One Function to Load Image and Create OpenGL Texture from File, in C++

leothenerd 2:58 am on November 18, 2009 | Answers: 1    
Tags: file (47), function (49), image (24), opengl (8), texture (3)

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• leothenerd 2:58 am on November 18, 2009
  

  
  loadImage(string fileName, GLuint *texture)
  {
    assert(texture != NULL);
  
    SDL_Surface *surface;
    GLenum texture_format;
    GLint  nOfColors;
    if ( (surface = IMG_Load(fileName.c_str())) ) 
    { 
      nOfColors = surface->format->BytesPerPixel;
      if (nOfColors == 4) 
      {
        if (surface->format->Rmask == 0x000000ff)
          texture_format = GL_RGBA;
        else
          texture_format = GL_BGRA;
      } else if (nOfColors == 3)  
      {
        if (surface->format->Rmask == 0x000000ff)
          texture_format = GL_RGB;
        else
          texture_format = GL_BGR;
      } 
    
      glGenTextures( 1, texture );
  
      // Bind the texture object
      glBindTexture( GL_TEXTURE_2D, *texture );
  
      // Set the texture's stretching properties
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
      glTexImage2D( GL_TEXTURE_2D, 0, nOfColors, surface->w, surface->h, 0,
        texture_format, GL_UNSIGNED_BYTE, surface->pixels );
    } 
    else 
    {
      cout << "cannot load the file: " << fileName << endl;
    }    
    if ( surface ) 
      SDL_FreeSurface( surface);
  }