Point mapping contributions to Godot in Controllers, gamepads and joysticks

[Calinou]

GameControllerDB's upstream does not accept contributions from Godot since it does not use SDL. Users can still create custom mappings, but they should be submitted to Godot's controller database instead of the SDL one.

This also adds a reference to godotcontrollerdb.txt which was missing in the first place. This file is used as a complement to gamecontrollerdb.txt.

[akien-mga]

I would remove any explicit reference to https://github.com/gabomdq/SDL_GameControllerDB/ as we shouldn't be sending users there, since they made it clear our use case is out of scope for them.

That's their prerogative and it's totally fair, we seem to have misinterpreted how much overlap there is between our needs for SDL-compatible mappings, and SDL's own need for a mapping DB for those not supported out of the box by its driver.

If we do find bugs in mappings needed for SDL itself, we can contribute them back, but this should be done by Godot maintainers after properly evaluating that they're in scope for SDL, and not by Godot users.

FYI @offalynne

See above

[offalynne]

Thanks ! For what it's worth I'm perfectly happy to accept SDL-compatible mappings upstream, the problem is that testing with Godot's gamepad tools may produce mappings incompatible with SDL and vice versa; working out those incompatibilities should ideally not be a persistent issue for either party.

The SDL community db gets a lot of issues related to downstream software that are beyond our scope, and I don't want that maintenance burden given Godot does not presently use SDL so the HIDAPI/XInput/etc. drivers do not interoperate.

I'm content to skim godotcontrollerdb.txt a few times a year to upstream mutually compatible mappings and remove them from your list, or accept PRs (that are tested on SDL tools) to do the same. I think it makes good sense and is in the interest of your users to default to godotcontrollerdb.txt.

If the GameControllerDB repo continues to see incompatible contributions from Godot users I'll update our README to reflect this change as well

[tetrapod00]

Thanks, and thanks for the reviews!