(defun sdl-backend ()
  (make-instance 'rm::sdl-window
                 :width 320 :height 240
                 :title-caption "Using OpenRM as a backend for SDL."
                 :icon-caption "Using OpenRM as a backend for SDL.")
  (make-instance 'rm:scene
                 :window (rm::default-window)
                 :camera (make-instance 'rm::camera-2d)
                 :viewport #(0.0 0.0 1.0 1.0)
                 :compute-view-from-geometry nil) 
  (let* ((surface (sdl:create-surface 100 100))
         (image (rm::load-image surface))
         (sprite (rm::new-sprite :xy/z (calculate-image-center (rm::default-window) image)
                                 :images image)))
    (rm::add-node sprite (rm::default-scene))
  
    (setf (sdl:frame-rate) nil)  
    (sdl:with-events ()
      (:key-down-event ()
       (sdl:push-quit-event))
      (:quit-event () t)
      (:idle ()
       (sdl:fill-surface (sdl:color :r (random 255) :g (random 255) :b (random 255) :a (random 255))
                         :surface surface)
       (rm::render (rm::default-window)))))
  (rm::clean-up))