Force feedback effects don't work in console applications

[jcmonnin]

When using force feedback on a racing wheel in a console application, all the calls do the API work as expected, but IsForceFeedbackMotorPoweredOn returns false and no force feedback effect is active.

I tested with a Logitech G29. The default center spring stays like if no force feedback effect has been configured.

As I test, I copied the same code to a regular win32 application, and it works as expected there.

I haven't seen this documented anywhere. With DirectInput, you have to create a fake hidden window for exclusive mode to work; using HWND of the console window is not enough. With GameInput, there seems to be no API to provide a HWND.

Is it a know issues that it won't work on console application? Are there possible workaround?

[jcmonnin]

To avoid misunderstanding, with console application, I mean an application using /SUBSYSTEM:CONSOLE as opposed to /SUBSYSTEM:WINDOWS. Use case is professional simulations with rendering on separate machine.

[AlexYatskov]

Hi @jcmonnin , as you mentioned GameInput does not have an explicit API for you to specify a window handle. Instead, it follows the logic below:

1. Check to see if the current foreground window belongs to the current process. If it does, then use it as the force feedback window.
2. If there is no foreground window, then pick the first window that belongs to the application.

These actions happen if/when force feedback events fail to play because the device gets unacquired. Does your current approach with creating a hidden window not work with you on GameInput?

[jcmonnin]

Hi @AlexYatskov,

Thanks for your feedback. Knowing that there is some interaction with some window handle helps to figure out a workaround.

In case of DirectInput, the situation is the following according to my experience:

• Providing HWND from GetConsoleWindow() doesn't work.
• Creating a hidden window (without event loop) and supplying this windows handle works [1]

Just having this hidden window around before initializing GameInput doesn't work

In my test in a real WIN32 GUI application, I had the GameInput test code attached to a file open dialog by chance. As described it seems to take the foreground window as a handle, as the effect doesn't start before the event loop of the window is handled, and when the dialog closes, the effect stops, even tough the lifetime of game input stuff and effects outlive the dialog.
It's seems to have a bigger dependence on window handle and their event loop compared to DirectInput, yet it's hidden from the API and seems to be not documented, which is not ideal.

I didn't have time to do further tests yet, but any guidance for workarounds for command line applications are welcome.

[1] Code I use in DirectInput to have that hidden window

static HWND createHiddenWindow()
{
    static const char* kClass = " ";
    WNDCLASSEXA wc = {};
    wc.cbSize = sizeof(wc);
    wc.lpfnWndProc = DefWindowProcA;
    wc.hInstance = GetModuleHandle(nullptr);
    wc.lpszClassName = kClass;
    RegisterClassExA(&wc);
    return CreateWindowExA(0, kClass, "", WS_POPUP,
       0, 0, 0, 0, HWND_MESSAGE, nullptr, GetModuleHandle(nullptr), nullptr);
}