打乒乓程序的PeekMessage版本

今天看到Programming Windows多任务及多线程那章，提到了PeekMessage( )函数，那这个不是正好可以用在打乒乓程序中吗，就不用定时器了，应用PeekMessage( )函数的版本如下：

#include <windows.h>
#include "resource.h"

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
void DrawRect(HWND);
static int cxClient,cyClient,cxStart, cyStart,xStart,yStart;
static int i,j,delay,direction=1;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("Bounce_PeekMessageEditon") ;
HWND hwnd ;
MSG msg ;
WNDCLASS wndclass ;
int delay;

wndclass.style = CS_HREDRAW | CS_VREDRAW ;
wndclass.lpfnWndProc = WndProc ;
wndclass.cbClsExtra = 0 ;
wndclass.cbWndExtra = 0 ;
wndclass.hInstance = hInstance ;
wndclass.hIcon = LoadIcon (hInstance, MAKEINTRESOURCE(IDI_ICON)) ;
wndclass.hCursor = LoadCursor (hInstance, MAKEINTRESOURCE(IDC_CURSOR)) ;
wndclass.hbrBackground = (HBRUSH)CreateSolidBrush(RGB(208,221,238));
wndclass.lpszMenuName = NULL ;
wndclass.lpszClassName = szAppName ;

if (!RegisterClass (&wndclass))
{
MessageBox (NULL, TEXT ("Program requires Windows NT!"),
szAppName, MB_ICONERROR) ;
return 0 ;
}

hwnd = CreateWindow (szAppName, TEXT ("Bounce_PeekMessageEdition"),
WS_OVERLAPPED | WS_SYSMENU,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
NULL, NULL, hInstance, NULL) ;

ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ;

while (TRUE)
{
if (PeekMessage (&msg, NULL, 0, 0, PM_REMOVE))
{
if (msg.message == WM_QUIT)
break ;

TranslateMessage (&msg) ;
DispatchMessage (&msg) ;
}
else
{
delay=1000000;
while(delay)
{
delay--;
}
DrawRect(hwnd) ;
}
}
return msg.wParam ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc ;
PAINTSTRUCT ps ;

switch (message)
{
case WM_SIZE:
cxClient=LOWORD (lParam);
cyClient=HIWORD (lParam);
cxStart =LOWORD (lParam)/2-5;
cyStart =HIWORD (lParam)-10-10;
xStart =cxClient/2-30;
yStart =cyClient-10;
cyClient-=11;
return 0;
case WM_PAINT:
hdc=BeginPaint(hwnd,&ps);
for(i=0;i<10;i++)
{
for(j=0;j<60;j++)
{
SetPixel(hdc,xStart+j,yStart+i,RGB(0,128,0));
}
}
for(i=0;i<10;i++)
{
for(j=0;j<10;j++)
{
SetPixel(hdc,cxStart+i,cyStart+j,RGB(255,128,0));
}
}
EndPaint(hwnd,&ps);
return 0;
case WM_KEYDOWN:
switch(wParam)
{
case VK_LEFT:
if(xStart>=0)
{
xStart-=5;
}
break;
case VK_RIGHT:
if(xStart<=cxClient-60)
{
xStart+=5;
}
break;
}
return 0;
case WM_DESTROY:
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}

void DrawRect(HWND hwnd)
{
HDC hdc;
hdc=GetDC(hwnd);
switch(direction)
{
case 1:
if(cxStart>0 && cyStart>=0)
{
cxStart-=1;
cyStart-=1;
InvalidateRect(hwnd,NULL,TRUE);
}
if(cxStart<=0)
{
direction=2;
}
if(cyStart<=0)
{
direction=4;
}
break;
case 2:
if(cyStart>0 && cxStart<cxClient-10)
{
cxStart+=1;
cyStart-=1;
InvalidateRect(hwnd,NULL,TRUE);
}
if(cyStart<=0)
{
direction=3;
}
if(cxStart>=cxClient-10)
{
direction=1;
}
break;
case 3:
if(cxStart<cxClient-10 && cyStart<cyClient-10)
{
cxStart+=1;
cyStart+=1;
InvalidateRect(hwnd,NULL,TRUE);
}
if(cyStart>=cyClient-10)
{
if(cxStart+10<xStart+60 && cxStart>=xStart)
{
direction=2;
}
else
{
cxStart+=1;
cyStart+=1;
InvalidateRect(hwnd,NULL,TRUE);
if(cyStart>cyClient+10)
{
MessageBox(hwnd,"AWOH,You lost!","Fail !",MB_OK);
SendMessage(hwnd,WM_DESTROY,0,0);
}
}
}
if(cxStart>=cxClient-10)
{
direction=4;
}
break;
case 4:
if(cyStart<cyClient-10 && cxStart>0)
{
cxStart-=1;
cyStart+=1;
InvalidateRect(hwnd,NULL,TRUE);
}
if(cyStart>=cyClient-10)
{
if(cxStart+10<xStart+60 && cxStart>=xStart)
{
direction=1;
}
else
{
cxStart-=1;
cyStart+=1;
InvalidateRect(hwnd,NULL,TRUE);
if(cyStart>cyClient+10)
{
MessageBox(hwnd,"AWOH,You fail!","Fail !",MB_OK);
SendMessage(hwnd,WM_DESTROY,0,0);
}
}
}
if(cxStart<=0)
{
direction=3;
}
break;
}
}

没错，这样程序确实可以实现既画运动的小球，又监视板的移动，但是我发现了一个问题栏 就是当我将指针放在标题栏上，按下指针时(我本意是想试试拖动窗口)，小球停止了运动，好像WINDOWS产生了什么特殊的消息，可这时究竟发生了什么事情呢，我不知道，然后我把前一个，就是用TIMER的那个版本运行了一下，情况是当我按下时，小球停顿了一下，然后接着开始运动，然后我就可以开始拖动窗口了，拖的时候小球仍然在动。那么当我在标题栏上按下鼠标时，WINDOWS内部倒底发生了什么事情呢？谁肯指教我一下啊!!!!!!!

我想用多线程的方法实现时它应该不会有这个问题，明天把它写出来试试。