   Simple Picking
  I have done more advanced picking in windows c++ but now i am working with opengl. All i need is very simple picking of 2D square objects, and it seems to me openGL has  some built in picking, if someone could point me to a really basic tutorial i would be thankfull, I have found some tutorials out there, even some on this site but so far they have all been part of a much bigger tutorial, making it hard to pick out the picking specific parts.   
  Refer to the RedBook Ch13.   ;  Thank you that helps.   