代码段， 对directdraw 初始化！

一个比较规范的代码段对directdraw进行初始化。

.h文件
#include <ddraw.h>

DIRECTDRAW dd ;
DDRAWCLIPPER dcClipper ;
DDRAWSURFACE dsFront, dsBack ;
DDSURFACEDESC ddsd ;
HWND m_hArea ;

.cpp文件
#define RGBFMT

BOOL CreateObject()
{
    //创建DirectDraw对像
    HRESULT hr ;
    hr = DirectDrawCreate(NULL, &dd, NULL) ;
    if(FAILED(hr))    return FALSE ;
    hr = dd->SetCooperativeLevel(m_hArea, DDSCL_NORMAL) ;
    if(FAILED(hr)) return FALSE;

    ZeroMemory(&ddsd, sizeof(ddsd)) ;
    ddsd.dwSize = sizeof(ddsd) ;
    ddsd.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN ;
    ddsd.dwFlags = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_PIXELFORMAT ;
    ddsd.dwWidth = 352 ;
    ddsd.dwHeight = 288 ;
#ifdef RGBFMT  //显示RGB
    ddsd.ddpfPixelFormat.dwSize = sizeof(DDPIXELFORMAT) ;
    ddsd.ddpfPixelFormat.dwFlags = DDPF_RGB ;
    ddsd.ddpfPixelFormat.dwRGBBitCount = 16 ;
#else         //显示YUV
    ddsd.ddpfPixelFormat.dwFlags = DDPF_FOURCC | DDPF_YUV ;
    ddsd.ddpfPixelFormat.dwFourCC = MAKEFOURCC('Y', 'V', '1', '2') ;
    ddsd.ddpfPixelFormat.dwYUVBitCount = 8 ;
#endif

    hr = dd->CreateSurface(&ddsd, &dsBack, NULL) ; //创建离屏表面
    if(hr != DD_OK)
    {
        dd.Release() ;
        return FALSE ;
    }

    ZeroMemory(&ddsd, sizeof(ddsd)) ;
    ddsd.dwSize = sizeof(ddsd) ;
    ddsd.dwFlags = DDSD_CAPS ;
    ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE ;

    hr = dd->CreateSurface(&ddsd, &dsFront, NULL) ; //创建主表面
    if(FAILED(hr))
    {
        dsBack.Release() ;
        dd.Release() ;
        return FALSE ;
    }

    hr = dd->CreateClipper(0, &dcClipper, NULL) ; //创建裁剪区
    if(FAILED(hr))
    {
        dsBack.Release() ;
        dsFront.Release() ;
        dd.Release() ;
        return FALSE ;
    }

    dcClipper->SetHWnd(0, m_hArea) ; //设置裁剪区区域
    hr = dsFront->SetClipper(dcClipper) ;

    return TRUE ;
}

void Draw(FrameStruct struFrame)
{
    if(CreateObject())
    {
        DDSURFACEDESC ddsd ;
        HRESULT ddRval ;

        ZeroMemory(&ddsd, sizeof(DDSURFACEDESC)) ;
        ddsd.dwSize = sizeof(DDSURFACEDESC) ;       
        ddRval = dsBack->Lock(NULL, &ddsd, DDLOCK_WAIT|DDLOCK_WRITEONLY|DDLOCK_NOSYSLOCK, NULL);
        if( ddRval == DDERR_SURFACELOST )
        {
            ddRval = dsFront->Restore();
            ddRval = dsBack->Restore();
            ddRval = dsBack->Lock(NULL, &ddsd, DDLOCK_WAIT|DDLOCK_WRITEONLY|DDLOCK_NOSYSLOCK, NULL);
        }

        if(ddRval != DD_OK)
        {
            return ;
        }

        LPBYTE lpSurf = (LPBYTE)ddsd.lpSurface;
        LPBYTE PtrY = struFrame.pY ;
        LPBYTE PtrU = struFrame.pU ;
        LPBYTE PtrV = struFrame.pV ;                       

#ifdef RGBFMT
        //RGB填充方式
        memcpy(lpSurf, PtrY, struFrame.iWidth * struFrame.iHeight * 2) ;
#else
        //YUV420填充方式           
        long lSize = 0 ;
        if(lpSurf != NULL)
        {
        for (int i=0; i<struFrame.iHeight; i++)
        {
            memcpy(lpSurf, PtrY, struFrame.iYStride );
            PtrY +=struFrame.iYStride ;
            lpSurf += ddsd.lPitch;                                   
        }                               

        for (int i=0;i<struFrame.iHeight/2;i++)
        {
            memcpy(lpSurf, PtrV, ddsd.dwWidth/2);
            PtrV += struFrame.iUVStride ;
            lpSurf += ddsd.lPitch/2;
        }   

        for (int i=0;i<struFrame.iHeight/2;i++)
        {
            memcpy(lpSurf, PtrU, ddsd.dwWidth/2);
            PtrU += struFrame.iUVStride ;
            lpSurf += ddsd.lPitch/2;
            lSize += ddsd.lPitch / 2 ;
        }
#endif

        dsBack->Unlock(NULL);
        CRect rcDest, rcSource ;
        rcSource.left = 0 ;
        rcSource.top = 0 ;
        rcSource.right = ddsd.dwWidth ;
        rcSource.bottom = ddsd.dwHeight ;

        GetDlgItem(IDC_SHOWAREA)->GetWindowRect(&rcDest) ;
        ddRval = dsFront->Blt(rcDest, dsBack, NULL, DDBLT_WAIT, NULL) ;
        while(ddRval == DDERR_WASSTILLDRAWING) ;
    }

}