n-sphere

// hyper-sphere coordinates
void n_sphere(float *out, float *in, int n)
{
	double x; int i;

	x = in[0] * in[0] + in[1] * in[1];
	out[1] = in[0] < 0 ? M_PI*2 - acos(in[1] / sqrt(x)) : acos(in[1] / sqrt(x));

	for (i = 2; i < n; i++) {
		x += in[i] * in[i];
		out[i] = acos(in[i] / sqrt(x));
	}

	out[0] = sqrt(x);
}