在vc 6中设置好opengl开发环境,视口的大小设置成与客户区大小

1、在vc 6中设置好opengl开发环境，视口的大小设置成与客户区大小一样，欲将客户区的图像保存为24位真彩色位图，源代码如下，可是存在这样的问题：程序运行，窗口刚创建时（此时不拉动边框改变客户区大小），可以正常保存。当最大化窗口或将最大化窗口复原，都可以正常保存。而当人为拉动边框改变客户区大小后，保存的图像出现问题，如下：调试信息如下：源代码如下：void CMySDOpenGLView:OnCaptureImage() /保存位图的消息函数/ TODO: Add your command handler code hereCString s("Windows Bitmap(*.bm

2、p)|*.bmp|");CFileDialog fd(FALSE,"bmp",0,OFN_OVERWRITEPROMPT|OFN_HIDEREADONLY|OFN_PATHMUSTEXIST,s);if(fd.DoModal()=IDOK)BeginWaitCursor();int viewport4;glGetIntegerv(GL_VIEWPORT,viewport); bool success = false; DWORD nFileType=0;if(strcmp(fd.GetFileExt(),"bmp")=0) nFileType=

3、1; if(nFileType=1)success=m_imagecapture.CaptureGLBufferToBMP(fd.GetPathName(),/调用保存位图类的 viewport0,viewport1,/函数保存位图 viewport2,viewport3);else / Invalid file extension specified. MessageBox("WTF? Unknown file extension specified for screen capture.n","Error",MB_OK); if (!success)

4、 char errorMsg64; if(nFileType = 0) sprintf(errorMsg, "Specified file extension is not recognized."); else sprintf(errorMsg, "Could not save image file."); MessageBox(errorMsg, "Error", MB_OK | MB_ICONERROR); EndWaitCursor();保存位图类的定义class CImageCapturepublic:CImageCaptu

5、re();virtual CImageCapture();bool CaptureGLBufferToBMP(CString filename, int x, int y, int width, int height);int WriteBitmapFile(CString filename, int width, int height, unsigned char *imageData);CImageCapture:CImageCapture()CImageCapture:CImageCapture()bool CImageCapture:CaptureGLBufferToBMP(CStri

6、ng filename, int x, int y, int width, int height)void* imageData = malloc(width*height*3);/ allocate memory for the imageDatamemset(imageData, 0, width*height*3); / clear imageData memory contents/ read the image data from the windowglReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, (unsign

7、ed char*)imageData);/ write the image data to a fileWriteBitmapFile(filename, width, height, (unsigned char*)imageData);/ free the image data memoryfree(imageData);return true;/ WriteBitmapFile()/ desc: takes image data and saves it into a 24-bit RGB .BMP file/ with width X height dimensionsint CIma

8、geCapture:WriteBitmapFile(CString filename, int width, int height, unsigned char *imageData)FILE *filePtr;/ file pointerBITMAPFILEHEADER bitmapFileHeader;/ bitmap file headerBITMAPINFOHEADER bitmapInfoHeader;/ bitmap info headerunsigned int imageIdx;/ used for swapping RGB->BGRunsigned char tempR

9、GB;/ used for swapping/ open file for writing binary modefilePtr = fopen(filename, "wb");if (!filePtr)return 0;/ define the bitmap file headerbitmapFileHeader.bfSize = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+(4*(width*24+31)/32) * height);bitmapFileHeader.bfType = 0x4D42;bitmapFi

10、leHeader.bfReserved1 = 0;bitmapFileHeader.bfReserved2 = 0;bitmapFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);/ define the bitmap information headerbitmapInfoHeader.biSize = sizeof(BITMAPINFOHEADER);bitmapInfoHeader.biPlanes = 1;bitmapInfoHeader.biBitCount = 24;/ 24-bitb

11、itmapInfoHeader.biCompression = BI_RGB;/ no compressionbitmapInfoHeader.biSizeImage = 4*(width*24+31)/32) * height;/ width * height * (RGB bytes)bitmapInfoHeader.biXPelsPerMeter = 0;bitmapInfoHeader.biYPelsPerMeter = 0;bitmapInfoHeader.biClrUsed = 0;bitmapInfoHeader.biClrImportant = 0;bitmapInfoHead

12、er.biWidth = width;/ bitmap widthbitmapInfoHeader.biHeight = height;/ bitmap height/ switch the image data from RGB to BGRfor (imageIdx = 0; imageIdx < bitmapInfoHeader.biSizeImage; imageIdx+=3)tempRGB = imageDataimageIdx;imageDataimageIdx = imageDataimageIdx + 2;imageDataimageIdx + 2 = tempRGB;/

13、add empty Byte to every row, if this row cannot be divided exactly by 4. unsigned char *imageDataAfterAdding =(unsigned char *) malloc(4*(width*24+31)/32) * height);memset(imageDataAfterAdding, 0, 4*(width*24+31)/32) * height); for(int k=0; k<height; k+)for(int i=0; i<width*3; i+)imageDataAfterAddingk*width*3+i+k*(4*(width*24+31)/32)-width*3)= imageDatak*width*3+i;/ write the bitmap file headerfwrite(&bitmapFileHeader, 1, sizeof(BITMAPFILEHEADER), filePtr);/ write the bitmap info headerfwrite(&bitmapInfoHeader, 1, sizeof(B