JoyToKey

[paoloambrosio]

Replicate JoyToKey:

• [ ] Generate events on USB button inputs
• [ ] Generate key presses on events
  • It should stay pressed until the button is released
• [ ] Node to transform one into the other
• [ ] Support button combinations (multiple buttons simultaneously) to produce a single key press
  • Each device is independent, no cross-device combinations

Example configuration:

usb_input:
- device: Fanatec CSL Elite
  rules:
  - controls:
    - Button 1
    - Button 7
    events:
    - name: look_back
  - controls:
    - Button 1
    events:
    - name: look_left
  - controls:
    - Button 7
    events:
    - name: look_right
keyboard_output:
  look_back:
  - scan_code: LookBack_ScanCode 
  look_left:
  - scan_code: LookLeft_ScanCode
  look_right:
  - scan_code: LookRight_ScanCode

Depends on #15.

Do not:

• Support short or long key presses (separate issue #29)

I/O libraries and methods:

• Listening to buttons
  • HidDevices (Apache)
    • Cross-platform
    • Simple API
    • Uses HidSharp below without exposing its internals (probably because it's dead), inheriting the same technical limitations
  • HidSharp (Apache)
    • Cross-platform
    • Unmaintained for 2 years, can't even find a git repo apart from an unofficial one
    • Can't get an identifier for a device that wouldn't change when connected to a different port or different for two devices of the same type (perhaps using the device name would cover most use cases and there's no need to complicate things)
  • SharpDX.DirectInput (MIT)
    • Windows only
    • API requires polling
    • No longer maintained since March 2019
    • Used by CrewChief
  • Hid.Net (MIT)
    • Cross-platform
    • Low level API (not useful)
    • Project "on pause" since August 2022
  • HidLibrary (MIT)
    • Not maintained
• Emitting virtual keys
  • Windows
    • SendInput function (winuser.h) (~example: How to Send Inputs using C#~ PInvoke.User32 and the new C#/Win32 P/Invoke Source Generator in pre-release)
    • To make sure that we are sending keys to the game, we might want to make sure that the game is the foreground window. Unfortunately it looks like it doesn't exist in C# (but calling the C API is easy enough: 1, 2). Or we could make it configurable but only the active window will receive it with SendInput.
    • Virtual-Key Codes.
    • VkKeyScanW function (winuser.h) transforms charachters to virtual key codes.
    • MapVirtualKeyW function (winuser.h) transforms to and from virtual key codes and scan codes.
    • What the %$#!* is wrong with VkKeyScan[Ex]? explains that you can't always convert virtual keys to scan codes.
    • The Scan Code values generated by the PC Keyboard.
    • Scan Codes Demystified.
    • Overview of using the keyboard (Windows Forms .NET) explains how keyboard events work in Windows Forms application and Control.KeyPress Event contains a few useful constants worth considering.
    • CrewChief's KeyPresser shows how to use SendInput.
    • SendKeys.Send(String) Method is a Windows Forms C# wrapper around SendInput and Get/SetKeyboardState.
    • It can be used even from outside of a Windows Forms application using the SendWait variant! It still requires the Windows version of .NET though.
    • VkKeyScanW is pretty useful to convert characters into virtual-key codes!
    • SetKeyboardState and GetKeyboardState could be an easier alternative. Worth reading Keyboard Input Overview article.
    • ~SendMessage function (winuser.h) can send messages directly to the right window. Does not work with most DirectX applications.~
  • Linux (not for now)
    • xdotool is a command line application that does it
    • XSendEvent can send key presses to X11 applications: example 1 and 2.