Brushing the gcc connector aside for a second because that will take additional hardware or hardware modifications.
I use a dolphin emulator quite frequently. I would love an app that tricks the emulator into detecting my monome as a gc controller, and let’s me choose which button is mapped where on the monome. I would prefer an easy hardware option so I could use the monome with an actual game cube and blow friends minds, but getting it working with dolphin is a good place to start.
Changing how joystick data is handled to work with basically a D pad will take some cleverness/modifiers like on the Boxx.
I’ve wanted to use the monome 64 as a smash controller since I first laid eyes on it. Here’s some additional documentation that might help.
In this link the controller is outputting data to an mbed:
https://os.mbed.com/users/christopherjwang/code/gamecube_controller/wiki/Homepage
I may have misunderstood what I read here, but it seems like this person was able to make an Arduino act as the output source for the gcc protocol: https://github.com/NicoHood/Nintendo