I want to create AVI out of my OpenGL applications directly without generating thousands of pictures. The following is my key program: //===================================================== HDC hdc = ::GetDC(¶ÇCurrent windows handle); static PIXELFORMATDESCRIPTOR pfd; int nPixelFormat; nPixelFormat = GetPixelFormat(hdc); if (DescribePixelFormat(hdc, nPixelFormat, sizeof(PIXELFORMATDESCRIPTOR),&pfd) == 0) {// DescribePixelFormat error return; } HGLRC hRC; hRC = ::wglCreateContext(hdc); ::wglMakeCurrent(hdc, hRC); BYTE* bmBits; //³]©wbmBits¡K¡K glReadBuffer(GL_BACK); CAVIGenerator AVIGenerator; //Do some AVI setting¡K for(int i = 1; i < 10; i ++) { //Changing openGL data¡K ¡K. //ReDrawWin(); //To redraw window, cause the OpenGL data has changed. And the window will call SwapBuffer, to refresh buffer and pixels data. glReadPixels(0,0,bmpheader->biWidth, bmpheader ->biHeight,GL_BGR_EXT,GL_UNSIGNED_BYTE,bmBits); AVIGenerator .Add Frames(); } glReadBuffer(GL_FRONT); //=========================================================== 1.When de-active ReDrawWin() function, glReadPixels() could get one frame. But what I get is look like just before into the ¡§for¡¨ loop. (I think this is because the OpenGL data didn¡¦t refresh yet.) And the following frames in the ¡§for¡¨ loop seems didn¡¦t get successfully. Open AVI file and just see the same frame. (I am not sure that isn¡¦t success, or all success but look like the same.) So I suppose that my problem is that I didn¡¦t refresh my OpenGL data. Then I add the ReDrawWin() function. 2.When active ReDrawWin() function, and just add frames in the ¡§for¡¨ loop, the whole frames are all dark. Nothing I can see. I wonder know why the first frame I can get? But the following can¡¦t? Is there any wrong with OpenGL or Windows settings? Please tell me where my problem is.