SurfaceMeshReader.ih

/**
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 **/
 
/**
 * @file SurfaceMeshReader.ih
 * @author Jacques-Olivier Lachaud (\c jacques-olivier.lachaud@univ-savoie.fr )
 * Laboratory of Mathematics (CNRS, UMR 5127), University of Savoie, France
 *
 * @date 2020/02/18
 *
 * Implementation of inline methods defined in SurfaceMeshReader.h
 *
 * This file is part of the DGtal library.
 */
 
 
//////////////////////////////////////////////////////////////////////////////
#include <cstdlib>
#include <limits>
//////////////////////////////////////////////////////////////////////////////
 
 
///////////////////////////////////////////////////////////////////////////////
// IMPLEMENTATION of inline methods.
///////////////////////////////////////////////////////////////////////////////
 
//-----------------------------------------------------------------------------
template <typename TRealPoint, typename TRealVector>
bool
DGtal::SurfaceMeshReader<TRealPoint, TRealVector>::
verifyIndicesUniqueness( const std::vector< Index > &indices )
{
  std::set<Index> sindices( indices.begin(), indices.end() );
  return sindices.size() == indices.size();
}
 
//-----------------------------------------------------------------------------
template <typename TRealPoint, typename TRealVector>
std::vector< std::string > 
DGtal::SurfaceMeshReader<TRealPoint, TRealVector>::
split( const std::string& str, char delim )
{
  std::stringstream ss(str);
  std::string token;
  std::vector< std::string > cont;
  while ( std::getline( ss, token, delim ) ) cont.push_back(token);
  return cont;
}    
 
//-----------------------------------------------------------------------------
template <typename TRealPoint, typename TRealVector>
bool
DGtal::SurfaceMeshReader<TRealPoint, TRealVector>::
readOBJ( std::istream & input, SurfaceMesh & smesh )
{
  std::vector<RealPoint>  vertices;
  std::vector<RealVector> normals;
  std::vector< std::vector< Index > > faces;
  std::vector< std::vector< Index > > faces_normals_idx;
  std::string linestr;
  std::string keyword;
  std::string indices;
  RealPoint  p;
  RealVector n;
  std::getline( input, linestr );
  Index l = 0;
  for ( ; input.good() && ! input.eof(); std::getline( input, linestr ), l++ )
    {
      if ( linestr.empty() ) continue; // skip empty line
      if ( linestr[0] == '#' ) continue; // skip comment line
      std::istringstream lineinput( linestr );
      std::operator>>( lineinput, keyword ); // lineinput >> keyword;
      if ( keyword == "v" ) {
        lineinput >> p[ 0 ] >> p[ 1 ] >> p[ 2 ];
        vertices.push_back( p );
      } else if ( keyword == "vn" ) {
        lineinput >> n[ 0 ] >> n[ 1 ] >> n[ 2 ];
        normals.push_back( n );
      } else if ( keyword == "f" ) {
        std::vector< Index > face, face_normals;
        while ( ! lineinput.eof() ) {
          std::operator>>( lineinput, indices ); // lineinput >> indices;
          if ( indices.empty() ) break;
          auto vtxinfo = split( indices, '/' );
          if ( vtxinfo.size() == 0 ) break;
          Index  v  = static_cast<Index>((int)std::stoi( vtxinfo[ 0 ] )-1);
          if (v < 0 ){ // special case of relative indices (ie negative index);
            v = vertices.size() + v+1; 
          }
          face.push_back(v);
          Index vn = vtxinfo.size() >= 3 ? std::stoi( vtxinfo[ 2 ] ) : v-1;
          face_normals.push_back( vn - 1 );
          indices = "";
        }
        if ( ! face.empty() && verifyIndicesUniqueness( face ) )
          {
            faces.push_back( face );
            faces_normals_idx.push_back( face_normals );
          }
      }
      // Weird: necessary to clear them.
      keyword = ""; linestr = "";
    }
  // Creating SurfaceMesh
  trace.info() << "[SurfaceMeshReader::readOBJ] Read"
               << " #lines=" << l
               << " #V=" << vertices.size()
               << " #VN=" << normals.size()
               << " #F=" << faces.size() << std::endl;
  if ( input.bad() )
    trace.warning() << "[SurfaceMeshReader::readOBJ] Some I/O error occured."
                    << " Proceeding but the mesh may be damaged." << std::endl;
  bool ok = smesh.init( vertices.begin(), vertices.end(),
                        faces.begin(), faces.end() );
  if ( ! ok )
    trace.warning() << "[SurfaceMeshReader::readOBJ]"
                    << " Error initializing mesh." << std::endl;
  if ( ( ! normals.empty() ) && ( normals.size() == vertices.size() ) )
    { // Build vertex normal map
      bool ok_vtx_normals = smesh.setVertexNormals( normals.begin(), normals.end() );
      if ( ! ok_vtx_normals )
        trace.warning() << "[SurfaceMeshReader::readOBJ]"
                        << " Error setting vertex normals." << std::endl;
      ok = ok && ok_vtx_normals;
    }
  if ( ! normals.empty() )
    { // Build face normal map
      std::vector< RealVector > faces_normals;
      Index i = 0;
      for ( auto face_n_indices : faces_normals_idx )
        { 
          RealVector n;
          for ( auto k : face_n_indices ) n += normals[ k ];
          n /= face_n_indices.size();
          faces_normals.push_back( n );
        }
      bool ok_face_normals = smesh.setFaceNormals( faces_normals.begin(),
                                                   faces_normals.end() );
      if ( ! ok_face_normals )
        trace.warning() << "[SurfaceMeshReader::readOBJ]"
                        << " Error setting face normals." << std::endl;
      ok = ok && ok_face_normals;
    }
  return ( ! input.bad() ) && ok;
}
 
///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////