void genCircle(float radius, int splits)
{
    int N = 4;
    for (int i=0; i<splits; i++) N *= 2;

    float xs[N];
    float ys[N];

    int step = N/4;
    xs[0] = radius;
    ys[0] = 0;

    xs[step] = 0;
    ys[step] = radius;

    xs[2*step] = -radius;
    ys[2*step] = 0;

    xs[3*step] = 0;
    ys[3*step] = -radius;

    for (int k=0; k<splits; k++) {
        for (int i=0; i<N; i+=step) {
            float sx, sy;
            sx = (xs[i] + xs[(i+step)%N]) / 2;
            sy = (ys[i] + ys[(i+step)%N]) / 2;

            float f = radius / sqrt(sx*sx + sy*sy);
            xs[i + step/2] = sx*f;
            ys[i + step/2] = sy*f;
        }
        step /= 2;
    }


    float circumference = 0;
    for (int i=0; i<N; i++) {
        float xd = xs[i] - xs[(i+1)%N];
        float yd = ys[i] - ys[(i+1)%N];
        circumference += sqrt(xd*xd + yd*yd);
    }

    // Now, (xs[i], ys[i]) are coordinates on the circle.
}