How to detect mouse scroll events if my program is not in foreground

Question

I wrote a program which render overlay in game, showing some additional info. I can detect keyboard and some of mouse keypresses by using GetKeyState, however there is no Virtual Key Code for scroll up and down which I would like to use as well.

I know that scroll is handled more in a way of an event, rather than keypress, but that doesn't really help. So is there any solutions for my problem?

Things that came to my mind:

Detect scroll events by some function?
Somehow get Windows Messages sent to game in my program (thats called Hooking IIRC)

I'm using Visual Studio 2013 Express [C++]

score 1 · Answer 1 · answered Feb 02 '14 at 00:43

1

Check SetWindowsHookEx: http://msdn.microsoft.com/en-us/library/windows/desktop/ms644990(v=vs.85).aspx and WH_MOUSE in particular.

answered Feb 02 '14 at 00:43

c-smile

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Best to recommend WH_MOUSE_LL instead. – Hans Passant Feb 02 '14 at 00:47
I found code in this thread ,now I can detect if user has used scroll, but still I cant determine is it scroll up or down. http://stackoverflow.com/questions/11180773/setwindowshookex-for-wh-mouse – user3213103 Feb 02 '14 at 02:16
@user3213103 Check WM_MOUSEWHEEL parameters from the link below. – c-smile Feb 02 '14 at 02:23
I tried checking all wheel parameters, but for some reason all values are the same for scroll up and down. – user3213103 Feb 02 '14 at 08:52

score 1 · Accepted Answer · answered Mar 08 '14 at 10:09

I solved the issue by using following code.

LRESULT CALLBACK mouseProc(int nCode, WPARAM wParam, LPARAM lParam)
{
    using namespace MouseLog;
    MSLLHOOKSTRUCT * pMouseStruct = (MSLLHOOKSTRUCT *)lParam;

    if (pMouseStruct != NULL)
    {
        if (wParam == WM_MOUSEWHEEL)
        {
            if (HIWORD(pMouseStruct->mouseData) == 120) MScrollUp = 1;
            else MScrollDown = 1;
        }
        if (wParam == WM_MBUTTONDOWN)
            MScrollBtn = 1;

        //printf("Mouse position X = %d  Mouse Position Y = %d\n", pMouseStruct->pt.x, pMouseStruct->pt.y);
    }
    return CallNextHookEx(hMouseHook, nCode, wParam, lParam);
}

DWORD WINAPI MouseLogger(LPVOID lpParm)
{
    HINSTANCE hInstance = GetModuleHandle(NULL);
    hMouseHook = SetWindowsHookEx(WH_MOUSE_LL, mouseProc, hInstance, NULL);

    MSG message;
    while (GetMessage(&message, NULL, 0, 0)) {
        TranslateMessage(&message);
        DispatchMessage(&message);
    }
    UnhookWindowsHookEx(hMouseHook);
    return 0;
}

For starting MouseLogger use CreateThread().

score 0 · Answer 3 · answered Feb 02 '14 at 00:42

I understand that theres no keystate for mouse scrolling but theres something else like WM_MOUSEWHEEL

If this answers your question you might want to check out this

http://msdn.microsoft.com/en-us/library/windows/desktop/ms645617(v=vs.85).aspx

otherwise if this dont help you i would be glad to help you if this dosent help

score 0 · Answer 4 · answered Feb 02 '14 at 19:31

0

You can use the legacy gaming API, DirectInput. I know that definitely works when the window is in the background when you use the DISCL_BACKGROUND flag.

answered Feb 02 '14 at 19:31

selbie

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How to detect mouse scroll events if my program is not in foreground

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