xkey

xkey is a Linux utility that maps keyboard events to a virtual Xbox 360 controller using the uinput kernel module. It allows you to use your keyboard as a game controller for applications that support X-Input or generic gamepads.

Features

• Virtual Controller: Creates a virtual "Microsoft X-Box 360 pad".
• Keyboard Grabbing: Optionally grabs the keyboard device to prevent keys from being sent to other applications while in controller mode.
• Toggle Mode: Use the Esc key to toggle between normal keyboard usage and controller emulation.
• Comprehensive Mappings: Maps common keys to buttons, triggers, and D-pad.

Default Mappings

Left Stick (ABS_X / ABS_Y)

Keys held	X	Y
W	0	−32767
S	0	+32767
A	−32767	0
D	+32767	0
W + A	−23170	−23170
W + D	+23170	−23170
S + A	−23170	+23170
S + D	+23170	+23170
Opposing keys (e.g. W+S)	cancel → 0	cancel → 0
All four	0	0

Diagonals are normalised to ≈ 32767 / √2 = 23170 to preserve vector length. Key-repeat events (value 2) are treated as pressed, so the stick stays active while a key is held.

Buttons & D-pad

Keyboard Key	Controller Action
I	North Button (Y)
K	South Button (A)
J	West Button (X)
L	East Button (B)
Left Ctrl	Left Bumper (LB)
Right Ctrl	Right Bumper (RB)
Up Arrow	D-pad Up
Down Arrow	D-pad Down
Left Arrow	D-pad Left
Right Arrow	D-pad Right
Left Shift	Left Trigger
Right Shift	Right Trigger
Enter	Start Button
Backspace	Select Button
Esc	Toggle Mode

Prerequisites

• Linux OS
• uinput kernel module enabled (sudo modprobe uinput)
• Permissions to access /dev/uinput and the keyboard device node (usually requires sudo or being in the input group).

Installation

1. Clone the repository.
2. Build the project using make:

   make

Usage

1. Identify your keyboard device path. The default in main.c is: /dev/input/by-path/pci-0000:06:00.3-usb-0:1:1.0-event-kbd Note: You may need to edit main.c to match your hardware path.

2. Run the executable with root privileges:

   sudo ./xkey

3. Press Esc to enable the controller mapping. Press Esc again to disable it.

Configuration

To change the keyboard device path or modify mappings, edit main.c and virtual.c respectively, then recompile.