Mandelbrot - frame

gistfile1.c

void mandelbrot_frame(double zoom, int max_iter, int xofs, int yofs) {
	double zx = 0, zy = 0, cx = 0, cy = 0;

        /* enumerate all of the rows */
	for (int y = 0; y < 200; y ++) {

                /* enumerate all of the columns */
		for (int x = 0; x < 320; x ++) {

                        /* initialize step variables */
			zx = zy = 0;
			cx = (x - xofs) / zoom;
			cy = (y - yofs) / zoom;

			int iter = max_iter;

                        /* calculate the iterations at this particular point */
			while (zx * zx + zy * zy < 4 && iter > 0) {
				double tmp = zx * zx - zy * zy + cx;
				zy = 2.0 * zx * zy + cy;
				zx = tmp;

				iter --;
			}

                        /* plot the applicable pixel */
			video[x + (y * 320)] = (unsigned char) iter & 0xff;
		}
	}
}