/*
 *  call-seq:
 *    pixels  ->  String
 *
 *  Return a string of pixel data for the Surface. Most users will not
 *  need to use this method. If you want to convert a Surface into an
 *  OpenGL texture, pass the returned string to the TexImage2D method
 *  of the ruby-opengl library. (See samples/demo_gl_tex.rb for an example.)
 *
 *  (Please note that the dimensions of OpenGL textures must be powers of 2
 *  (e.g. 64x128, 512x512), so if you want to use a Surface as an OpenGL
 *  texture, the Surface's dimensions must also be powers of 2!)
 */
VALUE rbgm_surface_pixels( VALUE self )
{
        SDL_Surface *surf;
        Data_Get_Struct(self, SDL_Surface, surf);
        return rb_str_new(surf->pixels, (long)surf->pitch * surf->h);
}