anchor.diff:        (sdl2:with-init (:everything)
   	(sdl2:with-window (win :title "Learn3D" :flags '(:shown)
   			       :w *x-res* :h *y-res*)
  -	  (setq *win* win)			       
  -	  (sdl2:with-renderer (renderer win :flags '(:software))
  -	    (setq 
  -	     *renderer* renderer
  -	     *tex* (sdl2:create-texture renderer :rgba8888 :streaming *x-res* *y-res*))
  +			       
  +	  (sdl2:with-renderer (renderer win :flags '(:accelerated :presentvsync))
   	    (sdl2:with-event-loop (:method :poll)
   	      (:idle
   	       ()
  
positive.code:      renderer
       sx1 sy1 sx2 sy2)))
  
  (defun draw-axes (&optional (renderer *renderer*))
    (sdl2:set-render-draw-color renderer 255 0 0 255)
    (draw-line 0.0 0.0 0.0 1.0 0.0 0.0 renderer)
    (sdl2:set-render-draw-color renderer 0 255 0 255)
  
negative.code:     
  (let ((coords (make-array 6 :element-type
  			  '(signed-byte 32))))
    (defun draw-triangle (tri renderer)
      (loop for i below 3 do
  	 (let* ((tmat (sb-cga:matrix* *pmat* *vmat* *rotmat*))
  		(tv (sb-cga:transform-point 
  