1#!/usr/bin/env python
2
3'''
4Multiscale Turing Patterns generator
5====================================
6
7Inspired by http://www.jonathanmccabe.com/Cyclic_Symmetric_Multi-Scale_Turing_Patterns.pdf
8'''
9
10import numpy as np
11import cv2
12from common import draw_str
13import getopt, sys
14from itertools import count
15
16help_message = '''
17USAGE: turing.py [-o <output.avi>]
18
19Press ESC to stop.
20'''
21
22if __name__ == '__main__':
23    print help_message
24
25    w, h = 512, 512
26
27    args, args_list = getopt.getopt(sys.argv[1:], 'o:', [])
28    args = dict(args)
29    out = None
30    if '-o' in args:
31        fn = args['-o']
32        out = cv2.VideoWriter(args['-o'], cv2.VideoWriter_fourcc(*'DIB '), 30.0, (w, h), False)
33        print 'writing %s ...' % fn
34
35    a = np.zeros((h, w), np.float32)
36    cv2.randu(a, np.array([0]), np.array([1]))
37
38    def process_scale(a_lods, lod):
39        d = a_lods[lod] - cv2.pyrUp(a_lods[lod+1])
40        for i in xrange(lod):
41            d = cv2.pyrUp(d)
42        v = cv2.GaussianBlur(d*d, (3, 3), 0)
43        return np.sign(d), v
44
45    scale_num = 6
46    for frame_i in count():
47        a_lods = [a]
48        for i in xrange(scale_num):
49            a_lods.append(cv2.pyrDown(a_lods[-1]))
50        ms, vs = [], []
51        for i in xrange(1, scale_num):
52            m, v = process_scale(a_lods, i)
53            ms.append(m)
54            vs.append(v)
55        mi = np.argmin(vs, 0)
56        a += np.choose(mi, ms) * 0.025
57        a = (a-a.min()) / a.ptp()
58
59        if out:
60            out.write(a)
61        vis = a.copy()
62        draw_str(vis, (20, 20), 'frame %d' % frame_i)
63        cv2.imshow('a', vis)
64        if 0xFF & cv2.waitKey(5) == 27:
65            break
66    cv2.destroyAllWindows()
67