Function: bb-trace-ray-2

bb-trace-ray-2 is a byte-compiled function defined in blackbox.el.gz.

Signature

(bb-trace-ray-2 FIRST X DX Y DY)

Source Code

;; Defined in /usr/src/emacs/lisp/play/blackbox.el.gz
(defun bb-trace-ray-2 (first x dx y dy)
  (cond
   ((and (not first)
	 (bb-outside-box x y))
    (cons x y))
   ((member (cons (+ x dx) (+ y dy)) bb-board)
    'hit)
   ((member (cons (+ x dx dy) (+ y dy dx)) bb-board)
    (bb-trace-ray-2 nil x (- dy) y (- dx)))
   ((member (cons (+ x dx (- dy)) (+ y dy (- dx))) bb-board)
    (bb-trace-ray-2 nil x dy y dx))
   (t
    (bb-trace-ray-2 nil (+ x dx) dx (+ y dy) dy))))