Function insphere

pub fn insphere(
    a: Point3,
    b: Point3,
    c: Point3,
    d: Point3,
    e: Point3,
) -> Certified

Is e inside the sphere through a, b, c, d?

Sign::Positive means inside when a, b, c, d are positively oriented (orient3d(a, b, c, d) > 0). As with incircle, the sign flips with the base orientation, so a caller must normalise it.

Always Certified::Certain.