anchor.diff:  (defun2 viewport-resolution-y (viewport)
     (%viewport-resolution-y viewport))
   
  -;;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  +;;------------------------------------------------------------
   
   (defun2 viewport-origin (viewport)
     (v! (%viewport-origin-x viewport)
  
positive.code:                    "but we do have a gl context. This is a bug"
                     "because the GL context is not yet available")))))
  
  ;;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
  (defmethod dimensions ((viewport viewport))
    (viewport-dimensions viewport))
  
negative.code:         (%viewport-origin-y viewport) (floor (v:y value)))
    value)
  
  ;;------------------------------------------------------------
  
  (defun2 %viewport (viewport)
    (%gl:viewport
  