anchor.diff:                                  :element-type p-format
                                   :row-alignment 1)))
       (setf (gpu-buffer-bound (cepl-context) :pixel-pack-buffer) nil)
  -    (pack-pixels-from-texture src p-format 1 (c-array-pointer c-array))
  +    (pack-pixels-from-texture src p-format 1 (c-array-pointer c-array)
  +                              (cepl.c-arrays:c-array-byte-size c-array))
       c-array))
   
   (defn copy-texture-backed-gpu-array-to-c-array ((src gpu-array-t)
  
positive.code:   (let ((pixel-format (lisp-type->pixel-format
                         (c-array-element-type dst))))
      (setf (gpu-buffer-bound (cepl-context) :pixel-pack-buffer) nil)
      (pack-pixels-from-texture src
                                pixel-format
                                (c-array-row-alignment dst)
                                (c-array-pointer dst)))
    dst)
  
  (defn copy-texture-backed-gpu-array-to-new-buffer-backed-gpu-array
  
negative.code:   (let ((pixel-format (lisp-type->pixel-format dst)))
      (setf (gpu-buffer-bound (cepl-context) :pixel-pack-buffer)
            (gpu-array-bb-buffer dst))
      (pack-pixels-from-texture
       src
       pixel-format
       (gpu-array-bb-row-alignment dst)
       (cffi:make-pointer
        (gpu-array-bb-offset-in-bytes-into-buffer dst))
       (cepl.c-arrays::%gl-calc-byte-size
        (gpu-array-bb-element-byte-size dst)
        (gpu-array-dimensions src)
        (gpu-array-bb-row-alignment dst))))
    dst)
  
  (defn copy-texture-backed-gpu-array-to-new-lisp-data ((src gpu-array-t))
  