anchor.diff:             (gl:vertex 0.25 0.75 0))
            (gl:flush)
            (glop:swap-buffers win))))
  +
  +(defun test-multiple-windows ()
  +  (let ((window-1 (glop:create-window "window 1" 800 600))
  +	(window-2 (glop:create-window "window 2" 800 600)))
  +    (when (and window-1 window-2)
  +      (unwind-protect 
  +	   (progn
  +	     (glop:attach-gl-context window-1 (glop:window-gl-context window-1))
  +	     (gl:clear-color 0.3 0.3 1.0 0)
  +	     ;; setup view
  +	     (gl:matrix-mode :projection)
  +	     (gl:load-identity)
  +	     (gl:ortho 0 1 0 1 -1 1)
  +	     (glop:attach-gl-context window-2 (glop:window-gl-context window-2))
  +	     (gl:clear-color 0.3 0.3 1.0 0)
  +	     ;; setup view
  +	     (gl:matrix-mode :projection)
  +	     (gl:load-identity)
  +	     (gl:ortho 0 1 0 1 -1 1)
  +	     (loop 
  +	       while (and (glop:dispatch-events window-1 :blocking nil)
  +			 (glop:dispatch-events window-2 :blocking nil)) do
  +			   (glop:attach-gl-context window-1 (glop:window-gl-context window-1))
  +			   (gl:clear :color-buffer)
  +			   (gl:color 1 1 1)
  +			   (gl:with-primitive :polygon
  +			     (gl:vertex 0.25 0.25 0)
  +			     (gl:vertex 0.75 0.25 0)
  +			     (gl:vertex 0.75 0.75 0)
  +			     (gl:vertex 0.25 0.75 0))
  +			   (gl:flush)
  +			   (glop:swap-buffers window-1)
  +			   (glop:attach-gl-context window-2 (glop:window-gl-context window-2))
  +			   (gl:clear :color-buffer)
  +			   (gl:color 1 1 1)
  +			   (gl:with-primitive :polygon
  +			     (gl:vertex 0.25 0.25 0)
  +			     (gl:vertex 0.75 0.25 0)
  +			     (gl:vertex 0.75 0.75 0)
  +			     (gl:vertex 0.25 0.75 0))
  +			   (gl:flush)
  +			   (glop:swap-buffers window-2)))
  +	(glop:destroy-window window-1)
  +	(glop:destroy-window window-2)))))
positive.code: (defmethod glop:on-key (window state key)
    (format t "Key: ~S~%" key)
    (when (eql key #\Escape)
      (glop:push-close-event window))
    (when (and (eql key #\f) (eql state :press))
      (glop:toggle-fullscreen window)))
  
  (defmethod glop:on-button (window state button)
    (declare (ignore window state))
  
negative.code:          (glop:swap-buffers win))))
  
  (defun test-gl-hello-fullscreen ()
    (defmethod glop:on-key :after (window state key)
      (format t "Key: ~S~%" key)
      (when (and (eql key #\f) (eql state :press))
        (glop:toggle-fullscreen window)))
    (glop:with-window (win "Glop test window" 800 600 :fullscreen t)
      (format t "Created window: ~S~%" win)
      ;; GL init
  