1 //参照FreeImage官网给出的CTextrueManager写的加载函数 2 //官方给的例子是用opengl3.0以下的旧GL写的，没有使用glGenerateMipmap(GL_TEXTURE_2D)来产生mipmap 3 //在GL3.0以后，渲染时默认是开启了MIPMAP的，如果不调用glGenerateMipmap来生成MIPMAP，则渲染出的贴图一片黑色 　　//另外要注意freeimage的颜色分量顺序是gbr,不知为什么，故这里fmt应传GL_BGR  4 GLuint CResMgr::LoadTextrue(const char* texFile, GLenum fmt, GLuint ifmt, GLuint level, GLuint border) { 5     FREE_IMAGE_FORMAT fifmt = FreeImage_GetFileType(texFile, 0); 6     if (fifmt == FIF_UNKNOWN) { 7         fifmt = FreeImage_GetFIFFromFilename(texFile); 8         if (fifmt == FIF_UNKNOWN) { 9             xsMsg(texFile, "图片加载失败:未知的格式", MB_ICONERROR);10             return 0;11         }12     }13 14     if (!FreeImage_FIFSupportsReading(fifmt)) {15         xMsg(texFile, "freeImage不支持该文件格式的读取", MB_ICONERROR);16         return 0;17     }18 19     FIBITMAP* dib = FreeImage_Load(fifmt, texFile);20     if (!dib) {21         xMsg(texFile, "freeImage_load失败", MB_ICONERROR);22         return 0;23     }24 25     BYTE* bits = FreeImage_GetBits(dib);26     GLuint width = FreeImage_GetWidth(dib);27     GLuint height = FreeImage_GetHeight(dib);28 29     if (!bits || width == 0 || height == 0) {30         xMsg(texFile, "freeImage_getbits, getwidth, getheight-failed", MB_ICONERROR);31         return 0;32     }33 34     GLuint texId;35     glGenTextures(1, &texId);36     glBindTexture(GL_TEXTURE_2D, texId);37     glTexImage2D(GL_TEXTURE_2D, level, ifmt, width, height, border, fmt, GL_UNSIGNED_BYTE, bits);38     39     glGenerateMipmap(GL_TEXTURE_2D); //注意，不加这句渲染出的贴图是一片黑色，40     FreeImage_Unload(dib);41     return texId;42 }