/***************************************************************************
 *   Copyright (c) 2005 Imetric 3D GmbH                                    *
 *                                                                         *
 *   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"
#include "Definitions.h"
#include "Iterator.h"

#include "MeshKernel.h"
#include "MeshIO.h"
#include "Algorithm.h"
#include "Builder.h"
#include "Degeneration.h"
#include "IO/Reader3MF.h"
#include "IO/Writer3MF.h"

#include <Base/Builder3D.h>
#include <Base/Console.h>
#include <Base/Exception.h>
#include <Base/Reader.h>
#include <Base/Writer.h>
#include <Base/FileInfo.h>
#include <Base/Sequencer.h>
#include <Base/Stream.h>
#include <Base/Placement.h>
#include <Base/Tools.h>
#include <zipios++/gzipoutputstream.h>
#include <zipios++/zipoutputstream.h>

#include <cmath>
#include <sstream>
#include <iomanip>
#include <algorithm>
#include <string_view>
#include <boost/regex.hpp>
#include <boost/algorithm/string.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/convert.hpp>
#include <boost/convert/spirit.hpp>


using namespace MeshCore;

namespace MeshCore {

std::string& ltrim(std::string& str)
{
    std::string::size_type pos=0;
    for (std::string::iterator it = str.begin(); it != str.end(); ++it) {
        if (*it != 0x20 && *it != 0x09)
            break;
        pos++;
    }
    if (pos > 0)
        str = str.substr(pos);
    return str;
}

int numDigits(int number)
{
    number = std::abs(number);
    int digits = 1;
    int step = 10;
    while (step <= number) {
        digits++;
        step *= 10;
    }
    return digits;
}

/* Usage by CMeshNastran, CMeshCadmouldFE. Added by Sergey Sukhov (26.04.2002)*/
struct NODE {float x, y, z;};
struct TRIA {int iV[3];};
struct QUAD {int iV[4];};

struct Color_Less
{
    bool operator()(const App::Color& x,
                    const App::Color& y) const
    {
        if (x.r != y.r)
            return x.r < y.r;
        if (x.g != y.g)
            return x.g < y.g;
        if (x.b != y.b)
            return x.b < y.b;
        return false; // equal colors
    }
};

}

// --------------------------------------------------------------

std::vector<std::string> MeshInput::supportedMeshFormats()
{
    std::vector<std::string> fmt;
    fmt.emplace_back("bms");
    fmt.emplace_back("ply");
    fmt.emplace_back("stl");
    fmt.emplace_back("ast");
    fmt.emplace_back("obj");
    fmt.emplace_back("nas");
    fmt.emplace_back("bdf");
    fmt.emplace_back("off");
    fmt.emplace_back("smf");
    return fmt;
}

MeshIO::Format MeshInput::getFormat(const char* FileName)
{
     Base::FileInfo fi(FileName);
     if (fi.hasExtension("bms")) {
         return MeshIO::Format::BMS;
     }
     else if (fi.hasExtension("ply")) {
         return MeshIO::Format::PLY;
     }
     else if (fi.hasExtension("stl")) {
         return MeshIO::Format::STL;
     }
     else if (fi.hasExtension("ast")) {
         return MeshIO::Format::ASTL;
     }
     else if (fi.hasExtension("obj")) {
         return MeshIO::Format::OBJ;
     }
     else if (fi.hasExtension("off")) {
         return MeshIO::Format::OFF;
     }
     else if (fi.hasExtension("smf")) {
         return MeshIO::Format::SMF;
     }
     else {
         throw Base::FileException("File extension not supported",FileName);
     }
}

bool MeshInput::LoadAny(const char* FileName)
{
    // ask for read permission
    Base::FileInfo fi(FileName);
    if (!fi.exists() || !fi.isFile())
        throw Base::FileException("File does not exist",FileName);
    if (!fi.isReadable())
        throw Base::FileException("No permission on the file",FileName);

    Base::ifstream str(fi, std::ios::in | std::ios::binary);

    if (fi.hasExtension("bms")) {
        _rclMesh.Read(str);
        return true;
    }
    else {
        // read file
        bool ok = false;
        if (fi.hasExtension("stl") || fi.hasExtension("ast")) {
            ok = LoadSTL(str);
        }
        else if (fi.hasExtension("iv")) {
            ok = LoadInventor( str );
            if (ok && _rclMesh.CountFacets() == 0)
                Base::Console().Warning("No usable mesh found in file '%s'", FileName);
        }
        else if (fi.hasExtension("nas") || fi.hasExtension("bdf")) {
            ok = LoadNastran( str );
        }
        else if (fi.hasExtension("obj")) {
            ok = LoadOBJ( str );
        }
        else if (fi.hasExtension("smf")) {
            ok = LoadSMF( str );
        }
        else if (fi.hasExtension("3mf")) {
            ok = Load3MF( str );
        }
        else if (fi.hasExtension("off")) {
            ok = LoadOFF( str );
        }
        else if (fi.hasExtension("ply")) {
            ok = LoadPLY( str );
        }
        else {
            throw Base::FileException("File extension not supported",FileName);
        }

        return ok;
    }
}

bool  MeshInput::LoadFormat(std::istream &str, MeshIO::Format fmt)
{
    switch (fmt) {
    case MeshIO::BMS:
        _rclMesh.Read(str);
        return true;
    case MeshIO::APLY:
    case MeshIO::PLY:
        return LoadPLY(str);
    case MeshIO::ASTL:
        return LoadAsciiSTL(str);
    case MeshIO::BSTL:
        return LoadBinarySTL(str);
    case MeshIO::STL:
        return LoadSTL(str);
    case MeshIO::OBJ:
        return LoadOBJ(str);
    case MeshIO::SMF:
        return LoadSMF(str);
    case MeshIO::ThreeMF:
        return Load3MF(str);
    case MeshIO::OFF:
        return LoadOFF(str);
    case MeshIO::IV:
        return LoadInventor(str);
    case MeshIO::NAS:
        return LoadNastran(str);
    default:
        throw Base::FileException("Unsupported file format");
    }
}

/** Loads an STL file either in binary or ASCII format.
 * Therefore the file header gets checked to decide if the file is binary or not.
 */
bool MeshInput::LoadSTL (std::istream &rstrIn)
{
    char szBuf[200];

    if (!rstrIn || rstrIn.bad())
        return false;

    // Read in 50 characters from position 80 on and check for keywords like 'SOLID', 'FACET', 'NORMAL',
    // 'VERTEX', 'ENDFACET' or 'ENDLOOP'.
    // As the file can be binary with one triangle only we must not read in more than (max.) 54 bytes because
    // the file size has only 134 bytes in this case. On the other hand we must overread the first 80 bytes
    // because it can happen that the file is binary but contains one of these keywords.
    std::streambuf* buf = rstrIn.rdbuf();
    if (!buf)
        return false;
    buf->pubseekoff(80, std::ios::beg, std::ios::in);
    uint32_t ulCt, ulBytes=50;
    rstrIn.read((char*)&ulCt, sizeof(ulCt));
    // if we have a binary STL with a single triangle we can only read-in 50 bytes
    if (ulCt > 1)
        ulBytes = 100;
    // Either it's really an invalid STL file or it's just empty. In this case the number of facets must be 0.
    if (!rstrIn.read(szBuf, ulBytes))
        return (ulCt==0);
    szBuf[ulBytes] = 0;
    boost::algorithm::to_upper(szBuf);

    try {
        if (!strstr(szBuf, "SOLID") && !strstr(szBuf, "FACET") && !strstr(szBuf, "NORMAL") &&
            !strstr(szBuf, "VERTEX") && !strstr(szBuf, "ENDFACET") && !strstr(szBuf, "ENDLOOP")) {
            // probably binary STL
            buf->pubseekoff(0, std::ios::beg, std::ios::in);
            return LoadBinarySTL(rstrIn);
        }
        else {
            // Ascii STL
            buf->pubseekoff(0, std::ios::beg, std::ios::in);
            return LoadAsciiSTL(rstrIn);
        }
    }
    catch (const Base::MemoryException&) {
        _rclMesh.Clear();
        throw; // Throw the same instance of Base::MemoryException
    }
    catch (const Base::AbortException&) {
        _rclMesh.Clear();
        return false;
    }
    catch (const Base::Exception&) {
        _rclMesh.Clear();
        throw;  // Throw the same instance of Base::Exception
    }
    catch (...) {
        _rclMesh.Clear();
        throw;
    }

    return true;
}

/** Loads an OBJ file. */
bool MeshInput::LoadOBJ (std::istream &rstrIn)
{
    boost::regex rx_m("^mtllib\\s+(.+)\\s*$");
    boost::regex rx_u("^usemtl\\s+([\\x21-\\x7E]+)\\s*$");
    boost::regex rx_g("^g\\s+([\\x21-\\x7E]+)\\s*$");
    boost::regex rx_p("^v\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*$");
    boost::regex rx_c("^v\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+(\\d{1,3})\\s+(\\d{1,3})\\s+(\\d{1,3})\\s*$");
    boost::regex rx_t("^v\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*$");
    boost::regex rx_f3("^f\\s+([-+]?[0-9]+)/?[-+]?[0-9]*/?[-+]?[0-9]*"
                         "\\s+([-+]?[0-9]+)/?[-+]?[0-9]*/?[-+]?[0-9]*"
                         "\\s+([-+]?[0-9]+)/?[-+]?[0-9]*/?[-+]?[0-9]*\\s*$");
    boost::regex rx_f4("^f\\s+([-+]?[0-9]+)/?[-+]?[0-9]*/?[-+]?[0-9]*"
                         "\\s+([-+]?[0-9]+)/?[-+]?[0-9]*/?[-+]?[0-9]*"
                         "\\s+([-+]?[0-9]+)/?[-+]?[0-9]*/?[-+]?[0-9]*"
                         "\\s+([-+]?[0-9]+)/?[-+]?[0-9]*/?[-+]?[0-9]*\\s*$");
    boost::cmatch what;

    unsigned long segment=0;
    MeshPointArray meshPoints;
    MeshFacetArray meshFacets;

    std::string line;
    float fX, fY, fZ;
    int  i1=1,i2=1,i3=1,i4=1;
    MeshFacet item;

    if (!rstrIn || rstrIn.bad())
        return false;

    std::streambuf* buf = rstrIn.rdbuf();
    if (!buf)
        return false;

    MeshIO::Binding rgb_value = MeshIO::OVERALL;
    bool new_segment = true;
    std::string groupName;
    std::string materialName;
    unsigned long countMaterialFacets = 0;

    while (std::getline(rstrIn, line)) {
        if (boost::regex_match(line.c_str(), what, rx_p)) {
            fX = (float)std::atof(what[1].first);
            fY = (float)std::atof(what[4].first);
            fZ = (float)std::atof(what[7].first);
            meshPoints.push_back(MeshPoint(Base::Vector3f(fX, fY, fZ)));
        }
        else if (boost::regex_match(line.c_str(), what, rx_c)) {
            fX = (float)std::atof(what[1].first);
            fY = (float)std::atof(what[4].first);
            fZ = (float)std::atof(what[7].first);
            float r = std::min<int>(std::atof(what[10].first),255) / 255.0f;
            float g = std::min<int>(std::atof(what[11].first),255) / 255.0f;
            float b = std::min<int>(std::atof(what[12].first),255) / 255.0f;
            meshPoints.push_back(MeshPoint(Base::Vector3f(fX, fY, fZ)));

            App::Color c(r,g,b);
            unsigned long prop = static_cast<uint32_t>(c.getPackedValue());
            meshPoints.back().SetProperty(prop);
            rgb_value = MeshIO::PER_VERTEX;
        }
        else if (boost::regex_match(line.c_str(), what, rx_t)) {
            fX = (float)std::atof(what[1].first);
            fY = (float)std::atof(what[4].first);
            fZ = (float)std::atof(what[7].first);
            float r = static_cast<float>(std::atof(what[10].first));
            float g = static_cast<float>(std::atof(what[13].first));
            float b = static_cast<float>(std::atof(what[16].first));
            meshPoints.push_back(MeshPoint(Base::Vector3f(fX, fY, fZ)));

            App::Color c(r,g,b);
            unsigned long prop = static_cast<uint32_t>(c.getPackedValue());
            meshPoints.back().SetProperty(prop);
            rgb_value = MeshIO::PER_VERTEX;
        }
        else if (boost::regex_match(line.c_str(), what, rx_g)) {
            new_segment = true;
            groupName = Base::Tools::escapedUnicodeToUtf8(what[1].first);
        }
        else if (boost::regex_match(line.c_str(), what, rx_m)) {
            if (_material)
                _material->library = Base::Tools::escapedUnicodeToUtf8(what[1].first);
        }
        else if (boost::regex_match(line.c_str(), what, rx_u)) {
            if (!materialName.empty()) {
                _materialNames.emplace_back(materialName, countMaterialFacets);
            }
            materialName = Base::Tools::escapedUnicodeToUtf8(what[1].first);
            countMaterialFacets = 0;
        }
        else if (boost::regex_match(line.c_str(), what, rx_f3)) {
            // starts a new segment
            if (new_segment) {
                if (!groupName.empty()) {
                    _groupNames.push_back(groupName);
                    groupName.clear();
                }
                new_segment = false;
                segment++;
            }

            // 3-vertex face
            i1 = std::atoi(what[1].first);
            i1 = i1 > 0 ? i1-1 : i1+static_cast<int>(meshPoints.size());
            i2 = std::atoi(what[2].first);
            i2 = i2 > 0 ? i2-1 : i2+static_cast<int>(meshPoints.size());
            i3 = std::atoi(what[3].first);
            i3 = i3 > 0 ? i3-1 : i3+static_cast<int>(meshPoints.size());
            item.SetVertices(i1,i2,i3);
            item.SetProperty(segment);
            meshFacets.push_back(item);
            countMaterialFacets++;
        }
        else if (boost::regex_match(line.c_str(), what, rx_f4)) {
            // starts a new segment
            if (new_segment) {
                if (!groupName.empty()) {
                    _groupNames.push_back(groupName);
                    groupName.clear();
                }
                new_segment = false;
                segment++;
            }

            // 4-vertex face
            i1 = std::atoi(what[1].first);
            i1 = i1 > 0 ? i1-1 : i1+static_cast<int>(meshPoints.size());
            i2 = std::atoi(what[2].first);
            i2 = i2 > 0 ? i2-1 : i2+static_cast<int>(meshPoints.size());
            i3 = std::atoi(what[3].first);
            i3 = i3 > 0 ? i3-1 : i3+static_cast<int>(meshPoints.size());
            i4 = std::atoi(what[4].first);
            i4 = i4 > 0 ? i4-1 : i4+static_cast<int>(meshPoints.size());

            item.SetVertices(i1,i2,i3);
            item.SetProperty(segment);
            meshFacets.push_back(item);
            countMaterialFacets++;

            item.SetVertices(i3,i4,i1);
            item.SetProperty(segment);
            meshFacets.push_back(item);
            countMaterialFacets++;
        }
    }

    // Add the last added material name
    if (!materialName.empty()) {
        _materialNames.emplace_back(materialName, countMaterialFacets);
    }

    // now get back the colors from the vertex property
    if (rgb_value == MeshIO::PER_VERTEX) {
        if (_material) {
            _material->binding = MeshIO::PER_VERTEX;
            _material->diffuseColor.reserve(meshPoints.size());

            for (MeshPointArray::iterator it = meshPoints.begin(); it != meshPoints.end(); ++it) {
                unsigned long prop = it->_ulProp;
                App::Color c;
                c.setPackedValue(static_cast<uint32_t>(prop));
                _material->diffuseColor.push_back(c);
            }
        }
    }
    else if (!materialName.empty()) {
        // At this point the materials from the .mtl file are not known and will be read-in by the calling instance
        // but the color list is pre-filled with a default value
        if (_material) {
            _material->binding = MeshIO::PER_FACE;
            _material->diffuseColor.resize(meshFacets.size(), App::Color(0.8f, 0.8f, 0.8f));
        }
    }

    this->_rclMesh.Clear(); // remove all data before

    MeshCleanup meshCleanup(meshPoints, meshFacets);
    if (_material)
        meshCleanup.SetMaterial(_material);
    meshCleanup.RemoveInvalids();
    MeshPointFacetAdjacency meshAdj(meshPoints.size(),meshFacets);
    meshAdj.SetFacetNeighbourhood();
    this->_rclMesh.Adopt(meshPoints,meshFacets);

    return true;
}

bool MeshInput::LoadMTL (std::istream &rstrIn)
{
    boost::regex rx_n("^newmtl\\s+([\\x21-\\x7E]+)\\s*$");
    boost::regex rx_Kd("^\\s*Kd\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                       "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                       "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*$");
    boost::cmatch what;

    std::string line;

    if (!_material)
        return false;

    if (!rstrIn || rstrIn.bad())
        return false;

    std::streambuf* buf = rstrIn.rdbuf();
    if (!buf)
        return false;

    std::map<std::string, App::Color> materials;
    std::string materialName;
    std::vector<App::Color> diffuseColor;

    while (std::getline(rstrIn, line)) {
        if (boost::regex_match(line.c_str(), what, rx_n)) {
            materialName = Base::Tools::escapedUnicodeToUtf8(what[1].first);
        }
        else if (boost::regex_match(line.c_str(), what, rx_Kd)) {
            float r = static_cast<float>(std::atof(what[1].first));
            float g = static_cast<float>(std::atof(what[4].first));
            float b = static_cast<float>(std::atof(what[7].first));
            materials[materialName] = App::Color(r,g,b);
        }
    }

    for (auto it = _materialNames.begin(); it != _materialNames.end(); ++it) {
        auto jt = materials.find(it->first);
        if (jt != materials.end()) {
            std::vector<App::Color> mat(it->second, jt->second);
            diffuseColor.insert(diffuseColor.end(), mat.begin(), mat.end());
        }
    }

    if (diffuseColor.size() == _material->diffuseColor.size()) {
        _material->binding = MeshIO::PER_FACE;
        _material->diffuseColor.swap(diffuseColor);
        return true;
    }
    else {
        _material->binding = MeshIO::OVERALL;
        _material->diffuseColor.clear();
        return false;
    }
}

/** Loads an SMF file. */
bool MeshInput::LoadSMF (std::istream &rstrIn)
{
    boost::regex rx_p("^v\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                        "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*$");
    boost::regex rx_f3("^f\\s+([-+]?[0-9]+)"
                         "\\s+([-+]?[0-9]+)"
                         "\\s+([-+]?[0-9]+)\\s*$");
    boost::cmatch what;

    unsigned long segment=0;
    MeshPointArray meshPoints;
    MeshFacetArray meshFacets;

    std::string line;
    float fX, fY, fZ;
    int  i1=1,i2=1,i3=1;
    MeshFacet item;

    if (!rstrIn || rstrIn.bad())
        return false;

    std::streambuf* buf = rstrIn.rdbuf();
    if (!buf)
        return false;

    while (std::getline(rstrIn, line)) {
        if (boost::regex_match(line.c_str(), what, rx_p)) {
            fX = (float)std::atof(what[1].first);
            fY = (float)std::atof(what[4].first);
            fZ = (float)std::atof(what[7].first);
            meshPoints.push_back(MeshPoint(Base::Vector3f(fX, fY, fZ)));
        }
        else if (boost::regex_match(line.c_str(), what, rx_f3)) {
            // 3-vertex face
            i1 = std::atoi(what[1].first);
            i1 = i1 > 0 ? i1-1 : i1+static_cast<int>(meshPoints.size());
            i2 = std::atoi(what[2].first);
            i2 = i2 > 0 ? i2-1 : i2+static_cast<int>(meshPoints.size());
            i3 = std::atoi(what[3].first);
            i3 = i3 > 0 ? i3-1 : i3+static_cast<int>(meshPoints.size());
            item.SetVertices(i1,i2,i3);
            item.SetProperty(segment);
            meshFacets.push_back(item);
        }
    }

    this->_rclMesh.Clear(); // remove all data before

    MeshCleanup meshCleanup(meshPoints,meshFacets);
    meshCleanup.RemoveInvalids();
    MeshPointFacetAdjacency meshAdj(meshPoints.size(),meshFacets);
    meshAdj.SetFacetNeighbourhood();
    this->_rclMesh.Adopt(meshPoints,meshFacets);

    return true;
}

/** Loads an OFF file. */
bool MeshInput::LoadOFF (std::istream &rstrIn)
{
    // http://edutechwiki.unige.ch/en/3D_file_format
    boost::regex rx_n("^\\s*([0-9]+)\\s+([0-9]+)\\s+([0-9]+)\\s*$");
    boost::cmatch what;

    bool colorPerVertex = false;
    std::vector<App::Color> diffuseColor;
    MeshPointArray meshPoints;
    MeshFacetArray meshFacets;

    std::string line;
    MeshFacet item;

    if (!rstrIn || rstrIn.bad())
        return false;

    std::streambuf* buf = rstrIn.rdbuf();
    if (!buf)
        return false;

    std::getline(rstrIn, line);
    boost::algorithm::to_lower(line);
    if (line.find("coff") != std::string::npos) {
        // we expect colors to be there per vertex: x y z r g b a
        colorPerVertex = true;
    }
    else if (line.find("off") == std::string::npos) {
        return false; // not an OFF file
    }

    // get number of vertices and faces
    int numPoints=0, numFaces=0;

    while (true) {
        std::getline(rstrIn, line);
        boost::algorithm::to_lower(line);
        if (boost::regex_match(line.c_str(), what, rx_n)) {
            numPoints = std::atoi(what[1].first);
            numFaces = std::atoi(what[2].first);
            break;
        }
    }

    if (numPoints == 0 || numFaces == 0)
        return false;

    meshPoints.reserve(numPoints);
    meshFacets.reserve(numFaces);
    if (colorPerVertex)
        diffuseColor.reserve(numPoints);
    else
        diffuseColor.reserve(numFaces);

    int cntPoints = 0;
    while (cntPoints < numPoints) {
        if (!std::getline(rstrIn, line))
            break;
        std::istringstream str(line);
        str.unsetf(std::ios_base::skipws);
        str >> std::ws;
        if (str.eof())
            continue; // empty line

        float fX, fY, fZ;
        str >> fX >> std::ws >> fY >> std::ws >> fZ;
        if (str) {
            meshPoints.push_back(MeshPoint(Base::Vector3f(fX, fY, fZ)));
            cntPoints++;

            if (colorPerVertex) {
                std::size_t pos = std::size_t(str.tellg());
                if (line.size() > pos) {
                    float r,g,b,a;
                    str >> std::ws >> r >> std::ws >> g >> std::ws >> b;
                    if (str) {
                        str >> std::ws >> a;
                        // no transparency
                        if (!str)
                            a = 0.0f;

                        if (r > 1.0f || g > 1.0f || b > 1.0f || a > 1.0f) {
                            r = static_cast<float>(r)/255.0f;
                            g = static_cast<float>(g)/255.0f;
                            b = static_cast<float>(b)/255.0f;
                            a = static_cast<float>(a)/255.0f;
                        }
                        diffuseColor.emplace_back(r, g, b, a);
                    }
                }
            }
        }
    }

    int cntFaces = 0;
    while (cntFaces < numFaces) {
        if (!std::getline(rstrIn, line))
            break;
        std::istringstream str(line);
        str.unsetf(std::ios_base::skipws);
        str >> std::ws;
        if (str.eof())
            continue; // empty line
        int count, index;
        str >> count;
        if (count >= 3) {
            std::vector<int> faces;
            faces.reserve(count);

            for (int i = 0; i < count; i++) {
                str >> std::ws;
                str >> index;
                faces.push_back(index);
            }

            for (int i = 0; i < count-2; i++) {
                item.SetVertices(faces[0],faces[i+1],faces[i+2]);
                meshFacets.push_back(item);
            }
            cntFaces++;

            std::size_t pos = std::size_t(str.tellg());
            if (line.size() > pos) {
                float r,g,b,a;
                str >> std::ws >> r >> std::ws >> g >> std::ws >> b;
                if (str) {
                    str >> std::ws >> a;
                    // no transparency
                    if (!str)
                        a = 0.0f;

                    if (r > 1.0f || g > 1.0f || b > 1.0f || a > 1.0f) {
                        r = static_cast<float>(r)/255.0f;
                        g = static_cast<float>(g)/255.0f;
                        b = static_cast<float>(b)/255.0f;
                        a = static_cast<float>(a)/255.0f;
                    }
                    for (int i = 0; i < count-2; i++) {
                        diffuseColor.emplace_back(r, g, b, a);
                    }
                }
            }
        }
    }

    if (_material) {
        if (colorPerVertex) {
            if (meshPoints.size() == diffuseColor.size()) {
                _material->binding = MeshIO::PER_VERTEX;
                _material->diffuseColor.swap(diffuseColor);
            }
        }
        else {
            if (meshFacets.size() == diffuseColor.size()) {
                _material->binding = MeshIO::PER_FACE;
                _material->diffuseColor.swap(diffuseColor);
            }
        }
    }
    this->_rclMesh.Clear(); // remove all data before

    MeshCleanup meshCleanup(meshPoints,meshFacets);
    if (_material)
        meshCleanup.SetMaterial(_material);
    meshCleanup.RemoveInvalids();
    MeshPointFacetAdjacency meshAdj(meshPoints.size(),meshFacets);
    meshAdj.SetFacetNeighbourhood();
    this->_rclMesh.Adopt(meshPoints,meshFacets);

    return true;
}

namespace MeshCore {
    namespace Ply {
        enum Number {
            int8, uint8, int16, uint16, int32, uint32, float32, float64
        };
        struct Property
        {
            using first_argument_type = std::pair<std::string, int>;
            using second_argument_type = std::string;
            using result_type = bool;

            bool operator()(const std::pair<std::string, int>& x,
                            const std::string& y) const
            {
                return x.first == y;
            }
        };
    }
    using namespace Ply;
}

bool MeshInput::LoadPLY (std::istream &inp)
{
    // http://local.wasp.uwa.edu.au/~pbourke/dataformats/ply/
    std::size_t v_count=0, f_count=0;
    MeshPointArray meshPoints;
    MeshFacetArray meshFacets;

    enum {
        unknown, ascii, binary_little_endian, binary_big_endian
    } format = unknown;

    if (!inp || inp.bad())
        return false;

    std::streambuf* buf = inp.rdbuf();
    if (!buf)
        return false;

    // read in the first three characters
    char ply[3];
    inp.read(ply, 3);
    inp.ignore(1);
    if (!inp)
        return false;
    if ((ply[0] != 'p') || (ply[1] != 'l') || (ply[2] != 'y'))
        return false; // wrong header

    std::vector<std::pair<std::string, Ply::Number> > vertex_props;
    std::vector<Ply::Number> face_props;
    std::string line, element;

    MeshIO::Binding rgb_value = MeshIO::OVERALL;
    while (std::getline(inp, line)) {
        std::istringstream str(line);
        str.unsetf(std::ios_base::skipws);
        str >> std::ws;
        if (str.eof())
            continue; // empty line
        std::string kw;
        str >> kw;
        if (kw == "format") {
            std::string format_string, version;
            char space_format_string, space_format_version;
            str >> space_format_string >> std::ws
                >> format_string >> space_format_version
                >> std::ws >> version;
            if (/*!str || !str.eof() ||*/
                !std::isspace(space_format_string) ||
                !std::isspace(space_format_version)) {
                return false;
            }
            if (format_string == "ascii") {
                format = ascii;
            }
            else if (format_string == "binary_big_endian") {
                format = binary_big_endian;
            }
            else if (format_string == "binary_little_endian") {
                format = binary_little_endian;
            }
            else {
                // wrong format version
                return false;
            }
            if (version != "1.0") {
                // wrong version
                return false;
            }
        }
        else if (kw == "element") {
            std::string name;
            std::size_t count;
            char space_element_name, space_name_count;
            str >> space_element_name >> std::ws
                >> name >> space_name_count >> std::ws
                >> count;
            if (/*!str || !str.eof() ||*/
                !std::isspace(space_element_name) ||
                !std::isspace(space_name_count)) {
                return false;
            }
            else if (name == "vertex") {
                element = name;
                v_count = count;
                meshPoints.reserve(count);
            }
            else if (name == "face") {
                element = name;
                f_count = count;
                meshFacets.reserve(count);
            }
            else {
                element.clear();
            }
        }
        else if (kw == "property") {
            std::string type, name;
            char space;
            if (element == "vertex") {
                str >> space >> std::ws
                    >> type >> space >> std::ws >> name >> std::ws;

                Ply::Number number;
                if (type == "char" || type == "int8") {
                    number = int8;
                }
                else if (type == "uchar" || type == "uint8") {
                    number = uint8;
                }
                else if (type == "short" || type == "int16") {
                    number = int16;
                }
                else if (type == "ushort" || type == "uint16") {
                    number = uint16;
                }
                else if (type == "int" || type == "int32") {
                    number = int32;
                }
                else if (type == "uint" || type == "uint32") {
                    number = uint32;
                }
                else if (type == "float" || type == "float32") {
                    number = float32;
                }
                else if (type == "double" || type == "float64") {
                    number = float64;
                }
                else {
                    // no valid number type
                    return false;
                }

                // store the property name and type
                vertex_props.emplace_back(name, number);
            }
            else if (element == "face") {
                std::string list, uchr;
                str >> space >> std::ws
                    >> list >> std::ws;
                if (list == "list") {
                    str >> uchr >> std::ws
                        >> type >> std::ws >> name >> std::ws;
                }
                else {
                    // not a 'list'
                    type = list;
                    str >> name;
                }
                if (name != "vertex_indices" && name != "vertex_index") {
                    Number number;
                    if (type == "char" || type == "int8") {
                        number = int8;
                    }
                    else if (type == "uchar" || type == "uint8") {
                        number = uint8;
                    }
                    else if (type == "short" || type == "int16") {
                        number = int16;
                    }
                    else if (type == "ushort" || type == "uint16") {
                        number = uint16;
                    }
                    else if (type == "int" || type == "int32") {
                        number = int32;
                    }
                    else if (type == "uint" || type == "uint32") {
                        number = uint32;
                    }
                    else if (type == "float" || type == "float32") {
                        number = float32;
                    }
                    else if (type == "double" || type == "float64") {
                        number = float64;
                    }
                    else {
                        // no valid number type
                        return false;
                    }

                    // store the property name and type
                    face_props.push_back(number);
                }
            }
        }
        else if (kw == "end_header") {
            break; // end of the header, now read the data
        }
    }

    // check if valid 3d points
    Property property;
    std::size_t num_x = std::count_if(vertex_props.begin(), vertex_props.end(),
                    [&property](const std::pair<std::string, int>& p) { return property(p, "x"); });
    if (num_x != 1)
        return false;

    std::size_t num_y = std::count_if(vertex_props.begin(), vertex_props.end(),
                    [&property](const std::pair<std::string, int>& p) { return property(p, "y"); });
    if (num_y != 1)
        return false;

    std::size_t num_z = std::count_if(vertex_props.begin(), vertex_props.end(),
                    [&property](const std::pair<std::string, int>& p) { return property(p, "z"); });
    if (num_z != 1)
        return false;

    for (std::vector<std::pair<std::string, Ply::Number> >::iterator it =
        vertex_props.begin(); it != vertex_props.end(); ++it) {
        if (it->first == "diffuse_red")
            it->first = "red";
        else if (it->first == "diffuse_green")
            it->first = "green";
        else if (it->first == "diffuse_blue")
            it->first = "blue";
    }

    // check if valid colors are set
    std::size_t num_r = std::count_if(vertex_props.begin(), vertex_props.end(),
                    [&property](const std::pair<std::string, int>& p) { return property(p, "red"); });
    std::size_t num_g = std::count_if(vertex_props.begin(), vertex_props.end(),
                    [&property](const std::pair<std::string, int>& p) { return property(p, "green"); });
    std::size_t num_b = std::count_if(vertex_props.begin(), vertex_props.end(),
                    [&property](const std::pair<std::string, int>& p) { return property(p, "blue"); });
    std::size_t rgb_colors = num_r + num_g + num_b;
    if (rgb_colors != 0 && rgb_colors != 3)
        return false;

    // only if set per vertex
    if (rgb_colors == 3) {
        rgb_value = MeshIO::PER_VERTEX;
        if (_material) {
            _material->binding = MeshIO::PER_VERTEX;
            _material->diffuseColor.reserve(v_count);
        }
    }

    if (format == ascii) {
        boost::regex rx_d("(([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?))\\s*");
        boost::regex rx_s("\\b([-+]?[0-9]+)\\s*");
        boost::regex rx_u("\\b([0-9]+)\\s*");
        boost::regex rx_f("^\\s*3\\s+([0-9]+)\\s+([0-9]+)\\s+([0-9]+)\\s*");
        boost::smatch what;

        for (std::size_t i = 0; i < v_count && std::getline(inp, line); i++) {
            // go through the vertex properties
            std::map<std::string, float> prop_values;
            for (std::vector<std::pair<std::string, Number> >::iterator it = vertex_props.begin(); it != vertex_props.end(); ++it) {
                switch (it->second) {
                case int8:
                case int16:
                case int32:
                    {
                        if (boost::regex_search(line, what, rx_s)) {
                            int v;
                            v = boost::lexical_cast<int>(what[1]);
                            prop_values[it->first] = static_cast<float>(v);
                            line = line.substr(what[0].length());
                        }
                        else {
                            return false;
                        }
                    } break;
                case uint8:
                case uint16:
                case uint32:
                    {
                        if (boost::regex_search(line, what, rx_u)) {
                            int v;
                            v = boost::lexical_cast<int>(what[1]);
                            prop_values[it->first] = static_cast<float>(v);
                            line = line.substr(what[0].length());
                        }
                        else {
                            return false;
                        }
                    } break;
                case float32:
                case float64:
                    {
                        if (boost::regex_search(line, what, rx_d)) {
                            double v;
                            v = boost::lexical_cast<double>(what[1]);
                            prop_values[it->first] = static_cast<float>(v);
                            line = line.substr(what[0].length());
                        }
                        else {
                            return false;
                        }
                    } break;
                default:
                    return false;
                }
            }

            Base::Vector3f pt;
            pt.x = (prop_values["x"]);
            pt.y = (prop_values["y"]);
            pt.z = (prop_values["z"]);
            meshPoints.push_back(pt);

            if (_material && (rgb_value == MeshIO::PER_VERTEX)) {
                float r = (prop_values["red"]) / 255.0f;
                float g = (prop_values["green"]) / 255.0f;
                float b = (prop_values["blue"]) / 255.0f;
                _material->diffuseColor.emplace_back(r, g, b);
            }
        }

        int f1, f2, f3;
        for (std::size_t i = 0; i < f_count && std::getline(inp, line); i++) {
            if (boost::regex_search(line, what, rx_f)) {
                f1 = boost::lexical_cast<int>(what[1]);
                f2 = boost::lexical_cast<int>(what[2]);
                f3 = boost::lexical_cast<int>(what[3]);
                meshFacets.push_back(MeshFacet(f1,f2,f3));
            }
        }
    }
    // binary
    else {
        Base::InputStream is(inp);
        if (format == binary_little_endian)
            is.setByteOrder(Base::Stream::LittleEndian);
        else
            is.setByteOrder(Base::Stream::BigEndian);

        for (std::size_t i = 0; i < v_count; i++) {
            // go through the vertex properties
            std::map<std::string, float> prop_values;
            for (std::vector<std::pair<std::string, Number> >::iterator it = vertex_props.begin(); it != vertex_props.end(); ++it) {
                switch (it->second) {
                case int8:
                    {
                        int8_t v; is >> v;
                        prop_values[it->first] = static_cast<float>(v);
                    } break;
                case uint8:
                    {
                        uint8_t v; is >> v;
                        prop_values[it->first] = static_cast<float>(v);
                    } break;
                case int16:
                    {
                        int16_t v; is >> v;
                        prop_values[it->first] = static_cast<float>(v);
                    } break;
                case uint16:
                    {
                        uint16_t v; is >> v;
                        prop_values[it->first] = static_cast<float>(v);
                    } break;
                case int32:
                    {
                        int32_t v; is >> v;
                        prop_values[it->first] = static_cast<float>(v);
                    } break;
                case uint32:
                    {
                        uint32_t v; is >> v;
                        prop_values[it->first] = static_cast<float>(v);
                    } break;
                case float32:
                    {
                        float v; is >> v;
                        prop_values[it->first] = v;
                    } break;
                case float64:
                    {
                        double v; is >> v;
                        prop_values[it->first] = static_cast<float>(v);
                    } break;
                default:
                    return false;
                }
            }

            Base::Vector3f pt;
            pt.x = (prop_values["x"]);
            pt.y = (prop_values["y"]);
            pt.z = (prop_values["z"]);
            meshPoints.push_back(pt);

            if (_material && (rgb_value == MeshIO::PER_VERTEX)) {
                float r = (prop_values["red"]) / 255.0f;
                float g = (prop_values["green"]) / 255.0f;
                float b = (prop_values["blue"]) / 255.0f;
                _material->diffuseColor.emplace_back(r, g, b);
            }
        }

        unsigned char n;
        uint32_t f1, f2, f3;
        for (std::size_t i = 0; i < f_count; i++) {
            is >> n;
            if (n==3) {
                is >> f1 >> f2 >> f3;
                if (f1 < v_count && f2 < v_count && f3 < v_count)
                    meshFacets.push_back(MeshFacet(f1,f2,f3));
                for (std::vector<Number>::iterator it = face_props.begin(); it != face_props.end(); ++it) {
                    switch (*it) {
                    case int8:
                        {
                            int8_t v; is >> v;
                        } break;
                    case uint8:
                        {
                            uint8_t v; is >> v;
                        } break;
                    case int16:
                        {
                            int16_t v; is >> v;
                        } break;
                    case uint16:
                        {
                            uint16_t v; is >> v;
                        } break;
                    case int32:
                        {
                            int32_t v; is >> v;
                        } break;
                    case uint32:
                        {
                            uint32_t v; is >> v;
                        } break;
                    case float32:
                        {
                            is >> n;
                            float v;
                            for (unsigned char j=0; j<n; j++)
                                is >> v;
                        } break;
                    case float64:
                        {
                            is >> n;
                            double v;
                            for (unsigned char j=0; j<n; j++)
                                is >> v;
                        } break;
                    default:
                        return false;
                    }
                }
            }
        }
    }

    this->_rclMesh.Clear(); // remove all data before

    MeshCleanup meshCleanup(meshPoints,meshFacets);
    if (_material)
        meshCleanup.SetMaterial(_material);
    meshCleanup.RemoveInvalids();
    MeshPointFacetAdjacency meshAdj(meshPoints.size(),meshFacets);
    meshAdj.SetFacetNeighbourhood();
    this->_rclMesh.Adopt(meshPoints,meshFacets);

    return true;
}

bool MeshInput::LoadMeshNode (std::istream &rstrIn)
{
    boost::regex rx_p("^v\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                      "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                      "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*$");
    boost::regex rx_f("^f\\s+([0-9]+)\\s+([0-9]+)\\s+([0-9]+)\\s*$");
    boost::regex rx_e("\\s*]\\s*");
    boost::cmatch what;

    MeshPointArray meshPoints;
    MeshFacetArray meshFacets;

    std::string line;
    float fX, fY, fZ;
    unsigned int  i1=1,i2=1,i3=1;
    MeshGeomFacet clFacet;

    if (!rstrIn || rstrIn.bad())
        return false;

    std::streambuf* buf = rstrIn.rdbuf();
    if (!buf)
        return false;

    while (std::getline(rstrIn, line)) {
        boost::algorithm::to_lower(line);
        if (boost::regex_match(line.c_str(), what, rx_p)) {
            fX = (float)std::atof(what[1].first);
            fY = (float)std::atof(what[4].first);
            fZ = (float)std::atof(what[7].first);
            meshPoints.push_back(MeshPoint(Base::Vector3f(fX, fY, fZ)));
        }
        else if (boost::regex_match(line.c_str(), what, rx_f)) {
            i1 = std::atoi(what[1].first);
            i2 = std::atoi(what[2].first);
            i3 = std::atoi(what[3].first);
            meshFacets.push_back(MeshFacet(i1-1,i2-1,i3-1));
        }
        else if (boost::regex_match(line.c_str(), what, rx_e)) {
            break;
        }
    }

    this->_rclMesh.Clear(); // remove all data before

    MeshCleanup meshCleanup(meshPoints,meshFacets);
    meshCleanup.RemoveInvalids();
    MeshPointFacetAdjacency meshAdj(meshPoints.size(),meshFacets);
    meshAdj.SetFacetNeighbourhood();
    this->_rclMesh.Adopt(meshPoints,meshFacets);

    return true;
}

/** Loads an ASCII STL file. */
bool MeshInput::LoadAsciiSTL (std::istream &rstrIn)
{
    boost::regex rx_p("^\\s*VERTEX\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                      "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                      "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*$");
    boost::regex rx_f("^\\s*FACET\\s+NORMAL\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                      "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                      "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*$");
    boost::cmatch what;

    std::string line;
    float fX, fY, fZ;
    unsigned long ulVertexCt, ulFacetCt=0;
    MeshGeomFacet clFacet;

    if (!rstrIn || rstrIn.bad())
        return false;

    std::streamoff ulSize = 0;
    std::streambuf* buf = rstrIn.rdbuf();
    ulSize = buf->pubseekoff(0, std::ios::end, std::ios::in);
    buf->pubseekoff(0, std::ios::beg, std::ios::in);
    ulSize -= 20;

    // count facets
    while (std::getline(rstrIn, line)) {
        boost::algorithm::to_upper(line);
        if (line.find("ENDFACET") != std::string::npos)
            ulFacetCt++;
        // prevent from reading EOF (as I don't know how to reread the file then)
        if (rstrIn.tellg() > ulSize)
            break;
        else if (line.find("ENDSOLID") != std::string::npos)
            break;
    }

    // restart from the beginning
    buf->pubseekoff(0, std::ios::beg, std::ios::in);

#if 0
    MeshBuilder builder(this->_rclMesh);
#else
    MeshFastBuilder builder(this->_rclMesh);
#endif
    builder.Initialize(ulFacetCt);

    ulVertexCt = 0;
    while (std::getline(rstrIn, line)) {
        boost::algorithm::to_upper(line);
        if (boost::regex_match(line.c_str(), what, rx_f)) {
            fX = (float)std::atof(what[1].first);
            fY = (float)std::atof(what[4].first);
            fZ = (float)std::atof(what[7].first);
            clFacet.SetNormal(Base::Vector3f(fX, fY, fZ));
        }
        else if (boost::regex_match(line.c_str(), what, rx_p)) {
            fX = (float)std::atof(what[1].first);
            fY = (float)std::atof(what[4].first);
            fZ = (float)std::atof(what[7].first);
            clFacet._aclPoints[ulVertexCt++].Set(fX, fY, fZ);
            if (ulVertexCt == 3) {
                ulVertexCt = 0;
                builder.AddFacet(clFacet);
            }
        }
    }

    builder.Finish();

    return true;
}

/** Loads a binary STL file. */
bool MeshInput::LoadBinarySTL (std::istream &rstrIn)
{
    char szInfo[80];
    Base::Vector3f clVects[4];
    uint16_t usAtt = 0;
    uint32_t ulCt = 0;

    if (!rstrIn || rstrIn.bad())
        return false;

    // Header-Info ueberlesen
    rstrIn.read(szInfo, sizeof(szInfo));

    // Anzahl Facets
    rstrIn.read((char*)&ulCt, sizeof(ulCt));
    if (rstrIn.bad())
        return false;

    // get file size and calculate the number of facets
    std::streamoff ulSize = 0;
    std::streambuf* buf = rstrIn.rdbuf();
    if (buf) {
        std::streamoff ulCurr;
        ulCurr = buf->pubseekoff(0, std::ios::cur, std::ios::in);
        ulSize = buf->pubseekoff(0, std::ios::end, std::ios::in);
        buf->pubseekoff(ulCurr, std::ios::beg, std::ios::in);
    }

    uint32_t ulFac = (ulSize - (80 + sizeof(uint32_t))) / 50;

    // compare the calculated with the read value
    if (ulCt > ulFac)
        return false;// not a valid STL file

#if 0
    MeshBuilder builder(this->_rclMesh);
#else
    MeshFastBuilder builder(this->_rclMesh);
#endif
    builder.Initialize(ulCt);

    for (uint32_t i = 0; i < ulCt; i++) {
        // read normal, points
        rstrIn.read((char*)&clVects, sizeof(clVects));

        std::swap(clVects[0], clVects[3]);
        builder.AddFacet(clVects);

        // overread 2 bytes attribute
        rstrIn.read((char*)&usAtt, sizeof(usAtt));
    }

    builder.Finish();

    return true;
}

/** Loads the mesh object from an XML file. */
void MeshInput::LoadXML (Base::XMLReader &reader)
{
    MeshPointArray cPoints;
    MeshFacetArray cFacets;

//  reader.readElement("Mesh");

    reader.readElement("Points");
    int Cnt = reader.getAttributeAsInteger("Count");

    cPoints.resize(Cnt);
    for (int i=0 ;i<Cnt ;i++) {
        reader.readElement("P");
        cPoints[i].x = (float)reader.getAttributeAsFloat("x");
        cPoints[i].y = (float)reader.getAttributeAsFloat("y");
        cPoints[i].z = (float)reader.getAttributeAsFloat("z");
    }
    reader.readEndElement("Points");

    reader.readElement("Faces");
    Cnt = reader.getAttributeAsInteger("Count");

    cFacets.resize(Cnt);
    for (int i=0 ;i<Cnt ;i++) {
        reader.readElement("F");
        cFacets[i]._aulPoints[0] = reader.getAttributeAsInteger("p0");
        cFacets[i]._aulPoints[1] = reader.getAttributeAsInteger("p1");
        cFacets[i]._aulPoints[2] = reader.getAttributeAsInteger("p2");
        cFacets[i]._aulNeighbours[0] = reader.getAttributeAsInteger("n0");
        cFacets[i]._aulNeighbours[1] = reader.getAttributeAsInteger("n1");
        cFacets[i]._aulNeighbours[2] = reader.getAttributeAsInteger("n2");
    }

    reader.readEndElement("Faces");
    reader.readEndElement("Mesh");

    _rclMesh.Adopt(cPoints, cFacets);
}

/** Loads a 3MF file. */
bool MeshInput::Load3MF(std::istream &inp)
{
    Reader3MF reader(inp);
    reader.Load();
    std::vector<int> ids = reader.GetMeshIds();
    if (!ids.empty()) {
        MeshKernel compound = reader.GetMesh(ids[0]);
        compound.Transform(reader.GetTransform(ids[0]));

        for (std::size_t index = 1; index < ids.size(); index++) {
            MeshKernel mesh = reader.GetMesh(ids[index]);
            mesh.Transform(reader.GetTransform(ids[index]));
            compound.Merge(mesh);
        }

        _rclMesh = compound;
        return true;
    }

    return false;
}

/** Loads an OpenInventor file. */
bool MeshInput::LoadInventor (std::istream &inp)
{
    Base::InventorLoader loader(inp);
    if (!loader.read())
        return false;

    if (!loader.isValid())
        return false;

    const auto& points = loader.getPoints();
    const auto& faces = loader.getFaces();

    MeshPointArray meshPoints;
    meshPoints.reserve(points.size());
    std::transform(points.begin(), points.end(), std::back_inserter(meshPoints),
                   [](const Base::Vector3f& v) {
        return MeshPoint(v);
    });

    MeshFacetArray meshFacets;
    meshFacets.reserve(faces.size());
    std::transform(faces.begin(), faces.end(), std::back_inserter(meshFacets),
                   [](const Base::InventorLoader::Face& f) {
        return MeshFacet(f.p1, f.p2, f.p3);
    });

    MeshCleanup meshCleanup(meshPoints, meshFacets);
    meshCleanup.RemoveInvalids();
    MeshPointFacetAdjacency meshAdj(meshPoints.size(), meshFacets);
    meshAdj.SetFacetNeighbourhood();
    this->_rclMesh.Adopt(meshPoints, meshFacets);

    if (loader.isNonIndexed()) {
        if (!MeshEvalDuplicatePoints(this->_rclMesh).Evaluate()) {
            MeshFixDuplicatePoints(this->_rclMesh).Fixup();
        }
    }

    return true;
}

/** Loads a Nastran file. */
bool MeshInput::LoadNastran (std::istream &rstrIn)
{
    if (!rstrIn || rstrIn.bad())
        return false;

    boost::regex rx_t("\\s*CTRIA3\\s+([0-9]+)\\s+([0-9]+)"
                      "\\s+([0-9]+)\\s+([0-9]+)\\s+([0-9]+)\\s*");
    boost::regex rx_q("\\s*CQUAD4\\s+([0-9]+)\\s+([0-9]+)"
                      "\\s+([0-9]+)\\s+([0-9]+)\\s+([0-9]+)\\s+([0-9]+)\\s*");
    boost::cmatch what;

    std::string line;
    MeshFacet clMeshFacet;
    MeshPointArray vVertices;
    MeshFacetArray vTriangle;

    int index;
    std::map <int, NODE> mNode;
    std::map <int, TRIA> mTria;
    std::map <int, QUAD> mQuad;

    int badElementCounter = 0;

    while (std::getline(rstrIn, line)) {
        boost::algorithm::to_upper(ltrim(line));
        if (line.empty()) {
            // Skip all the following tests
        }
        else if (line.rfind("GRID*", 0) == 0) {
            // This element is the 16-digit-precision GRID element, which occupies two lines of the card. Note that
            // FreeCAD discards the extra precision, downcasting to an four-byte float.
            //
            // The two lines are:
            // 1      8               24             40             56
            // GRID*  Index(16)       Blank(16)      x(16)          y(at least one)
            // *      z(at least one)
            //
            // The first character is typically the sign, and may be omitted for positive numbers,
            // so it is possible for a field to begin with a blank. Trailing zeros may be omitted, so
            // a field may also end with blanks. No space or other delimiter is required between
            // the numbers. The following is a valid NASTRAN GRID* element:
            //
            // GRID*  1                               0.1234567890120.
            // *      1.
            //
            if (line.length() < 8 + 16 + 16 + 16 + 1) { // Element type(8), index(16), empty(16), x(16), y(>=1)
                badElementCounter++;
                continue;
            }
            auto indexView = std::string_view(&line[8], 16);
            //auto blankView = std::string_view(&line[8+16], 16); // No data is needed here
            auto xView = std::string_view(&line[8+16+16], 16);
            auto yView = std::string_view(&line[8+16+16+16]);

            std::string line2;
            std::getline(rstrIn, line2);
            if ((!line2.empty() && line2[0] != '*') ||
                line2.length() < 9) {
                badElementCounter++;
                continue; // File format error: second line is not a continuation line
            }
            auto zView = std::string_view(&line2[8]);

            // We have to strip off any whitespace (technically really just any *trailing* whitespace):
            auto indexString = boost::trim_copy(std::string(indexView));
            auto xString = boost::trim_copy(std::string(xView));
            auto yString = boost::trim_copy(std::string(yView));
            auto zString = boost::trim_copy(std::string(zView));

            auto converter = boost::cnv::spirit();
            auto indexCheck = boost::convert<int>(indexString, converter);
            if (!indexCheck.is_initialized()) {
                // File format error: index couldn't be converted to an integer
                badElementCounter++;
                continue;
            }
            index = indexCheck.get() - 1; // Minus one so we are zero-indexed to match existing code

            // Get the high-precision versions first
            auto x = boost::convert<double>(xString, converter);
            auto y = boost::convert<double>(yString, converter);
            auto z = boost::convert<double>(zString, converter);

            if (!x.is_initialized() || !y.is_initialized() || !z.is_initialized()) {
                // File format error: x, y or z could not be converted
                badElementCounter++;
                continue;
            }

            // Now drop precision:
            mNode[index].x = (float)x.get();
            mNode[index].y = (float)y.get();
            mNode[index].z = (float)z.get();
        }
        else if (line.rfind("GRID", 0) == 0) {

            boost::regex rx_spaceDelimited("\\s*GRID\\s+([0-9]+)"
                "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)"
                "\\s+([-+]?[0-9]*)\\.?([0-9]+([eE][-+]?[0-9]+)?)\\s*");

            if (boost::regex_match(line.c_str(), what, rx_spaceDelimited)) {
                // insert the read-in vertex into a map to preserve the order
                index = std::atol(what[1].first)-1;
                mNode[index].x = (float)std::atof(what[2].first);
                mNode[index].y = (float)std::atof(what[5].first);
                mNode[index].z = (float)std::atof(what[8].first);
            }
            else {
                // Classic NASTRAN uses a fixed 8 character field width:
                // 1       8       16      24      32      40
                // $-------ID------CP------X1------X2------X3------CD------PS------9-------+-------
                // GRID    1               1.2345671.2345671.234567
                // GRID    112             6.0000000.5000000.00E+00

                if (line.length() < 41) { // Element type(8), id(8), cp(8), x(8), y(8), z(at least 1)
                    badElementCounter++;
                    continue;
                }
                auto indexView = std::string_view(&line[8], 8);
                auto xView = std::string_view(&line[24], 8);
                auto yView = std::string_view(&line[32], 8);
                auto zView = std::string_view(&line[40], 8);

                auto indexString = boost::trim_copy(std::string(indexView));
                auto xString = boost::trim_copy(std::string(xView));
                auto yString = boost::trim_copy(std::string(yView));
                auto zString = boost::trim_copy(std::string(zView));

                auto converter = boost::cnv::spirit();
                auto indexCheck = boost::convert<int>(indexString, converter);
                if (!indexCheck.is_initialized()) {
                    // File format error: index couldn't be converted to an integer
                    badElementCounter++;
                    continue;
                }
                index = indexCheck.get() - 1; // Minus one so we are zero-indexed to match existing code

                auto x = boost::convert<float>(xString, converter);
                auto y = boost::convert<float>(yString, converter);
                auto z = boost::convert<float>(zString, converter);

                if (!x.is_initialized() || !y.is_initialized() || !z.is_initialized()) {
                    // File format error: x, y or z could not be converted
                    badElementCounter++;
                    continue;
                }

                mNode[index].x = x.get();
                mNode[index].y = y.get();
                mNode[index].z = z.get();
            }
        }
        else if (line.rfind("CTRIA3 ", 0) == 0) {
            if (boost::regex_match(line.c_str(), what, rx_t)) {
                // insert the read-in triangle into a map to preserve the order
                index = std::atol(what[1].first)-1;
                mTria[index].iV[0] = std::atol(what[3].first)-1;
                mTria[index].iV[1] = std::atol(what[4].first)-1;
                mTria[index].iV[2] = std::atol(what[5].first)-1;
            }
        }
        else if (line.rfind("CQUAD4", 0) == 0) {
            if (boost::regex_match(line.c_str(), what, rx_q)) {
                // insert the read-in quadrangle into a map to preserve the order
                index = std::atol(what[1].first)-1;
                mQuad[index].iV[0] = std::atol(what[3].first)-1;
                mQuad[index].iV[1] = std::atol(what[4].first)-1;
                mQuad[index].iV[2] = std::atol(what[5].first)-1;
                mQuad[index].iV[3] = std::atol(what[6].first)-1;
            }
        }
    }

    if (badElementCounter > 0) {
        Base::Console().Warning("Found bad elements while reading NASTRAN file.\n");
    }

    // Check the triangles to make sure the vertices they refer to actually exist:
    for (const auto& tri : mTria) {
        for (int i = 0; i < 3; ++i) {
            if (mNode.find(tri.second.iV[i]) == mNode.end()) {
                Base::Console().Error("CTRIA3 element refers to a node that does not exist, or could not be read.\n");
                return false;
            }
        }
    }

    // Check the quads to make sure the vertices they refer to actually exist:
    for (const auto& quad : mQuad) {
        for (int i = 0; i < 4; ++i) {
            if (mNode.find(quad.second.iV[i]) == mNode.end()) {
                Base::Console().Error("CQUAD4 element refers to a node that does not exist, or could not be read.\n");
                return false;
            }
        }
    }

    float fLength[2];
    if (mTria.empty())
        index = 0;
    else
        index = mTria.rbegin()->first + 1;
    for (std::map <int, QUAD>::iterator QI=mQuad.begin(); QI!=mQuad.end(); ++QI) {
        for (int i = 0; i < 2; i++) {
            float fDx = mNode[(*QI).second.iV[i+2]].x - mNode[(*QI).second.iV[i]].x;
            float fDy = mNode[(*QI).second.iV[i+2]].y - mNode[(*QI).second.iV[i]].y;
            float fDz = mNode[(*QI).second.iV[i+2]].z - mNode[(*QI).second.iV[i]].z;
            fLength[i] = fDx*fDx + fDy*fDy + fDz*fDz;
        }
        if (fLength[0] < fLength[1]) {
            mTria[index].iV[0] = (*QI).second.iV[0];
            mTria[index].iV[1] = (*QI).second.iV[1];
            mTria[index].iV[2] = (*QI).second.iV[2];

            mTria[index+1].iV[0] = (*QI).second.iV[0];
            mTria[index+1].iV[1] = (*QI).second.iV[2];
            mTria[index+1].iV[2] = (*QI).second.iV[3];
        }
        else {
            mTria[index].iV[0] = (*QI).second.iV[0];
            mTria[index].iV[1] = (*QI).second.iV[1];
            mTria[index].iV[2] = (*QI).second.iV[3];

            mTria[index+1].iV[0] = (*QI).second.iV[1];
            mTria[index+1].iV[1] = (*QI).second.iV[2];
            mTria[index+1].iV[2] = (*QI).second.iV[3];
        }

        index += 2;
    }

    // Applying the nodes
    vVertices.reserve(mNode.size());
    for (std::map<int, NODE>::iterator MI=mNode.begin(); MI!=mNode.end(); ++MI) {
        vVertices.push_back(Base::Vector3f(MI->second.x, MI->second.y, MI->second.z));
    }

    // Converting data to Mesh. Negative conversion for right orientation of normal-vectors.
    vTriangle.reserve(mTria.size());
    for (std::map<int, TRIA>::iterator MI=mTria.begin(); MI!=mTria.end(); ++MI) {
        clMeshFacet._aulPoints[0] = (*MI).second.iV[1];
        clMeshFacet._aulPoints[1] = (*MI).second.iV[0];
        clMeshFacet._aulPoints[2] = (*MI).second.iV[2];
        vTriangle.push_back (clMeshFacet);
    }

    // make sure to add only vertices which are referenced by the triangles
    _rclMesh.Merge(vVertices, vTriangle);

    return true;
}

/** Loads a Cadmould FE file. */
bool MeshInput::LoadCadmouldFE (std::ifstream &rstrIn)
{
    if (!rstrIn || rstrIn.bad())
        return false;
    assert(0);
    return false;
}

// --------------------------------------------------------------

std::string MeshOutput::stl_header = "MESH-MESH-MESH-MESH-MESH-MESH-MESH-MESH-"
                                     "MESH-MESH-MESH-MESH-MESH-MESH-MESH-MESH\n";

void MeshOutput::SetSTLHeaderData(const std::string& header)
{
    if (header.size() > 80) {
        stl_header = header.substr(0, 80);
    }
    else if (header.size() < 80) {
        std::fill(stl_header.begin(), stl_header.end(), ' ');
        std::copy(header.begin(), header.end(), stl_header.begin());
    }
    else {
        stl_header = header;
    }
}

std::string MeshOutput::asyWidth = "500";
std::string MeshOutput::asyHeight = "500";

void MeshOutput::SetAsymptoteSize(const std::string& w, const std::string& h)
{
    asyWidth = w;
    asyHeight = h;
}

void MeshOutput::Transform(const Base::Matrix4D& mat)
{
    _transform = mat;
    if (mat != Base::Matrix4D())
        apply_transform = true;
}

std::vector<std::string> MeshOutput::supportedMeshFormats()
{
    std::vector<std::string> fmt;
    fmt.emplace_back("bms");
    fmt.emplace_back("ply");
    fmt.emplace_back("stl");
    fmt.emplace_back("obj");
    fmt.emplace_back("off");
    fmt.emplace_back("smf");
    fmt.emplace_back("x3d");
    fmt.emplace_back("x3dz");
    fmt.emplace_back("xhtml");
    fmt.emplace_back("wrl");
    fmt.emplace_back("wrz");
    fmt.emplace_back("amf");
    fmt.emplace_back("asy");
    fmt.emplace_back("3mf");
    return fmt;
}

MeshIO::Format MeshOutput::GetFormat(const char* FileName)
{
    Base::FileInfo file(FileName);
    if (file.hasExtension("bms")) {
        return MeshIO::BMS;
    }
    else if (file.hasExtension("stl")) {
        return MeshIO::BSTL;
    }
    else if (file.hasExtension("ast")) {
        return MeshIO::ASTL;
    }
    else if (file.hasExtension("obj")) {
        return MeshIO::OBJ;
    }
    else if (file.hasExtension("off")) {
        return MeshIO::OFF;
    }
    else if (file.hasExtension("ply")) {
        return MeshIO::PLY;
    }
    else if (file.hasExtension("idtf")) {
        return MeshIO::IDTF;
    }
    else if (file.hasExtension("mgl")) {
        return MeshIO::MGL;
    }
    else if (file.hasExtension("iv")) {
        return MeshIO::IV;
    }
    else if (file.hasExtension("x3d")) {
        return MeshIO::X3D;
    }
    else if (file.hasExtension("x3dz")) {
        return MeshIO::X3DZ;
    }
    else if (file.hasExtension("xhtml")) {
        return MeshIO::X3DOM;
    }
    else if (file.hasExtension("py")) {
        return MeshIO::PY;
    }
    else if (file.hasExtension("wrl") || file.hasExtension("vrml")) {
        return MeshIO::VRML;
    }
    else if (file.hasExtension("wrz")) {
        return MeshIO::WRZ;
    }
    else if (file.hasExtension("nas") || file.hasExtension("bdf")) {
        return MeshIO::NAS;
    }
    else if (file.hasExtension("amf")) {
        return MeshIO::AMF;
    }
    else if (file.hasExtension("3mf")) {
        return MeshIO::ThreeMF;
    }
    else if (file.hasExtension("smf")) {
        return MeshIO::SMF;
    }
    else if (file.hasExtension("asy")) {
        return MeshIO::ASY;
    }
    else {
        return MeshIO::Undefined;
    }
}

/// Save in a file, format is decided by the extension if not explicitly given
bool MeshOutput::SaveAny(const char* FileName, MeshIO::Format format) const
{
    // ask for write permission
    Base::FileInfo file(FileName);
    Base::FileInfo directory(file.dirPath());
    if ((file.exists() && !file.isWritable()) || !directory.exists() || !directory.isWritable())
        throw Base::FileException("No write permission for file",FileName);

    MeshIO::Format fileformat = format;
    if (fileformat == MeshIO::Undefined) {
        fileformat = GetFormat(FileName);
    }

    Base::ofstream str(file, std::ios::out | std::ios::binary);

    if (fileformat == MeshIO::BMS) {
        _rclMesh.Write(str);
    }
    else if (fileformat == MeshIO::BSTL) {
        MeshOutput aWriter(_rclMesh);
        aWriter.Transform(this->_transform);

        // write file
        bool ok = false;
        ok = aWriter.SaveBinarySTL( str );
        if (!ok)
            throw Base::FileException("Export of STL mesh failed",FileName);

    }
    else if (fileformat == MeshIO::ASTL) {
        MeshOutput aWriter(_rclMesh);
        aWriter.SetObjectName(objectName);
        aWriter.Transform(this->_transform);

        // write file
        bool ok = false;
        ok = aWriter.SaveAsciiSTL( str );
        if (!ok)
            throw Base::FileException("Export of STL mesh failed",FileName);
    }
    else if (fileformat == MeshIO::OBJ) {
        // write file
        if (!SaveOBJ(str))
            throw Base::FileException("Export of OBJ mesh failed",FileName);
    }
    else if (fileformat == MeshIO::SMF) {
        // write file
        if (!SaveSMF(str))
            throw Base::FileException("Export of SMF mesh failed",FileName);
    }
    else if (fileformat == MeshIO::OFF) {
        // write file
        if (!SaveOFF(str))
            throw Base::FileException("Export of OFF mesh failed",FileName);
    }
    else if (fileformat == MeshIO::PLY) {
        // write file
        if (!SaveBinaryPLY(str))
            throw Base::FileException("Export of PLY mesh failed",FileName);
    }
    else if (fileformat == MeshIO::APLY) {
        // write file
        if (!SaveAsciiPLY(str))
            throw Base::FileException("Export of PLY mesh failed",FileName);
    }
    else if (fileformat == MeshIO::IDTF) {
        // write file
        if (!SaveIDTF(str))
            throw Base::FileException("Export of IDTF mesh failed",FileName);
    }
    else if (fileformat == MeshIO::MGL) {
        // write file
        if (!SaveMGL(str))
            throw Base::FileException("Export of MGL mesh failed",FileName);
    }
    else if (fileformat == MeshIO::IV) {
        // write file
        if (!SaveInventor(str))
            throw Base::FileException("Export of Inventor mesh failed",FileName);
    }
    else if (fileformat == MeshIO::X3D) {
        // write file
        if (!SaveX3D(str))
            throw Base::FileException("Export of X3D failed",FileName);
    }
    else if (fileformat == MeshIO::X3DZ) {
        // Compressed X3D is nothing else than a GZIP'ped X3D ascii file
        zipios::GZIPOutputStream gzip(str);
        // write file
        if (!SaveX3D(gzip))
            throw Base::FileException("Export of compressed X3D mesh failed",FileName);
    }
    else if (fileformat == MeshIO::X3DOM) {
        // write file
        if (!SaveX3DOM(str))
            throw Base::FileException("Export of X3DOM failed",FileName);
    }
    else if (fileformat == MeshIO::ThreeMF) {
        // write file
        if (!Save3MF(str))
            throw Base::FileException("Export of 3MF failed",FileName);
    }
    else if (fileformat == MeshIO::PY) {
        // write file
        if (!SavePython(str))
            throw Base::FileException("Export of Python mesh failed",FileName);
    }
    else if (fileformat == MeshIO::VRML) {
        // write file
        if (!SaveVRML(str))
            throw Base::FileException("Export of VRML mesh failed",FileName);
    }
    else if (fileformat == MeshIO::WRZ) {
        // Compressed VRML is nothing else than a GZIP'ped VRML ascii file
        // str.close();
        //Base::ogzstream gzip(FileName, std::ios::out | std::ios::binary);
        //Hint: The compression level seems to be higher than with ogzstream
        //which leads to problems to load the wrz file in debug mode, the
        //application simply crashes.
        zipios::GZIPOutputStream gzip(str);
        // write file
        if (!SaveVRML(gzip))
            throw Base::FileException("Export of compressed VRML mesh failed",FileName);
    }
    else if (fileformat == MeshIO::NAS) {
        // write file
        if (!SaveNastran(str))
            throw Base::FileException("Export of NASTRAN mesh failed",FileName);
    }
    else if (fileformat == MeshIO::ASY) {
        // write file
        if (!SaveAsymptote(str))
            throw Base::FileException("Export of ASY mesh failed",FileName);
    }
    else {
        throw Base::FileException("File format not supported", FileName);
    }

    return true;
}

bool MeshOutput::SaveFormat(std::ostream &str, MeshIO::Format fmt) const
{
    switch (fmt) {
    case MeshIO::BMS:
        _rclMesh.Write(str);
        return true;
    case MeshIO::ASTL:
        return SaveAsciiSTL(str);
    case MeshIO::BSTL:
        return SaveBinarySTL(str);
    case MeshIO::OBJ:
        return SaveOBJ(str);
    case MeshIO::SMF:
        return SaveSMF(str);
    case MeshIO::OFF:
        return SaveOFF(str);
    case MeshIO::IDTF:
        return SaveIDTF(str);
    case MeshIO::MGL:
        return SaveMGL(str);
    case MeshIO::IV:
        return SaveInventor(str);
    case MeshIO::X3D:
        return SaveX3D(str);
    case MeshIO::X3DOM:
        return SaveX3DOM(str);
    case MeshIO::VRML:
        return SaveVRML(str);
    case MeshIO::WRZ:
        // it's up to the client to create the needed stream
        return SaveVRML(str);
    case MeshIO::ThreeMF:
        return Save3MF(str);
    case MeshIO::NAS:
        return SaveNastran(str);
    case MeshIO::PLY:
        return SaveBinaryPLY(str);
    case MeshIO::APLY:
        return SaveAsciiPLY(str);
    case MeshIO::PY:
        return SavePython(str);
    case MeshIO::ASY:
        return SaveAsymptote(str);
    default:
        throw Base::FileException("Unsupported file format");
    }
}

/** Saves the mesh object into an ASCII file. */
bool MeshOutput::SaveAsciiSTL (std::ostream &rstrOut) const
{
    MeshFacetIterator clIter(_rclMesh), clEnd(_rclMesh);
    clIter.Transform(this->_transform);
    const MeshGeomFacet *pclFacet;

    if (!rstrOut || rstrOut.bad() || _rclMesh.CountFacets() == 0)
        return false;

    rstrOut.precision(6);
    rstrOut.setf(std::ios::fixed | std::ios::showpoint);
    Base::SequencerLauncher seq("saving...", _rclMesh.CountFacets() + 1);

    if (this->objectName.empty())
        rstrOut << "solid Mesh\n";
    else
        rstrOut << "solid " << this->objectName << '\n';

    clIter.Begin();
    clEnd.End();
    while (clIter < clEnd) {
        pclFacet = &(*clIter);

        // normal
        rstrOut << "  facet normal " << pclFacet->GetNormal().x << " "
                                     << pclFacet->GetNormal().y << " "
                                     << pclFacet->GetNormal().z << '\n';
        rstrOut << "    outer loop\n";

        // vertices
        for (int i = 0; i < 3; i++) {
            rstrOut << "      vertex "  << pclFacet->_aclPoints[i].x << " "
                                        << pclFacet->_aclPoints[i].y << " "
                                        << pclFacet->_aclPoints[i].z << '\n';
        }

        rstrOut << "    endloop\n";
        rstrOut << "  endfacet\n";

        ++clIter;
        seq.next(true);// allow to cancel
    }

    rstrOut << "endsolid Mesh\n";

    return true;
}

/** Saves the mesh object into a binary file. */
bool MeshOutput::SaveBinarySTL (std::ostream &rstrOut) const
{
    MeshFacetIterator clIter(_rclMesh), clEnd(_rclMesh);
    clIter.Transform(this->_transform);
    const MeshGeomFacet *pclFacet;
    uint32_t i;
    uint16_t usAtt;
    char szInfo[81];

    if (!rstrOut || rstrOut.bad() /*|| _rclMesh.CountFacets() == 0*/)
        return false;

    Base::SequencerLauncher seq("saving...", _rclMesh.CountFacets() + 1);

    // stl_header has a length of 80
    strcpy(szInfo, stl_header.c_str());
    rstrOut.write(szInfo, std::strlen(szInfo));

    uint32_t uCtFts = (uint32_t)_rclMesh.CountFacets();
    rstrOut.write((const char*)&uCtFts, sizeof(uCtFts));

    usAtt = 0;
    clIter.Begin();
    clEnd.End();
    while (clIter < clEnd) {
        pclFacet = &(*clIter);
        // normal
        Base::Vector3f normal = pclFacet->GetNormal();
        rstrOut.write((const char*)&(normal.x), sizeof(float));
        rstrOut.write((const char*)&(normal.y), sizeof(float));
        rstrOut.write((const char*)&(normal.z), sizeof(float));

        // vertices
        for (i = 0; i < 3; i++) {
            rstrOut.write((const char*)&(pclFacet->_aclPoints[i].x), sizeof(float));
            rstrOut.write((const char*)&(pclFacet->_aclPoints[i].y), sizeof(float));
            rstrOut.write((const char*)&(pclFacet->_aclPoints[i].z), sizeof(float));
        }

        // attribute
        rstrOut.write((const char*)&usAtt, sizeof(usAtt));

        ++clIter;
        seq.next(true); // allow to cancel
    }

    return true;
}

/** Saves an OBJ file. */
bool MeshOutput::SaveOBJ (std::ostream &out) const
{
    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();

    if (!out || out.bad())
        return false;

    Base::SequencerLauncher seq("saving...", _rclMesh.CountPoints() + _rclMesh.CountFacets());
    bool exportColorPerVertex = false;
    bool exportColorPerFace = false;

    if (_material) {
        if (_material->binding == MeshIO::PER_FACE) {
            if (_material->diffuseColor.size() != rFacets.size()) {
                Base::Console().Warning("Cannot export color information because there is a different number of faces and colors");
            }
            else {
                exportColorPerFace = true;
            }
        }
        else if (_material->binding == MeshIO::PER_VERTEX) {
            if (_material->diffuseColor.size() != rPoints.size()) {
                Base::Console().Warning("Cannot export color information because there is a different number of points and colors");
            }
            else {
                exportColorPerVertex = true;
            }
        }
        else if (_material->binding == MeshIO::OVERALL) {
            if (_material->diffuseColor.empty()) {
                Base::Console().Warning("Cannot export color information because there is no color defined");
            }
            else {
                exportColorPerVertex = true;
            }
        }
    }

    // Header
    out << "# Created by FreeCAD <http://www.freecadweb.org>\n";
    if (exportColorPerFace) {
        out << "mtllib " << _material->library << '\n';
    }

    out.precision(6);
    out.setf(std::ios::fixed | std::ios::showpoint);

    // vertices
    Base::Vector3f pt;
    std::size_t index = 0;
    for (MeshPointArray::_TConstIterator it = rPoints.begin(); it != rPoints.end(); ++it, ++index) {
        if (this->apply_transform) {
            pt = this->_transform * *it;
        }
        else {
            pt.Set(it->x, it->y, it->z);
        }

        if (exportColorPerVertex) {
            App::Color c;
            if (_material->binding == MeshIO::PER_VERTEX) {
                c = _material->diffuseColor[index];
            }
            else {
                c = _material->diffuseColor.front();
            }

            int r = static_cast<int>(c.r * 255.0f);
            int g = static_cast<int>(c.g * 255.0f);
            int b = static_cast<int>(c.b * 255.0f);

            out << "v " << pt.x << " " << pt.y << " " << pt.z << " " << r << " " << g << " " << b << '\n';
        }
        else {
            out << "v " << pt.x << " " << pt.y << " " << pt.z << '\n';
        }
        seq.next(true); // allow to cancel
    }
    // Export normals
    MeshFacetIterator clIter(_rclMesh), clEnd(_rclMesh);
    const MeshGeomFacet* pclFacet;

    clIter.Begin();
    clEnd.End();

    while (clIter < clEnd) {
        pclFacet = &(*clIter);
        out << "vn " << pclFacet->GetNormal().x << " "
            << pclFacet->GetNormal().y << " "
            << pclFacet->GetNormal().z << '\n';
        ++clIter;
        seq.next(true); // allow to cancel
    }

    if (_groups.empty()) {
        if (exportColorPerFace) {
            // facet indices (no texture and normal indices)

            // make sure to use the 'usemtl' statement as less often as possible
            std::vector<App::Color> colors = _material->diffuseColor;
            std::sort(colors.begin(), colors.end(), Color_Less());
            colors.erase(std::unique(colors.begin(), colors.end()), colors.end());

            std::size_t index = 0;
            App::Color prev;
            int faceIdx = 1;
            const std::vector<App::Color>& Kd = _material->diffuseColor;
            for (MeshFacetArray::_TConstIterator it = rFacets.begin(); it != rFacets.end(); ++it, index++) {
                if (index == 0 || prev != Kd[index]) {
                    prev = Kd[index];
                    std::vector<App::Color>::iterator c_it = std::find(colors.begin(), colors.end(), prev);
                    if (c_it != colors.end()) {
                        out << "usemtl material_" << (c_it - colors.begin()) << '\n';
                    }
                }
                out << "f " << it->_aulPoints[0]+1 << "//" << faceIdx << " "
                            << it->_aulPoints[1]+1 << "//" << faceIdx << " "
                            << it->_aulPoints[2]+1 << "//" << faceIdx << '\n';
                seq.next(true); // allow to cancel
                faceIdx++;
            }
        }
        else {
            // facet indices (no texture and normal indices)
            std::size_t faceIdx = 1;
            for (MeshFacetArray::_TConstIterator it = rFacets.begin(); it != rFacets.end(); ++it) {
                out << "f " << it->_aulPoints[0]+1 << "//" << faceIdx << " "
                            << it->_aulPoints[1]+1 << "//" << faceIdx << " "
                            << it->_aulPoints[2]+1 << "//" << faceIdx << '\n';
                seq.next(true); // allow to cancel
                faceIdx++;
            }
        }
    }
    else {
        if (exportColorPerFace) {
            // make sure to use the 'usemtl' statement as less often as possible
            std::vector<App::Color> colors = _material->diffuseColor;
            std::sort(colors.begin(), colors.end(), Color_Less());
            colors.erase(std::unique(colors.begin(), colors.end()), colors.end());

            bool first = true;
            App::Color prev;
            const std::vector<App::Color>& Kd = _material->diffuseColor;

            for (std::vector<Group>::const_iterator gt = _groups.begin(); gt != _groups.end(); ++gt) {
                out << "g " << Base::Tools::escapedUnicodeFromUtf8(gt->name.c_str()) << '\n';
                for (std::vector<FacetIndex>::const_iterator it = gt->indices.begin(); it != gt->indices.end(); ++it) {
                    const MeshFacet& f = rFacets[*it];
                    if (first || prev != Kd[*it]) {
                        first = false;
                        prev = Kd[*it];
                        std::vector<App::Color>::iterator c_it = std::find(colors.begin(), colors.end(), prev);
                        if (c_it != colors.end()) {
                            out << "usemtl material_" << (c_it - colors.begin()) << '\n';
                        }
                    }

                    out << "f " << f._aulPoints[0]+1 << "//" << *it + 1 << " "
                                << f._aulPoints[1]+1 << "//" << *it + 1 << " "
                                << f._aulPoints[2]+1 << "//" << *it + 1 << '\n';
                    seq.next(true); // allow to cancel
                }
            }
        }
        else {
            for (std::vector<Group>::const_iterator gt = _groups.begin(); gt != _groups.end(); ++gt) {
                out << "g " << Base::Tools::escapedUnicodeFromUtf8(gt->name.c_str()) << '\n';
                for (std::vector<FacetIndex>::const_iterator it = gt->indices.begin(); it != gt->indices.end(); ++it) {
                    const MeshFacet& f = rFacets[*it];
                    out << "f " << f._aulPoints[0]+1 << "//" << *it + 1 << " "
                                << f._aulPoints[1]+1 << "//" << *it + 1 << " "
                                << f._aulPoints[2]+1 << "//" << *it + 1 << '\n';
                    seq.next(true); // allow to cancel
                }
            }
        }
    }

    return true;
}

bool MeshOutput::SaveMTL(std::ostream &out) const
{
    if (!out || out.bad())
        return false;

    if (_material) {
        if (_material->binding == MeshIO::PER_FACE) {

            std::vector<App::Color> Kd = _material->diffuseColor;
            std::sort(Kd.begin(), Kd.end(), Color_Less());
            Kd.erase(std::unique(Kd.begin(), Kd.end()), Kd.end());

            out.precision(6);
            out.setf(std::ios::fixed | std::ios::showpoint);
            out << "# Created by FreeCAD <http://www.freecadweb.org>: 'None'\n";
            out << "# Material Count: " << Kd.size() << '\n';

            for (std::size_t i=0; i<Kd.size(); i++) {
                out << '\n';
                out << "newmtl material_" << i << '\n';
                out << "    Ns 10.000000" << '\n';
                out << "    Ni 1.000000" << '\n';
                out << "    d 1.000000" << '\n';
                out << "    illum 2" << '\n';
                out << "    Kd " << Kd[i].r << " " << Kd[i].g << " " << Kd[i].b << '\n';
            }

            return true;
        }
    }

    return false;
}

/** Saves an SMF file. */
bool MeshOutput::SaveSMF (std::ostream &out) const
{
    // http://people.sc.fsu.edu/~jburkardt/data/smf/smf.txt
    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();

    if (!out || out.bad())
        return false;

    Base::SequencerLauncher seq("saving...", _rclMesh.CountPoints() + _rclMesh.CountFacets());

    // Header
    out << "#$SMF 1.0\n";
    out << "#$vertices " << rPoints.size() << '\n';
    out << "#$faces " << rFacets.size() << '\n';
    out << "#\n";
    out << "# Created by FreeCAD <http://www.freecadweb.org>\n";

    out.precision(6);
    out.setf(std::ios::fixed | std::ios::showpoint);

    // vertices
    Base::Vector3f pt;
    std::size_t index = 0;
    for (MeshPointArray::_TConstIterator it = rPoints.begin(); it != rPoints.end(); ++it, ++index) {
        if (this->apply_transform) {
            pt = this->_transform * *it;
        }
        else {
            pt.Set(it->x, it->y, it->z);
        }

        out << "v " << pt.x << " " << pt.y << " " << pt.z << '\n';
        seq.next(true); // allow to cancel
    }

    // facet indices
    for (MeshFacetArray::_TConstIterator it = rFacets.begin(); it != rFacets.end(); ++it) {
        out << "f " << it->_aulPoints[0]+1 << " "
                    << it->_aulPoints[1]+1 << " "
                    << it->_aulPoints[2]+1 << '\n';
        seq.next(true); // allow to cancel
    }

    return true;
}

/** Saves an Asymptote file. */
bool MeshOutput::SaveAsymptote(std::ostream &out) const
{
    out << "/*\n"
           " * Created by FreeCAD <http://www.freecadweb.org>\n"
           " */\n\n";

    out << "import three;\n\n";

    if (!asyWidth.empty()) {
        out << "size(" << asyWidth;
        if (!asyHeight.empty())
            out << ", " << asyHeight;
        out << ");\n\n";
    }

    Base::BoundBox3f bbox = _rclMesh.GetBoundBox();
    Base::Vector3f center = bbox.GetCenter();
    this->_transform.multVec(center, center);
    Base::Vector3f camera(center);
    camera.x += std::max<float>(std::max<float>(bbox.LengthX(), bbox.LengthY()), bbox.LengthZ());
    Base::Vector3f target(center);
    Base::Vector3f upvec(0.0f, 0.0f, 1.0f);

    out << "// CA:Camera, OB:Camera\n"
        << "currentprojection = orthographic(camera = (" << camera.x << ", "
                                                         << camera.y << ", "
                                                         << camera.z << "),\n"
        << "                                 target = (" << target.x << ", "
                                                         << target.y << ", "
                                                         << target.z << "),\n"
           "                                 showtarget = false,\n"
           "                                 up = (" << upvec.x << ", "
                                                     << upvec.y << ", "
                                                     << upvec.z << "));\n\n";

    //out << "// LA:Spot, OB:Lamp\n"
    //    << "// WO:World\n"
    //    << "currentlight = light(diffuse = rgb(1, 1, 1),\n"
    //       "                     specular = rgb(1, 1, 1),\n"
    //       "                     background = rgb(0.078281, 0.16041, 0.25),\n"
    //       "                     0.56639, 0.21839, 0.79467);\n\n";

    out << "// ME:Mesh, OB:Mesh\n";

    MeshFacetIterator clIter(_rclMesh), clEnd(_rclMesh);
    clIter.Transform(this->_transform);
    clIter.Begin();
    clEnd.End();

    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();
    bool saveVertexColor = (_material && _material->binding == MeshIO::PER_VERTEX &&
                            _material->diffuseColor.size() == rPoints.size());
    bool saveFaceColor   = (_material && _material->binding == MeshIO::PER_FACE &&
                            _material->diffuseColor.size() == rFacets.size());
    // global mesh color
    App::Color mc(0.8f, 0.8f, 0.8f);
    if (_material && _material->binding == MeshIO::OVERALL &&
        _material->diffuseColor.size() == 1) {
        mc = _material->diffuseColor[0];
    }

    std::size_t index = 0;
    const MeshGeomFacet *pclFacet;
    while (clIter < clEnd) {
        pclFacet = &(*clIter);

        out << "draw(surface(";

        // vertices
        for (int i = 0; i < 3; i++) {
            out << '(' << pclFacet->_aclPoints[i].x << ", "
                       << pclFacet->_aclPoints[i].y << ", "
                       << pclFacet->_aclPoints[i].z << ")--";
        }

        out << "cycle";

        if (saveVertexColor) {
            const MeshFacet& face = rFacets[index];
            out << ",\n             new pen[] {";
            for (int i = 0; i < 3; i++) {
                const App::Color& c = _material->diffuseColor[face._aulPoints[i]];
                out << "rgb(" << c.r << ", " << c.g << ", " << c.b << ")";
                if (i < 2)
                    out << ", ";
            }
            out << "}));\n";
        }
        else if (saveFaceColor) {
            const App::Color& c = _material->diffuseColor[index];
            out << "),\n     rgb(" << c.r << ", " << c.g << ", " << c.b << "));\n";
        }
        else {
            out << "),\n     rgb(" << mc.r << ", " << mc.g << ", " << mc.b << "));\n";
        }

        ++clIter;
        ++index;
    }

    return true;
}

/** Saves an OFF file. */
bool MeshOutput::SaveOFF (std::ostream &out) const
{
    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();

    if (!out || out.bad())
        return false;

    Base::SequencerLauncher seq("saving...", _rclMesh.CountPoints() + _rclMesh.CountFacets());

    bool exportColor = false;
    if (_material) {
        if (_material->binding == MeshIO::PER_FACE) {
            Base::Console().Warning("Cannot export color information because it's defined per face");
        }
        else if (_material->binding == MeshIO::PER_VERTEX) {
            if (_material->diffuseColor.size() != rPoints.size()) {
                Base::Console().Warning("Cannot export color information because there is a different number of points and colors");
            }
            else {
                exportColor = true;
            }
        }
        else if (_material->binding == MeshIO::OVERALL) {
            if (_material->diffuseColor.empty()) {
                Base::Console().Warning("Cannot export color information because there is no color defined");
            }
            else {
                exportColor = true;
            }
        }
    }

    if (exportColor)
        out << "COFF\n";
    else
        out << "OFF\n";
    out << rPoints.size() << " " << rFacets.size() << " 0\n";

    // vertices
    Base::Vector3f pt;
    std::size_t index = 0;
    for (MeshPointArray::_TConstIterator it = rPoints.begin(); it != rPoints.end(); ++it, ++index) {
        if (this->apply_transform) {
            pt = this->_transform * *it;
        }
        else {
            pt.Set(it->x, it->y, it->z);
        }

        if (exportColor) {
            App::Color c;
            if (_material->binding == MeshIO::PER_VERTEX) {
                c = _material->diffuseColor[index];
            }
            else {
                c = _material->diffuseColor.front();
            }

            int r = static_cast<int>(c.r * 255.0f);
            int g = static_cast<int>(c.g * 255.0f);
            int b = static_cast<int>(c.b * 255.0f);
            int a = static_cast<int>(c.a * 255.0f);

            out << pt.x << " " << pt.y << " " << pt.z << " " << r << " " << g << " " << b << " " << a << '\n';
        }
        else {
            out << pt.x << " " << pt.y << " " << pt.z << '\n';
        }
        seq.next(true); // allow to cancel
    }

    // facet indices (no texture and normal indices)
    for (MeshFacetArray::_TConstIterator it = rFacets.begin(); it != rFacets.end(); ++it) {
        out << "3 " << it->_aulPoints[0]
            << " " << it->_aulPoints[1]
            << " " << it->_aulPoints[2] << '\n';
        seq.next(true); // allow to cancel
    }

    return true;
}

bool MeshOutput::SaveBinaryPLY (std::ostream &out) const
{
    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();
    std::size_t v_count = rPoints.size();
    std::size_t f_count = rFacets.size();
    if (!out || out.bad())
        return false;
    bool saveVertexColor = (_material && _material->binding == MeshIO::PER_VERTEX
        && _material->diffuseColor.size() == rPoints.size());
    out << "ply\n"
        << "format binary_little_endian 1.0\n"
        << "comment Created by FreeCAD <http://www.freecadweb.org>\n"
        << "element vertex " << v_count << '\n'
        << "property float32 x\n"
        << "property float32 y\n"
        << "property float32 z\n";
    if (saveVertexColor) {
        out << "property uchar red\n"
            << "property uchar green\n"
            << "property uchar blue\n";
    }
    out << "element face " << f_count << '\n'
        << "property list uchar int vertex_index\n"
        << "end_header\n";

    Base::OutputStream os(out);
    os.setByteOrder(Base::Stream::LittleEndian);

    for (std::size_t i = 0; i < v_count; i++) {
        const MeshPoint& p = rPoints[i];
        if (this->apply_transform) {
            Base::Vector3f pt = this->_transform * p;
            os << pt.x << pt.y << pt.z;
        }
        else {
            os << p.x << p.y << p.z;
        }
        if (saveVertexColor) {
            const App::Color& c = _material->diffuseColor[i];
            uint8_t r = uint8_t(255.0f * c.r);
            uint8_t g = uint8_t(255.0f * c.g);
            uint8_t b = uint8_t(255.0f * c.b);
            os << r << g << b;
        }
    }
    unsigned char n = 3;
    int f1, f2, f3;
    for (std::size_t i = 0; i < f_count; i++) {
        const MeshFacet& f = rFacets[i];
        f1 = (int)f._aulPoints[0];
        f2 = (int)f._aulPoints[1];
        f3 = (int)f._aulPoints[2];
        os << n;
        os << f1 << f2 << f3;
    }

    return true;
}

bool MeshOutput::SaveAsciiPLY (std::ostream &out) const
{
    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();
    std::size_t v_count = rPoints.size();
    std::size_t f_count = rFacets.size();
    if (!out || out.bad())
        return false;

    bool saveVertexColor = (_material && _material->binding == MeshIO::PER_VERTEX
        && _material->diffuseColor.size() == rPoints.size());
    out << "ply\n"
        << "format ascii 1.0\n"
        << "comment Created by FreeCAD <http://www.freecadweb.org>\n"
        << "element vertex " << v_count << '\n'
        << "property float32 x\n"
        << "property float32 y\n"
        << "property float32 z\n";
    if (saveVertexColor) {
        out << "property uchar red\n"
            << "property uchar green\n"
            << "property uchar blue\n";
    }
    out << "element face " << f_count << '\n'
        << "property list uchar int vertex_index\n"
        << "end_header\n";

    out.precision(6);
    out.setf(std::ios::fixed | std::ios::showpoint);
    if (saveVertexColor) {
        for (std::size_t i = 0; i < v_count; i++) {
            const MeshPoint& p = rPoints[i];
            if (this->apply_transform) {
                Base::Vector3f pt = this->_transform * p;
                out << pt.x << " " << pt.y << " " << pt.z;
            }
            else {
                out << p.x << " " << p.y << " " << p.z;
            }

            const App::Color& c = _material->diffuseColor[i];
            int r = (int)(255.0f * c.r);
            int g = (int)(255.0f * c.g);
            int b = (int)(255.0f * c.b);
            out << " " << r << " " << g << " " << b << '\n';
        }
    }
    else {
        for (std::size_t i = 0; i < v_count; i++) {
            const MeshPoint& p = rPoints[i];
            if (this->apply_transform) {
                Base::Vector3f pt = this->_transform * p;
                out << pt.x << " " << pt.y << " " << pt.z << '\n';
            }
            else {
                out << p.x << " " << p.y << " " << p.z << '\n';
            }
        }
    }

    unsigned int n = 3;
    int f1, f2, f3;
    for (std::size_t i = 0; i < f_count; i++) {
        const MeshFacet& f = rFacets[i];
        f1 = (int)f._aulPoints[0];
        f2 = (int)f._aulPoints[1];
        f3 = (int)f._aulPoints[2];
        out << n << " " << f1 << " " << f2 << " " << f3 << '\n';
    }

    return true;
}

bool MeshOutput::SaveMeshNode (std::ostream &rstrOut)
{
    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();

    if (!rstrOut || rstrOut.bad())
        return false;

    // vertices
    rstrOut << "[" << '\n';
    if (this->apply_transform) {
        Base::Vector3f pt;
        for (MeshPointArray::_TConstIterator it = rPoints.begin(); it != rPoints.end(); ++it) {
            pt = this->_transform * *it;
            rstrOut << "v " << pt.x << " " << pt.y << " " << pt.z << '\n';
        }
    }
    else {
        for (MeshPointArray::_TConstIterator it = rPoints.begin(); it != rPoints.end(); ++it) {
            rstrOut << "v " << it->x << " " << it->y << " " << it->z << '\n';
        }
    }
    // facet indices (no texture and normal indices)
    for (MeshFacetArray::_TConstIterator it = rFacets.begin(); it != rFacets.end(); ++it) {
        rstrOut << "f " << it->_aulPoints[0]+1 << " "
                        << it->_aulPoints[1]+1 << " "
                        << it->_aulPoints[2]+1 << '\n';
    }
    rstrOut << "]" << '\n';

    return true;
}

/** Saves the mesh object into an XML file. */
void MeshOutput::SaveXML (Base::Writer &writer) const
{
    const MeshPointArray& rPoints = _rclMesh.GetPoints();
    const MeshFacetArray& rFacets = _rclMesh.GetFacets();

    //  writer << writer.ind() << "<Mesh>" << '\n';

    writer.incInd();
    writer.Stream() << writer.ind() << "<Points Count=\"" << _rclMesh.CountPoints() << "\">" << '\n';

    writer.incInd();
    if (this->apply_transform) {
        Base::Vector3f pt;
        for (MeshPointArray::_TConstIterator itp = rPoints.begin(); itp != rPoints.end(); ++itp) {
            pt = this->_transform * *itp;
            writer.Stream() <<  writer.ind() << "<P "
                            << "x=\"" <<  pt.x << "\" "
                            << "y=\"" <<  pt.y << "\" "
                            << "z=\"" <<  pt.z << "\"/>"
                            << '\n';
        }
    }
    else {
        for (MeshPointArray::_TConstIterator itp = rPoints.begin(); itp != rPoints.end(); ++itp) {
            writer.Stream() <<  writer.ind() << "<P "
                            << "x=\"" <<  itp->x << "\" "
                            << "y=\"" <<  itp->y << "\" "
                            << "z=\"" <<  itp->z << "\"/>"
                            << '\n';
        }
    }
    writer.decInd();
    writer.Stream() << writer.ind() << "</Points>" << '\n';

    // write the faces
    writer.Stream() << writer.ind() << "<Faces Count=\"" << _rclMesh.CountFacets() << "\">" << '\n';

    writer.incInd();
    for (MeshFacetArray::_TConstIterator it = rFacets.begin(); it != rFacets.end(); ++it) {
        writer.Stream() << writer.ind() << "<F "
                        << "p0=\"" <<  it->_aulPoints[0] << "\" "
                        << "p1=\"" <<  it->_aulPoints[1] << "\" "
                        << "p2=\"" <<  it->_aulPoints[2] << "\" "
                        << "n0=\"" <<  it->_aulNeighbours[0] << "\" "
                        << "n1=\"" <<  it->_aulNeighbours[1] << "\" "
                        << "n2=\"" <<  it->_aulNeighbours[2] << "\"/>"
                        << '\n';
    }
    writer.decInd();
    writer.Stream() << writer.ind() << "</Faces>" << '\n';

    writer.Stream() << writer.ind() << "</Mesh>" << '\n';
    writer.decInd();
}

/** Saves the mesh object into a 3MF file. */
bool MeshOutput::Save3MF(std::ostream &str) const
{
    Writer3MF writer(str);
    writer.AddMesh(_rclMesh, _transform);
    return writer.Save();
}

/** Writes an IDTF file. */
bool MeshOutput::SaveIDTF (std::ostream &str) const
{
    if (!str || str.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    const MeshPointArray& pts = _rclMesh.GetPoints();
    const MeshFacetArray& fts = _rclMesh.GetFacets();
    std::string resource = objectName;
    if (resource.empty())
        resource = "Resource";

    str.precision(6);
    str.setf(std::ios::fixed | std::ios::showpoint);

    str << "FILE_FORMAT \"IDTF\"\n"
        << "FORMAT_VERSION 100\n\n";

    str << Base::tabs(0) << "NODE \"MODEL\" {\n";
    str << Base::tabs(1) << "NODE_NAME \"FreeCAD\"\n";
    str << Base::tabs(1) << "PARENT_LIST {\n";
    str << Base::tabs(2) << "PARENT_COUNT 1\n";
    str << Base::tabs(2) << "PARENT 0 {\n";
    str << Base::tabs(3) << "PARENT_NAME \"<NULL>\"\n";
    str << Base::tabs(3) << "PARENT_TM {\n";
    str << Base::tabs(4) << "1.000000 0.000000 0.000000 0.000000\n";
    str << Base::tabs(4) << "0.000000 1.000000 0.000000 0.000000\n";
    str << Base::tabs(4) << "0.000000 0.000000 1.000000 0.000000\n";
    str << Base::tabs(4) << "0.000000 0.000000 0.000000 1.000000\n";
    str << Base::tabs(3) << "}\n";
    str << Base::tabs(2) << "}\n";
    str << Base::tabs(1) << "}\n";
    str << Base::tabs(1) << "RESOURCE_NAME \"" << resource << "\"\n";
    str << Base::tabs(0) << "}\n\n";

    str << Base::tabs(0) << "RESOURCE_LIST \"MODEL\" {\n";
    str << Base::tabs(1) << "RESOURCE_COUNT 1\n";
    str << Base::tabs(1) << "RESOURCE 0 {\n";
    str << Base::tabs(2) << "RESOURCE_NAME \"" << resource << "\"\n";
    str << Base::tabs(2) << "MODEL_TYPE \"MESH\"\n";
    str << Base::tabs(2) << "MESH {\n";
    str << Base::tabs(3) << "FACE_COUNT " << fts.size() << '\n';
    str << Base::tabs(3) << "MODEL_POSITION_COUNT " << pts.size() << '\n';
    str << Base::tabs(3) << "MODEL_NORMAL_COUNT " << 3*fts.size() << '\n';
    str << Base::tabs(3) << "MODEL_DIFFUSE_COLOR_COUNT 0\n";
    str << Base::tabs(3) << "MODEL_SPECULAR_COLOR_COUNT 0\n";
    str << Base::tabs(3) << "MODEL_TEXTURE_COORD_COUNT 0\n";
    str << Base::tabs(3) << "MODEL_BONE_COUNT 0\n";
    str << Base::tabs(3) << "MODEL_SHADING_COUNT 1\n";
    str << Base::tabs(3) << "MODEL_SHADING_DESCRIPTION_LIST {\n";
    str << Base::tabs(4) << "SHADING_DESCRIPTION 0 {\n";
    str << Base::tabs(5) << "TEXTURE_LAYER_COUNT 0\n";
    str << Base::tabs(5) << "SHADER_ID 0\n";
    str << Base::tabs(4) << "}\n";
    str << Base::tabs(3) << "}\n";
    str << Base::tabs(3) << "MESH_FACE_POSITION_LIST {\n";
    for (MeshFacetArray::_TConstIterator it = fts.begin(); it != fts.end(); ++it) {
        str << Base::tabs(4) << it->_aulPoints[0] << " " << it->_aulPoints[1] << " " << it->_aulPoints[2] << '\n';
    }
    str << Base::tabs(3) << "}\n";
    str << Base::tabs(3) << "MESH_FACE_NORMAL_LIST {\n";
    int index = 0;
    for (MeshFacetArray::_TConstIterator it = fts.begin(); it != fts.end(); ++it) {
        str << Base::tabs(4) << index << " " << index + 1 << " " << index + 2 << '\n';
        index += 3;
    }
    str << Base::tabs(3) << "}\n";
    str << Base::tabs(3) << "MESH_FACE_SHADING_LIST {\n";
    for (MeshFacetArray::_TConstIterator it = fts.begin(); it != fts.end(); ++it) {
        str << Base::tabs(4) << "0\n";
    }
    str << Base::tabs(3) << "}\n";
    str << Base::tabs(3) << "MODEL_POSITION_LIST {\n";
    for (MeshPointArray::_TConstIterator it = pts.begin(); it != pts.end(); ++it) {
        str << Base::tabs(4) << it->x << " " << it->y << " " << it->z << '\n';
    }
    str << Base::tabs(3) << "}\n";
    str << Base::tabs(3) << "MODEL_NORMAL_LIST {\n";
    for (MeshFacetArray::_TConstIterator it = fts.begin(); it != fts.end(); ++it) {
        MeshGeomFacet face = _rclMesh.GetFacet(*it);
        Base::Vector3f normal = face.GetNormal();
        str << Base::tabs(4) << normal.x << " " << normal.y << " " << normal.z << '\n';
        str << Base::tabs(4) << normal.x << " " << normal.y << " " << normal.z << '\n';
        str << Base::tabs(4) << normal.x << " " << normal.y << " " << normal.z << '\n';
    }

    str << Base::tabs(3) << "}\n";
    str << Base::tabs(2) << "}\n";
    str << Base::tabs(1) << "}\n";
    str << Base::tabs(0) << "}\n";

    return true;
}

/** Writes an MGL file. */
bool MeshOutput::SaveMGL (std::ostream &str) const
{
/*
light on
list t 0 1 2 | 0 1 3 | 0 2 3 | 1 2 3
list xt 1 1 0 0
list yt -1 -1 1 0
list zt -1 -1 -1 1
triplot t xt yt zt 'b'
#triplot t xt yt zt '#k'
*/
    if (!str || str.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    const MeshPointArray& pts = _rclMesh.GetPoints();
    const MeshFacetArray& fts = _rclMesh.GetFacets();

    str.precision(2);
    str.setf(std::ios::fixed | std::ios::showpoint);

    str << "light on\n";
    str << "list t ";
    for (MeshFacetArray::_TConstIterator it = fts.begin(); it != fts.end(); ++it) {
        str << it->_aulPoints[0] << " " << it->_aulPoints[1] << " " << it->_aulPoints[2] << " | ";
    }
    str << std::endl;

    str << "list xt ";
    for (MeshPointArray::_TConstIterator it = pts.begin(); it != pts.end(); ++it) {
        str << it->x << " ";
    }
    str << std::endl;

    str << "list yt ";
    for (MeshPointArray::_TConstIterator it = pts.begin(); it != pts.end(); ++it) {
        str << it->y << " ";
    }
    str << std::endl;

    str << "list zt ";
    for (MeshPointArray::_TConstIterator it = pts.begin(); it != pts.end(); ++it) {
        str << it->z << " ";
    }
    str << std::endl;

    str << "triplot t xt yt zt 'b'" << std::endl;
    str << "#triplot t xt yt zt '#k'" << std::endl;

    return true;
}

/** Writes an OpenInventor file. */
bool MeshOutput::SaveInventor (std::ostream &rstrOut) const
{
    if (!rstrOut || rstrOut.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    MeshFacetIterator clIter(_rclMesh), clEnd(_rclMesh);
    clIter.Transform(this->_transform);
    MeshPointIterator clPtIter(_rclMesh), clPtEnd(_rclMesh);
    clPtIter.Transform(this->_transform);
    const MeshGeomFacet* pclFacet;

    Base::SequencerLauncher seq("Saving...", _rclMesh.CountFacets() + 1);
    rstrOut.precision(6);
    rstrOut.setf(std::ios::fixed | std::ios::showpoint);

    // Header info
    Base::InventorBuilder builder(rstrOut);
    builder.beginSeparator();
    builder.addInfo("Created by FreeCAD <http://www.freecadweb.org>");
    std::stringstream str;
    str << "Triangle mesh contains "
        << _rclMesh.CountPoints()
        << " vertices and "
        << _rclMesh.CountFacets()
        << " faces";
    builder.addLabel(str.str().c_str());

    // write out the normals of the facets
    builder.beginNormal();

    clIter.Begin();
    clEnd.End();

    while (clIter < clEnd) {
        pclFacet = &(*clIter);
        builder.addPoint(pclFacet->GetNormal());
        ++clIter;

        seq.next(true); // allow to cancel
    }

    builder.endNormal();

    // coordinates of the vertices
    builder.addNormalBinding("PER_FACE");

    builder.beginPoints();

    clPtIter.Begin();
    clPtEnd.End();

    while (clPtIter < clPtEnd) {
        builder.addPoint(*clPtIter);
        ++clPtIter;
        seq.next(true); // allow to cancel
    }

    builder.endPoints();

    // and finally the facets with their point indices
    const MeshFacetArray& faces = _rclMesh.GetFacets();
    std::vector<int> indices;
    indices.reserve(4*faces.size());
    for (MeshFacetArray::_TConstIterator it = faces.begin(); it != faces.end(); ++it) {
        indices.push_back(static_cast<int>(it->_aulPoints[0]));
        indices.push_back(static_cast<int>(it->_aulPoints[1]));
        indices.push_back(static_cast<int>(it->_aulPoints[2]));
        indices.push_back(-1);
    }
    builder.addIndexedFaceSet(indices);
    builder.endSeparator();

    return true;
}

/** Writes an X3D file. */
bool MeshOutput::SaveX3D (std::ostream &out) const
{
    if (!out || out.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    // XML header info
    out << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";

    return SaveX3DContent(out, false);
}

/** Writes an X3D file. */
bool MeshOutput::SaveX3DContent (std::ostream &out, bool exportViewpoints) const
{
    if (!out || out.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    const MeshPointArray& pts = _rclMesh.GetPoints();
    const MeshFacetArray& fts = _rclMesh.GetFacets();
    Base::BoundBox3f bbox = _rclMesh.GetBoundBox();
    if (apply_transform)
        bbox = bbox.Transformed(_transform);

    App::Color mat(0.65f, 0.65f, 0.65f);
    if (_material && _material->binding == MeshIO::Binding::OVERALL) {
        if (!_material->diffuseColor.empty())
            mat = _material->diffuseColor.front();
    }
    bool saveVertexColor = (_material && _material->binding == MeshIO::PER_VERTEX &&
                            _material->diffuseColor.size() == pts.size());
    bool saveFaceColor   = (_material && _material->binding == MeshIO::PER_FACE &&
                            _material->diffuseColor.size() == fts.size());

    Base::SequencerLauncher seq("Saving...", _rclMesh.CountFacets() + 1);
    out.precision(6);
    out.setf(std::ios::fixed | std::ios::showpoint);

    // Header info
    out << "<X3D profile=\"Immersive\" version=\"3.2\" xmlns:xsd="
        << "\"http://www.w3.org/2001/XMLSchema-instance\" xsd:noNamespaceSchemaLocation="
        << "\"http://www.web3d.org/specifications/x3d-3.2.xsd\" width=\"1280px\"  height=\"1024px\">\n";
    out << "  <head>\n"
        << "    <meta name=\"generator\" content=\"FreeCAD\"/>\n"
        << "    <meta name=\"author\" content=\"\"/> \n"
        << "    <meta name=\"company\" content=\"\"/>\n"
        << "  </head>\n";

    // Beginning
    out << "  <Scene>\n";

    if (exportViewpoints) {
        auto viewpoint = [&out](const char* text, const Base::Vector3f& cnt,
                                const Base::Vector3f& pos, const Base::Vector3f& axis, float angle) {
            out << "    <Viewpoint id=\"" << text
                << "\" centerOfRotation=\"" << cnt.x << " " << cnt.y << " " << cnt.z
                << "\" position=\"" << pos.x << " " << pos.y << " " << pos.z
                << "\" orientation=\"" << axis.x << " " << axis.y << " " << axis.z << " " << angle
                << "\" description=\"camera\" fieldOfView=\"0.9\">"
                << "</Viewpoint>\n";
        };

        Base::Vector3f cnt = bbox.GetCenter();
        float dist = 1.2f * bbox.CalcDiagonalLength();
        float dist3 = 0.577350f * dist; // sqrt(1/3) * dist

        viewpoint("Iso", cnt, Base::Vector3f(cnt.x + dist3, cnt.y - dist3, cnt.z + dist3), Base::Vector3f(0.742906f, 0.307722f, 0.594473f), 1.21712f);
        viewpoint("Front", cnt, Base::Vector3f(cnt.x, cnt.y - dist, cnt.z), Base::Vector3f(1.0f, 0.0f, 0.0f), 1.5707964f);
        viewpoint("Back", cnt, Base::Vector3f(cnt.x, cnt.y + dist, cnt.z), Base::Vector3f(0.0f, 0.707106f, 0.707106f), 3.141592f);
        viewpoint("Right", cnt, Base::Vector3f(cnt.x + dist, cnt.y, cnt.z), Base::Vector3f(0.577350f, 0.577350f, 0.577350f), 2.094395f);
        viewpoint("Left", cnt, Base::Vector3f(cnt.x - dist, cnt.y, cnt.z), Base::Vector3f(-0.577350f, 0.577350f, 0.577350f), 4.188790f);
        viewpoint("Top", cnt, Base::Vector3f(cnt.x, cnt.y, cnt.z + dist), Base::Vector3f(0.0f, 0.0f, 1.0f), 0.0f);
        viewpoint("Bottom", cnt, Base::Vector3f(cnt.x, cnt.y, cnt.z - dist), Base::Vector3f(1.0f, 0.0f, 0.0f), 3.141592f);
    }

    if (apply_transform) {
        Base::Placement p(_transform);
        const Base::Vector3d& v = p.getPosition();
        const Base::Rotation& r = p.getRotation();
        Base::Vector3d axis; double angle;
        r.getValue(axis, angle);
        out << "    <Transform "
            << "translation='"
            << v.x << " "
            << v.y << " "
            << v.z << "' "
            << "rotation='"
            << axis.x << " "
            << axis.y << " "
            << axis.z << " "
            << angle << "'>\n";
    }
    else {
        out << "    <Transform>\n";
    }
    out << "      <Shape>\n";
    out << "        <Appearance>\n"
           "          <Material diffuseColor='" << mat.r << " " << mat.g << " " << mat.b << "' shininess='0.9' specularColor='1 1 1'></Material>\n"
           "        </Appearance>\n";

    out << "        <IndexedFaceSet solid=\"false\" ";
    if (saveVertexColor) {
        out << "colorPerVertex=\"true\" ";
    }
    else if (saveFaceColor) {
        out << "colorPerVertex=\"false\" ";
    }

    out << "coordIndex=\"";
    for (MeshFacetArray::_TConstIterator it = fts.begin(); it != fts.end(); ++it) {
        out << it->_aulPoints[0] << " " << it->_aulPoints[1] << " " << it->_aulPoints[2] << " -1 ";
    }
    out << "\">\n";

    out << "          <Coordinate point=\"";
    for (MeshPointArray::_TConstIterator it = pts.begin(); it != pts.end(); ++it) {
        out << it->x << " " << it->y << " " << it->z << ", ";
    }
    out << "\"/>\n";

    // write colors per vertex or face
    if (saveVertexColor || saveFaceColor) {
        out << "          <Color color=\"";
        for (const auto& c : _material->diffuseColor) {
            out << c.r << " " << c.g << " " << c.b << ", ";
        }
        out << "\"/>\n";
    }

    // End
    out << "        </IndexedFaceSet>\n"
        << "      </Shape>\n"
        << "    </Transform>\n"
        << "    <Background groundColor=\"0.7 0.7 0.7\" skyColor=\"0.7 0.7 0.7\" />\n"
        << "    <NavigationInfo/>\n"
        << "  </Scene>\n"
        << "</X3D>\n";

    return true;
}

/** Writes an X3DOM file. */
bool MeshOutput::SaveX3DOM (std::ostream &out) const
{
    if (!out || out.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    // See:
    // https://stackoverflow.com/questions/31976056/unable-to-color-faces-using-indexedfaceset-in-x3dom
    //
    out << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
        << "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n";
    out << "<html xmlns='http://www.w3.org/1999/xhtml'>\n"
        << "  <head>\n"
        << "    <script type='text/javascript' src='http://www.x3dom.org/download/x3dom.js'> </script>\n"
        << "    <link rel='stylesheet' type='text/css' href='http://www.x3dom.org/download/x3dom.css'></link>\n"
        << "  </head>\n";

    auto onclick = [&out](const char* text) {
        out << "  <button onclick=\"document.getElementById('" << text << "').setAttribute('set_bind','true');\">" << text << "</button>\n";
    };

    onclick("Iso");
    onclick("Front");
    onclick("Back");
    onclick("Right");
    onclick("Left");
    onclick("Top");
    onclick("Bottom");

#if 0 // https://stackoverflow.com/questions/32305678/x3dom-how-to-make-zoom-buttons
    function zoom (delta) {
        var x3d = document.getElementById("right");
        var vpt = x3d.getElementsByTagName("Viewpoint")[0];
        vpt.fieldOfView = parseFloat(vpt.fieldOfView) + delta;
    }

    <button onclick="zoom(0.15);">Zoom out</button>
#endif

    SaveX3DContent(out, true);

    out << "</html>\n";

    return true;
}

/** Writes a Nastran file. */
bool MeshOutput::SaveNastran (std::ostream &rstrOut) const
{
    if (!rstrOut || rstrOut.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    MeshPointIterator clPIter(_rclMesh);
    clPIter.Transform(this->_transform);
    MeshFacetIterator clTIter(_rclMesh);
    int iIndx = 1;

    Base::SequencerLauncher seq("Saving...", _rclMesh.CountFacets() + 1);

    rstrOut.precision(3);
    rstrOut.setf(std::ios::fixed | std::ios::showpoint);
    for (clPIter.Init(); clPIter.More(); clPIter.Next()) {
        float x = clPIter->x;
        float y = clPIter->y;
        float z = clPIter->z;

        rstrOut << "GRID";

        rstrOut << std::setfill(' ') << std::setw(12) << iIndx;
        rstrOut << std::setfill(' ') << std::setw(16) << x;
        rstrOut << std::setfill(' ') << std::setw(8)  << y;
        rstrOut << std::setfill(' ') << std::setw(8)  << z;
        rstrOut << '\n';

        iIndx++;
        seq.next();
    }

    iIndx = 1;
    for (clTIter.Init(); clTIter.More(); clTIter.Next()) {
        rstrOut << "CTRIA3";

        rstrOut << std::setfill(' ') << std::setw(10) << iIndx;
        rstrOut << std::setfill(' ') << std::setw(8) << (int)0;
        rstrOut << std::setfill(' ') << std::setw(8) << clTIter.GetIndices()._aulPoints[1]+1;
        rstrOut << std::setfill(' ') << std::setw(8) << clTIter.GetIndices()._aulPoints[0]+1;
        rstrOut << std::setfill(' ') << std::setw(8) << clTIter.GetIndices()._aulPoints[2]+1;
        rstrOut << '\n';

        iIndx++;
        seq.next();
    }

    rstrOut << "ENDDATA";

    return true;
}

/** Writes a Cadmould FE file. */
bool MeshOutput::SaveCadmouldFE (std::ostream & /*rstrOut*/) const
{
    return false;
}

/** Writes a Python module */
bool MeshOutput::SavePython (std::ostream &str) const
{
    if (!str || str.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    MeshFacetIterator clIter(_rclMesh);
    clIter.Transform(this->_transform);
    str.precision(4);
    str.setf(std::ios::fixed | std::ios::showpoint);

    str << "faces = [\n";
    for (clIter.Init(); clIter.More(); clIter.Next()) {
        const MeshGeomFacet& rFacet = *clIter;
        for (int i = 0; i < 3; i++) {
            str << "[" << rFacet._aclPoints[i].x
                << "," << rFacet._aclPoints[i].y
                << "," << rFacet._aclPoints[i].z
                << "],";
        }
        str << '\n';
    }

    str << "]\n";

    return true;
}

/** Writes a VRML file. */
bool MeshOutput::SaveVRML (std::ostream &rstrOut) const
{
    if (!rstrOut || rstrOut.bad() || (_rclMesh.CountFacets() == 0))
        return false;

    Base::BoundBox3f clBB = _rclMesh.GetBoundBox();

    Base::SequencerLauncher seq("Saving VRML file...",
        _rclMesh.CountPoints() + _rclMesh.CountFacets());

    rstrOut << "#VRML V2.0 utf8\n";
    rstrOut << "WorldInfo {\n"
            << "  title \"Exported triangle mesh to VRML97\"\n"
            << "  info [\"Created by FreeCAD\"\n"
            << "        \"<http://www.freecadweb.org>\"]\n"
            << "}\n\n";

    // Transform
    rstrOut.precision(3);
    rstrOut.setf(std::ios::fixed | std::ios::showpoint);
    rstrOut << "Transform {\n"
            << "  scale 1 1 1\n"
            << "  rotation 0 0 1 0\n"
            << "  scaleOrientation 0 0 1 0\n"
            << "  center "
            << 0.0f << " "
            << 0.0f << " "
            << 0.0f << "\n"
            << "  translation "
            << 0.0f << " "
            << 0.0f << " "
            << 0.0f << "\n";

    rstrOut << "  children\n";
    rstrOut << "    Shape { \n";

    // write appearance
    rstrOut << "      appearance\n"
            << "      Appearance {\n"
            << "        material\n"
            << "        Material {\n";
    if (_material && _material->binding == MeshIO::OVERALL) {
        if (!_material->diffuseColor.empty()) {
            App::Color c = _material->diffuseColor.front();
            rstrOut << "          diffuseColor "
                    << c.r << " "
                    << c.g << " "
                    << c.b << "\n";
        }
        else {
            rstrOut << "          diffuseColor 0.8 0.8 0.8\n";
        }
    }
    else {
        rstrOut << "          diffuseColor 0.8 0.8 0.8\n";
    }
    rstrOut << "        }\n      }\n"; // end write appearance


    // write IndexedFaceSet
    rstrOut << "      geometry\n"
            << "      IndexedFaceSet {\n";

    rstrOut.precision(2);
    rstrOut.setf(std::ios::fixed | std::ios::showpoint);

    // write coords
    rstrOut << "        coord\n        Coordinate {\n          point [\n";
    MeshPointIterator pPIter(_rclMesh);
    pPIter.Transform(this->_transform);
    unsigned long i = 0, k = _rclMesh.CountPoints();
    rstrOut.precision(3);
    rstrOut.setf(std::ios::fixed | std::ios::showpoint);
    for (pPIter.Init(); pPIter.More(); pPIter.Next()) {
        rstrOut << "            "
                << pPIter->x << " "
                << pPIter->y << " "
                << pPIter->z;
        if (i++ < (k-1))
            rstrOut << ",\n";
        else
            rstrOut << "\n";

        seq.next();
    }

    rstrOut << "          ]\n        }\n";  // end write coord

    if (_material && _material->binding != MeshIO::OVERALL) {
        // write colors for each vertex
        rstrOut << "        color\n        Color {\n          color [\n";
        rstrOut.precision(3);
        rstrOut.setf(std::ios::fixed | std::ios::showpoint);
        for (std::vector<App::Color>::const_iterator pCIter = _material->diffuseColor.begin();
            pCIter != _material->diffuseColor.end(); ++pCIter) {
            rstrOut << "          "
                    << float(pCIter->r) << " "
                    << float(pCIter->g) << " "
                    << float(pCIter->b);
            if (pCIter < (_material->diffuseColor.end() - 1))
                rstrOut << ",\n";
            else
                rstrOut << "\n";
        }

        rstrOut << "      ]\n    }\n";
        if (_material->binding == MeshIO::PER_VERTEX)
            rstrOut << "    colorPerVertex TRUE\n";
        else
            rstrOut << "    colorPerVertex FALSE\n";
    }

    // write face index
    rstrOut << "        coordIndex [\n";
    MeshFacetIterator pFIter(_rclMesh);
    pFIter.Transform(this->_transform);
    i = 0, k = _rclMesh.CountFacets();

    for (pFIter.Init(); pFIter.More(); pFIter.Next()) {
        MeshFacet clFacet = pFIter.GetIndices();
        rstrOut << "          "
                << clFacet._aulPoints[0] << ", "
                << clFacet._aulPoints[1] << ", "
                << clFacet._aulPoints[2] << ", -1";
        if (i++ < (k-1))
            rstrOut << ",\n";
        else
            rstrOut << "\n";

        seq.next();
    }

    rstrOut << "        ]\n      }\n";  // End IndexedFaceSet
    rstrOut << "    }\n";  // End Shape
    rstrOut << "}\n"; // close children and Transform

    return true;
}

// ----------------------------------------------------------------------------

MeshCleanup::MeshCleanup(MeshPointArray& p, MeshFacetArray& f)
  : pointArray(p)
  , facetArray(f)
  , materialArray(nullptr)
{
}

MeshCleanup::~MeshCleanup()
{
}

void MeshCleanup::SetMaterial(Material* mat)
{
    materialArray = mat;
}

void MeshCleanup::RemoveInvalids()
{
    // first mark all points as invalid
    pointArray.SetFlag(MeshPoint::INVALID);
    std::size_t numPoints = pointArray.size();

    // Now go through the facets and invalidate facets with wrong indices
    // If a facet is valid all its referenced points are validated again
    // Points that are not referenced are still invalid and thus can be deleted
    for (MeshFacetArray::_TIterator it = facetArray.begin(); it != facetArray.end(); ++it) {
        for (int i=0; i<3; i++) {
            // vertex index out of range
            if (it->_aulPoints[i] >= numPoints) {
                it->SetInvalid();
                break;
            }
        }

        // validate referenced points
        if (it->IsValid()) {
            pointArray[it->_aulPoints[0]].ResetInvalid();
            pointArray[it->_aulPoints[1]].ResetInvalid();
            pointArray[it->_aulPoints[2]].ResetInvalid();
        }
    }

    // Remove the invalid items
    RemoveInvalidFacets();
    RemoveInvalidPoints();
}

void MeshCleanup::RemoveInvalidFacets()
{
    MeshIsFlag<MeshFacet> flag;
    std::size_t countInvalidFacets = std::count_if(facetArray.begin(), facetArray.end(),
                    [flag](const MeshFacet& f) { return flag(f, MeshFacet::INVALID); });
    if (countInvalidFacets > 0) {

        // adjust the material array if needed
        if (materialArray && materialArray->binding == MeshIO::PER_FACE &&
            materialArray->diffuseColor.size() == facetArray.size()) {
            std::vector<App::Color> colors;
            colors.reserve(facetArray.size() - countInvalidFacets);
            for (std::size_t index = 0; index < facetArray.size(); index++) {
                if (facetArray[index].IsValid()) {
                    colors.push_back(materialArray->diffuseColor[index]);
                }
            }

            materialArray->diffuseColor.swap(colors);
        }

        MeshFacetArray copy_facets(facetArray.size() - countInvalidFacets);
        // copy all valid facets to the new array
        std::remove_copy_if(facetArray.begin(), facetArray.end(), copy_facets.begin(),
            [flag](const MeshFacet& f) { return flag(f, MeshFacet::INVALID); });
        facetArray.swap(copy_facets);
    }
}

void MeshCleanup::RemoveInvalidPoints()
{
    MeshIsFlag<MeshPoint> flag;
    std::size_t countInvalidPoints = std::count_if(pointArray.begin(), pointArray.end(),
                    [flag](const MeshPoint& p) { return flag(p, MeshPoint::INVALID); });
    if (countInvalidPoints > 0) {
        // generate array of decrements
        std::vector<PointIndex> decrements;
        decrements.resize(pointArray.size());
        PointIndex decr = 0;

        MeshPointArray::_TIterator p_end = pointArray.end();
        std::vector<PointIndex>::iterator decr_it = decrements.begin();
        for (MeshPointArray::_TIterator p_it = pointArray.begin(); p_it != p_end; ++p_it, ++decr_it) {
            *decr_it = decr;
            if (!p_it->IsValid())
                decr++;
        }

        // correct point indices of the facets
        MeshFacetArray::_TIterator f_end = facetArray.end();
        for (MeshFacetArray::_TIterator f_it = facetArray.begin(); f_it != f_end; ++f_it) {
            f_it->_aulPoints[0] -= decrements[f_it->_aulPoints[0]];
            f_it->_aulPoints[1] -= decrements[f_it->_aulPoints[1]];
            f_it->_aulPoints[2] -= decrements[f_it->_aulPoints[2]];
        }

        // delete point, number of valid points
        std::size_t validPoints = pointArray.size() - countInvalidPoints;

        // adjust the material array if needed
        if (materialArray && materialArray->binding == MeshIO::PER_VERTEX &&
            materialArray->diffuseColor.size() == pointArray.size()) {
            std::vector<App::Color> colors;
            colors.reserve(validPoints);
            for (std::size_t index = 0; index < pointArray.size(); index++) {
                if (pointArray[index].IsValid()) {
                    colors.push_back(materialArray->diffuseColor[index]);
                }
            }

            materialArray->diffuseColor.swap(colors);
        }

        MeshPointArray copy_points(validPoints);
        // copy all valid facets to the new array
        std::remove_copy_if(pointArray.begin(), pointArray.end(), copy_points.begin(),
            [flag](const MeshPoint& p) { return flag(p, MeshPoint::INVALID); });
        pointArray.swap(copy_points);
    }
}

// ----------------------------------------------------------------------------

MeshPointFacetAdjacency::MeshPointFacetAdjacency(std::size_t p, MeshFacetArray& f)
  : numPoints(p)
  , facets(f)
{
    Build();
}

MeshPointFacetAdjacency::~MeshPointFacetAdjacency()
{
}

void MeshPointFacetAdjacency::Build()
{
    std::vector<std::size_t> numFacetAdjacency(numPoints);
    for (MeshFacetArray::iterator it = facets.begin(); it != facets.end(); ++it) {
        numFacetAdjacency[it->_aulPoints[0]]++;
        numFacetAdjacency[it->_aulPoints[1]]++;
        numFacetAdjacency[it->_aulPoints[2]]++;
    }

    pointFacetAdjacency.resize(numPoints);
    for (std::size_t i = 0; i < numPoints; i++)
        pointFacetAdjacency[i].reserve(numFacetAdjacency[i]);

    std::size_t numFacets = facets.size();
    for (std::size_t i = 0; i < numFacets; i++) {
        for (int j = 0; j < 3; j++) {
            pointFacetAdjacency[facets[i]._aulPoints[j]].push_back(i);
        }
    }
}

void MeshPointFacetAdjacency::SetFacetNeighbourhood()
{
    std::size_t numFacets = facets.size();
    for (std::size_t index = 0; index < numFacets; index++) {
        MeshFacet& facet1 = facets[index];
        for (int i = 0; i < 3; i++) {
            std::size_t n1 = facet1._aulPoints[i];
            std::size_t n2 = facet1._aulPoints[(i+1)%3];

            bool success = false;
            const std::vector<std::size_t>& refFacets = pointFacetAdjacency[n1];
            for (std::vector<std::size_t>::const_iterator it = refFacets.begin(); it != refFacets.end(); ++it) {
                if (*it != index) {
                    MeshFacet& facet2 = facets[*it];
                    if (facet2.HasPoint(n2)) {
                        facet1._aulNeighbours[i] = *it;
                        success = true;
                        break;
                    }
                }
            }

            if (!success) {
                facet1._aulNeighbours[i] = FACET_INDEX_MAX;
            }
        }
    }
}