halfedge.cpp

/***************************************************************************
 *   Copyright (C) 2007 by Pablo Diaz-Gutierrez   *
 *   pablo@ics.uci.edu   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU Library General Public License as       *
 *   published by the Free Software Foundation; either version 2 of the    *
 *   License, or (at your option) any later version.                       *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this program; if not, write to the                 *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#ifdef _WIN32
#pragma warning(disable:4786)
#endif

#include <cstdio>
#include <cassert>
#include "halfedge.h"
#include "face.h"
#include "vertex.h"

using namespace std;
using namespace Geometry;
using namespace HE;

HalfEdge* HalfEdge::prev()
{
        HalfEdge* he = _next;
        while (he->next() != this)
                he = he->next();

        return he;
}

const HalfEdge* HalfEdge::prev() const
{
        HalfEdge* he = _next;
        while (he->next() != this)
                he = he->next();

        return he;
}


ostream& HE::operator<< (ostream& out, const HalfEdge& he)
{
        char s[128];
        if (he.twin())
        {
                if (he.src())
                        sprintf(s, "%d", he.src()->index());
                else
                        strcpy(s, "NULL");
        }
        else
                strcpy(s, "unreachable through twin");

        char d[128];
        if (he.dst())
                sprintf(d, "%d", he.dst()->index());
        else
                strcpy(d, "NULL");

        return out << "[(src " << s
                        << "), (dst " << d
                        << "), (face " << (int) he.face()
                        << "), (twin " << (int) he.twin()
                        << "), (next " << (int) he.next() << ")]";
}

Vector3Df HalfEdge::normal() const
{
         return (src()->normal()+dst()->normal())/2;
}


Vector3Df HalfEdge::tangent() const 
{
  return dst()->position() - src()->position(); 
}

Vector3Df HalfEdge::midpoint() const 
{
  //return src()->position() + tangent()/2; 
  return (src()->position() + dst()->position()) / 2; 
}

bool HalfEdge::isBoundary() const
{
         return face()->hole() || twin()->face()->hole();
}

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