- Fixed handling of antipodal points in construction of Sphere_circle

from two points.

Packages/Nef_S2/changes.txt

@@ -1,6 +1,11 @@
 Nef_S2 Package: Release changes
 ----------------------------------------------------------------------
 
+1.2 (16 Apr 2002)
+
+     - Fixed handling of antipodal points in construction of Sphere_circle
+       from two points.
+
 1.1 (19 Mar 2002)
 
      - include/CGAL/Nef_S2/SM_overlayer.h and SM_triangulator.h: 

Packages/Nef_S2/include/CGAL/Nef_S2/Sphere_circle.h

@@ -48,7 +48,14 @@ create any great circle that contains $p$ and $q$.}*/
     if ( CGAL::orientation(p1,p,q,p4) != CGAL::POSITIVE )
       *this = Self(opposite());
   } else {
-    *this = Self(Plane_3(p1,q-p));
+    /* previous method was: *this = Self(Plane_3(p1,q-p)); 
+       but p, q don't belong to he plane ((0,0,0), q-p) */
+
+    if(!Line_3(p,q).has_on(Point_3(1,0,0)))
+      *this = Self(Plane_3(p,q,Point_3(1,0,0)));
+    else
+      *this = Self(Plane_3(p,q,Point_3(0,1,0)));
+    /* take one point that doesn't belong to the line (p, q-p) */
   }
 }
 

Packages/Nef_S2/version

@@ -1 +1 @@
-1.1 (19 Mar 2002)
+1.2 (16 Apr 2002)