CrossSection.cpp

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/***************************************************************************
 *   Copyright (c) 2010 Werner Mayer <wmayer[at]users.sourceforge.net>     *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library 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 library  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 Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file COPYING.LIB. If not,    *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/


#include "PreCompiled.h"
#ifndef _PreComp_
# include <BRepAlgoAPI_Section.hxx>
# include <BRepBuilderAPI_MakeWire.hxx>
# include <gp_Pln.hxx>
# include <TopExp_Explorer.hxx>
# include <TopoDS.hxx>
# include <TopoDS_Edge.hxx>
# include <TopoDS_Wire.hxx>
#endif

#include "CrossSection.h"

using namespace Part;


CrossSection::CrossSection(double a, double b, double c, const TopoDS_Shape& s)
  : a(a), b(b), c(c), s(s)
{
}

std::list<TopoDS_Wire> CrossSection::section(double d) const
{
    std::list<TopoDS_Wire> wires;
    BRepAlgoAPI_Section cs(s, gp_Pln(a,b,c,-d));
    if (cs.IsDone()) {
        std::list<TopoDS_Edge> edges;
        TopExp_Explorer xp;
        for (xp.Init(cs.Shape(), TopAbs_EDGE); xp.More(); xp.Next())
            edges.push_back(TopoDS::Edge(xp.Current()));
        connectEdges(edges, wires);
    }

    return wires;
}

void CrossSection::connectEdges (const std::list<TopoDS_Edge>& edges, std::list<TopoDS_Wire>& wires) const
{
    std::list<TopoDS_Edge> edge_list = edges;
    while (edge_list.size() > 0) {
        BRepBuilderAPI_MakeWire mkWire;
        // add and erase first edge
        mkWire.Add(edge_list.front());
        edge_list.erase(edge_list.begin());

        TopoDS_Wire new_wire = mkWire.Wire();  // current new wire

        // try to connect each edge to the wire, the wire is complete if no more egdes are connectible
        bool found = false;
        do {
            found = false;
            for (std::list<TopoDS_Edge>::iterator pE = edge_list.begin(); pE != edge_list.end();++pE) {
                mkWire.Add(*pE);
                if (mkWire.Error() != BRepBuilderAPI_DisconnectedWire) {
                    // edge added ==> remove it from list
                    found = true;
                    edge_list.erase(pE);
                    new_wire = mkWire.Wire();
                    break;
                }
            }
        }
        while (found);
        wires.push_back(new_wire);
    }
}