Function continuous_line2_sphere2 

pub fn continuous_line2_sphere2<S>(
    line: Line2<S>,
    sphere: Sphere2<S>,
) -> Option<(Line2Point<S>, Line2Point<S>)>
where
    S: OrderedField + Sqrt,

Compute the intersection of a 2D line with a 2D sphere (circle).

If the line and circle intersect, the two intersection points are returned with the scalar parameter corresponding to that point along the line.

let sphere = Sphere2::unit();
let line   = Line2::new  ([0.0, 0.0].into(), Unit2::axis_x());
assert_eq!(
  continuous_line2_sphere2 (line, sphere).unwrap(),
  ( (-1.0, [-1.0, 0.0].into()),
    ( 1.0, [ 1.0, 0.0].into())
  )
);

Returns None if the line and circle are tangent:

let sphere = Sphere2::unit();
let line   = Line2::new  ([0.0, 1.0].into(), Unit2::axis_x());
assert_eq!(continuous_line2_sphere2 (line, sphere), None);