Programming a Multiplayer FPS in DirectX/Programming a Multiplayer FPS in DirectX (Companion CD).iso/DirectX/dxsdk_oct2004.exe/dxsdk.exe/Samples/C++/DirectInput/Scrawl/scrawl.cpp

C/C++ Source or Header | 2004-09-27 | 32.1 KB | 1,012 lines

//-----------------------------------------------------------------------------
// File: Scrawl.cpp
//
// Desc: Demonstrates an application which receives relative mouse data
//       in non-exclusive mode via a dialog timer.
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------
#define STRICT
#define DIRECTINPUT_VERSION 0x0800

#include <tchar.h>
#include <windows.h>
#include <commctrl.h>
#include <windowsx.h>
#include <basetsd.h>
#include <dinput.h>
#include "resource.h"




//-----------------------------------------------------------------------------
// Function prototypes
//-----------------------------------------------------------------------------
HRESULT InitVariables();
HWND    RegisterWindowClass( HINSTANCE hInst );
LRESULT CALLBACK WndProc( HWND, UINT, WPARAM, LPARAM );

HRESULT OnClear( HWND hWnd );
VOID    OnAbout( HWND hWnd );
VOID    InvalidateCursorRect(HWND hWnd);
VOID    OnPaint( HWND hWnd );
BOOL    OnCreate( HWND hWnd, LPCREATESTRUCT lpCreateStruct );
VOID    OnInitMenuPopup( HWND hWnd, HMENU hMenu, UINT item, BOOL fSystemMenu );
VOID    OnKeyDown( HWND hWnd, UINT vk, BOOL fDown, int cRepeat, UINT flags );
HRESULT InitDirectInput( HWND hWnd );
HRESULT SetAcquire();
HRESULT FreeDirectInput();
VOID    OnMouseInput( HWND hWnd );
VOID    OnLeftButtonDown( HWND hWnd );
VOID    OnRightButtonUp( HWND hWnd );




//-----------------------------------------------------------------------------
// Defines, constants, and global variables
//-----------------------------------------------------------------------------
#define SAFE_DELETE(p)  { if(p) { delete (p);     (p)=NULL; } }
#define SAFE_RELEASE(p) { if(p) { (p)->Release(); (p)=NULL; } }

#define SCRAWL_CXBITMAP             512
#define SCRAWL_CYBITMAP             300
#define SAMPLE_BUFFER_SIZE           16
#define IDC_CLEAR               64
#define IDC_ABOUT               65

struct LEFTBUTTONINFO
{
    HDC   hdcWindow;
    BOOL  bMoved;
    DWORD dwSeqLastSeen;
};


HDC     g_hDC           = NULL; // Memory DC our picture lives in
HBITMAP g_hBitmap       = NULL; // Our picture
HBITMAP g_hbmpDeselect  = NULL; // Stock bitmap for deselecting
HCURSOR g_hCursorCross  = NULL; // cross hair
HMENU   g_hMenuSense    = NULL; // Sensitivity popup menu
int     g_cxCross;              // Width of crosshairs cursor
int     g_cyCross;              // Height of crosshairs cursor
int     g_dxCrossHot;           // Hotspot location of crosshairs
int     g_dyCrossHot;           // Hotspot location of crosshairs
BOOL    g_bShowCursor   = TRUE; // Should the cursor be shown?
int     g_x;                    // Virtual x-coordinate
int     g_y;                    // Virtual y-coordinate
int     g_dxFuzz;               // Leftover x-fuzz from scaling
int     g_dyFuzz;               // Leftover y-fuzz from scaling
int     g_iSensitivity;         // Mouse sensitivity

LPDIRECTINPUT8          g_pDI           = NULL;
LPDIRECTINPUTDEVICE8    g_pMouse        = NULL;
HANDLE                  g_hMouseEvent   = NULL;
BOOL                    g_bActive       = TRUE;
BOOL                    g_bSwapMouseButtons;




//-----------------------------------------------------------------------------
// Name: WinMain()
// Desc: Entry point for the application.  Since we use a simple dialog for
//       user interaction we don't need to pump messages.
//-----------------------------------------------------------------------------
int APIENTRY WinMain( HINSTANCE hInstance, HINSTANCE, LPSTR, int )
{
    HRESULT hr;
    HWND    hWnd;
    BOOL    bDone;
    DWORD   dwResult;
    MSG     msg;

    InitCommonControls();

    // Initialize global varibles
    if ( FAILED( hr = InitVariables() ) )
    {
        MessageBox( NULL, _T("Error Initializing Variables"),
                    _T("Scrawl"),  MB_ICONERROR | MB_OK );
        return TRUE;
    }

    // Display the main dialog box.
    hWnd = RegisterWindowClass( hInstance );
    if( NULL == hWnd )
    {
        MessageBox( NULL, _T("Error Creating Window"),
                    _T("Scrawl"), MB_ICONERROR | MB_OK );
        return TRUE;
    }

    // Start message pump. Since we use notification handles, we need to use
    // MsgWaitForMultipleObjects() to wait for the event or a message,
    // whichever comes first.

    bDone = FALSE;
    while( !bDone )
    {
        dwResult = MsgWaitForMultipleObjects( 1, &g_hMouseEvent,
                                              FALSE, INFINITE, QS_ALLINPUT );
        switch( dwResult )
        {
            // WAIT_OBJECT_0 + 0 means that g_hevtMouse was signalled
            case WAIT_OBJECT_0 + 0:
                OnMouseInput( hWnd );
                break;

            // WAIT_OBJECT_0 + 1 means that we have messages to process
            case WAIT_OBJECT_0 + 1:
                while( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )
                {
                    if( msg.message == WM_QUIT )
                    {
                        // Stop loop if it's a quit message
                        bDone = TRUE;
                    }
                    else
                    {
                        TranslateMessage( &msg );
                        DispatchMessage( &msg );
                    }
                }
                break;
        }
    }

    // Clean up DirectInput
    FreeDirectInput();


    // Release events
    if( g_hMouseEvent )
        CloseHandle( g_hMouseEvent );

    // Delete bitmaps
    if( g_hDC )
    {
        if( g_hbmpDeselect )
            SelectObject( g_hDC, g_hbmpDeselect );

        DeleteDC( g_hDC );
    }

    if( g_hBitmap )
        DeleteObject( g_hBitmap );

    // Destroy loaded menus
    if( g_hMenuSense )
        DestroyMenu( g_hMenuSense );

    return TRUE;
}




//-----------------------------------------------------------------------------
// Name: InitVariables()
// Desc: Initialize global varibles
//-----------------------------------------------------------------------------
HRESULT InitVariables()
{
    ICONINFO iconInfo;
    BITMAP   bitmap;

    // Get our crosshairs cursor and extract the the width and
    // hotspot location so we can draw it manually.
    g_hCursorCross = LoadCursor( NULL, IDC_CROSS );

    GetIconInfo( g_hCursorCross, &iconInfo );
    GetObject( iconInfo.hbmMask, sizeof(BITMAP), &bitmap );

    // Delete un-needed handles
    if( iconInfo.hbmMask)
        DeleteObject( iconInfo.hbmMask );
    if( iconInfo.hbmColor)
        DeleteObject( iconInfo.hbmColor );

    // Save x-y info
    g_dxCrossHot = iconInfo.xHotspot;
    g_dyCrossHot = iconInfo.yHotspot;

    g_cxCross = bitmap.bmWidth;
    g_cyCross = bitmap.bmHeight;

    // create and setup our scrawl bitmap.
    g_hDC = CreateCompatibleDC( NULL );
    if( NULL == g_hDC )
        return E_FAIL;

    g_hBitmap = CreateBitmap( SCRAWL_CXBITMAP, SCRAWL_CYBITMAP, 1, 1, 0 );
    if( NULL == g_hBitmap )
        return E_FAIL;

    g_hbmpDeselect = (HBITMAP)SelectObject( g_hDC, g_hBitmap );

    // Clear bitmap
    OnClear( NULL );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: RegisterWindowClass()
// Desc: Set up the window class.
//-----------------------------------------------------------------------------
HWND RegisterWindowClass( HINSTANCE hInst )
{
    WNDCLASS wc;
    wc.hCursor        = LoadCursor( 0, IDC_ARROW );
    wc.hIcon          = LoadIcon( hInst, MAKEINTRESOURCE(IDI_MAIN) );
    wc.lpszMenuName   = NULL;
    wc.lpszClassName  = _T("Scrawl");
    wc.hbrBackground  = NULL;
    wc.hInstance      = hInst;
    wc.style          = 0;
    wc.lpfnWndProc    = WndProc;
    wc.cbClsExtra     = 0;
    wc.cbWndExtra     = 0;
    if( FALSE == RegisterClass(&wc) )
        return NULL;

    RECT rc;
    rc.left     = 0;
    rc.top      = 0;
    rc.right    = SCRAWL_CXBITMAP;
    rc.bottom   = SCRAWL_CYBITMAP;
    AdjustWindowRectEx( &rc, WS_OVERLAPPED|WS_CAPTION|WS_SYSMENU|WS_MINIMIZEBOX,
                        FALSE, WS_EX_APPWINDOW );

    HWND hWnd = CreateWindowEx( WS_EX_APPWINDOW, _T("Scrawl"), _T("Scrawl"),
                                WS_OVERLAPPED|WS_CAPTION|WS_SYSMENU|WS_MINIMIZEBOX,
                                CW_USEDEFAULT, CW_USEDEFAULT,
                                rc.right - rc.left,
                                rc.bottom - rc.top,
                                NULL, NULL, hInst, NULL );

    ShowWindow( hWnd, TRUE );

    return hWnd;
}




//-----------------------------------------------------------------------------
// Name: WndProc()
// Desc: Handles window messages
//-----------------------------------------------------------------------------
LRESULT CALLBACK WndProc( HWND hWnd, UINT msg, WPARAM wParam,
                          LPARAM lParam )
{
    LRESULT lr = 0;

    switch( msg )
    {
        // Pass these messages to user defined functions
        HANDLE_MSG( hWnd, WM_CREATE,        OnCreate );
        HANDLE_MSG( hWnd, WM_PAINT,         OnPaint );
        HANDLE_MSG( hWnd, WM_INITMENUPOPUP, OnInitMenuPopup );
        HANDLE_MSG( hWnd, WM_KEYDOWN,       OnKeyDown );

        case WM_ACTIVATE:   // sent when window changes active state
            g_bActive = ( WA_ACTIVE == wParam );

            // Set exclusive mode access to the mouse based on active state
            SetAcquire();
            return 0;

        case WM_NCLBUTTONDOWN:
            switch (wParam)
            {
                case HTMINBUTTON:
                    ShowWindow( hWnd, SW_MINIMIZE);
                    break;

                case HTCLOSE:
                    PostQuitMessage(0);
                    break;
            }
            return 0;

        case WM_ENTERMENULOOP:
            // In case the user opens the menu through the keyboard shortcut
        case WM_ENTERSIZEMOVE:
            // un-acquire device when entering menu or re-sizing
            // this will show the mouse cursor again
            g_bActive = FALSE;
            SetAcquire();
            return 0;

        case WM_CAPTURECHANGED:
            // re-acquire device when leaving menu or re-sizing
            // this will hide the default windows mouse cursor
            g_bActive = TRUE;
            SetAcquire();
            return 0;

        case WM_SYSCOMMAND:
            lr = 0;
            switch ( LOWORD(wParam) )
            {
                case IDC_CLEAR:
                    OnClear( hWnd );
                    break;

                case IDC_ABOUT:
                    OnAbout( hWnd );
                    break;

                case SC_SCREENSAVE:
                    // eat the screen-saver notification.
                    break;

                case IDC_SENSITIVITY_LOW:
                    g_iSensitivity = -1;
                    break;

                case IDC_SENSITIVITY_NORMAL:
                    g_iSensitivity = 0;
                    break;

                case IDC_SENSITIVITY_HIGH:
                    g_iSensitivity = 1;
                    break;

                default:
                    lr = DefWindowProc( hWnd, msg, wParam, lParam );
                    break;
            }

            return lr;



       case WM_DESTROY:
            PostQuitMessage(0);
            break;
    }

    return DefWindowProc( hWnd, msg, wParam, lParam );
}




//-----------------------------------------------------------------------------
// Name: OnCreate()
// Desc: Handles the WM_CREATE window message
//-----------------------------------------------------------------------------
BOOL OnCreate( HWND hWnd, LPCREATESTRUCT lpCreateStruct )
{
    HRESULT hr;
    HMENU   hMenu;

    // Initialize direct input
    hr = InitDirectInput( hWnd );
    if( FAILED(hr) )
    {
        MessageBox( NULL, _T("Error Initializing DirectInput"),
                    _T("Scrawl"), MB_ICONERROR | MB_OK );
        return FALSE;
    }

    // Fix up the popup system menu with custom commands
    hMenu = GetSystemMenu( hWnd, FALSE );
    g_hMenuSense = LoadMenu( (HINSTANCE)GetModuleHandle(NULL),
                             MAKEINTRESOURCE(IDM_SENSITIVITY) );

    EnableMenuItem( hMenu, SC_SIZE,     MF_BYCOMMAND | MF_DISABLED | MF_GRAYED );
    EnableMenuItem( hMenu, SC_MAXIMIZE, MF_BYCOMMAND | MF_DISABLED | MF_GRAYED );
    AppendMenu( hMenu, MF_ENABLED | MF_STRING, IDC_CLEAR, _T("C&lear\tDel") );
    AppendMenu( hMenu, MF_ENABLED | MF_STRING, IDC_ABOUT, _T("&About\tF1") );
    AppendMenu( hMenu, MF_ENABLED | MF_STRING | MF_POPUP,
                (UINT_PTR)g_hMenuSense, _T("Sensitivit&y") );

    return TRUE;
}




//-----------------------------------------------------------------------------
// Name: OnAbout()
// Desc: Handles the IDC_ABOUT window message
//-----------------------------------------------------------------------------
VOID OnAbout( HWND hWnd )
{
    MessageBox( hWnd, TEXT("Scrawl DirectInput Sample v1.0\n\n")
                      TEXT("The Scrawl application demonstrates use of the mouse\n")
                      TEXT("in exclusive mode in a windowed application.\n\n")
                      TEXT("The main mouse button is always the left button,\n")
                      TEXT("and the secondary button is always the right button,\n")
                      TEXT("regardless of any settings the user may have made in\n")
                      TEXT("Control Panel.\n\n")
                      TEXT("To scrawl, hold down the left button and move the mouse.\n")
                      TEXT("Click the right mouse button to invoke a pop-up menu. \n")
                      TEXT("From the pop-up menu you can clear the client window,\n")
                      TEXT("set the mouse sensitivity, or close the application."),
                TEXT("Scrawl"), MB_OK );
}




//-----------------------------------------------------------------------------
// Name: OnPaint()
// Desc: Handles the WM_PAINT window message
//-----------------------------------------------------------------------------
VOID OnPaint( HWND hWnd )
{
    PAINTSTRUCT ps;
    HDC         hDC;

    hDC = BeginPaint( hWnd, &ps );
    if( NULL == hDC )
        return;

    BitBlt( hDC, ps.rcPaint.left, ps.rcPaint.top,
            ps.rcPaint.right - ps.rcPaint.left, ps.rcPaint.bottom - ps.rcPaint.top,
            g_hDC, ps.rcPaint.left, ps.rcPaint.top, SRCCOPY );

    if( g_bActive && g_bShowCursor )
        DrawIcon( hDC, g_x - g_dxCrossHot, g_y - g_dyCrossHot, g_hCursorCross );

    EndPaint( hWnd, &ps );
}




//-----------------------------------------------------------------------------
// Name: OnInitMenuPopup()
// Desc: Handles the WM_INITMENUPOPUP window message
//-----------------------------------------------------------------------------
VOID OnInitMenuPopup( HWND hWnd, HMENU hMenu, UINT item, BOOL fSystemMenu )
{
    for( int iSensitivity = -1; iSensitivity <= 1; iSensitivity++ )
    {
        if( g_iSensitivity == iSensitivity )
        {
            CheckMenuItem( hMenu, IDC_SENSITIVITY_NORMAL + iSensitivity,
                           MF_BYCOMMAND | MF_CHECKED );
        }
        else
        {
            CheckMenuItem( hMenu, IDC_SENSITIVITY_NORMAL + iSensitivity,
                           MF_BYCOMMAND | MF_UNCHECKED );
        }
    }
}




//-----------------------------------------------------------------------------
// Name: OnKeyDown()
// Desc: Handles the WM_KEYDOWN window message
//-----------------------------------------------------------------------------
VOID OnKeyDown( HWND hWnd, UINT vk, BOOL fDown, int cRepeat, UINT flags )
{
    switch( vk )
    {
        case '1':
        case '2':
        case '3':
            PostMessage( hWnd, WM_SYSCOMMAND, IDC_SENSITIVITY_NORMAL + vk - '2', 0 );
            break;

        case VK_DELETE:
            PostMessage( hWnd, WM_SYSCOMMAND, IDC_CLEAR, 0 );
            break;

        case VK_F1:
            PostMessage( hWnd, WM_SYSCOMMAND, IDC_ABOUT, 0 );
            break;
    }
}




//-----------------------------------------------------------------------------
// Name: OnClear()
// Desc: Makes the bitmap white
//-----------------------------------------------------------------------------
HRESULT OnClear( HWND hWnd )
{
    PatBlt( g_hDC, 0, 0, SCRAWL_CXBITMAP, SCRAWL_CYBITMAP, WHITENESS );

    if( hWnd )
        InvalidateRect( hWnd, 0, 0 );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: InvalidateCursorRect()
// Desc: Invalidate the rectangle that contains the cursor.
//       The coordinates are in client coordinates.
//-----------------------------------------------------------------------------
VOID InvalidateCursorRect( HWND hWnd )
{
    RECT rc = { g_x - g_dxCrossHot,             g_y - g_dyCrossHot,
                g_x - g_dxCrossHot + g_cxCross, g_y - g_dyCrossHot + g_cyCross };
    InvalidateRect( hWnd, &rc, 0 );
}




//-----------------------------------------------------------------------------
// Name: UpdateCursorPosition()
// Desc: Move our private cursor in the requested direction, subject
//       to clipping, scaling, and all that other stuff.
//
//       This does not redraw the cursor.  You need to do that yourself.
//-----------------------------------------------------------------------------
VOID UpdateCursorPosition( int dx, int dy )
{
    // Pick up any leftover fuzz from last time.  This is important
    // when scaling down mouse motions.  Otherwise, the user can
    // drag to the right extremely slow for the length of the table
    // and not get anywhere.
    dx += g_dxFuzz;
    g_dxFuzz = 0;

    dy += g_dyFuzz;
    g_dyFuzz = 0;

    switch( g_iSensitivity )
    {
        case 1:     // High sensitivity: Magnify!
            dx *= 2;
            dy *= 2;
            break;

        case -1:    // Low sensitivity: Scale down
            g_dxFuzz = dx % 2;  // remember the fuzz for next time
            g_dyFuzz = dy % 2;
            dx /= 2;
            dy /= 2;
            break;

        case 0:     // normal sensitivity
            // No adjustments needed
            break;
    }

    g_x += dx;
    g_y += dy;

    // clip the cursor to our client area
    if( g_x < 0 )
        g_x = 0;

    if( g_x >= SCRAWL_CXBITMAP )
        g_x = SCRAWL_CXBITMAP - 1;

    if( g_y < 0 )
        g_y = 0;

    if( g_y >= SCRAWL_CYBITMAP )
        g_y = SCRAWL_CYBITMAP - 1;
}




//-----------------------------------------------------------------------------
// Name: StartPenDraw()
// Desc: Called when starting pen draw.
//-----------------------------------------------------------------------------
VOID StartPenDraw( HWND hWnd, LEFTBUTTONINFO* plbInfo )
{
    // Hide the cursor while scrawling
    g_bShowCursor = FALSE;

    plbInfo->hdcWindow = GetDC( hWnd );
    MoveToEx( plbInfo->hdcWindow, g_x, g_y, 0 );
    MoveToEx( g_hDC, g_x, g_y, 0 );

    SelectObject( plbInfo->hdcWindow, GetStockObject(BLACK_PEN) );
    SelectObject( g_hDC, GetStockObject(BLACK_PEN) );

    plbInfo->bMoved = FALSE;
    plbInfo->dwSeqLastSeen = 0;
}




//-----------------------------------------------------------------------------
// Name: FinishPenDraw()
// Desc: Called when ending pen draw.
//-----------------------------------------------------------------------------
VOID FinishPenDraw( HANDLE hWnd )
{
    g_bShowCursor = TRUE;
}




//-----------------------------------------------------------------------------
// Name: OnLeftButtonDown_FlushMotion()
// Desc: Flush out any motion that we are holding.
//-----------------------------------------------------------------------------
VOID OnLeftButtonDown_FlushMotion( LEFTBUTTONINFO* plbInfo )
{
    if( plbInfo->bMoved )
    {
        plbInfo->bMoved = FALSE;
        plbInfo->dwSeqLastSeen = 0;
        LineTo( plbInfo->hdcWindow, g_x, g_y );
        LineTo( g_hDC, g_x, g_y );
    }
}




//-----------------------------------------------------------------------------
// Name: OnRightButtonUp()
// Desc: Pop up a context menu.
//-----------------------------------------------------------------------------
VOID OnRightButtonUp( HWND hWnd )
{
    // Place a popup menu where the mouse curent is
    POINT pt;
    pt.x = g_x;
    pt.y = g_y;
    ClientToScreen( hWnd, &pt );
    HMENU hMenuPopup = GetSystemMenu( hWnd, FALSE );

    // Hide the cursor while moving it so you don't get annoying flicker.
    ShowCursor( FALSE );
    InvalidateCursorRect( hWnd );

    // Unacquire the devices so the user can interact with the menu.
    g_bActive = FALSE;
    SetAcquire();

    // Put the Windows cursor at the same location as our virtual cursor.
    SetCursorPos( pt.x, pt.y );

    // Show the cursor now that it is moved
    ShowCursor( TRUE );
    InvalidateCursorRect( hWnd );

    // Track the popup menu and return the menu item selected
    UINT iMenuID = TrackPopupMenuEx( hMenuPopup, TPM_RIGHTBUTTON|TPM_RETURNCMD,
                                     pt.x, pt.y, hWnd, 0 );

    if( 0 != iMenuID ) // If a menu item was selected
        PostMessage( hWnd, WM_SYSCOMMAND, iMenuID, 0L );
}




//-----------------------------------------------------------------------------
// Name: InitDirectInput()
// Desc: Initialize the DirectInput variables.
//-----------------------------------------------------------------------------
HRESULT InitDirectInput( HWND hWnd )
{
    HRESULT hr;

    // Register with the DirectInput subsystem and get a pointer
    // to a IDirectInput interface we can use.
    // Create a DInput object
    if( FAILED( hr = DirectInput8Create( GetModuleHandle(NULL), DIRECTINPUT_VERSION,
                                         IID_IDirectInput8, (VOID**)&g_pDI, NULL ) ) )
        return hr;

    // Obtain an interface to the system mouse device.
    if( FAILED( hr = g_pDI->CreateDevice( GUID_SysMouse, &g_pMouse, NULL ) ) )
        return hr;

    // Set the data format to "mouse format" - a predefined data format
    //
    // A data format specifies which controls on a device we
    // are interested in, and how they should be reported.
    //
    // This tells DirectInput that we will be passing a
    // DIMOUSESTATE structure to IDirectInputDevice::GetDeviceState.
    if( FAILED( hr = g_pMouse->SetDataFormat( &c_dfDIMouse ) ) )
        return hr;

    // Set the cooperativity level to let DirectInput know how
    // this device should interact with the system and with other
    // DirectInput applications.
    if( FAILED( hr = g_pMouse->SetCooperativeLevel( hWnd,
                                         DISCL_EXCLUSIVE|DISCL_FOREGROUND ) ) )
        return hr;

    // Create a win32 event which is signaled when mouse data is availible
    g_hMouseEvent = CreateEvent( NULL, FALSE, FALSE, NULL );
    if( NULL == g_hMouseEvent )
        return E_FAIL;

    // Give the event to the mouse device
    if( FAILED( hr = g_pMouse->SetEventNotification( g_hMouseEvent ) ) )
        return hr;

    // Setup the buffer size for the mouse data
    DIPROPDWORD dipdw;
    dipdw.diph.dwSize       = sizeof(DIPROPDWORD);
    dipdw.diph.dwHeaderSize = sizeof(DIPROPHEADER);
    dipdw.diph.dwObj        = 0;
    dipdw.diph.dwHow        = DIPH_DEVICE;
    dipdw.dwData            = SAMPLE_BUFFER_SIZE; // Arbitary buffer size

    if( FAILED( hr = g_pMouse->SetProperty( DIPROP_BUFFERSIZE, &dipdw.diph ) ) )
        return hr;

    // Not necessary, but nice for left handed users that have
    // their swapped mouse buttons
    g_bSwapMouseButtons = GetSystemMetrics( SM_SWAPBUTTON );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: SetAcquire()
// Desc: Acquire or unacquire the mouse, depending on if the app is active
//       Input device must be acquired before the GetDeviceState is called
//-----------------------------------------------------------------------------
HRESULT SetAcquire()
{
    // Nothing to do if g_pMouse is NULL
    if( NULL == g_pMouse )
        return S_FALSE;

    if( g_bActive )
        g_pMouse->Acquire();
    else
        g_pMouse->Unacquire();

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: FreeDirectInput()
// Desc: Initialize the DirectInput variables.
//-----------------------------------------------------------------------------
HRESULT FreeDirectInput()
{
    // Unacquire the device one last time just in case
    // the app tried to exit while the device is still acquired.
    if( g_pMouse )
        g_pMouse->Unacquire();

    // Release any DirectInput objects.
    SAFE_RELEASE( g_pMouse );
    SAFE_RELEASE( g_pDI );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: OnMouseInput()
// Desc: Handles responding to any mouse input that is generated from
//       the mouse event being triggered.
//-----------------------------------------------------------------------------
VOID OnMouseInput( HWND hWnd )
{
    BOOL                bDone;
    DIDEVICEOBJECTDATA  od;
    DWORD               dwElements;
    HRESULT             hr;

    // Invalidate the old cursor so it will be erased
    InvalidateCursorRect( hWnd );

    // Attempt to read one data element.  Continue as long as
    // device data is available.
    bDone = FALSE;
    while( !bDone )
    {
        dwElements = 1;
        hr = g_pMouse->GetDeviceData( sizeof(DIDEVICEOBJECTDATA),
                                      &od, &dwElements, 0 );

        if( hr == DIERR_INPUTLOST )
        {
            SetAcquire();
            break;
        }

        // Unable to read data or no data available
        if( FAILED(hr) || dwElements == 0 )
        {
            break;
        }

        // Look at the element to see what happened
        switch( od.dwOfs )
        {
            case DIMOFS_X:       // Mouse horizontal motion
                UpdateCursorPosition( od.dwData, 0 );
                break;

            case DIMOFS_Y:       // Mouse vertical motion
                UpdateCursorPosition( 0, od.dwData );
                break;

            case DIMOFS_BUTTON0: // Right button pressed or released
            case DIMOFS_BUTTON1: // Left button pressed or released
                // Is the right or a swapped left button down?
                if( ( g_bSwapMouseButtons  && DIMOFS_BUTTON1 == od.dwOfs ) ||
                    ( !g_bSwapMouseButtons && DIMOFS_BUTTON0 == od.dwOfs ) )
                {
                    if( od.dwData & 0x80 )
                    {
                        // left button pressed, so go into button-down mode
                        bDone = TRUE;
                        OnLeftButtonDown( hWnd );
                    }
                }


                // is the left or a swapped right button down?
                if( ( g_bSwapMouseButtons  && DIMOFS_BUTTON0 == od.dwOfs ) ||
                    ( !g_bSwapMouseButtons && DIMOFS_BUTTON1 == od.dwOfs ) )
                {
                    if( !(od.dwData & 0x80) )
                    {
                        // button released, so check context menu
                        bDone = TRUE;
                        OnRightButtonUp( hWnd );
                    }
                }
                break;
        }
    }

    // Invalidate the new cursor so it will be drawn
    InvalidateCursorRect( hWnd );
}




//-----------------------------------------------------------------------------
// Name: OnLeftButtonDown()
// Desc: If we are drawing a curve, then read buffered data and draw
//      lines from point to point.  By reading buffered data, we can
//      track the motion of the mouse accurately without coalescing.
//
//      This function illustrates how a non-message-based program can
//      process buffered data directly from a device, processing
//      messages only occasionally (as required by Windows).
//
//      This function also illustrates how an application can piece
//      together buffered data elements based on the sequence number.
//      A single mouse action (e.g., moving diagonally) is reported
//      as a series of events, all with the same sequence number.
//      Zero is never a valid DirectInput sequence number, so it is
//      safe to use it as a sentinel value.
//-----------------------------------------------------------------------------
VOID OnLeftButtonDown( HWND hWnd )
{
    HRESULT             hr;
    LEFTBUTTONINFO      lbInfo;
    BOOL                bDone;
    DIDEVICEOBJECTDATA  od;
    DWORD               dwElements;
    MSG                 msg;

    // For performance, draw directly onto the window's DC instead of
    // invalidating and waiting for the WM_PAINT message.  Of course,
    // we always draw onto our bitmap, too, since that's what really
    // counts.

    // hide cursor and initialize button info with cursor position
    StartPenDraw( hWnd, &lbInfo );
    InvalidateCursorRect( hWnd );
    UpdateWindow( hWnd );

    // Keep reading data elements until we see a "mouse button up" event.
    bDone = FALSE;
    while( !bDone )
    {
        dwElements = 1;
        hr = g_pMouse->GetDeviceData( sizeof(DIDEVICEOBJECTDATA),
                                      &od, &dwElements, 0 );
        if( FAILED(hr) )
            break;

        // If theres no data available, finish the element
        // we have been collecting, and then process our message
        // queue so the system doesn't think the app has hung.
        if( dwElements == 0 )
        {
            // if there is a partial motion, flush it out
            OnLeftButtonDown_FlushMotion( &lbInfo );

            while( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )
            {
                // If it's a quit message, we're outta here
                if( msg.message == WM_QUIT )
                {
                    // Re-post the quit message so the
                    // outer loop will see it and exit.
                    PostQuitMessage( (int)msg.wParam );
                    bDone = TRUE;
                    break;
                }
                else
                {
                    TranslateMessage( &msg );
                    DispatchMessage( &msg );
                }
            }
            continue;
        }

        // If this is the start of a new event, flush out the old one
        if( od.dwSequence != lbInfo.dwSeqLastSeen )
        {
            OnLeftButtonDown_FlushMotion( &lbInfo );
            lbInfo.dwSeqLastSeen = od.dwSequence;
        }

        // Look at the element to see what happened
        switch( od.dwOfs )
        {
            case DIMOFS_X:      // Mouse horizontal motion
                UpdateCursorPosition( od.dwData, 0 );
                lbInfo.bMoved = TRUE;
                break;

            case DIMOFS_Y:      // Mouse vertical motion
                UpdateCursorPosition( 0, od.dwData );
                lbInfo.bMoved = TRUE;
                break;

            case DIMOFS_BUTTON0: // Button 0 pressed or released
            case DIMOFS_BUTTON1: // Button 1 pressed or released
                if( ( g_bSwapMouseButtons  && DIMOFS_BUTTON1 == od.dwOfs ) ||
                    ( !g_bSwapMouseButtons && DIMOFS_BUTTON0 == od.dwOfs ) )
                {
                    if( !(od.dwData & 0x80) )
                    {
                        // Button released, so flush out dregs
                        bDone = TRUE;
                        OnLeftButtonDown_FlushMotion( &lbInfo );
                    }
                }
                break;
        }
    }

    ReleaseDC( hWnd, lbInfo.hdcWindow );

    // Re-show the cursor now that scrawling is finished
    FinishPenDraw( hWnd );
    InvalidateCursorRect( hWnd );
}