学步园

http://real.zdell.com/a/200512/818.html

在网上找了一段代码，能工作，但是颜色不对，红的变成蓝色的，黄的变青色了，有时间找找问题。

这个问题在我初学DirectX是困惑了我很久，贴出来为初学者提供一个参考。

 

#include "ddraw.h"
#pragma comment(lib,"ddraw.lib")

#define FILE_HEIGHT            288
#define FILE_WIDTH            352

#define DRAW_TOP            0
#define DRAW_LEFT            0
#define DRAW_HEIGHT            288
#define DRAW_WIDHT            352

BOOL DrawYV12(HWND hWnd)
{
    LPDIRECTDRAW            lpDD;                // DirectDraw 对象指针
    LPDIRECTDRAWSURFACE     lpDDSPrimary;        // DirectDraw 主表面指针
    LPDIRECTDRAWSURFACE     lpDDSOffScr;        // DirectDraw 离屏表面指针
    DDSURFACEDESC            ddsd;                // DirectDraw 表面描述
    RECT                    rctDest;            // 目标区域
    RECT                    rctSour;            // 源区域
    HRESULT                    ddRval;                // DirectDraw 函数返回值

    // 创建DirectCraw对象
    if (DirectDrawCreate(NULL, &lpDD, NULL) != DD_OK) 
        return FALSE;
    // 设置协作层
    if (lpDD->SetCooperativeLevel(hWnd,
            DDSCL_NORMAL | DDSCL_NOWINDOWCHANGES) != DD_OK)
        return FALSE;
    // 创建主表面
    ZeroMemory(&ddsd, sizeof(ddsd));
    ddsd.dwSize = sizeof(ddsd);
    ddsd.dwFlags = DDSD_CAPS;
    ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE;
    if (lpDD->CreateSurface(&ddsd, &lpDDSPrimary, NULL) != DD_OK)
        return FALSE;
    // 创建离屏表面对象
    ZeroMemory(&ddsd, sizeof(ddsd));
    ddsd.dwSize = sizeof(ddsd);
    ddsd.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN | DDSCAPS_VIDEOMEMORY; //DDSCAPS_OVERLAY

DDSCAPS_OFFSCREENPLAIN;
    ddsd.dwFlags = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_PIXELFORMAT;
    ddsd.dwWidth = DRAW_WIDHT;
    ddsd.dwHeight = DRAW_HEIGHT;
    ddsd.ddpfPixelFormat.dwSize = sizeof(DDPIXELFORMAT);
    ddsd.ddpfPixelFormat.dwFlags  = DDPF_FOURCC | DDPF_YUV ;
    ddsd.ddpfPixelFormat.dwFourCC = MAKEFOURCC('Y','V','1','2');
    ddsd.ddpfPixelFormat.dwYUVBitCount = 8;
    if (lpDD->CreateSurface(&ddsd, &lpDDSOffScr, NULL) != DD_OK)
        return FALSE;

    // 加载yv12图像文件
    FILE * f = fopen("test.yv12","rb");
    LPBYTE lpYV12 = new BYTE[FILE_WIDTH * FILE_HEIGHT * 3 / 2];
    UINT iLen = fread(lpYV12, 1, FILE_WIDTH * FILE_HEIGHT * 3 / 2, f);
    fclose(f);
    LPBYTE lpY = lpYV12;
    LPBYTE lpV = lpYV12 + FILE_WIDTH * FILE_HEIGHT;
    LPBYTE lpU = lpYV12 + FILE_WIDTH * FILE_HEIGHT * 5 / 4;
    ddRval = lpDDSOffScr->Lock(NULL,&ddsd,DDLOCK_WAIT | DDLOCK_WRITEONLY,NULL);
    while(ddRval == DDERR_WASSTILLDRAWING);
    if(ddRval != DD_OK)
        return FALSE;
    LPBYTE lpSurf = (LPBYTE)ddsd.lpSurface;
    LPBYTE lpY1 = lpSurf;
    LPBYTE lpV1 = lpSurf + ddsd.lPitch * FILE_HEIGHT;
    LPBYTE lpU1 = lpV1 + ddsd.lPitch  * FILE_HEIGHT / 4;
    int nOffset = DRAW_TOP*FILE_WIDTH+DRAW_LEFT;
    // 填充离屏表面
    if(lpSurf)
    {
        int i = 0;
        // fill Y data
        lpY += nOffset;
        for(i=0; i<ddsd.dwHeight; i++)
        {
            memcpy(lpSurf, lpY, ddsd.dwWidth);
            lpY += FILE_WIDTH;
            lpSurf += ddsd.lPitch;
        }
        // fill V data
        lpV += DRAW_TOP * FILE_WIDTH / 4 + DRAW_LEFT / 2;
        for(i=0; i<ddsd.dwHeight/2; i++)
        {
            memcpy(lpSurf, lpV, ddsd.dwWidth / 2);
            lpV += FILE_WIDTH / 2;
            lpSurf += ddsd.lPitch / 2;
        }
        // fill U data
        lpU += DRAW_TOP * FILE_WIDTH / 4 + DRAW_LEFT / 2;
        for(i=0; i<ddsd.dwHeight/2; i++)
        {
            memcpy(lpSurf, lpU, ddsd.dwWidth / 2);
            lpU += FILE_WIDTH / 2;
            lpSurf += ddsd.lPitch / 2;
        }
    }
    lpDDSOffScr->Unlock(NULL);
    delete lpYV12;

    // Blt到主表面上
    rctSour.left = 0;
    rctSour.top = 0;
    rctSour.right = ddsd.dwWidth;
    rctSour.bottom = ddsd.dwHeight;
    GetClientRect(hWnd,&rctDest);
    ClientToScreen(hWnd, (LPPOINT)&rctDest.left);
    ClientToScreen(hWnd, (LPPOINT)&rctDest.right);

    ddRval = lpDDSPrimary->Blt(&rctDest, lpDDSOffScr, &rctSour, DDBLT_WAIT, NULL);
    while(ddRval == DDERR_WASSTILLDRAWING);
    if(ddRval != DD_OK)
        return FALSE;
    // 释放DirectDraw对象
    if(lpDD != NULL)
    {
        if(lpDDSPrimary != NULL)
        {
            lpDDSPrimary->Release();
            lpDDSPrimary = NULL;
        }
        if(lpDDSOffScr != NULL)
        {
            lpDDSOffScr->Release();
            lpDDSOffScr = NULL;
        }
        lpDD->Release();
        lpDD = NULL;
    }
    return TRUE;
}