repos / gbc

mandelbrot.b

 1W 80;
 2H 40;
 3IT 100;
 4
 5f 1000;
 6
 7gradient "@%#*+=-:. ";
 8
 9m(cr,ci) {
10    auto a, b, i, tmp;
11    cr -= 3*W/4;
12    ci -= H/2;
13
14    cr = (cr * f * 3) / W;
15    ci = (ci * f * 3) / H;
16
17    a = b = 0;
18
19    i = 0; while (i < IT) {
20        if (a*a/f + b*b/f > 2*2*f) {
21            return (9 - (i*10 / IT));
22        }
23
24        tmp = (a*a - b*b)/f + cr;
25        b = (a*b)/f*2 + ci;
26        a = tmp;
27
28        i++;
29    }
30
31    return (0);
32}
33
34main() {
35    extrn char, putchar;
36
37    // we can't use more precision on 16-bit systems.
38    if (&0[1] <= 2) {
39        f = 50;
40        IT = 90;
41    }
42
43    auto i, j;
44    j = 0; while (j < H) {
45        i = 0; while (i < W) {
46            putchar(char(gradient, m(i,j)));
47            i++;
48        }
49        putchar('\n');
50
51        j++;
52    }
53}