CGAL users discussion list

[Query Cgal <>]

Excuse me, may I ask something about Sphere_3 in CGAL?

I have read some function about it in the manual but I am not sure if I have understood them correctly. May I take the chance here to ask about them?

(1)
For

Sphere_3<Kernel> c (

Point_3<Kernel> p, Point_3<Kernel> q, Orientation o = COUNTERCLOCKWISE);

introduces a variable c of type Sphere_3<Kernel>. It is initialized to the smallest sphere which passes through the points p and q. The orientation of the sphere is o.
Precondition: o is not COPLANAR.

can I use that to create a sphere with diameter as the length pq?

(2)
for

Oriented_side	c.oriented_side ( Point_3<Kernel> p)
		returns either the constant ON_ORIENTED_BOUNDARY, ON_POSITIVE_SIDE, or ON_NEGATIVE_SIDE, iff p lies on the boundary, properly on the positive side, or properly on the negative side of c, resp.

May I ask if it is that "positive side" mean the point p lie inside the sphere
and "negative side" mean the point lie outside of the sphere?

Thank you very much

---

Yahoo!香港提供網上安全攻略，教你如何防範黑客!了解更多