anchor.diff:     (source
       :initarg :source)
      texture
  -   (size
  -    :reader size))
  +   size)
     (:documentation
      "Wrapper over an Open GL texture."))
   
  
positive.code:          (sdl-base::pixel-data pixels)))
      (values texture surface)))
  
  (defmethod texture ((image image))
    (if (slot-boundp image 'texture)
        (slot-value image 'texture)
        (with-slots (source) image
  
negative.code:           (setf (slot-value image 'texture) texture
                  (slot-value image 'size)
                  (complex (sdl:width surface) (sdl:height surface)))
            (values texture surface)))))
  
  (defmethod size ((image image))
    ;; Automatically load the image texture.
    (texture image)
    (slot-value image 'size))
  
  (defgeneric x (object)
    (:method ((n number)) (realpart n)))
  