anchor.diff:      :initform nil)
      (vert-shader
       :reader vert-shader
  +    :initform nil)
  +   (geo-shader
  +    :reader geo-shader
       :initform nil)
      (attributes
       :reader attributes 
  
positive.code: 					fragment-shader-text))
      (print "Compiling fragment shader...")
      (gl:compile-shader fs)
      (print (gl:get-shader-info-log vs))
      (unless (gl:get-shader fs :compile-status)
        (error "Could not compile fragment shader!"))
  
  
      (setf program (gl:create-program))
      ;; You can attach the same shader to multiple different programs.
      (gl:attach-shader program vs)
      (gl:attach-shader program fs)
      ;; Don't forget to link the program after attaching the
      ;; shaders. This step actually puts the attached shader together
      ;; to form the program.
  
negative.code:       (gl:detach-shader program fs))
  
      (when vs (gl:delete-shader vs))
      (when fs (gl:delete-shader fs))
      (when geo (gl:delete-shader geo))
  
      (when program (gl:delete-program program))
  
  