anchor.diff:  smooth out vec3 theColor;
   
   vec3 in_Color = vec3(1.0, 0.0, 1.0);
  -vec4 lightDir = vec4(-0.577350, -0.577350, -0.577350, 0);
   
  +uniform vec4 lightDir;
   uniform mat4 projectionMatrix;
   uniform mat4 cameraMatrix;
   uniform mat4 modelMatrix;
  
positive.code:                     (sb-cga:vec 0.0 0.0 -5.0)
                      (sb-cga:vec 0.0 1.0 0.0)))
  
  (defmethod glop:on-event :after ((window cube-window) (event glop:expose-event))
    (unless (exposed window)
      (let* ((cube (lpsg:make-cube-shape))
  
negative.code:                            :shaders (list (make-instance 'lpsg:shader
                                                           :shader-type :vertex-shader
                                                           :source *vertex-shader-source*
                                                           :usets '(camera model light))
                                            (make-instance 'lpsg:shader
                                                           :shader-type :fragment-shader
                                                           :source *fragment-shader-source*
  