How to combinate SDL and Arduino

I'd like to make a Project, in wich you for example press a button on the arduino, and in a game on the PC something happens. I would prefer to use SDL for the PC game.
I already found out how to write arduino files with visual Studio. But there you can't Combine both - Arduino AND Sdl. Maybe there's another way.

Hopefully someone could help me

greetings MrArduino2000

Well, the 32U4 based boards can emulate a PC keyboard/mouse.