Strange buzzing force feedback and sound from DirectInput damper effect after alt-tabbing
I develop a modification for a game, Grand Theft Auto V, that adds wheel support with force feedback.
Something weird seems to happen with Fanatec wheels, specifically regarding the damper effect after alt-tabbing away from the game and back into it, on my CSL DD wheel base (8Nm).
Here is a demo: https://www.youtube.com/watch?v=YAmo8yEqRU0
The script I've written sends DirectInput force feedback commands every frame, which normally works well. But after alt-tabbing back into the game, there is a strange buzzing noise from the damper effect. The issue disappears when the damper effect is configured to send 0 (every frame) and is exacerbated when turning it all the way up to 10000. Pausing the game (passively) halts the damper effect, and the issue disappears along with that.
Other effects (constant force) seem unaffected by this issue.
Creating the effect:
Updating the effect: https://github.com/E66666666/GTAVManualTransmission/blob/master/Gears/Input/WheelDirectInput.cpp#L640
The only thing happening on losing and regaining focus is (re)-Acquiring the device interface, and playing 0 for both constant force and damper force: https://github.com/E66666666/GTAVManualTransmission/blob/master/Gears/script.cpp#L320
I've not noticed anything similar when I had my old G27, but I can't verify again since I sold that.
I honestly have no idea why this happens. Has anybody at Fanatec seen similar behavior when testing games?