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Commit | Line | Data |
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7c673cae FG |
1 | /* |
2 | * Mandelbrot example: | |
3 | * | |
4 | * $ ./duk mandel.js | |
5 | * [...] | |
6 | */ | |
7 | ||
8 | function mandel() { | |
9 | var w = 76, h = 28, iter = 100; | |
10 | var i, j, k, c; | |
11 | var x0, y0, xx, yy, xx2, yy2; | |
12 | var line; | |
13 | ||
14 | for (i = 0; i < h; i++) { | |
15 | y0 = (i / h) * 2.5 - 1.25; | |
16 | ||
17 | for (j = 0, line = []; j < w; j++) { | |
18 | x0 = (j / w) * 3.0 - 2.0; | |
19 | ||
20 | for (k = 0, xx = 0, yy = 0, c = '#'; k < iter; k++) { | |
21 | /* z -> z^2 + c | |
22 | * -> (xx+i*yy)^2 + (x0+i*y0) | |
23 | * -> xx*xx+i*2*xx*yy-yy*yy + x0 + i*y0 | |
24 | * -> (xx*xx - yy*yy + x0) + i*(2*xx*yy + y0) | |
25 | */ | |
26 | ||
27 | xx2 = xx*xx; yy2 = yy*yy; | |
28 | ||
29 | if (xx2 + yy2 < 4.0) { | |
30 | yy = 2*xx*yy + y0; | |
31 | xx = xx2 - yy2 + x0; | |
32 | } else { | |
33 | /* xx^2 + yy^2 >= 4.0 */ | |
34 | if (k < 3) { c = '.'; } | |
35 | else if (k < 5) { c = ','; } | |
36 | else if (k < 10) { c = '-'; } | |
37 | else { c = '='; } | |
38 | break; | |
39 | } | |
40 | } | |
41 | ||
42 | line.push(c); | |
43 | } | |
44 | ||
45 | print(line.join('')); | |
46 | } | |
47 | } | |
48 | ||
49 | try { | |
50 | mandel(); | |
51 | } catch (e) { | |
52 | print(e.stack || e); | |
53 | } |