anchor.diff:    (/ y spritesheet-height))
   
   (defun draw (px0 py0 px1 py1 spritesheet-width spritesheet-height &key (xshift 0) (yshift 0))
  +  "gets pixel coordinates converts them into tex coordinates and draws them. It is recommended to leave some space between objects on a spritesheet for this function to accurately draw the specified object" 
     (gl:enable :blend)
     (gl:blend-func :src-alpha :one-minus-src-alpha)
     (let* ((tx0 (pixel-x-to-texcoord px0 spritesheet-width))
  
positive.code:   (gl:flush))
  
  (defun append-frame-list (frame-list pixel-coord-list)
    (setf frame-list (mapcar #'append frame-list pixel-coord-list)))
  
  (defun pixel-coord-list (path num-of-columns num-of-rows
  
negative.code: 	 collect columns)))
  
  (defun row-list (frames sprite-row-start sprite-row-end)
    "collect the sprite row coordinates on a spritesheet"
    (if (<= sprite-row-end 0)
        (loop repeat frames
  	 collect sprite-row-start)
  