1 12687dd9 2023-08-04 jrmu ;; The first three lines of this file were inserted by DrScheme. They record metadata
2 12687dd9 2023-08-04 jrmu ;; about the language level of this file in a form that our tools can easily process.
3 12687dd9 2023-08-04 jrmu #reader(lib "htdp-intermediate-lambda-reader.ss" "lang")((modname |25.1|) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp")))))
4 12687dd9 2023-08-04 jrmu (define-struct ball (radius x y delta-x delta-y color))
6 12687dd9 2023-08-04 jrmu ;A ball is a structure
7 12687dd9 2023-08-04 jrmu ;(make-ball number number number number number symbol)
9 12687dd9 2023-08-04 jrmu ;draw-and-clear-ball : ball -> true
10 12687dd9 2023-08-04 jrmu (define (draw-and-clear-ball a-ball)
11 12687dd9 2023-08-04 jrmu (and (draw-solid-disk (make-posn (ball-x a-ball)
12 12687dd9 2023-08-04 jrmu (ball-y a-ball))
13 12687dd9 2023-08-04 jrmu (ball-radius a-ball)
14 12687dd9 2023-08-04 jrmu (ball-color a-ball))
15 12687dd9 2023-08-04 jrmu (sleep-for-a-while DELAY)
16 12687dd9 2023-08-04 jrmu (clear-solid-disk (make-posn (ball-x a-ball)
17 12687dd9 2023-08-04 jrmu (ball-y a-ball))
18 12687dd9 2023-08-04 jrmu (ball-radius a-ball)
19 12687dd9 2023-08-04 jrmu (ball-color a-ball))))
21 12687dd9 2023-08-04 jrmu ;move-ball : ball -> ball
22 12687dd9 2023-08-04 jrmu (define (move-ball a-ball)
23 12687dd9 2023-08-04 jrmu (make-ball (ball-radius a-ball)
24 12687dd9 2023-08-04 jrmu (+ (ball-x a-ball) (ball-delta-x a-ball))
25 12687dd9 2023-08-04 jrmu (+ (ball-y a-ball) (ball-delta-y a-ball))
26 12687dd9 2023-08-04 jrmu (ball-delta-x a-ball)
27 12687dd9 2023-08-04 jrmu (ball-delta-y a-ball)
28 12687dd9 2023-08-04 jrmu (ball-color a-ball)))
30 12687dd9 2023-08-04 jrmu ;out-of-bounds? : ball -> boolean
31 12687dd9 2023-08-04 jrmu (define (out-of-bounds? a-ball)
32 12687dd9 2023-08-04 jrmu (not (and (<= 0 (ball-x a-ball) WIDTH)
33 12687dd9 2023-08-04 jrmu (<= 0 (ball-y a-ball) HEIGHT))))
35 12687dd9 2023-08-04 jrmu ;move-until-out : ball -> true
36 12687dd9 2023-08-04 jrmu ;Move the ball until it is out of bounds.
38 12687dd9 2023-08-04 jrmu (define (move-until-out a-ball)
40 12687dd9 2023-08-04 jrmu [(out-of-bounds? a-ball) true]
41 12687dd9 2023-08-04 jrmu [(draw-and-clear-ball a-ball) (move-until-out (move-ball a-ball))]))
43 12687dd9 2023-08-04 jrmu (define VOLLEYBALL (make-ball 20 0 0 5 2 'black))
44 12687dd9 2023-08-04 jrmu (define BEACHBALL (make-ball 50 25 25 3 2 'green))
45 12687dd9 2023-08-04 jrmu (define BASEBALL (make-ball 10 470 470 -10 -14 'blue))
46 12687dd9 2023-08-04 jrmu (define TENNISBALL (make-ball 8 470 20 -6 8 'yellow))
48 12687dd9 2023-08-04 jrmu (define LISTOFBALLS (list VOLLEYBALL
51 12687dd9 2023-08-04 jrmu TENNISBALL))
54 12687dd9 2023-08-04 jrmu ;move-balls : (listof balls) -> true
55 12687dd9 2023-08-04 jrmu ;Moves alob (listof balls).
57 12687dd9 2023-08-04 jrmu (define (move-balls alob)
58 12687dd9 2023-08-04 jrmu (andmap move-until-out alob))
60 12687dd9 2023-08-04 jrmu ;move-simultaneous : (listof balls) -> true
61 12687dd9 2023-08-04 jrmu ;Moves alob simultaneously.
63 12687dd9 2023-08-04 jrmu (define (move-simultaneous alob)
65 12687dd9 2023-08-04 jrmu [(andmap out-of-bounds? alob) true]
66 12687dd9 2023-08-04 jrmu [else (and (andmap draw-and-clear-ball alob)
67 12687dd9 2023-08-04 jrmu (move-simultaneous (map move-ball alob)))]))
69 12687dd9 2023-08-04 jrmu (define WIDTH 500)
70 12687dd9 2023-08-04 jrmu (define HEIGHT 500)
71 12687dd9 2023-08-04 jrmu (define DELAY 1)
72 12687dd9 2023-08-04 jrmu (start WIDTH HEIGHT)
73 12687dd9 2023-08-04 jrmu ;(move-balls LISTOFBALLS)
74 12687dd9 2023-08-04 jrmu (move-simultaneous LISTOFBALLS)
