OpenGL为什么有的图像可以读取有的读取不了

#define  BMP_Header_Length 54

GLuint MyGLWidget::load_texture(const char* file_name)

{

    GLint width, height, total_bytes;

    GLubyte* pixels = 0;

    GLuint texture_ID = 0;

    FILE* pFile = fopen(file_name, "rb");

    if( pFile == 0 )

     return 0;

    fseek(pFile, 0x0012, SEEK_SET);

    fread(&width, sizeof(width), 1, pFile);

    fread(&height, sizeof(height), 1, pFile);

    fseek(pFile, BMP_Header_Length, SEEK_SET);

     {

        GLint line_bytes = width * 3;

        while( line_bytes % 4 != 0 )

           ++line_bytes;

        total_bytes = line_bytes * height;

     }

    pixels = NULL;

    pixels=(GLubyte*)malloc(total_bytes);



    if( pixels == 0 )

     {

        fclose(pFile);

        return 0;

     }







         GLint max;

         glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max);

         if( !power_of_two(width)

           || !power_of_two(height)

           || width > max

           || height > max )

          {

             const GLint new_width = 256;

             const GLint new_height = 256;

             GLint new_line_bytes, new_total_bytes;

             GLubyte* new_pixels = 0;

                  new_line_bytes = new_width * 3;

             while( new_line_bytes % 4 != 0 )

                  ++new_line_bytes;

             new_total_bytes = new_line_bytes * new_height;

             new_pixels = (GLubyte*)malloc(new_total_bytes);

             if( new_pixels == 0 )

              {

                 free(pixels);

                 fclose(pFile);

                 return 0;

              }

              gluScaleImage(GL_RGB,width, height, GL_UNSIGNED_BYTE, pixels,new_width, new_height, GL_UNSIGNED_BYTE, new_pixels);

              free(pixels);

              pixels = new_pixels;

              width = new_width;

              height = new_height;

          }

         if( fread(pixels, total_bytes, 1, pFile) <= 0 )

          {

             free(pixels);

             fclose(pFile);

             return 0;

          }



    glGenTextures(1, &texture_ID);



    if( texture_ID == 0 )

     {

        free(pixels);

        fclose(pFile);

        return 0;

     }



     glBindTexture(GL_TEXTURE_2D, texture_ID);

     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);

     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

     glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_BGR_EXT, GL_UNSIGNED_BYTE, pixels);

     free(pixels);

     fclose(pFile);

     return texture_ID;}