anchor.diff:  (defparameter *ratio* (/ *width* *height*))
   
   (defun main-loop ()
  -  (defun keydown-actions (scancode)
  -    (cond
  -      ((sdl2:scancode= scancode :scancode-w) "W")
  -      ((sdl2:scancode= scancode :scancode-s) "S")
  -      ((sdl2:scancode= scancode :scancode-a) "A")
  -      ((sdl2:scancode= scancode :scancode-d) "D")))
  -
  -  (defun keyup-actions (scancode)
  -    (when (sdl2:scancode= scancode :scancode-escape)
  -      (sdl2:push-event :quit)))
  -
  -  (defun init ()
  -    (gl:enable :cull-face :lighting :light0 :depth-test)
  -    (gl:matrix-mode :projection)
  -    (gl:load-identity)
  -    (gl:ortho 0 2 0 2 -2 10)
  -;    (glu:perspective 45.0 *ratio* 0.1 10)
  -    (gl:matrix-mode :modelview)
  -    (gl:load-identity)
  -    (gl:clear-color 19/255 19/255 39/255 1.0) ; #131327 background color
  -    (gl:clear :color-buffer :depth-buffer))
  -
     (sdl2:with-init (:everything)
       (sdl2:with-window (win :w *width* :h *height* :flags '(:shown :opengl))
         (sdl2:with-gl-context (gl-context win)
           (sdl2:gl-make-current win gl-context)
           (sdl2:hide-cursor)
  -        (init)
  +        (gl:enable :cull-face :lighting :light0 :depth-test)
  +        (gl:matrix-mode :projection)
  +        (gl:load-identity)
  +        (gl:ortho 0 2 0 2 -2 10)
  +        ;; (glu:perspective 45.0 *ratio* 0.1 10)
  +        (gl:matrix-mode :modelview)
  +        (gl:load-identity)
  +        (gl:clear-color 19/255 19/255 39/255 1.0) ; #131327 background color
           (gl:clear :color-buffer :depth-buffer)
  +
           ;; todo: polygon instead?
           (gl:begin :quad-strip)
           (gl:material :front :ambient-and-diffuse #(1.0 0.0 0.0 1.0))
  
positive.code:         (sdl2:with-event-loop (:method :poll)
            (:keydown
             (:keysym keysym)
             (keydown-actions (sdl2:scancode-value keysym)))
  
            (:keyup
             (:keysym keysym)
             (keyup-actions (sdl2:scancode-value keysym)))
  
            (:idle
             ())
  
negative.code: (in-package #:cl-foo)
  
  (require :sdl2)
  
  