07763: 'Constant drift' when trackball analog assigned to gamepad analog stick

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07763	DIP/Input	Minor	Always	Oct 3, 2020, 11:25	Oct 10, 2020, 14:30

Tester	brainskis	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	No change required	OS	Windows 10 (64-bit)
Status [?]	Closed			Driver	taito/bking.cpp
Version	0.225	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07763: 'Constant drift' when trackball analog assigned to gamepad analog stick
Description	Applies to all trackball games I've tested: Marble Madness, Golden Tee Fore version, Birdie King, and others. Happens in at least the last 3 major versions of MAME. Reproduce: Assign Mame Trackball analog X and Y to gamepad Left analog stick X and Y respectively. Please see attached image. The Track X and Track Y sliders always decrement even when the stick is not being touched. (This effect is more noticable when sensitivity value is high). I have 2 XBox One gamepads and 2 DS4 Gamepads, and the gradual X & Y decrement happens on all 4 controllers. I am certain this is not a deazone / hardware drift issue.
Steps To Reproduce	- Assign Mame Trackball analog X and Y to gamepad Left analog stick X and Y respectively. - See the MAME analog control settings screen and watch X and Y sliders decrement even when analog stick is not being touched.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems

Attached Files	trackball.png (532,988 bytes) Oct 3, 2020, 11:25 Uploaded by brainskis

No.18040 Tafoid Administrator Oct 6, 2020, 22:15	I don't have a controller to duplicate your issue. Hopefully someone else may be able to help. Can you test the controller(s) through Control Panel in Windows an see if the same type of drifting is happening?
No.18042 hap Developer Oct 7, 2020, 11:49	It works fine for me, Xbone pad. However, mame.ini: joystick_deadzone 0.1 If i set this to a much lower value, eg, 0.01, then I get the drift you describe. It's a problem with most analog controls, they wear down. I can see it on Windows's control panel too that the crosshair is not in the exact center.
No.18048 brainskis Tester Oct 9, 2020, 10:46	Thanks guys. I will double check this. I don't recall if I adjusted joystick_deadzone!
No.18050 brainskis Tester Oct 10, 2020, 11:31	hap, Tafoid - I can confirm this happened because joystick_deadzone was set to an extremely low value. I am kicking myself for not being more thorough in my testing. I thank you both very much. Please by all means mark this ticket as resolved, and add a 'the tester was a muppet' flag, or whatever fits XD