我可以将原始鼠标输入作为 WM_INPUT 两次吗？

Question

我正在尝试通过在其主线程之外添加输入收集线程来修改现有应用程序。

原始应用程序已经在其主循环内处理了鼠标输入，但它以我项目正确工作的速度非常慢。

因此，我想以很高的速率处理主线程外部的鼠标输入，而不会干扰原始应用程序的输入处理过程？我该怎么做？我可以注册鼠标设备并获取相应的WM_INPUT，而无需阻止原始应用程序执行自己的处理？

Answer 1

您可以在单独的线程中注册原始输入。但首先您需要在该线程中创建不可见窗口。另外，要在该线程中接收输入，您需要向 RegisterRawInputDevices() 调用提供 RIDEV_INPUTSINK 。

这是我的代码：

void RawInputDeviceManager::RawInputManagerImpl::ThreadRun()
{
    m_WakeUpEvent = ::CreateEventExW(nullptr, nullptr, 0, EVENT_ALL_ACCESS);
    CHECK(IsValidHandle(m_WakeUpEvent));

    HINSTANCE hInstance = ::GetModuleHandleW(nullptr);
    m_hWnd = ::CreateWindowExW(0, L"Static", nullptr, 0, 0, 0, 0, 0, HWND_MESSAGE, nullptr, hInstance, 0);
    CHECK(IsValidHandle(m_hWnd));

    SUBCLASSPROC subClassProc = [](HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR /*uIdSubclass*/, DWORD_PTR dwRefData) -> LRESULT
    {
        auto manager = reinterpret_cast<RawInputManagerImpl*>(dwRefData);
        CHECK(manager);

        switch (uMsg)
        {
        case WM_CHAR:
        {
            wchar_t ch = LOWORD(wParam);

            DBGPRINT("WM_CHAR: `%s` (U+%04X %s)\n", GetUnicodeCharacterForPrint(ch).c_str(), ch, GetUnicodeCharacterName(ch).c_str());

            return 0;
        }
        case WM_INPUT_DEVICE_CHANGE:
        {
            CHECK(wParam == GIDC_ARRIVAL || wParam == GIDC_REMOVAL);
            HANDLE deviceHandle = reinterpret_cast<HANDLE>(lParam);
            bool isConnected = (wParam == GIDC_ARRIVAL);
            manager->OnInputDeviceConnected(deviceHandle, isConnected);

            return 0;
        }
        case WM_INPUT:
        {
            HRAWINPUT dataHandle = reinterpret_cast<HRAWINPUT>(lParam);
            manager->OnInputMessage(dataHandle);

            return 0;
        }

        }

        return ::DefSubclassProc(hWnd, uMsg, wParam, lParam);
    };

    CHECK(::SetWindowSubclass(m_hWnd, subClassProc, 0, reinterpret_cast<DWORD_PTR>(this)));

    CHECK(Register());

    // enumerate devices before start
    EnumerateDevices();

    // main message loop
    while (m_Running)
    {
        // wait for new messages
        ::MsgWaitForMultipleObjectsEx(1, &m_WakeUpEvent, INFINITE, QS_ALLEVENTS, MWMO_INPUTAVAILABLE);

        MSG msg;
        while (::PeekMessageW(&msg, NULL, 0, 0, PM_REMOVE))
        {
            if (msg.message == WM_QUIT)
            {
                m_Running = false;
                break;
            }

            ::TranslateMessage(&msg);
            ::DispatchMessageW(&msg);
        }
    }

    CHECK(Unregister());
    CHECK(::RemoveWindowSubclass(m_hWnd, subClassProc, 0));
    CHECK(::DestroyWindow(m_hWnd));
    m_hWnd = nullptr;
}

bool RawInputDeviceManager::RawInputManagerImpl::Register()
{
    RAWINPUTDEVICE rid[] =
    {
        {
            HID_USAGE_PAGE_GENERIC,
            0,
            RIDEV_DEVNOTIFY | RIDEV_INPUTSINK | RIDEV_PAGEONLY,
            m_hWnd
        }
    };

    return ::RegisterRawInputDevices(rid, static_cast<UINT>(std::size(rid)), sizeof(RAWINPUTDEVICE));
}

你甚至可以使WM_CHAR 通过从 WM_INPUT 键盘消息发布 WM_KEYDOWN 来在您的线程中工作：

void RawInputDeviceManager::RawInputManagerImpl::OnKeyboardEvent(const RAWKEYBOARD& keyboard) const
{
    if (keyboard.VKey >= 0xff/*VK__none_*/)
        return;

    // Sync keyboard layout with parent thread
    HKL keyboardLayout = ::GetKeyboardLayout(m_ParentThreadId);
    if (keyboardLayout != m_KeyboardLayout)
    {
        m_KeyboardLayout = keyboardLayout;

        // This will post WM_INPUTLANGCHANGE
        ::ActivateKeyboardLayout(m_KeyboardLayout, 0);
    }

    // To be able to receive WM_CHAR in our thread we need WM_KEYDOWN/WM_KEYUP messages.
    // But we wouldn't have them in invisible unfocused window that we have there.
    // Just emulate them from RawInput message manually.

    uint16_t keyFlags = LOBYTE(keyboard.MakeCode);

    if (keyboard.Flags & RI_KEY_E0)
        keyFlags |= KF_EXTENDED;

    if (keyboard.Message == WM_SYSKEYDOWN || keyboard.Message == WM_SYSKEYUP)
        keyFlags |= KF_ALTDOWN;

    if (keyboard.Message == WM_KEYUP || keyboard.Message == WM_SYSKEYUP)
        keyFlags |= KF_REPEAT;

    if (keyboard.Flags & RI_KEY_BREAK)
        keyFlags |= KF_UP;

    ::PostMessageW(m_hWnd, keyboard.Message, keyboard.VKey, MAKELONG(1/*repeatCount*/, keyFlags));
}

另一种更常见的方法是推送队列中的 WM_INPUT 事件（可能是无锁的）并在某些输入工作线程中处理它们，该线程可以向程序的其他部分发出输入事件等。