关于 c：各种输入 API 的问题(RAWINPUT、WINAPI)

RECT m_screenMouseBounds;
POINT m_mouseDelta;
POINT m_mouseScreenPosition;
POINT m_mouseScreenPositionGETCURSOR;
RAWMOUSE m_rawMouse;

// …

// Somewhere during class initialisation

GetCursorPos(&m_mouseScreenPosition); // Get initial mouse cursor position

// Determine maximum and minimum boundaires of current display
m_screenMouseBounds.right = GetSystemMetrics(SM_CXSCREEN);
m_screenMouseBounds.bottom = GetSystemMetrics(SM_CYSCREEN);
m_screenMouseBounds.top = 0;
m_screenMouseBounds.left = 0;

// Prepare the devices for registering
RAWINPUTDEVICE theInputDevices[2];

// 0 = keyboard
theInputDevices[0].usUsagePage = 0x01;
theInputDevices[0].usUsage = 0x06;
theInputDevices[0].dwFlags = RIDEV_NOLEGACY;
theInputDevices[0].hwndTarget = theWindowToHandle;

// 1 = mouse
theInputDevices[1].usUsagePage = 0x01;
theInputDevices[1].usUsage = 0x02;
theInputDevices[1].dwFlags = 0; // RIDEV_NOLEGACY
theInputDevices[1].hwndTarget = theWindowToHandle;

// Register each device with raw input
if(RegisterRawInputDevices(theInputDevices,2,sizeof(RAWINPUTDEVICE))==FALSE)
{
    // throw exception
    return false;
}

// …

// In the WM_INPUT processing function with parameters : (WPARAM wParam, LPARAM lParam)

char inputBuffer[sizeof(RAWINPUT)] = {};
UINT inputBufferSize = sizeof(RAWINPUT);
GetRawInputData(reinterpret_cast<HRAWINPUT>(lParam), RID_INPUT, inputBuffer, &inputBufferSize, sizeof(RAWINPUTHEADER));
RAWINPUT* rawData = reinterpret_cast<RAWINPUT*>(inputBuffer);

if(rawData–>header.dwType == RIM_TYPEMOUSE)
{
    m_rawMouse = rawData–>data.mouse;

    // Add the movement deltas acquired from the WM_INPUT message
    m_mouseDelta.x = m_rawMouse.lLastX;
    m_mouseDelta.y = m_rawMouse.lLastY;

    // Update the screen position using the delta values (Does not work as expected!)
    m_mouseScreenPosition.x += m_mouseDelta.x;
    m_mouseScreenPosition.y += m_mouseDelta.y;

    // Ensure mouse coords are within the screens boundaries
    if (m_mouseScreenPosition.x < m_screenMouseBounds.left)
    {
        m_mouseScreenPosition.x = m_screenMouseBounds.left;
    }
    if (m_mouseScreenPosition.x > m_screenMouseBounds.right)
    {
        m_mouseScreenPosition.x = m_screenMouseBounds.right;
    }
    if (m_mouseScreenPosition.y < m_screenMouseBounds.top)
    {
        m_mouseScreenPosition.y = m_screenMouseBounds.top;
    }
    if (m_mouseScreenPosition.y > m_screenMouseBounds.bottom)
    {
        m_mouseScreenPosition.y = m_screenMouseBounds.bottom;
    }        

    // Double check to make sure that the screen position coordinates calculated
    // above match the screen coordinates as determined by Windows
    // using GetCursorPos() (Hint: They don’t! :( )
    GetCursorPos(&m_mouseScreenPositionGETCURSOR);

    TCHAR s[256];
    swprintf(s, L"MouseDX: %ld MouseDY: %ld/
", m_mouseDelta.x, m_mouseDelta.y);
    OutputDebugString(s);

    swprintf(s, L"MouseX(Screen(WM_INPUT)): %ld MouseY(Screen(WM_INPUT)): %ld/
", m_mouseScreenPosition.x, m_mouseScreenPosition.y);
    OutputDebugString(s);

    swprintf(s, L"MouseX(Screen(GetCursorPos)): %ld MouseY(Screen(GetCursorPos)): %ld/
", m_mouseScreenPositionGETCURSOR.x, m_mouseScreenPositionGETCURSOR.y);
    OutputDebugString(s);
}