scene.lisp

   1
   2 (in-package :tuple-trace)
   3
   4 (defclass scene ()
   5   ((primitives :accessor primitives-of
   6                :initform (make-array 0
   7                                      :element-type 'primitive
   8                                      :adjustable t
   9                                      :fill-pointer 0))))
  10
  11 (defgeneric primitive-of (scene index)
  12   (:method ((scene scene) index)
  13     (aref (primitives-of scene) index)))
  14
  15 (defgeneric add-primitive (scene primitive)
  16   (:method  ((scene scene) primitive)
  17     (vector-push-extend primitive (primitives-of scene))))
  18
  19 (defmethod (setf primitive-of) (primitive (scene scene) index)
  20   (setf (aref (primitives-of scene) index) primitive))
  21
  22 (defun make-scene (&rest primitives)
  23   (let
  24       ((result (make-instance 'scene)))
  25     (loop
  26        for primitive in primitives
  27        do
  28          (add-primitive result primitive))
  29     result))