| /* |
| * Mandelbrot example: |
| * |
| * $ ./duk mandel.js |
| * [...] |
| */ |
| |
| function mandel() { |
| var w = 76, h = 28, iter = 100; |
| var i, j, k, c; |
| var x0, y0, xx, yy, xx2, yy2; |
| var line; |
| |
| for (i = 0; i < h; i++) { |
| y0 = (i / h) * 2.5 - 1.25; |
| |
| for (j = 0, line = []; j < w; j++) { |
| x0 = (j / w) * 3.0 - 2.0; |
| |
| for (k = 0, xx = 0, yy = 0, c = '#'; k < iter; k++) { |
| /* z -> z^2 + c |
| * -> (xx+i*yy)^2 + (x0+i*y0) |
| * -> xx*xx+i*2*xx*yy-yy*yy + x0 + i*y0 |
| * -> (xx*xx - yy*yy + x0) + i*(2*xx*yy + y0) |
| */ |
| |
| xx2 = xx*xx; yy2 = yy*yy; |
| |
| if (xx2 + yy2 < 4.0) { |
| yy = 2*xx*yy + y0; |
| xx = xx2 - yy2 + x0; |
| } else { |
| /* xx^2 + yy^2 >= 4.0 */ |
| if (k < 3) { c = '.'; } |
| else if (k < 5) { c = ','; } |
| else if (k < 10) { c = '-'; } |
| else { c = '='; } |
| break; |
| } |
| } |
| |
| line.push(c); |
| } |
| |
| print(line.join('')); |
| } |
| } |
| |
| try { |
| mandel(); |
| } catch (e) { |
| print(e.stack || e); |
| } |