Switch Joy-Con (Left / Right) support on macOS

[terhechte]

Bevy version

6b75589

[Optional] Relevant system information

macOS 12.6

What you did

When I connect a single Switch Joy-Con (either left or right) to my Mac via bluetooth the D-Pad (left right up down) is not being registered. E.g. moving it doesn't generate any events in Bevy. The buttons (a, b, x, y) work fine.

What went wrong

I tracked the issue down to two places:

• gilrs did not register the EvCode for Hat types. I created a PR for that.
• Bevy ignores all D-Pad events for reasons that I don't understand

When I use my gilrs fork and when I change the bevy_gilrs/converter.rs locally to:

        gilrs::Axis::DPadX => Some(GamepadAxisType::LeftStickX),
        gilrs::Axis::DPadY => Some(GamepadAxisType::LeftStickY),
        // The `axis_dpad_to_button` gilrs filter should filter out all DPadX and DPadY events. If
        // it doesn't then we probably need an entry added to the following repo and an update to
        // GilRs to use the updated database: https://github.com/gabomdq/SDL_GameControllerDB
        gilrs::Axis::Unknown => None,

Then I get the correct events and I can use my Joy-Con's for controlling a Bevy game. However I don't have enough knowledge about this code to know why the filter for D-Pad events existed in the first place. I'll happily create a PR with these changes if somebody who understands this can confirm that this is indeed a useful solution.

[mockersf]

DPadX and DPadY were removed in #5220

You should receive events for DPadUp / DPad... instead

[rparrett]

Just checking on the current state of this. I tested JoyCon on macOS with bevy main and gamepad_input_events.

If I connect one JoyCon at a time, I get some events, but the mapping doesn't seem to make sense with any controller orientation.

If I connect the matching JoyCon, I see a connection event for that particular JoyCon, but afterwards I get no events at all when pressing buttons. (This behavior is the same in gilrs master branch)

Testing with L JoyCon

button	event
up	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: North, value: 1.0 }
left	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: South, value: 1.0 }
down	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: East, value: 1.0 }
right	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: West, value: 1.0 }
L1	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: DPadRight, value: 1.0 }
L2	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: C, value: 1.0 }
stick (press)	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: Mode, value: 1.0 }
stick	Nothing
-	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: Start, value: 1.0 }
Home	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: DPadLeft, value: 1.0 }
SL	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: LeftTrigger, value: 1.0 }
SR	GamepadButtonChangedEvent { gamepad: Gamepad { id: 0 }, button_type: RightTrigger, value: 1.0 }

Testing with R JoyCon

button	event
X	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: East, value: 1.0 }
Y	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: West, value: 1.0 }
B	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: North, value: 1.0 }
A	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: South, value: 1.0 }
R1	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: DPadRight, value: 1.0 }
R2	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: C, value: 1.0 }
stick(press)	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: DPadUp, value: 1.0 }
stick	Nothing
+	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: Select, value: 1.0 }
Home	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: DPadDown, value: 1.0 }
SL	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: LeftTrigger, value: 1.0 }
SR	GamepadButtonChangedEvent { gamepad: Gamepad { id: 3 }, button_type: RightTrigger, value: 1.0 }

I didn't test as thoroughly on the gilrs master branch, but moving sticks there results in dpad events like:

Event { id: GamepadId(0), event: AxisChanged(DPadX, 1.0, Code(EvCode(EvCode { page: 1, usage: 57 }))), time: SystemTime { tv_sec: 1674092067, tv_nsec: 727176000 } }

and the mapping for directional buttons seems similar.

[rparrett]

I don't know if I am going to keep working on this, so to summarize my findings:

• Adding "proper" support for analog values from an individual Joy-Con's stick would be difficult. I think this would require some major work in the platform-specific HID code and down the chain from there.

• The current mapping for Joy-Con (L) and JoyCon (R) in SDL_GameControllerDB is attempting to map the "hat" to an axis, but gilrs does not support this.

  This causes the entire mapping to fail to parse and be thrown out. gilrs#96

  Consequently, axis_dpad_to_button fails to turn the resulting AxisChanged events into ButtonChanged events.

  Bevy is relying on that filter working, so it intentionally ignores the the dpad in AxisChanged events.

  This seems much easier to fix, and we would probably want to fix this upstream in gilrs.