ray.lisp

   1
   2
   3 (in-package :tuple-trace)
   4
   5 ;; this is a small enough thing it might be a primitive in cl-tuples..
   6 (def-tuple-class ray
   7     (:tuples
   8      ((origin :type vector3d)
   9       (direction :type vector3d))))
  10
  11
  12 (defun make-ray (xo yo zo xr yr zr)
  13   (let ((result
  14          (make-instance 'ray
  15                         :origin (make-vector3d* xo yo zo)
  16                         :direction (make-vector3d* xr yr zr))))
  17     result))
  18
  19 (defmethod distance-of ((self ray))
  20   (vector3d-length (direction-of self)))
  21
  22 (defmethod direction-normal-of ((self ray))
  23   (vector3d-normal (direction-of self)))
  24
  25 (def-tuple-op extrapolate
  26     ((origin vector3d (xo yo zo))
  27      (direction vector3d (xd yd zd))
  28      (alpha single-float))
  29   (:return vector3d
  30            (vector3d*
  31             (+ xo (* xd alpha))
  32             (+ yo (* yd alpha))
  33             (+ zo (* zd alpha)))))
  34
  35 (defmethod point-on ((self ray) interval)
  36   (extrapolate
  37    (origin-of self)
  38    (direction-of self)
  39    interval))
  40
  41 ;; test code
  42 ;; (defparameter *ray* (make-ray 0.0 1.0 0.0 0.0 -1.0 0.0))
  43 ;; (direction-of *ray*)
  44 ;; (distance-of *ray*)
  45 ;; (direction-normal-of  *ray*)
  46 ;; (setf (direction-of *ray*) #{ 0.0 -2.0 0.0 })
  47 ;; (direction-normal-of *ray*)
  48 ;; (point-on *ray* 4.0)