gistfile1.txt

surface
mandel()
{
        float window_size = 512.0;

        float xx, yy;
        float x0, y0;

        float max_iter = 255;
        float iter = 0;
        float tmp;

        float zoom = 2.0 * window_size;
        xx = -zoom * (s - 0.5) / window_size;
        x0 = -zoom * (s - 0.5) / window_size;

        yy = zoom * (t - 0.5) / window_size;
        y0 = zoom * (t - 0.5) / window_size;

        while ( ((xx * xx + yy * yy) <= (2.0*2.0)) && (iter < max_iter)) {
                tmp = xx * xx - yy * yy + x0;
                yy = 2.0 * xx * yy + y0;
                xx = tmp;

                iter = iter + 1;
        }

        if (iter == max_iter) {
                Ci = color(0, 0, 0);
        } else {
                Ci = color(iter / 255.0, iter / 255.0, iter / 127.0);   // make result bluish a bit.
        }

}