emulators. Is this something that can be grabbed from KEGS and imported into MAME for Apple IIGS emulation (and possibly helpful for Apple II as well?) The person who added the TRIM settings to KEGS goes by the name Torquemander. He said: "This is a very old problem with the original GS hardware. It has to do with whether or not you were using the internal or external joyport and the speed that the GS runs at. Essentially, the problem is that some software polls the joyport too quickly and reports half the values. The fix in the old days was to calibrate the pots on your analog joystick to center at around 66, and then everything would work normally. I added a hack to KEGS years ago to allow users to change the offset via configuration, since no one has joysticks with potentiometers, anymore."
Steps To Reproduce	Plug in a joystick and use it in MAME .277 for the above noted games
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	apple2gs

Attached Files