Feature Request: Gyro controls

[jfenton]

Thought it would be neat to have gyro controls in Quake 3 :0)

Draft implementation on branch below ready to play with, but needs additional work.

Opening this issue for discussion around:

• [ ] Input smoothing (and constraints)
• [ ] Dead-zones (and gradient)
• [ ] Handling of other JoyCon layouts (e.g. Pro)
• [ ] On/off activation via button?
• [ ] Reset calibration button?
• [ ] Sensible initial values
• [ ] Maybe add some of these Settings to the menus?

Feel free to jump in and hack on it.

[jfenton]

Ideally we'd get the gyro sensor readings from SDL, but their current sensor impl. assumes a device gyro (like on a mobile device), with no clear way to tie that to an individual Controller having a gyro as on the Switch. I've just gone switch native here as a result, ignoring SDL and feeding them back in as mouse deltas. Couldn't find any other gyro controls reference code so kinda flying blind on this one.

[jfenton]

From the updated README:

  in_gyromouse                      - Set to 1 to enable use of gyroscope
                                      sensor as mouse freelook (gyro controls)
  in_gyromouse_debug                - Set to 1 to show raw gyro sensor readings
  in_gyromouse_pitch                - Amplify raw sensor readings for pitch
                                      up-down (negative values invert axis)
  in_gyromouse_yaw                  - Amplify raw sensor readings for yaw
                                      left-right (negative values invert axis)
  in_gyromouse_pitch_ui             - As above but for ui / in-menu
  in_gyromouse_yaw_ui               - As above but for ui / in-menu

(suggest rebasing off of #8 to make it easier to twiddle console values when you're testing)

[fgsfdsfgs]

Merged #7. Will add some settings to the menus and then roll out a release because of the impending breaking AMS changes.