Add possibility to re-map input codes

[pacomix]

When using some controlles I have found out that sometimes the sticks doesn't correspond with +-X +-Y values but to button numbers instead. Normally higher than 16.
The problems comes that mame recognizes only up to 16 buttons and due to this I can't use those specific controlles with it.
In windows I have solved this problem by using an input remapper tool that maps each of the input buttons that are recognized by windows to specific buttons and/or keys but after strugglin with the retropie documentation and looking inside the configuration files I have found out that there is not a similar option. If I have missed something please do let me know.

I think it would be a good idea to have the possibility to map the input codes that arrives from the input driver to any other key or button number, so, at least in my case, I could map the buttons 14, 15, 16 and 17 to -x, +x, -y, +y so the front end and the system see a +-x, +-y (or whatever we remap) arriving instead of buttons 14,15,16,17.

Regards!

[fawked]

@pacomix I've found myself asking the same question for different reasons. I have two controllers that use one receiver, leading to Linux seeing my two joypads as one 8axis/24 button controller.

[meleu]

@pacomix maybe this amazing guide can help you: https://github.com/RetroPie/RetroPie-Setup/wiki/Universal-Controller-Calibration-&-Mapping-Using-xboxdrv

I think our fellow @mediamogul can help you if you have doubts.

[mediamogul]

Glad to help if need be. Both problems can be alleviated with xboxdrv, but I believe there will still be issues in both cases. @pacomix, will need to make use of the --dpad-as-button and --mimic-xpad arguments and map the controller's joystick as if it were a digital DPad. That will get you through most scenarios in RetroPie, including all of the RetroArch cores. However, you'll still run into issue in any software that needs to make use of an actual analog stick axis.

@fawked's problem might also be solvable in most situations. I have a few controller setups that do what you're describing and the toughest part to overcome is if the two controller's single system event also combines both of the controller's axis into one. If that's the case, then there's really nothing to do. If you see two separate axis readouts controlled separately from both controllers when running jstest, then you can get away with key-mapping everything on both controllers. From there, you'll have to solely rely on using software that will accept keyboard input, which covers most of the options in RetroPie, but you too will have trouble with anything that needs to make use of the actual analog stick axis, as they will now be mapped to digital keyboard input.

[fawked]

@mediamogul you are correct about my joysticks Axis... the only hope I am holding on to, is when the mode button is enabled, my Dpad values go from hat #0/#1 to axis 4&5/6&7... My end game is two have two players on mupeb64plus. Thanks for the replies guys!