对于aero的桌面DC绘制,大家有什么好的方法没?解决办法

//#include "stdafx.h"  
#include <windows.h>    
#include <math.h>    
#include <stdlib.h>   
//#pragma comment(/Entry:WinMain)  
#define ID_TIMER    1    
#define SNOWNUM      500  // 雪花数量    
#define CONTRAST    50    // 对比度    
#define YSTART      5    // 用于确定雪花初始时的y坐标    
#define SNOWCR      RGB(0xFF, 0xFF, 0xFF) //雪花的颜色—白色    
#define SNOWGATHERCR RGB(0xDB, 0xDB, 0xFF) //堆积雪花的颜色    
  
typedef struct tagSnow   
{   
  POINT ptSnowsPos[SNOWNUM]; //用于保存各个雪花的坐标    
  COLORREF crOrg[SNOWNUM]; //用于画雪花前屏幕原来的颜色    
  int iVx, iVy, iAllVx, iAllVy;   
}Snow;   
  
void initSnow(HDC hdc, Snow *sn, int iSnow, int cxScreen);   
int GetContrast(HDC hdc, Snow *sn, int iSnow);   
void drawSnow(HDC hdc, Snow *sn, int cxScreen);   
  
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;   
  
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,   
                    PSTR szCmdLine, int iCmdShow)   
{   
        static TCHAR szAppName[] = TEXT ("clsDeskSnow") ;   
        HWND            hwnd ;   
        MSG            msg ;   
        WNDCLASS    wndclass ;   
  
        wndclass.style        = CS_HREDRAW | CS_VREDRAW ;   
        wndclass.lpfnWndProc  = WndProc ;   
        wndclass.cbClsExtra    = 0 ;   
        wndclass.cbWndExtra    = 0 ;   
        wndclass.hInstance    = hInstance ;   
        wndclass.hIcon        = LoadIcon (NULL, IDI_APPLICATION) ;   
        wndclass.hCursor      = LoadCursor (NULL, IDC_ARROW) ;   
        wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;   
        wndclass.lpszMenuName  = NULL ;   
        wndclass.lpszClassName = szAppName ;   
  
        if(!RegisterClass (&wndclass))   
        {   
            MessageBox (NULL, TEXT ("This program requires Windows NT!"), szAppName, MB_ICONERROR) ;   
            return 0;   
        }   
  
        hwnd = CreateWindow (szAppName,        TEXT ("桌面下雪"),   
                            WS_MINIMIZEBOX | WS_SYSMENU,   
                            CW_USEDEFAULT, CW_USEDEFAULT,   
                            240, 120,   
                            NULL, NULL, hInstance, NULL) ;   
  
        ShowWindow (hwnd, iCmdShow) ;   
        UpdateWindow (hwnd) ;   
  
        while (GetMessage (&msg, NULL, 0, 0))   
        {   
            TranslateMessage (&msg) ;   
            DispatchMessage (&msg) ;   
        }   
        return msg.wParam ;   
}   
  
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)   
{   
      HDC          hdc ;   
      PAINTSTRUCT  ps ;   
      RECT        rect ;   
      static int cxScreen, cyScreen; //屏幕宽高度(单位:像素)    
      static int iTimes, iLoopTimes=100;   
      static Snow snowDream;   
      int i;   
  
      switch (message)   
      {   
        case WM_CREATE:   
            cxScreen = GetSystemMetrics (SM_CXSCREEN) ;   
            cyScreen = GetSystemMetrics (SM_CYSCREEN) ;   
            srand ((int) GetCurrentTime ()) ; //初始化随机数发生器    
            snowDream.iAllVx = (unsigned)rand()%3 - 1; //雪花总体水平飘行速度(-1,0,1)    
            snowDream.iAllVy = (unsigned)rand()%2 + 1; //雪花总体垂直下落速度(1,2)    
            hdc = GetDC(NULL); //检索整个屏幕的设备上下文环境    
            for(i=0; i <SNOWNUM; i++)   
            {   
                snowDream.ptSnowsPos[i].x = rand() % cxScreen; //一个雪花开始下落的x坐标    
                snowDream.ptSnowsPos[i].y = rand() % YSTART; //一个雪花开始下落的y坐标    
                snowDream.crOrg[i] = GetPixel(hdc, snowDream.ptSnowsPos[i].x,   
                          snowDream.ptSnowsPos[i].y); //获取给定点的原来的颜色值    
            }   
            ReleaseDC(NULL, hdc);   
            SetTimer(hwnd, ID_TIMER, 10, NULL); //定时器，10毫秒    
            return 0 ;   
              
        case WM_DISPLAYCHANGE: //当显示分辨率改变的时候    
            cxScreen = GetSystemMetrics (SM_CXSCREEN) ;   
            cyScreen = GetSystemMetrics (SM_CYSCREEN) ;   
            return 0;   
              
        case WM_TIMER:   
            hdc = GetDC(NULL); //检索整个屏幕的设备上下文环境    
            if(iTimes > iLoopTimes)   
            {   
                iTimes = 0;   
                iLoopTimes = 50 + (unsigned)rand()%50;   
                if(snowDream.iAllVx != 0)   
                  snowDream.iAllVx = 0;   
                else                    
                  snowDream.iAllVx = (unsigned)rand()%3 - 1; //雪花总体水平飘行速度(-1,0,1)    
                snowDream.iAllVy = (unsigned)rand()%2 + 1; //雪花总体垂直下落速度(1,2)    
            }   
            else   
                iTimes++;   
            drawSnow(hdc, &snowDream, cxScreen);   
            ReleaseDC(NULL, hdc);   
            return 0;   
  
        case WM_PAINT:   
            hdc = BeginPaint (hwnd, &ps) ;   
            GetClientRect (hwnd, &rect) ;   
            DrawText (hdc, TEXT ("桌面下雪!"), -1, &rect,   
                      DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;   
            EndPaint (hwnd, &ps) ;   
            return 0 ;   
  
        case WM_DESTROY:   
            KillTimer(hwnd, ID_TIMER); // 中止定时器    
            InvalidateRect(NULL, NULL, TRUE); // 刷新桌面    
            PostQuitMessage (0) ;   
            return 0 ;   
        }   
        return DefWindowProc (hwnd, message, wParam, lParam) ;   
}   
  
void initSnow(HDC hdc, Snow *sn, int iSnow, int cxScreen) //初始化第iSnow个雪花    
{   
  sn->ptSnowsPos[iSnow].x = (unsigned)rand() % cxScreen; //x范围整个屏幕宽    
  sn->ptSnowsPos[iSnow].y = (unsigned)rand() % YSTART; //y范围离屏幕顶部YSTART像素点以内    
  sn->crOrg[iSnow] = GetPixel(hdc, sn->ptSnowsPos[iSnow].x,   
            sn->ptSnowsPos[iSnow].y ) ;//获取给定点的原来的颜色值    
}   
  
int GetContrast(HDC hdc, Snow *sn, int iSnow)   
{   
  int iR, iG, iB;   
  COLORREF crCmp;   
    
  if(0 == sn->iVx) //若水平速度为0，则取比其大一个像素的正下方的点    
    crCmp = GetPixel(hdc, sn->ptSnowsPos[iSnow].x, sn->ptSnowsPos[iSnow].y + 1);   
  else //若水平速度>0，取右下方的点。 <0则取左下方的点    
    crCmp = GetPixel(hdc, sn->ptSnowsPos[iSnow].x + (sn->iVx>0?1:-1), sn->ptSnowsPos[iSnow].y + 1);   
  
  if(crCmp==SNOWCR) //如果为雪花的颜色    
    return 0;   
  
  //分别获取crCmp与对比点的蓝、绿、红部分的差值    
  iB = abs((crCmp>>16)&0xFF - (sn->crOrg[iSnow]>>16)&0xFF);   
  iG = abs((crCmp>>8)&0xFF  - (sn->crOrg[iSnow]>>8)&0xFF);   
  iR = abs((crCmp)&0xFF    - (sn->crOrg[iSnow])&0xFF);   
  
  return (iR+iG+iB)/3;   
}   
  
void drawSnow(HDC hdc, Snow *sn, int cxScreen)   
{   
  int i;   
  for(i=0; i <SNOWNUM; i++)   
  {   
      //如果保存的原来的颜色不是雪花的颜色    
      if(sn->crOrg[i] != SNOWCR)   
        SetPixel(hdc, sn->ptSnowsPos[i].x, sn->ptSnowsPos[i].y,   
          sn->crOrg[i]); //还原上一个位置的颜色    
  
      sn->iVx = sn->iAllVx*(i%3+1); //雪花的x飘动速度    
      sn->iVy = sn->iAllVy*(i%3+1); //雪花的y飘动速度    
      //rand()%5-2使雪花下落的时候 有抖动效果    
      sn->ptSnowsPos[i].x += sn->iVx+rand()%5-2; //雪花的下一个x坐标    
      sn->ptSnowsPos[i].y += sn->iVy+1; //雪花的下一个y坐标    
  
      //获取给定点的原来的颜色值    
      sn->crOrg[i] = GetPixel(hdc, sn->ptSnowsPos[i].x, sn->ptSnowsPos[i].y);   
      
      if(CLR_INVALID == sn->crOrg[i]) //如果获取颜色失败,即雪花飘出了屏幕    
      {   
        initSnow(hdc, sn, i, cxScreen); //重新初始化 雪花    
        continue;   
      }   
      if(sn->crOrg[i] != SNOWCR) //若当前点的颜色 不等于 雪花的颜色    
      {   
        if(SNOWGATHERCR == sn->crOrg[i]) //当前点的颜色=堆积的雪的颜色    
      {  //设置为雪花的颜色    
          SetPixel(hdc, sn->ptSnowsPos[i].x, sn->ptSnowsPos[i].y, SNOWCR);   
          sn->crOrg[i] = SNOWCR;   
          //initSnow(hdc, sn, i, cxScreen); //重新初始化 雪花    
      }   
      else if(GetContrast(hdc, sn, i) > 50) //若对比度>50    
        {  //堆积雪花    
            SetPixel(hdc, sn->ptSnowsPos[i].x,  sn->ptSnowsPos[i].y,  SNOWGATHERCR);   
            SetPixel(hdc, sn->ptSnowsPos[i].x-1, sn->ptSnowsPos[i].y+1, SNOWGATHERCR);   
            SetPixel(hdc, sn->ptSnowsPos[i].x+1, sn->ptSnowsPos[i].y+1, SNOWGATHERCR);   
            initSnow(hdc, sn, i, cxScreen); //重新初始化 雪花    
        }   
        else //对比度 <50,不堆积,画出这帧雪花.等下次的时候再还原此点原本的颜色.以产生飘动效果    
          SetPixel(hdc, sn->ptSnowsPos[i].x, sn->ptSnowsPos[i].y, SNOWCR);   
      }   
  }   
}