anchor.diff:    (%2d-view-update-matrix view))
   
   (defun set-view-2d (view)
  -  (set-viewpoint (2d-view-mtx view) +matrix-identity+))
  +  (set-view (2d-view-mtx view) +matrix-identity+))
   
   (defun view-to-view (x y from-view to-view &optional (absolute t))
     (unless (or (zerop (2d-view-width from-view)) (zerop (2d-view-height from-view))
  
positive.code:   bbox
    shape
    texture
    (flip :none))
  
  (defun sprite-set-flip (it value)
  
negative.code: (defsetf sprite-flip sprite-set-flip)
  
  (defun create-sprite (x y width height texture &key (bbox (make-bbox)) (flip :none)
                                                      (angle 0) (color #(1.0 1.0 1.0 1.0)))
    (let ((sp (make-sprite :texture texture
                           :color color
                           :x x :y y :width width :height height
                           :bbox bbox :flip flip
                           :shape (create-rectangle-shape x y (+ x width) (+ y height)))))
  