A community sourced database of game controller mappings to be used with SDL2 Game Controller functionality.
Download gamecontrollerdb.txt, place it in your app's directory and load it.
For example :
SDL_GameControllerAddMappingsFromFile("gamecontrollerdb.txt");
The database is compatible with SDL v2.0.10 and newer. Older SDL versions are no longer supported.
A mapping looks like this :
030000004c050000c405000000010000,PS4 Controller,a:b1,b:b2,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,guide:b12,leftshoulder:b4,leftstick:b10,lefttrigger:a3,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:a4,rightx:a2,righty:a5,start:b9,x:b0,y:b3,platform:Mac OS X,
It is comprised of a controller GUID (030000004c050000c405000000010000), a name (PS4 Controller), button / axis mappings (leftshoulder:b4) and a platform (platform:Mac OS X).
There are a few different tools that let you create mappings.
Third party cross-platform tool with GUI (Windows, macOS and Linux). Likely the easiest tool to use.
The controllermap utility provided with SDL2 is the official tool to create these mappings, it runs on all the platforms SDL runs (Windows, Mac, Linux, iOS, Android, etc).
In Steam's Big Picture mode, configure your joystick. Then look in [steam_installation_directory]/config/config.vdf in your Steam installation directory for the SDL_GamepadBind entry. It is one of the last entries, it will look something like this.
"SDL_GamepadBind" "030000004c050000c405000000010000,PS4 Controller,platform:Windows,a:b1,b:b2,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,guide:b12,leftshoulder:b4,leftstick:b10,lefttrigger:a3,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:a4,rightx:a2,righty:a5,start:b9,x:b0,y:b3,"
Unfortunately, Steam outputs the platform field at the beginning, so you will need to move it to the end manually. Move platform:Windows, or platform:Mac OS X, or platform:Linux, to the end of the mapping (with the trailing comma).
You will also need check that the name is a good description of the controller. If relevant, include the controller's name and model number.