opencv+mfc 如果同时显示两个摄像画面？

出不来画面，这么写，怎么改
#include "stdafx.h"
#include "test.h"
#include "testDlg.h"
#include "afxdialogex.h"#include <opencv/cv.hpp>
#include <opencv/cv.h>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/highgui/highgui_c.h>using namespace cv;#ifdef _DEBUG
#define new DEBUG_NEW
#endifCvCapture* Cap1;
CvCapture* Cap2;
CRect Rect1;
CDC *Pdc;
HDC Hdc1,Hdc2;
CWnd *Pwnd;CvVideoWriter *Write1;
CvVideoWriter *Write2;// 用于应用程序“关于”菜单项的 CAboutDlg 对话框class CAboutDlg : public CDialogEx
{
public:
CAboutDlg();// 对话框数据
enum { IDD = IDD_ABOUTBOX }; protected:
virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV 支持// 实现
protected:
DECLARE_MESSAGE_MAP()
public:
afx_msg void OnBnClickedOk();
};CAboutDlg::CAboutDlg() : CDialogEx(CAboutDlg::IDD)
{
}void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
CDialogEx::DoDataExchange(pDX);
}BEGIN_MESSAGE_MAP(CAboutDlg, CDialogEx)
ON_BN_CLICKED(IDOK, &CAboutDlg::OnBnClickedOk)
END_MESSAGE_MAP()
// CtestDlg 对话框
CtestDlg::CtestDlg(CWnd* pParent /*=NULL*/)
: CDialogEx(CtestDlg::IDD, pParent)
{
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}void CtestDlg::DoDataExchange(CDataExchange* pDX)
{
CDialogEx::DoDataExchange(pDX);
}BEGIN_MESSAGE_MAP(CtestDlg, CDialogEx)
ON_WM_SYSCOMMAND()
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_BN_CLICKED(IDOK, &CtestDlg::OnBnClickedOk)
ON_BN_CLICKED(IDCANCEL, &CtestDlg::OnBnClickedCancel)
ON_WM_TIMER()
ON_STN_CLICKED(IDC_ShowImage1, &CtestDlg::OnStnClickedShowimage1)
ON_BN_CLICKED(IDC_BUTTON_OPEN1, &CtestDlg::OnBnClickedButtonOpen1)
ON_BN_CLICKED(IDC_BUTTON_CLOSE1, &CtestDlg::OnBnClickedButtonClose1)
ON_STN_CLICKED(IDC_ShowImage2, &CtestDlg::OnStnClickedShowimage2)
END_MESSAGE_MAP()
// CtestDlg 消息处理程序BOOL CtestDlg::OnInitDialog()
{
CDialogEx::OnInitDialog(); // 将“关于...”菜单项添加到系统菜单中。 // IDM_ABOUTBOX 必须在系统命令范围内。
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000); CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
{
BOOL bNameValid;
CString strAboutMenu;
bNameValid = strAboutMenu.LoadString(IDS_ABOUTBOX);
ASSERT(bNameValid);
if (!strAboutMenu.IsEmpty())
{
pSysMenu->AppendMenu(MF_SEPARATOR);
pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
}
} // 设置此对话框的图标。当应用程序主窗口不是对话框时，框架将自动
//  执行此操作
SetIcon(m_hIcon, TRUE); // 设置大图标
SetIcon(m_hIcon, FALSE); // 设置小图标 // TODO: 在此添加额外的初始化代码 Pwnd = GetDlgItem(IDC_ShowImage1); //从MFC的界面上获取Image控件，控件ID为IDC_ShowImage1
//Pwnd->MoveWindow(35,30,352,288);
Pdc = Pwnd->GetDC();
Hdc1= Pdc->GetSafeHdc();
Pwnd->GetClientRect(&Rect1); Pwnd = GetDlgItem(IDC_ShowImage2); //从MFC的界面上获取Image控件，控件ID为IDC_ShowImage2
//Pwnd->MoveWindow(35,30,352,288);
Pdc = Pwnd->GetDC();
Hdc2= Pdc->GetSafeHdc();
Pwnd->GetClientRect(&Rect1);
return TRUE;  // 除非将焦点设置到控件，否则返回 TRUE
}void CtestDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
if ((nID & 0xFFF0) == IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal();
}
else
{
CDialogEx::OnSysCommand(nID, lParam);
}
}// 如果向对话框添加最小化按钮，则需要下面的代码
//  来绘制该图标。对于使用文档/视图模型的 MFC 应用程序，
//  这将由框架自动完成。void CtestDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // 用于绘制的设备上下文 SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0); // 使图标在工作区矩形中居中
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2; // 绘制图标
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialogEx::OnPaint();
}
}//当用户拖动最小化窗口时系统调用此函数取得光标
//显示。
HCURSOR CtestDlg::OnQueryDragIcon()
{
return static_cast<HCURSOR>(m_hIcon);
}void CtestDlg::OnBnClickedOk()
{
// TODO: 在此添加控件通知处理程序代码
CDialogEx::OnOK();
}
void CtestDlg::OnBnClickedCancel()
{
// TODO: 在此添加控件通知处理程序代码
CDialogEx::OnCancel();
}void CAboutDlg::OnBnClickedOk()
{
// TODO: 在此添加控件通知处理程序代码
CDialogEx::OnOK();
}
void CtestDlg::OnTimer(UINT_PTR nIDEvent)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
IplImage* m_Frame1; 
IplImage* m_Frame2;
    m_Frame1=cvQueryFrame(Cap1);  
m_Frame2=cvQueryFrame(Cap2);  
    CvvImage m_CvvImage1;  
CvvImage m_CvvImage2;
    m_CvvImage1.CopyOf(m_Frame1,1);
m_CvvImage2.CopyOf(m_Frame2,1);
    if (true)  
    {  
        m_CvvImage1.DrawToHDC(Hdc1, &Rect1);  
m_CvvImage2.DrawToHDC(Hdc2, &Rect1);
        //cvWaitKey(10);  
    }  
CDialogEx::OnTimer(nIDEvent);
}void CtestDlg::OnStnClickedShowimage1()
{
// TODO: 在此添加控件通知处理程序代码
SetWindowPos(NULL,0,0,GetSystemMetrics(SM_CXSCREEN),GetSystemMetrics(SM_CYSCREEN),0);
}void CtestDlg::OnBnClickedButtonOpen1()
{
// TODO: 在此添加控件通知处理程序代码
if(!Cap1||Cap2)
{
Cap1 = cvCaptureFromCAM(-1); //Opencv方式读取视频
Cap2 = cvCaptureFromCAM(0);
//AfxMessageBox("OK");
} if (!Cap1||Cap2)
{
AfxMessageBox("Cannot open camera",MB_OK,0);
return;
}
Write1=cvCreateVideoWriter("camera1.avi",CV_FOURCC('x','v','I','D'),25,cvSize(640,480));  //创建视频写入
Write2=cvCreateVideoWriter("camera2.avi",CV_FOURCC('x','v','I','D'),25,cvSize(640,480));
// 测试
IplImage* m_Frame1;
IplImage* m_Frame2;
m_Frame1=cvQueryFrame(Cap1); //从摄像头获得IplImage类型的图片
m_Frame2=cvQueryFrame(Cap2);
CvvImage m_CvvImage1;
CvvImage m_CvvImage2;
m_CvvImage1.CopyOf(m_Frame1,1);
m_CvvImage2.CopyOf(m_Frame2,1);
if (true)
{
m_CvvImage1.DrawToHDC(Hdc1, &Rect1); //从MFC的界面上获取Image控件，控件ID为IDC_FRAME
m_CvvImage2.DrawToHDC(Hdc2, &Rect1);
//cvWaitKey(10);
}
SetTimer(1,10,NULL);  
}
void CtestDlg::OnBnClickedButtonClose1()
{
// TODO: 在此添加控件通知处理程序代码
cvReleaseVideoWriter(&Write1);
cvReleaseCapture(&Cap1);
CDC MemDC; 
CBitmap m_Bitmap1;
m_Bitmap1.LoadBitmap(IDR_JPG1); 
MemDC.CreateCompatibleDC(NULL);
MemDC.SelectObject(&m_Bitmap1);
Pdc->StretchBlt(Rect1.left,Rect1.top,Rect1.Width(),Rect1.Height(),&MemDC,0,0,48,48,SRCCOPY);  cvReleaseVideoWriter(&Write2);
cvReleaseCapture(&Cap2);
m_Bitmap1.LoadBitmap(IDR_JPG1); 
MemDC.CreateCompatibleDC(NULL);
MemDC.SelectObject(&m_Bitmap1);
Pdc->StretchBlt(Rect1.left,Rect1.top,Rect1.Width(),Rect1.Height(),&MemDC,0,0,48,48,SRCCOPY);
}
void CtestDlg::OnStnClickedShowimage2()
{
// TODO: 在此添加控件通知处理程序代码
}