anchor.diff:  
   (defun calc-light-position ()
     ;;NEXT-TODO:
  -  (glm:vec3 0.0 *light-height* 0.0))
  +  (let ((curr-time-through-loop (/ (sdl2:get-ticks) 1000.0))
  +	(ret (glm:vec4 0.0 *light-height* 0.0 1.0)))
  +    (setf (glm:vec. ret :x) (cos (* curr-time-through-loop
  +				    (* (coerce pi 'single-float) 2.0)
  +				    *light-radius*)))
  +    (setf (glm:vec. ret :z) (sin (* curr-time-through-loop
  +				    (* (coerce pi 'single-float) 2.0)
  +				    *light-radius*)))
  +    ret))
   
   (defun draw ()
     (let* ((model-matrix (make-instance 'glutil:matrix-stack))
  
positive.code: 	    
  	    (:keydown
  	     (:keysym keysym)
       	     (when (sdl2:scancode= (sdl2:scancode-value keysym) :scancode-t)
  
  	       )
  
  	     (when (sdl2:scancode= (sdl2:scancode-value keysym) :scancode-y)
  	       ;; toggle light rendering
  	       (setf *draw-light* (not *draw-light*)))
  
negative.code: 	 (light-pos-camera-space
  	  ;; TODO: make mat*vec smarter so we don't need to cast so much in code?
  	  (glm:vec4->vec3 (glm:mat*vec (glutil:top-ms model-matrix)
  				       world-light-pos))))
  
      (glutil:set-matrix model-matrix (glutil:calc-matrix *view-pole*))
  
  