   Great tutorials!
  The tutorials on your page are really great, NeHe! I''ve never seen such detailed explanations before... After I''ve worked through the first one (yes, I''m a beginner), I''ve got two questions:Why don''t you use global variables for height, width, ...?Why didn''t you write a function for all display changes, like the following one?BOOL ChangeGLDisplay(int width, int height, int bits, bool fullscreenflag){KillGLWindow();fullscreen = fullscreenflag;if (!CreateGLWindow(title, width, height, bits, fullscreen))    // title is global{return FALSE;}return TRUE;}  