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rewrite documentation of visitor()

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Don Bright 2012-02-13 20:42:36 -06:00
parent 662da67571
commit 4381762f5a
1 changed files with 6 additions and 8 deletions
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14
src/PolySetCGALEvaluator.cc
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@ -40,16 +40,14 @@ public:
void visit( CGAL_Nef_polyhedron3::SHalfloop_const_handle ) {}
void visit( CGAL_Nef_polyhedron3::SFace_const_handle ) {}
void visit( CGAL_Nef_polyhedron3::Halffacet_const_handle hfacet ) {
// This method is fed each 'facet' of the Nef_polyhedron3 that's been intersected
// This method is fed each 'half-facet' of the Nef_polyhedron3 that's been intersected
// with the flat x-y plane. I.e. it's fed a bunch of flat 3d polygons with z==0 at all vertexes.
// It is fed both the 'up' pointing half-facets and the 'down' pointing half-facets.
// We only need one set of vertexes, so we skip all of the 'down' facets.
//
// It takes the contours of the 2d polygons, and either does join() or intersection() based
// on whether the contour is a 'hole' or 'body'. The result is stored in nefpoly2d.
//
// On a Nef_Poly3 flat square in 3d space, there are 2 half-facets, one pointing 'up' and one 'down'.
// Now, we only want the vertexes--- and we only want one set of them. Not a duplicate set.
// So we don't need both 'up' and 'down' facets. What do we do? Just skip the 'down' facets!
//
// The vertexes are recorded in lists called 'contours'. Those are 'joined' or 'intersected'
// with the main result polyhedron, 'nefpoly2d', depending on whether it's a "hole" contour
// or a "body" contour.
CGAL::Direction_3<CGAL_Kernel3> up(0,0,1);
CGAL::Plane_3<CGAL_Kernel3> plane = hfacet->plane();
// out << " direction == up? " << ( plane.orthogonal_direction() == up ) << "\n";