On Android, MotionEvent with 0 values might come for axes when connecting
a gamepad, even though a user didn't touch any axes. This is problematic
especially for tirgger axes, where the default value should be -1.
This change fixes the issue by adding a new state `axesReady` to check
if an axis is really touched or not. If an axis is not touched yet,
a button value for a standard (trigger) button always returns 0.
This change also removes an old hack to initialize axis values for
triggers.
Closes#2598
This commit mirrors https://github.com/libsdl-org/SDL/pull/7405
(6f1f586086).
Note that for SDL, this code is used a lot less than for Ebitengine, as SDL
mostly migrated to HIDAPI and direct USB device access rather than using
Android's APIs. For Bluetooth devices, however, the Java APIs are used the
same way.
This was the remaining problem to be solved to automatically support standard
layout on most standard gamepads (this should cover most Xbox-ish and PS-ish
gamepads on the market).
In particular this covers gamepads with the following assignment:
- Left stick = X/Y, right stick = Z/RZ, triggers = LEFTTRIGGER/RIGHTTRIGGER
(which basically is what Android docs say and some PS gamepads do)
- Left stick = X/Y, right stick = RX/RY, triggers = Z/RZ
(Xbox gamepad style, apparently)
- Left stick = X/Y, right stick = RX/RY, triggers = LEFTTRIGGER/RIGHTTRIGGER
(Not sure if this exists, but it's conceivable)
As we found on the SDL pull request discussion, gamepads that offer flight
controls (e.g. THROTTLE and RUDDER) will likely not work well, before and
after this change.
Closes#2557
