JSDLGamepad

JSDLGamepad is a minimal wrapper for using SDL to get gamepad input in Java. The native glue is generated using SWIG to cover a subset of SDL gamepad handling.

Build

The build.sh shell script generates Java and native glue code, compiles the native code for Linux and Windows x64, compiles the Java code, and packages everything in a jar. Assuming everything builds okay and SDL2 is available, it also runs the included test code.

The build looks for the MinGW Windows SDL2 development libraries in the w64 folder for cross compiling for Windows from Linux. They can be downloaded from the SDL site linked above.

$ curl http://libsdl.org/release/SDL2-devel-2.0.10-mingw.tar.gz
$ tar -xf SDL2-devel-2.0.10-mingw.tar.gz -C w64

Use

The SDL2 runtime library must be available on java.library.path to use JSDLGamepad. Get it from the link above or your package manager.

JSDLGamepad consists of one class managing a thread that blocks on SDL_WaitEvent(...) to recieve events. Event data is passed through to one of the following methods based on type. To listen for events, extend JSDLGamepad and override some or all of these, then call startThread() to start the event thread.

public void gamepadAttached(int id) {}
public void gamepadRemoved(int id) {}
public void buttonPressed(int id, int button) {}
public void buttonReleased(int id, int button) {}
public void axisMotion(int id, int axis, int value) {}

The IDs used by the library start at zero and increase every time a controller connection has been detected. When startThread() is called, an "attached" event should be produced for every currently connected gamepad. Controllers should be detected no matter when they are connected.

The library can be restarted with reload() if necessary. This will produce new "attached" events for all connected gamepads. IDs do not reset. Controllers will be given higher IDs than what they had before the restart.

Button and Axis Constants

Below are the constants identifying buttons and axes (left and right sticks and analog triggers) usable from subclasses.

AXIS_LEFTX, AXIS_LEFTY, AXIS_RIGHTX, AXIS_RIGHTY, AXIS_TRIGGERLEFT, AXIS_TRIGGERRIGHT, BUTTON_A, BUTTON_B, BUTTON_X, BUTTON_Y, BUTTON_BACK, BUTTON_GUIDE, BUTTON_START, BUTTON_LEFTSTICK, BUTTON_RIGHTSTICK, BUTTON_LEFTSHOULDER, BUTTON_RIGHTSHOULDER, BUTTON_DPAD_UP, BUTTON_DPAD_DOWN, BUTTON_DPAD_LEFT, BUTTON_DPAD_RIGHT