anchor.diff:      (gl:uniform-matrix-4fv *glyph-scale* imat)
       (setf *glyph-rotate* (gl:get-uniform-location *glyph-program* "rotateMatrix"))
       (gl:uniform-matrix-4fv *glyph-rotate* imat)
  +    (gl:enable-vertex-attrib-array +glyph-vertex-loc+)
  +    (gl:enable-vertex-attrib-array +glyph-attrib-loc+)
       (gl:use-program 0)
   
       (setf *bounding-box-program* (create-program +bounding-box-vs+ +bounding-box-fs+))
       (gl:use-program *bounding-box-program*)
  -    (gl:bind-attrib-location *bounding-box-program* 0 "vertex")
  +;    (gl:bind-attrib-location *bounding-box-program* 2 "vertex")
  +    (setf +bounding-box-vertex-loc+ (gl:get-attrib-location *bounding-box-program* "vertex"))
       (setf *bounding-box-color* (gl:get-uniform-location *bounding-box-program* "color"))
       (gl:uniformf *bounding-box-color* 0.0 0.0 0.0 1.0)
       (setf *bounding-box-size* (gl:get-uniform-location *bounding-box-program* "sizeMatrix"))
  
positive.code:       (gl:bind-buffer :array-buffer 0)
        (gl:bind-buffer :array-buffer box-buffer)
        (gl:buffer-data :array-buffer :static-draw
                        (make-gl-array (vector xmin ymax xmin ymin xmax ymin xmax ymax)))
        (gl:bind-buffer :array-buffer 0)
        (make-vstring :content str :xmin xmin :xmax xmax :ymin ymin :ymax ymax
                      :buffer buffer :box-buffer box-buffer :count (/ count 4)))))
  
negative.code:   (gl:stencil-op :keep :invert :invert)
    (gl:color-mask nil nil nil nil)
    (gl:use-program *glyph-program*)
  ;  (gl:enable-vertex-attrib-array 0)
  ;  (gl:enable-vertex-attrib-array 1)
    (gl:bind-buffer :array-buffer (vstring-buffer vs))
    (gl:vertex-attrib-pointer +glyph-vertex-loc+ 2 :float nil 16 0)
    (gl:vertex-attrib-pointer +glyph-attrib-loc+ 2 :float nil 16 8)
    (gl:draw-arrays :triangles 0 (vstring-count vs))
  ;  (gl:disable-vertex-attrib-array 0)
  ;  (gl:disable-vertex-attrib-array 1)
    ;(gl:use-program 0)
    (gl:disable :sample-alpha-to-coverage)
    (gl:stencil-func :notequal 0 1)
    (gl:stencil-op :keep :keep :keep)
    (gl:color-mask t t t t)
    (gl:use-program *bounding-box-program*)
  ;  (gl:enable-vertex-attrib-array 0)
    (gl:bind-buffer :array-buffer (vstring-box-buffer vs))
    (gl:vertex-attrib-pointer +bounding-box-vertex-loc+ 2 :float nil 0 0)
    (gl:draw-arrays :triangle-strip 0 4)
  ;  (gl:disable-vertex-attrib-array 0)
    (gl:use-program 0)
    (gl:disable :stencil-test))
  
  