anchor.diff:  	(eval `(lambda (&key parent-transform projection-transform)
   		 (declare (optimize (speed 3)))
   		 (gl:matrix-mode :modelview)
  -		 (use-shader ,(shader this))
  +		 (when ,(shader this)
  +		   (use-shader ,(shader this)))
   		 ,@(loop
   		      with tex-unit = 0
   		      for (atr-or-uni name value) in (render-values this)
  
positive.code: (defmethod slow-render ((this entity))
    (gl:matrix-mode :modelview)
    ;;(use-transform this)
    (use-shader (shader this))
    (loop
       with tex-unit = 0
       for (atr-or-uni name value) in (render-values this)
  
negative.code: 		   (values bret iret)))
  	     
  	     
  (defun rec (primitives i distance u v index)
    )
  				   
  (defmethod triangle-intersection? ((this entity) start dir &key (vertex-name :vertices))
    (labels ((rec (primitives i distance u v index)
  	     (multiple-value-bind (new-distance new-u new-v)
  		 
  		 (ray-triangle-intersect? start dir (first (car primitives)) (second (car primitives)) (third (car primitives)))
  	       (when (and new-distance
  			  (or (null distance)
  