Chaotic Scattering: Gaspard-Rice System by _vince

[The Librarian]

Chaotic Scattering: Gaspard-Rice system

Author: @_vince
Source: qb64.org Forum
URL: https://www.qb64.org/forum/index.php?topic=78.0
Version: 2018
Tags: [geometry], [ray reflections]

Description:
https://en.wikipedia.org/wiki/Chaotic_scattering

Demo of the Gaspard-Rice system as described above.  Left-click to change location.

Source Code:

Code: QB64: [Select]

1. DEFINT A-Z
2. sw = 640
3. sh = 480
4. DIM pi AS DOUBLE
5. DIM t AS DOUBLE
6. DIM a AS DOUBLE, b AS DOUBLE
7. DIM a1 AS DOUBLE, a2 AS DOUBLE
8.  
9. DIM x AS DOUBLE, y AS DOUBLE
10. DIM x0 AS DOUBLE, y0 AS DOUBLE
11. DIM x1 AS DOUBLE, y1 AS DOUBLE
12.  
13. pi = 3.141593
14.  
15. SCREEN _NEWIMAGE(sw, sh, 12)
16.  
17. r = 150
18. rr = 100
19.  
20. xx = sw / 2
21. yy = sh / 2
22.  
23. DO
24.     DO
25.         mx = _MOUSEX
26.         my = _MOUSEY
27.         mb = _MOUSEBUTTON(1)
28.     LOOP WHILE _MOUSEINPUT
29.  
30.     LINE (0, 0)-(sw, sh), 0, BF
31.     FOR b = 0 TO 2 * pi STEP 2 * pi / 3
32.         CIRCLE (r * COS(b) + sw / 2, r * SIN(b) + sh / 2), rr
33.     NEXT
34.  
35.     IF mb THEN
36.         f = -1
37.         DO WHILE mb
38.             DO
39.                 mb = _MOUSEBUTTON(1)
40.             LOOP WHILE _MOUSEINPUT
41.         LOOP
42.         FOR b = 0 TO 2 * pi STEP 2 * pi / 3
43.             x1 = r * COS(b) + sw / 2
44.             y1 = r * SIN(b) + sh / 2
45.             IF (mx - x1) ^ 2 + (my - y1) ^ 2 < rr * rr THEN f = 0
46.         NEXT
47.         IF f THEN
48.             xx = mx
49.             yy = my
50.             f = -1
51.         END IF
52.     END IF
53.  
54.     x0 = xx
55.     y0 = yy
56.  
57.     a = _ATAN2(my - yy, mx - xx)
58.  
59.     t = 0
60.     DO
61.         t = t + 1
62.         x = t * COS(a) + x0
63.         y = t * SIN(a) + y0
64.         IF x < 0 OR x > sw OR y < 0 OR y > sh THEN EXIT DO
65.         FOR b = 0 TO 2 * pi STEP 2 * pi / 3
66.             x1 = r * COS(b) + sw / 2
67.             y1 = r * SIN(b) + sh / 2
68.             IF (x - x1) ^ 2 + (y - y1) ^ 2 < rr * rr THEN
69.                 a1 = _ATAN2(y - y1, x - x1)
70.                 a2 = 2 * a1 - a - pi
71.  
72.                 LINE (x0, y0)-(x, y), 14
73.  
74.                 x0 = x
75.                 y0 = y
76.                 a = a2
77.                 t = 0
78.                 EXIT FOR
79.             END IF
80.         NEXT
81.     LOOP
82.  
83.     LINE (x0, y0)-(x, y), 14
84.  
85.     _DISPLAY
86.     _LIMIT 50
87. LOOP UNTIL _KEYHIT = 27
88. SYSTEM
89.