racket/collects/frtime/demos/push-pull-ball.rkt
2010-04-27 16:50:15 -06:00

32 lines
927 B
Racket

#lang frtime
(require frtime/animation)
(define radius (new-cell 20))
(define pos1
(rec pos
(until (make-posn 200 200)
(inf-delay
(let ([brnch (posn+ pos
(posn* (normalize (posn- mouse-pos pos))
(- (posn-diff pos mouse-pos) (sub1 radius))))])
(if (> (posn-diff pos mouse-pos) radius)
brnch
pos))))))
(define pos2
(rec pos
(until (make-posn 100 100)
(inf-delay
(let ([brnch (posn+ pos
(posn* (normalize (posn- pos1 pos))
(- (posn-diff pos pos1) (add1 (* 2 radius)))))])
(if (< (posn-diff pos pos1) (* 2 radius))
brnch
pos))))))
(display-shapes
(list
(make-circle pos1 radius "blue")
(make-circle pos2 radius "gray")))