anchor.diff:  	(load-program "DirVertexLighting_PN.vert" "ColorPassthrough.frag"))
     (setf *vertex-diffuse-color*
   	(load-program "DirVertexLighting_PCN.vert" "ColorPassthrough.frag"))
  -
     (setf *white-amb-diffuse-color*
   	(load-program "DirAmbVertexLighting_PN.vert" "ColorPassthrough.frag"))
     (setf *vertex-amb-diffuse-color*
  
positive.code:       (glutil:apply-matrix model-matrix (glutil:calc-matrix *objt-pole*))
        ;; Render the Cylinder
        (glutil:with-transform (model-matrix)
  
  	  ;; TODO: here we see the limitation of the WITH-TRANSFORM macro, it can't check
  	  ;; for transform keywords inside forms yet, hence we need to leave them in their
  	  ;; verbose form
  	  (when *scale-cyl-p*
  	    ;; :scale 1.0 1.0 0.2		;doesn't work!
  	    (GLUTIL::SCALE MODEL-MATRIX (GLM:VEC3 1.0 1.0 0.2)))
  	  
  	  (gl:use-program (the-program *vertex-diffuse-color*))
  
  	(gl:uniform-matrix (model-to-camera-matrix-unif *vertex-diffuse-color*) 4
  			   (vector (glutil:top-ms model-matrix)) NIL)
  
negative.code: 	    (:keydown
  	     (:keysym keysym)
       	     (when (sdl2:scancode= (sdl2:scancode-value keysym) :scancode-t)
  	       (setf *show-ambient-p* (not *show-ambient-p*))
  	       (if *show-ambient-p*
  		   (print "Ambient Lighting On.")
  		   (print "Ambient Lighting Off.")))
  
  	     (when (sdl2:scancode= (sdl2:scancode-value keysym) :scancode-space)
  	       ;; toggle color on cylinder
  	       (setf *draw-colored-cyl* (not *draw-colored-cyl*)))
  
  	     (when (sdl2:scancode= (sdl2:scancode-value keysym) :scancode-escape)
  	       (sdl2:push-event :quit)))
  