//参照FreeImage官网给出的CTextrueManager写的加载函数

 //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

 //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

 GLuint CResMgr::LoadTextrue(const char* texFile, GLenum fmt, GLuint ifmt, GLuint level, GLuint border) {

     FREE_IMAGE_FORMAT fifmt = FreeImage_GetFileType(texFile, );

     if (fifmt == FIF_UNKNOWN) {

         fifmt = FreeImage_GetFIFFromFilename(texFile);

         if (fifmt == FIF_UNKNOWN) {

             xsMsg(texFile, "图片加载失败:未知的格式", MB_ICONERROR);

             return ;

         }

     }

     if (!FreeImage_FIFSupportsReading(fifmt)) {

         xMsg(texFile, "freeImage不支持该文件格式的读取", MB_ICONERROR);

         return ;

     }

     FIBITMAP* dib = FreeImage_Load(fifmt, texFile);

     if (!dib) {

         xMsg(texFile, "freeImage_load失败", MB_ICONERROR);

         return ;

     }

     BYTE* bits = FreeImage_GetBits(dib);

     GLuint width = FreeImage_GetWidth(dib);

     GLuint height = FreeImage_GetHeight(dib);

     if (!bits || width ==  || height == ) {

         xMsg(texFile, "freeImage_getbits, getwidth, getheight-failed", MB_ICONERROR);

         return ;

     }

     GLuint texId;

     glGenTextures(, &texId);

     glBindTexture(GL_TEXTURE_2D, texId);

     glTexImage2D(GL_TEXTURE_2D, level, ifmt, width, height, border, fmt, GL_UNSIGNED_BYTE, bits);

     glGenerateMipmap(GL_TEXTURE_2D); //注意，不加这句渲染出的贴图是一片黑色，

     FreeImage_Unload(dib);

     return texId;

 }