#!/usr/bin/env python3
import sys
import numpy as np
from PIL import Image

def depth_map(w, h):
    # simple demo: circular bump
    y, x = np.ogrid[:h, :w]
    cx, cy = w // 2, h // 2
    r = min(w, h) // 3
    d = ((x - cx)**2 + (y - cy)**2) <= r*r
    return d.astype(np.float32)

def stereogram(depth, pattern_w=64, max_shift=32):
    h, w = depth.shape
    img = np.random.randint(0, 256, (h, w), dtype=np.uint8)

    for y in range(h):
        for x in range(pattern_w, w):
            z = depth[y, x]
            shift = int(z * max_shift)
            src = x - pattern_w + shift
            if src >= 0:
                img[y, x] = img[y, src]
    return img

def main(argc, argv):
    w = int(argv[1]) if argc > 1 else 600
    h = int(argv[2]) if argc > 2 else 400
    out = argv[3] if argc > 3 else "stereogram.png"

    d = depth_map(w, h)
    s = stereogram(d)

    Image.fromarray(s).save(out)
    print(out)

if __name__ == "__main__":
    main(len(sys.argv), sys.argv)