raymatch a cube

fn ray_cube_intersection(origin: &Point3<f64>, direction: &Vector3<f64>, vertex_a: &Point3<f64>, vertex_b: &Point3<f64>) -> Option<f64> {
    let mut t_min = -f64::INFINITY;
    let mut t_max = f64::INFINITY;
    for (i, a) in vertex_a.iter().enumerate() {
        let b = vertex_b[i];
        let o = origin[i];
        let d = direction[i];
        if d.abs() < 1e-6 {
            if o < a || o > b {
                return None;
            }
        } else {
            let t0 = (a - o) / d;
            let t1 = (b - o) / d;
            if t0 > t1 {
                std::mem::swap(&mut t0, &mut t1);
            }
            t_min = t_min.max(t0);
            t_