PolyLineT_impl.hh

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//=============================================================================
//
//  CLASS PolyLineT - IMPLEMENTATION
//
//=============================================================================

#define ACG_POLYLINET_C

//== INCLUDES =================================================================

#include <OpenMesh/Core/Geometry/VectorT.hh>

#include <iostream>
#include <fstream>
#include <map>
#include <stack>

#include "PolyLineT.hh"

#include <cfloat>
#include <ACG/Geometry/Algorithms.hh>
#include <ACG/Utils/VSToolsT.hh>

#ifndef WIN32
#include <cstdlib>
#endif

#include <cstring>

#ifdef USE_OPENMP
#include <omp.h>
#endif

//== NAMESPACES ===============================================================

namespace ACG {

//== IMPLEMENTATION ==========================================================

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


template <class PointT>
PolyLineT<PointT>::
  PolyLineT( bool _closed )
    : closed_(_closed),
      vertex_radius_(0.01),
      edge_radius_(0.01),
      ref_count_vnormals_(0),
      ref_count_vbinormals_(0),
      ref_count_vcolors_(0),
      ref_count_vscalars_(0),
      ref_count_vselections_(0),
      ref_count_vvhandles_(0),
      ref_count_vehandles_(0),
      ref_count_vfhandles_(0),
      ref_count_enormals_(0),
      ref_count_ecolors_(0),
      ref_count_escalars_(0),
      ref_count_eselections_(0),
      ref_count_epreimage_direction_(0)
{
}

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

template <class PointT>
PolyLineT<PointT>::
  PolyLineT( const PolyLineT& _line ) :

    //copy points
    points_(_line.points_),

    closed_(_line.closed_),

    //copy vertex properties
    vnormals_(_line.vnormals_),
    vbinormals_(_line.vbinormals_),
    vcolors_(_line.vcolors_),
    vscalars_(_line.vscalars_),
    vselections_(_line.vselections_),
    vvhandles_(_line.vvhandles_),
    vehandles_(_line.vehandles_),
    vfhandles_(_line.vfhandles_),

    //copy edge properties
    enormals_(_line.enormals_),
    ecolors_(_line.ecolors_),
    escalars_(_line.escalars_),
    eselections_(_line.eselections_),
    epreimage_direction_(_line.epreimage_direction_),

    // property reference counter
    ref_count_vnormals_(_line.ref_count_vnormals_),
    ref_count_vbinormals_(_line.ref_count_vbinormals_),
    ref_count_vcolors_(_line.ref_count_vcolors_),
    ref_count_vscalars_(_line.ref_count_vscalars_),
    ref_count_vselections_(_line.ref_count_vselections_),
    ref_count_vvhandles_(_line.ref_count_vvhandles_),
    ref_count_vehandles_(_line.ref_count_vehandles_),
    ref_count_vfhandles_(_line.ref_count_vfhandles_),

    ref_count_enormals_(_line.ref_count_enormals_),
    ref_count_ecolors_(_line.ref_count_ecolors_),
    ref_count_escalars_(_line.ref_count_escalars_),
    ref_count_eselections_(_line.ref_count_eselections_),
    ref_count_epreimage_direction_(_line.ref_count_epreimage_direction_)

{

  // copy custom properties
  for (typename CustomPropertyMap::const_iterator it = _line.custom_properties.begin(); it != _line.custom_properties.end(); ++it) {

    const CustomProperty* src = it->second;
    CustomProperty* dst = new CustomProperty;

    dst->name = src->name;
    dst->ref_count = src->ref_count;
    dst->prop_size = src->prop_size;
    dst->prop_data = src->prop_data;

    dst->datatype = src->datatype;
    dst->shader_binding = src->shader_binding;

    custom_properties[it->first] = dst;
  }
}

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


template <class PointT>
void
PolyLineT<PointT>::
clear()
{
  points_.clear();

  // clear propertiy vectors
  vnormals_.clear();
  vbinormals_.clear();
  vcolors_.clear();
  vscalars_.clear();
  vselections_.clear();
  vvhandles_.clear();
  vehandles_.clear();
  vfhandles_.clear();

  enormals_.clear();
  ecolors_.clear();
  escalars_.clear();
  eselections_.clear();
  epreimage_direction_.clear();

  for (typename CustomPropertyMap::iterator it = custom_properties.begin(); it != custom_properties.end(); ++it)
    delete it->second;
  custom_properties.clear();
}

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

template <class PointT>
size_t
PolyLineT<PointT>::n_edges() const
{
  if (n_vertices() <= 1)
    return 0;
  else
    return n_vertices() - 1 + (unsigned int) closed_;
}


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


template <class PointT>
void
PolyLineT<PointT>::
resize( unsigned int _n)
{
  if( _n < n_vertices())
  {

    points_.resize( _n);

    // clear propertiy vectors
    if( vertex_normals_available() )
      vnormals_.resize( _n);
    if( vertex_binormals_available() )
      vbinormals_.resize( _n);
    if( vertex_colors_available())
      vcolors_.resize( _n);
    if( vertex_scalars_available())
      vscalars_.resize( _n);
    if( vertex_selections_available())
      vselections_.resize( _n);
    if( vertex_vhandles_available())
      vvhandles_.resize( _n);
    if( vertex_ehandles_available())
      vehandles_.resize( _n);
    if( vertex_fhandles_available())
      vfhandles_.resize( _n);

    if( edge_normals_available())
      enormals_.resize( _n);
    if( edge_colors_available())
      ecolors_.resize( _n);
    if( edge_scalars_available())
      escalars_.resize( _n);
    if( edge_preimage_directions_available())
      epreimage_direction_.resize( _n);


    for (typename CustomPropertyMap::iterator it = custom_properties.begin(); it != custom_properties.end(); ++it) {
      
      CustomProperty* p = it->second;
      
      p->prop_data.resize(p->prop_size * _n);
    }

  }
  else
  {
    while( n_vertices() < _n)
      add_point( Point());
  }
}


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


template <class PointT>
void
PolyLineT<PointT>::
add_point(const Point& _p)
{
  // add new point
  points_.push_back( _p );

  // add available properties
  if( vertex_normals_available() )
    vnormals_.push_back( Point(0,0,0));
  
  if( vertex_binormals_available() )
    vbinormals_.push_back( Point(0,0,0));

  if( vertex_colors_available())
    vcolors_.push_back( Point(1,0,1));

  if( vertex_scalars_available())
    vscalars_.push_back( 0.0 );

  if( vertex_selections_available())
    vselections_.push_back( false);

  if( vertex_vhandles_available())
    vvhandles_.push_back(-1);

  if( vertex_ehandles_available())
    vehandles_.push_back(-1);

  if( vertex_fhandles_available())
    vfhandles_.push_back(-1);

  if( edge_normals_available())
    enormals_.push_back( Point(0,0,0));

  if( edge_colors_available())
    ecolors_.push_back( Point(1,0,1));

  if( edge_scalars_available())
    escalars_.push_back( 0.0);

  if( edge_selections_available())
    eselections_.push_back(false);

  if( edge_preimage_directions_available())
    epreimage_direction_.push_back(Point(0,0,0));


  for (typename CustomPropertyMap::iterator it = custom_properties.begin(); it != custom_properties.end(); ++it) {

    CustomProperty* p = it->second;

    size_t cur_size = p->prop_data.size();

    p->prop_data.resize(cur_size + p->prop_size);

    if (p->buffer())
      memset(p->buffer() + cur_size, 0, p->prop_size);
  }
}

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

template <class PointT>
void
PolyLineT<PointT>::
insert_point(int _idx, const Point& _p)
{
  assert(_idx < (int)n_vertices() );
  
  // insert new point
  points_.insert(points_.begin()+_idx, _p);

  // insert available properties
  if( vertex_normals_available() )
    vnormals_.insert(vnormals_.begin()+_idx, Point(0,0,0));
  
  if( vertex_binormals_available() )
    vbinormals_.insert(vbinormals_.begin()+_idx, Point(0,0,0));

  if( vertex_colors_available())
    vcolors_.insert(vcolors_.begin()+_idx, Point(1,0,1));

  if( vertex_scalars_available())
    vscalars_.insert(vscalars_.begin()+_idx, 0.0 );

  if( vertex_selections_available())
    vselections_.insert(vselections_.begin()+_idx, false);

  if( vertex_vhandles_available())
    vvhandles_.insert(vvhandles_.begin()+_idx, -1);

  if( vertex_ehandles_available())
    vehandles_.insert(vehandles_.begin()+_idx, -1);

  if( vertex_fhandles_available())
    vfhandles_.insert(vfhandles_.begin()+_idx, -1);

  if( edge_normals_available())
    enormals_.insert(enormals_.begin()+_idx, Point(0,0,0));

  if( edge_colors_available())
    ecolors_.insert(ecolors_.begin()+_idx, Point(1,0,1));

  if( edge_scalars_available())
    escalars_.insert(escalars_.begin()+_idx, 0.0);

  if( edge_selections_available())
    eselections_.insert(eselections_.begin()+_idx, false);

  if( edge_preimage_directions_available())
    epreimage_direction_.insert(epreimage_direction_.begin()+_idx, Point(0,0,0));

  // custom properties: insert byte-wise
  for (typename CustomPropertyMap::iterator it = custom_properties.begin(); it != custom_properties.end(); ++it) {

    CustomProperty* p = it->second;
    unsigned int offset = p->prop_size * _idx;

    for (unsigned int i = 0; i < p->prop_size; ++i)
      p->prop_data.insert(p->prop_data.begin() + offset, 0);
  }
}


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

template <class PointT>
void
PolyLineT<PointT>::
delete_point(int _idx)
{
  assert(_idx < (int)n_vertices() );

  // delete point at given index
  points_.erase(points_.begin()+_idx);


  // delete available properties
  if( vertex_normals_available() )
    vnormals_.erase(vnormals_.begin()+_idx);
  
  if( vertex_binormals_available() )
    vbinormals_.erase(vbinormals_.begin()+_idx);

  if( vertex_colors_available())
    vcolors_.erase(vcolors_.begin()+_idx);

  if( vertex_scalars_available())
    vscalars_.erase(vscalars_.begin()+_idx);

  if( vertex_selections_available())
    vselections_.erase(vselections_.begin()+_idx);

  if( vertex_vhandles_available())
    vvhandles_.erase(vvhandles_.begin()+_idx);

  if( vertex_ehandles_available())
    vehandles_.erase(vehandles_.begin()+_idx);

  if( vertex_fhandles_available())
    vfhandles_.erase(vfhandles_.begin()+_idx);

  if( edge_normals_available())
    enormals_.erase(enormals_.begin()+_idx);

  if( edge_colors_available())
    ecolors_.erase(ecolors_.begin()+_idx);

  if( edge_scalars_available())
    escalars_.erase(escalars_.begin()+_idx);

  if( edge_selections_available())
    eselections_.erase(eselections_.begin()+_idx);

  if( edge_preimage_directions_available())
    epreimage_direction_.erase(epreimage_direction_.begin()+_idx);


  // custom properties: delete byte-wise
  for (typename CustomPropertyMap::iterator it = custom_properties.begin(); it != custom_properties.end(); ++it) {

    CustomProperty* p = it->second;
    unsigned int offset = p->prop_size * _idx;

    for (unsigned int i = 0; i < p->prop_size; ++i)
      p->prop_data.erase(p->prop_data.begin() + offset);
  }
}


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


template <class PointT>
typename PolyLineT<PointT>::Scalar
PolyLineT<PointT>::
length() const
{
  Scalar l = 0;

  unsigned int n = points_.size();

  if(!closed_)
  {
    for(unsigned int i=0; i<n-1; ++i)
    {
      l += (points_[(i+1)]-points_[i]).norm();
    }
  }
  else
  {
    for(unsigned int i=0; i<n; ++i)
    {
      l += (points_[(i+1)%n]-points_[i]).norm();
    }
  }

  return l;
}


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


template <class PointT>
typename PolyLineT<PointT>::Point
PolyLineT<PointT>::
position(const Scalar _t) const
{
  assert(_t >=0.0 && _t<=1.0);
  return position_arclength(_t*this->length());
}


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


template <class PointT>
typename PolyLineT<PointT>::Point
PolyLineT<PointT>::
position_arclength(const Scalar _t) const
{
  // handle degenerate polyline cases
  if(this->n_vertices() < 2)
  {
    if(this->n_vertices() == 1)
      return this->front();
    else
    {
      std::cerr << "Warning: called position_arclength on emptu PolyLine!!!" << std::endl;
      return Point(0,0,0);
    }
  }

  // return beginning of curve for negative parameter value
  if(_t < 0.0)
    return this->front();

  unsigned int nv = this->n_vertices();
  unsigned int ne = this->n_edges();

  Scalar l = 0;

  for(unsigned int i=0; i<ne; ++i)
  {
    Scalar dl = (points_[(i+1)%nv]-points_[i]).norm();

    if(l <= _t && _t <= (l+dl))
    {
      Scalar tl = (_t-l)/dl;
      if(!std::isfinite(tl))
        tl = 0.0;
      return (tl*points_[(i+1)%nv] + (1.0-tl)*points_[i]);
    }

    l += dl;
  }

  // return end of curve for too large parameter values
  if(!closed_)
    return this->back();
  else
    return this->front();
}


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


template <class PointT>
void
PolyLineT<PointT>::
resample_arclength_uniform(const unsigned int _n)
{
  unsigned int n = std::max((unsigned int)(2),_n);
  Scalar l = this->length();

  // add new polyline with similar properties
  PolyLineT<PointT> new_pl = *this;
  // copy first point
  new_pl.resize(n);
  new_pl.copy_vertex_complete(*this, 0, 0);

  if(!closed_)
  {
    Scalar s = l/Scalar(n-1);
    for(unsigned int i=1; i<n-1; ++i)
      new_pl.point(i) = this->position_arclength(i*s);
  }
  else
  {
    Scalar s = l/Scalar(n);
    for(unsigned int i=1; i<n; ++i)
    new_pl.point(i) = this->position_arclength(i*s);
  }

  // copy last point
  if(!closed_)
    new_pl.copy_vertex_complete(*this, std::max(int(0),int(this->n_vertices())-1), std::max(int(0),int(new_pl.n_vertices())-1));

  // update polyline
  *this = new_pl;
}


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


template <class PointT>
void
PolyLineT<PointT>::
subdivide(Scalar _largest)
{
  // check validity
  if (!n_vertices())
    return;

  unsigned int n_subdivisions = 1;

  while (n_subdivisions != 0) {

    n_subdivisions = 0;

    // add new polyline and add first point
    PolyLineT<PointT> new_pl = *this;
    new_pl.resize(1);
    new_pl.copy_vertex_complete(*this, 0, 0);

    // squared maximal length
    Scalar l2 = _largest * _largest;

    for (unsigned int i = 1; i < points_.size(); ++i) {
      if ((new_pl.point(new_pl.n_vertices() - 1) - points_[i]).sqrnorm() > l2) {
        Point mid_point = (new_pl.point(new_pl.n_vertices() - 1) + points_[i]) * 0.5;

        new_pl.add_point(mid_point);
        ++n_subdivisions;
      }

      // copy vertex
      new_pl.resize(new_pl.n_vertices() + 1);
      new_pl.copy_vertex_complete(*this, i, new_pl.n_vertices() - 1);
    }

    // last interval for closed polyline
    if (closed_) {
      if ((new_pl.point(new_pl.n_vertices() - 1) - points_[0]).sqrnorm() > l2) {
        Point mid_point = (new_pl.point(new_pl.n_vertices() - 1) + points_[0]) * 0.5;
        new_pl.add_point(mid_point);
        ++n_subdivisions;
      }
    }

    // update points
    *this = new_pl;
  }
}

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


template <class PointT>
void
PolyLineT<PointT>::
collapse(Scalar _smallest)
{
  // check validity
  if(!n_vertices()) return;

  unsigned int n_collapses = 1;

  unsigned int n_iter = 0;

  while( n_collapses != 0 && n_iter < 5)
  {
    ++n_iter;
    n_collapses = 0;

    // create new PolyLine (with all properties) and insert first point
    PolyLineT<PointT> new_pl = *this;
    new_pl.resize(1);
    new_pl.copy_vertex_complete( *this, 0, 0);

    // squared maximal length
    Scalar l2 = _smallest*_smallest;

    for(unsigned int i=1; i<points_.size(); ++i)
    {
      // check whether vertex is selected
      bool vertex_selected = false;
      if( vertex_selections_available() && vertex_selection(i))
        vertex_selected = true;

      if( (new_pl.point(new_pl.n_vertices()-1) - points_[i]).sqrnorm() >= l2 ||
          vertex_selected ||
          (!closed_ && i==points_.size()-1) )
      {
        // copy next point
        new_pl.resize( new_pl.n_vertices()+1);
        new_pl.copy_vertex_complete( *this, i, new_pl.n_vertices()-1);
      }
      else ++n_collapses;
    }

    // last interval for closed polyline
    if( closed_)
    {
      // check whether vertex is selected
      bool vertex_selected = false;
      if( vertex_selections_available() && vertex_selection(points_.size()-1))
        vertex_selected = true;

      if( (new_pl.point(new_pl.n_vertices()-1) - points_[0]).sqrnorm() < l2 && !vertex_selected)
      {
        new_pl.resize( new_pl.n_vertices()-1);
      }
      else ++n_collapses;
    }

    // update points
    *this = new_pl;
  }
}


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

template <class PointT>
void
PolyLineT<PointT>::
smooth_uniform_laplace()
{
  // copy point positions
  std::vector<Point> points_old( points_ );

  int n = points_.size();

  int is = 0;
  int ie = n;

  if( !closed_ )
  {
    ++is;
    --ie;
  }

  if( vertex_selections_available())
  {
    #ifdef USE_OPENMP
    #pragma omp parallel for
    #endif
    for( int i=is; i<ie; ++i)
    {
      // only smooth not selected vertices
      if( !vertex_selection(i))
      // laplace stencil 1,-2,1
             points_[i] = (points_old[ (i-1+n)%n ] +
                                points_old[ (i+n  )%n ]*2.0 +
                                points_old[ (i+1  )%n ]      )*0.25;

    }
  }
  else
  {
    #ifdef USE_OPENMP
    #pragma omp parallel for
    #endif
    for( int i=is; i<ie; ++i)
    {
      // laplace stencil 1,-2,1
      points_[i] = (points_old[ (i-1+n)%n ]       +
                              points_old[ (i+n  )%n ] * 2.0 +
                              points_old[ (i+1  )%n ]         )*0.25;
    }
  }
}


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


template <class PointT>
void
PolyLineT<PointT>::
smooth_uniform_laplace2()
{
  // copy point positions
  std::vector<Point> points_old( points_ );

  int n = points_.size();

  int is = 0;
  int ie = n;

  if( !closed_ )
  {
    is+=2;
    ie-=2;
  }

  if( vertex_selections_available())
  {
    #ifdef USE_OPENMP
    #pragma omp parallel for
    #endif
    for(int i=is; i<ie; ++i)
    {
      // only smooth not selected vertices
      if( !vertex_selection(i))
        // laplace^2 stencil 1,-4,6,-4,1
        points_[i] -= (points_old[ (i-2+2*n)%n ]      +
                       points_old[ (i-1+2*n)%n ]*-4.0 +
                       points_old[ (i      )%n ]* 6.0 +
                       points_old[ (i+1    )%n ]*-4.0 +
                       points_old[ (i+2    )%n ]      )/(16.0*2.0);
    }
  }
  else
  {
    #ifdef USE_OPENMP
    #pragma omp parallel for
    #endif
    for(int i=is; i<ie; ++i)
    {
      // laplace^2 stencil 1,-4,6,-4,1
      points_[i] -= (points_old[ (i-2+2*n)%n ]      +
                               points_old[ (i-1+2*n)%n ]*-4.0 +
                     points_old[ (i      )%n ]* 6.0 +
                     points_old[ (i+1    )%n ]*-4.0 +
                     points_old[ (i+2    )%n ]      )/(16.0*2.0);
    }
  }
}


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


template <class PointT>
void
PolyLineT<PointT>::
smooth_uniform_laplace3()
{
  // copy point positions
  std::vector<Point> points_old( points_ );

  int n = points_.size();

  int is = 0;
  int ie = n;

  if( !closed_ )
  {
    is+=3;
    ie-=3;
  }

  if( vertex_selections_available())
  {
    #ifdef USE_OPENMP
    #pragma omp parallel for
    #endif
    for( int i=is; i<ie; ++i)
    {
      // only smooth not selected vertices
      if( !vertex_selection(i))
             // laplace^3 stencil 1,-6,15,-20,15,-6,1
             points_[i] = (points_old[ (i-3+3*n)%n ]        +
                      points_old[ (i-2+3*n)%n ]*(-6.0) +
                      points_old[ (i-1+3*n)%n ]*15.0   +
                      points_old[ (i      )   ]*(44.0) +
                      points_old[ (i+1    )%n ]*15.0   +
                      points_old[ (i+2    )%n ]*(-6.0) +
                      points_old[ (i+3    )%n ]        )/64.0;

    }
  }
  else
  {
    #ifdef USE_OPENMP
    #pragma omp parallel for
    #endif
    for( int i=is; i<ie; ++i)
    {
           // laplace^3 stencil 1,-6,15,-20,15,-6,1
           points_[i] = (points_old[ (i-3+3*n)%n ]        +
                    points_old[ (i-2+3*n)%n ]*(-6.0) +
                    points_old[ (i-1+3*n)%n ]*15.0   +
                    points_old[ (i      )   ]*(44.0) +
                    points_old[ (i+1    )%n ]*15.0   +
                    points_old[ (i+2    )%n ]*(-6.0) +
                    points_old[ (i+3    )%n ]        )/64.0;
    }
  }
}


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


template <class PointT>
void
PolyLineT<PointT>::
set_to_circle(const PointT _center, const PointT _normal, double _radius, unsigned int _n_samples)
{
  this->clear();
  this->set_closed(true);

  // get local basis vectors
  PointT n = _normal; n.normalize();
  PointT u = ACG::Geometry::perpendicular(_normal); u*=_radius/u.norm();
  PointT v = n % u;

  for(unsigned int i=0; i<_n_samples; ++i)
  {
    double alpha = double(i)*2.0*M_PI/double(_n_samples);

    this->add_point(_center + u*cos(alpha) + v*sin(alpha));
  }
}


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


template <class PointT>
template <class MeshT, class SpatialSearchT>
void
PolyLineT<PointT>::
project_to_mesh( const MeshT& _mesh, SpatialSearchT * _ssearch)
{
  typename MeshT::FaceHandle fh;

  #ifdef USE_OPENMP
  #pragma omp parallel for
  #endif
  for(unsigned int i=0; i<points_.size(); ++i)
  {
    points_[i] = find_nearest_point( _mesh, points_[i], fh, _ssearch);
  }
}


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


template <class PointT>
template <class MeshT, class SpatialSearchT>
void
PolyLineT<PointT>::
project_to_mesh( const std::vector<MeshT*>&     _mesh,
                             std::vector<SpatialSearchT*>* _ssearch)
{
  typename MeshT::FaceHandle fh;

  #ifdef USE_OPENMP
  #pragma omp parallel for
  #endif
  for(int i=0; i< (int)points_.size(); ++i)
  {
    // init d_best
    typename MeshT::Scalar d_best = -1;

    // best point
    Point p_best(0,0,0);

    // iterate over all possible meshes
    for(unsigned int j=0; j<_mesh.size(); ++j)
    {
      double d_new(-1);

      Point p_new;
      if(_ssearch != 0)
             p_new = find_nearest_point( *(_mesh[j]), points_[i], fh, ((*_ssearch)[j]), &d_new);
      else
             p_new = find_nearest_point( *(_mesh[j]), points_[i], fh, (SpatialSearchT*)0, &d_new);

      // store best result
      if( d_new < d_best || d_best == -1)
      {
             p_best = p_new;
             d_best = d_new;
      }
    }

    if( d_best != -1)
      points_[i] = p_best;
  }
}


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


template <class PointT>
template <class MeshT, class SpatialSearchT>
typename PolyLineT<PointT>::Point
PolyLineT<PointT>::
find_nearest_point( const MeshT&                _mesh,
                                const Point&                _point,
                                typename MeshT::FaceHandle& _fh,
                                SpatialSearchT *            _ssearch,
                                double*                     _dbest)
{
  typename MeshT::Point p0 = (typename MeshT::Point) _point;

  typename MeshT::Point p_best = _mesh.point(_mesh.vertex_handle(0));
  typename MeshT::Scalar d_best = (p0 - p_best).sqrnorm();

  typename MeshT::FaceHandle fh_best;

  if (_ssearch == 0) {
    // exhaustive search
    typename MeshT::ConstFaceIter cf_it = _mesh.faces_begin();
    typename MeshT::ConstFaceIter cf_end = _mesh.faces_end();

    for (; cf_it != cf_end; ++cf_it) {
      typename MeshT::ConstFaceVertexIter cfv_it = _mesh.cfv_iter(*cf_it);

      const typename MeshT::Point& pt0 = _mesh.point(*cfv_it);
      const typename MeshT::Point& pt1 = _mesh.point(*(++cfv_it));
      const typename MeshT::Point& pt2 = _mesh.point(*(++cfv_it));

      typename MeshT::Point ptn;

      typename MeshT::Scalar d = Geometry::distPointTriangleSquared(p0, pt0, pt1, pt2, ptn);

      if (d < d_best) {
        d_best = d;
        p_best = ptn;

        fh_best = *cf_it;
      }
    }

    // return face handle
    _fh = fh_best;

    // return distance
    if (_dbest)
      *_dbest = sqrt(d_best);

    return (Point) p_best;
  } else {
    typename MeshT::FaceHandle fh = _ssearch->nearest(p0).handle;
    typename MeshT::CFVIter fv_it = _mesh.cfv_iter(fh);

    const typename MeshT::Point& pt0 = _mesh.point(*fv_it);
    const typename MeshT::Point& pt1 = _mesh.point(*(++fv_it));
    const typename MeshT::Point& pt2 = _mesh.point(*(++fv_it));

    // project
    d_best = Geometry::distPointTriangleSquared(p0, pt0, pt1, pt2, p_best);

    // return facehandle
    _fh = fh;

    // return distance
    if (_dbest)
      *_dbest = sqrt(d_best);

    return (Point) p_best;
  }
}

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


template <class PointT>
template <class LineNodeT>
LineNodeT*
PolyLineT<PointT>::
get_line_node(LineNodeT*& _line_node, int _mode)
{
  typedef typename LineNodeT::value_type Vec3fL;

  if (_mode == 0) {
    // LineSegmentsMode

    // create LineNode
    _line_node = new LineNodeT(LineNodeT::LineSegmentsMode, 0, "PolyLine");
    _line_node->set_line_width(5.0);
    //   _line_node->set_base_color(Vec4f(0,1,0,0));
    _line_node->set_base_color(
        OpenMesh::Vec4f(0.2 + double(rand()) / double(RAND_MAX) * 0.8, 0.2 + double(rand()) / double(RAND_MAX) * 0.8,
            0.2 + double(rand()) / double(RAND_MAX) * 0.8, 1.0));

    _line_node->show();

    // add line node
    for (unsigned int i = 0; i < this->points().size() - 1; ++i) {
      _line_node->add_line((Vec3fL) this->points()[i], (Vec3fL) this->points()[i + 1]);
    }

    // close loop
    if (closed_)
      if (!this->points().empty()) {
        _line_node->add_point((Vec3fL) this->points()[0]);
      }

    return _line_node;
  } else {
    // create LineNode
    _line_node = new LineNodeT(LineNodeT::PolygonMode, 0, "PolyLine");
    _line_node->set_line_width(5.0);
    //   _line_node->set_base_color(Vec4f(0,1,0,0));
    _line_node->set_base_color(
        OpenMesh::Vec4f(0.2 + double(rand()) / double(RAND_MAX) * 0.8, 0.2 + double(rand()) / double(RAND_MAX) * 0.8,
            0.2 + double(rand()) / double(RAND_MAX) * 0.8, 1.0));

    _line_node->show();

    // add line node
    for (unsigned int i = 0; i < this->points().size(); ++i) {
      _line_node->add_point((Vec3fL) this->points()[i]);
    }

    // close loop
    if (closed_)
      if (!this->points().empty()) {
        _line_node->add_point((Vec3fL) this->points()[0]);
      }

    return _line_node;
  }
}


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


template <class PointT>
template <class LineNodeT>
void
PolyLineT<PointT>::
set_line_node(LineNodeT*& _line_node, int _mode)
{
  //  typedef typename LineNodeT::value_type Vec3fL;

  // clear old values
  clear();

  if (_mode == 0) {
    // assume LineSegmentsMode

    const typename LineNodeT::PointVector& ln_points = _line_node->points();

    for (unsigned int i = 0; i < ln_points.size();) {
      if (i != ln_points.size() - 1)
        add_point((Point) ln_points[i]);
      else {
        // last point
        if ((ln_points[ln_points.size() - 1] - ln_points[0]).sqrnorm() == 0) {
          closed_ = true;
        } else {
          closed_ = false;
          add_point((Point) ln_points[i]);
        }
      }

      // increase counter
      if (i == 0)
        i += 1;
      else
        i += 2;
    }
  } else {
    // assume PolygonMode
    closed_ = true;

    const typename LineNodeT::PointVector& ln_points(_line_node->points());

    for (unsigned int i = 0; i < ln_points.size(); ++i) {
      add_point((Point) ln_points[i]);
    }
  }
}


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


template <class PointT>
void
PolyLineT<PointT>::
print() const
{
  std::cerr << "****** PolyInfo ******\n";
  std::cerr << "closed : " << closed_ << std::endl;
  std::cerr << "#points: " << points_.size() << std::endl;
  for(unsigned int i=0; i<points_.size(); ++i)
    std::cerr << points_[i] << std::endl;
}


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


template <class PointT>
template <class PropT>
void
PolyLineT<PointT>::
request_prop( unsigned int& _ref_count, PropT& _prop)
{
  if(_ref_count == 0)
  {
    _ref_count = 1;
    // always use vertex size!!!
    _prop.resize(n_vertices());
  }
  else ++_ref_count;
}


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


template <class PointT>
template <class PropT>
void
PolyLineT<PointT>::
release_prop( unsigned int& _ref_count, PropT& _prop)
{
  if( _ref_count <= 1)
  {
    _ref_count = 0;
    _prop.clear();
  }
  else --_ref_count;
}


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


template <class PointT>
void
PolyLineT<PointT>::
copy_vertex_complete(const PolyLineT<PointT>& _pl, unsigned int _i, unsigned int _j)
{
  // check range
  if( n_vertices() <= _j || _pl.n_vertices() <= _i)
  {
    std::cerr << "Warning: invalid range in PolyLine::copy_vertex_complete ( "
              << _i << " " << _j << " ) " << std::endl;
    return;
  }

  // copy point position
  point(_j) = _pl.point(_i);

  // copy properties if available

  // vertex normal
  if( _pl.vertex_normals_available())
    if(   vertex_normals_available())
      vertex_normal(_j) = _pl.vertex_normal(_i);
    
  if( _pl.vertex_binormals_available())
    if(   vertex_binormals_available())
      vertex_binormal(_j) = _pl.vertex_binormal(_i);

  // vertex colors
  if( _pl.vertex_colors_available())
    if(   vertex_colors_available())
      vertex_color(_j) = _pl.vertex_color(_i);

  // vertex scalar
  if( _pl.vertex_scalars_available())
    if(   vertex_scalars_available())
      vertex_scalar(_j) = _pl.vertex_scalar(_i);

  // vertex selection
  if( _pl.vertex_selections_available())
    if(   vertex_selections_available())
      vertex_selection(_j) = _pl.vertex_selection(_i);

  // vertex vhandle
  if( _pl.vertex_vhandles_available())
    if(   vertex_vhandles_available())
      vertex_vhandle(_j) = _pl.vertex_vhandle(_i);

  // vertex ehandle
  if( _pl.vertex_ehandles_available())
    if(   vertex_ehandles_available())
      vertex_ehandle(_j) = _pl.vertex_ehandle(_i);

  // vertex vhandle
  if( _pl.vertex_ehandles_available())
    if(   vertex_ehandles_available())
      vertex_ehandle(_j) = _pl.vertex_ehandle(_i);
}


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


template <class PointT>
void
PolyLineT<PointT>::
copy_edge_complete(const PolyLineT<PointT>& _pl, unsigned int _i, unsigned int _j)
{
  // check range
  if( n_edges() <= _j || _pl.n_edges() <= _i)
  {
    std::cerr << "Warning: invalid range in PolyLine::copy_edge_complete ( "
              << _i << " " << _j << " ) " << std::endl;
    return;
  }

  // edge normal
  if( _pl.edge_selections_available())
    if(   edge_selections_available())
      edge_selection(_j) = _pl.edge_selection(_i);


  // edge normal
  if( _pl.edge_normals_available())
    if(   edge_normals_available())
      edge_normal(_j) = _pl.edge_normal(_i);

  // edge color
  if( _pl.edge_colors_available())
    if(   edge_colors_available())
      edge_color(_j) = _pl.edge_color(_i);

  // edge scalar
  if( _pl.edge_scalars_available())
    if(   edge_scalars_available())
      edge_scalar(_j) = _pl.edge_scalar(_i);

  // edge normal
  if( _pl.edge_selections_available())
    if(   edge_selections_available())
      edge_selection(_j) = _pl.edge_selection(_i);

  // edge selection
  if( _pl.edge_selections_available())
    if(   edge_selections_available())
      edge_selection(_j) = _pl.edge_selection(_i);
}


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


template <class PointT>
void
PolyLineT<PointT>::
invert()
{
  // inversion is only supported for open polylines
  if(is_closed())
  {
    std::cerr << "Warning: inversion for closed polylines is not supported!!!\n";
    return;
  }

  PolyLineT<PointT> pl_temp = *this;

  // copy vertices in reverse order
  for(unsigned int i=0; i<n_vertices(); ++i)
    pl_temp.copy_vertex_complete( *this, n_vertices()-1-i, i);

  // copy edges in reverse order
  for(unsigned int i=0; i<n_edges(); ++i)
    pl_temp.copy_edge_complete( *this, n_edges()-1-i, i);

  // save inverted polyline
  *this = pl_temp;
}


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


template <class PointT>
void
PolyLineT<PointT>::
append(const PolyLineT<PointT>& _pl)
{
  // operation not supported for closed polylines
  if( is_closed() || _pl.is_closed())
  {
    std::cerr << is_closed() << " " << _pl.is_closed() << std::endl;
    std::cerr << "Warning: appending not supported for closed polylines!!!\n";
    return;
  }

  unsigned int old_nv = n_vertices();
  unsigned int old_ne = n_edges();

  resize( n_vertices() + _pl.n_vertices());

  for( unsigned int i=0; i<_pl.n_vertices(); ++i)
    copy_vertex_complete( _pl, i, i+old_nv);

  for( unsigned int i=0; i<_pl.n_edges(); ++i)
    copy_edge_complete( _pl, i, i+old_ne+1);
}


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


template <class PointT>
void
PolyLineT<PointT>::
prepend(const PolyLineT<PointT>& _pl)
{
  PolyLineT<PointT> pl_temp = _pl;

  pl_temp.append(*this);
  *this = pl_temp;
}


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


template <class PointT>
void
PolyLineT<PointT>::
split_closed( unsigned int _split_idx)
{
  if(!is_closed())
  {
    std::cerr << "Warning: split_closed was called for open polyline!\n";
    return;
  }

  // prepare new polyline
  PolyLineT<PointT> pl_temp = *this;
  pl_temp.resize(n_vertices()+1);
  pl_temp.set_closed( false);


  // splitted polyline has n+1 vertices
  for(unsigned int i=0; i<n_vertices()+1; ++i)
    pl_temp.copy_vertex_complete( *this, (i+_split_idx)%n_vertices(),i);

  for(unsigned int i=0; i<n_edges(); ++i)
    pl_temp.copy_edge_complete( *this, (i+_split_idx)%n_edges(),i);

  // copy updated polyline
  *this = pl_temp;
}


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


template <class PointT>
void
PolyLineT<PointT>::
split( unsigned int _split_idx, PolyLineT<PointT>& _new_pl)
{
  if( is_closed() ) split_closed( _split_idx);
  else
  {
    // copy properties
    _new_pl = *this;

    _new_pl.resize( n_vertices() - _split_idx);

    // copy vertex data
    for(unsigned int i=_split_idx; i<n_vertices(); ++i)
      _new_pl.copy_vertex_complete(*this, i, i-_split_idx);
    // copy edge data
    for(unsigned int i=_split_idx; i<n_edges(); ++i)
      _new_pl.copy_edge_complete(*this, i, i-_split_idx);

    // cut copied part
    resize(_split_idx+1);
  }
}


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


template <class PointT>
template <class IPoint>
bool
PolyLineT<PointT>::
plane_line_intersection( const IPoint& _p_plane,
                                           const IPoint& _n_plane,
                                         const IPoint& _p0,
                                         const IPoint& _p1,
                                         IPoint& _p_int)
{
  double a = (_n_plane | (_p_plane - _p0));
  double b = (_n_plane | (_p1 - _p0));

  if (fabs(b) > 1e-9) {
    double s = a / b;

    if (s >= 0.0 && s <= 1.0) {
      _p_int = _p0 + (_p1 - _p0) * s;

      // TEST Intersection Point
      if (fabs((_n_plane | (_p_int - _p_plane))) > 1e-9)
        std::cerr << "WARNING: wrong intersection point!!!\n";

      return true;
    } else
      return false;
  } else
    return false;
}


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


template <class PointT>
template<class MeshT>
void
PolyLineT<PointT>::
edge_points_in_segment( const MeshT&                             _mesh,
                                        const Point&                             _p0,
                                          const Point&                             _p1,
                        const typename MeshT::FaceHandle&        _fh0,
                        const typename MeshT::FaceHandle&        _fh1,
                                          std::vector<Point> &                     _points,
                                          std::vector<typename MeshT::EdgeHandle>& _ehandles )
{
  // initialize
  _points.clear();
  _ehandles.clear();

  Point p_start = _p0;
  Point p_end   = _p1;

  typename MeshT::FaceHandle fh_start = _fh0;
  typename MeshT::FaceHandle fh_end   = _fh1;

  if( fh_start == fh_end)
    return;

  // vectors for new points
  std::vector<Point> new_points0, new_points1;

  // vector for new edgehandle
  std::vector<typename MeshT::EdgeHandle> new_eh0, new_eh1;

//   // insert first point
//   new_points0.push_back( p_start);
//   new_points1.push_back( p_start);

  // construct cut plane
  // get first normal
  typename MeshT::HalfedgeHandle heh = _mesh.halfedge_handle(fh_start);
  Point p0      = (Point)_mesh.point(_mesh.to_vertex_handle( heh ));
  Point p1      = (Point)_mesh.point(_mesh.to_vertex_handle( heh = _mesh.next_halfedge_handle(heh) ));
  Point p2      = (Point)_mesh.point(_mesh.to_vertex_handle( heh = _mesh.next_halfedge_handle(heh) ));
  Point n_start = ((p1-p0)%(p2-p0)).normalize();

  // get second normal
  heh   = _mesh.halfedge_handle(fh_end);
  p0    = _mesh.point(_mesh.to_vertex_handle( heh ));
  p1    = _mesh.point(_mesh.to_vertex_handle( heh = _mesh.next_halfedge_handle(heh) ));
  p2    = _mesh.point(_mesh.to_vertex_handle( heh = _mesh.next_halfedge_handle(heh) ));
  Point n_end = ((p1-p0)%(p2-p0)).normalize();

  // get average normal
  Point n_avg = n_start + n_end;
  if( n_avg.sqrnorm() < 1e-7) n_avg = n_start - n_end;
  n_avg.normalize();

  // get plane data
  Point n_plane = n_avg % (p_start-p_end).normalize();
  if( n_plane.sqrnorm() > 1e-9) n_plane.normalize();
  else std::cerr << "WARNING: Edge Resampling -> not possible to construct stable cut plane!!!\n";
  Point p_plane = (p_start + p_end)*0.5;

  // get intersection halfedges of start triangle
  std::vector<typename MeshT::HalfedgeHandle > start_hehs;
  std::vector<Point>                          start_ps;
  heh = _mesh.halfedge_handle(fh_start);
  Point p_int;
  for(unsigned int i=0; i<3; ++i)
  {
    // edge endpoints
    p0 = (Point) _mesh.point(_mesh.from_vertex_handle(heh));
    p1 = (Point) _mesh.point(_mesh.to_vertex_handle  (heh));

    // intersection ?
    if( plane_line_intersection( p_plane, n_plane, p0, p1, p_int))
    {
      start_hehs.push_back( heh );
      start_ps.push_back(p_int);
    }
    // move to next halfedge handle
    heh = _mesh.next_halfedge_handle(heh);
  }

  // DEBUG
  // get intersection halfedges of end triangle
  std::vector<typename MeshT::HalfedgeHandle > end_hehs;
  std::vector<Point>                          end_ps;
  heh = _mesh.halfedge_handle(fh_end);
  for(unsigned int i=0; i<3; ++i)
  {
    // edge endpoints
    p0 = (Point) _mesh.point(_mesh.from_vertex_handle(heh));
    p1 = (Point) _mesh.point(_mesh.to_vertex_handle  (heh));

    // intersection ?
    if( plane_line_intersection( p_plane, n_plane, p0, p1, p_int))
    {
      end_hehs.push_back( heh );
      end_ps.push_back(p_int);
    }
    // move to next halfedge handle
    heh = _mesh.next_halfedge_handle(heh);
  }
  // END DEBUG

  // hack: debug hints
  if( start_hehs.size() != 2 || end_hehs.size() != 2)
  {
    std::cerr << "PolyLineResampling ERROR: wrong number of intersections... ";
    std::cerr << start_hehs.size() << " ";
    std::cerr << end_hehs.size()   << std::endl;
  }
  //  else std::cerr << "SUPI!!!\n";
  // end hack


  if( start_hehs.size() == 2 && end_hehs.size() == 2)
  {
    // initialize start points
    typename MeshT::HalfedgeHandle cur_heh0 = start_hehs[0];
    typename MeshT::HalfedgeHandle cur_heh1 = start_hehs[1];

    // store points and edge handles
    new_points0.push_back( start_ps[0]);
    new_eh0.push_back( _mesh.edge_handle( cur_heh0));

    new_points1.push_back( start_ps[1]);
    new_eh1.push_back( _mesh.edge_handle( cur_heh1));

    unsigned int count = 0;

    while( _mesh.face_handle(_mesh.opposite_halfedge_handle(cur_heh0)) != fh_end &&
           _mesh.face_handle(_mesh.opposite_halfedge_handle(cur_heh1)) != fh_end &&
           count < 1000 )
    {
      ++count;

      // move into first direction
      cur_heh0 = _mesh.opposite_halfedge_handle( cur_heh0);

      // test for boundary
      if( _mesh.is_boundary(cur_heh0))
      {
        std::cerr << "ERROR: found boundary in traversal!!!\n";
        cur_heh0 = _mesh.opposite_halfedge_handle( cur_heh0);
      } else {

        unsigned int old_size = new_points0.size();

        for(unsigned int i=0; i<2; ++i)
        {
          // move to next halfedge handle
          cur_heh0 = _mesh.next_halfedge_handle(cur_heh0);

          // edge endpoints
          p0 = (Point) _mesh.point(_mesh.from_vertex_handle(cur_heh0));
          p1 = (Point) _mesh.point(_mesh.to_vertex_handle  (cur_heh0));

          // intersection ?
          if( plane_line_intersection( p_plane, n_plane, p0, p1, p_int))
          {
            new_points0.push_back(p_int);
            new_eh0.push_back( _mesh.edge_handle( cur_heh0));
            break;
          }
        }

        // debug helper
        if( new_points0.size() != old_size + 1)
          std::cerr << "WARNING: could not find new point!!!\n";
      }

      // move into second direction
      cur_heh1 = _mesh.opposite_halfedge_handle( cur_heh1);

      // test for boundary
      if( _mesh.is_boundary(cur_heh1))
      {
        std::cerr << "ERROR: found boundary in traversal!!!\n";
        cur_heh1 = _mesh.opposite_halfedge_handle( cur_heh1);
      } else {

        unsigned int old_size = new_points1.size();

        for(unsigned int i=0; i<2; ++i)
        {
          // move to next halfedge handle
          cur_heh1 = _mesh.next_halfedge_handle(cur_heh1);

          // edge endpoints
          p0 = (Point) _mesh.point(_mesh.from_vertex_handle(cur_heh1));
          p1 = (Point) _mesh.point(_mesh.to_vertex_handle  (cur_heh1));

          // intersection ?
          if( plane_line_intersection( p_plane, n_plane, p0, p1, p_int))
          {
            new_points1.push_back(p_int);
            new_eh1.push_back( _mesh.edge_handle( cur_heh1));
            break;
          }
        }

        // debug helper
        if( new_points1.size() != old_size + 1)
          std::cerr << "WARNING: could not find new point!!!\n";
      }

    }

//     // add end points
//     new_points0.push_back( p_end );
//     new_points1.push_back( p_start );

    // set new points, test which direction converged first
    if(_mesh.face_handle(_mesh.opposite_halfedge_handle(cur_heh0)) == fh_end )
    {
      // return values
      _points   = new_points0;
      _ehandles = new_eh0;
    }
    else
      if (_mesh.face_handle(_mesh.opposite_halfedge_handle(cur_heh1)) == fh_end)
      {
        // return values
        _points   = new_points1;
        _ehandles = new_eh1;
      }
  }
}


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


template <class PointT>
void
PolyLineT<PointT>::
remove_subsequent_identical_points(const bool _keep_edge_vertices, const double _epsilon )
{
        if(is_closed())
        {
                for( int i=0; i<int(n_vertices()); ++i)
                {
                        int i_next = (i+1) % int(n_vertices());

                        if( (point(i) - point(i_next)).norm() < _epsilon)
                        {
                                if( vertex_ehandles_available())
                                {
                                        if( !_keep_edge_vertices || vertex_ehandle(i_next) == -1)
                                        {
                                                delete_point(i_next);
                                                --i;
                                        }
                                        else
                                                if( vertex_ehandle(i) == -1)
                                                {
                                                        delete_point(i);
                                                        --i;
                                                }
                                }
                                else // simply delete i_next
                                {
                                        delete_point(i_next);
                                        --i;
                                }
                        }
                }
        }
        else
        {
                for( int i=0; i<int(n_vertices())-1; ++i)
                {
                        int i_next = (i+1) % int(n_vertices());

                        if( (point(i) - point(i_next)).norm() < _epsilon)
                        {
                                if( vertex_ehandles_available())
                                {
                                        if( !_keep_edge_vertices || vertex_ehandle(i_next) == -1)
                                        {
                                                if(i_next != int(n_vertices())-1)
                                                {
                                                        delete_point(i_next);
                                                        --i;
                                                }
                                                else delete_point(i);
                                        }
                                        else
                                                if( vertex_ehandle(i) == -1)
                                                {
                                                        if(i != 0)
                                                        {
                                                                delete_point(i);
                                                                --i;
                                                        }
                                                }
                                }
                                else // simply delete i_next
                                {
                                        if(i_next != int(n_vertices())-1)
                                        {
                                                delete_point(i_next);
                                                --i;
                                        }
                                        else delete_point(i);
                                }
                        }
                }
        }
}


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


template <class PointT>
typename PolyLineT<PointT>::Scalar
PolyLineT<PointT>::
total_gaussian_curvature()
{
  // total gaussian curvature
  Scalar gcurv = 0.0;

  if (!edge_normals_available() || !is_closed()) {
    std::cerr << "Warning: PolyLineT::total_gaussian_curvature requires a closed loop and edge normals!!!\n";
  } else // closed and edge normals available
  {
    // sum over boundary
    for (unsigned int i = 0; i < n_edges(); ++i) {
      // get two consecutive edge vectors and corresponding normals
      Point e0 = edge_vector(i);
      Point n0 = edge_normal(i);
      Point e1 = edge_vector((i + 1) % n_edges());
      Point n1 = edge_normal((i + 1) % n_edges());

      // normalize edges
      if (e0.norm() > 1e-8)
        e0.normalize();
      else {
        std::cerr << "Warning: e0 is undefined...\n";
        continue;
      }
      if (e1.norm() > 1e-8)
        e1.normalize();
      else {
        std::cerr << "Warning: e1 is undefined...\n";
        continue;
      }

      // normalize normals
      if (n0.norm() > 1e-4)
        n0.normalize();
      else {
        std::cerr << "Warning: n0 is undefined...\n";
        continue;
      }
      if (n1.norm() > 1e-4)
        n1.normalize();
      else {
        std::cerr << "Warning: n1 is undefined...\n";
        continue;
      }

      // compute binormals
      Point b0 = n0 % e0;
      // Point b1 = n1%e0;

      // normalize binormals
      if (b0.norm() > 1e-8)
        b0.normalize();
      else {
        std::cerr << "Warning: b0 is undefined...\n";
        continue;
      }
      // if( b1.norm() > 1e-4) b1.normalize();
      // else std::cerr << "Warning: b1 is undefined...\n";

      // compute intersection of tangent planes
      Point d = n0 % n1;
      if ((d | b0) < 0) // reorientation necessary?
        d *= -1.0;

      // both in same tangent plane?
      if (d.norm() < 1e-3)
        d = b0;
      else
        d.normalize();

      // add both angles
      double dp = (-e0 | d);
      dp = std::max(-1.0, dp);
      dp = std::min(1.0, dp);

      // compute first boundary angle
      double boundary_angle = acos(dp);

      dp = (e1 | d);
      dp = std::max(-1.0, dp);
      dp = std::min(1.0, dp);

      // add second angle
      boundary_angle += acos(dp);

      gcurv += M_PI - boundary_angle;
    }
  }
  // return total gaussian curvature
  return (2.0 * M_PI - gcurv);
}

template <class PointT>
template <class MeshT>
void PolyLineT<PointT>::mark_components(
        OpenMesh::PropertyManager<
            OpenMesh::FPropHandleT<unsigned int>,
            MeshT> &component) {

    const MeshT &mesh = component.getMesh();

    for (typename MeshT::ConstFaceIter
            f_it = mesh.faces_begin(), f_end = mesh.faces_end();
            f_it != f_end; ++f_it) {
        component[*f_it] = 0;
    }

    unsigned int current_component = 0;
    for (typename MeshT::ConstFaceIter f_it = mesh.faces_begin(),
            f_end = mesh.faces_end(); f_it != f_end; ++f_it) {

        if (component[*f_it] != 0)
            continue;

        ++current_component;

        /*
         * Flood fill component.
         */
        std::stack<typename MeshT::FaceHandle> dfs;
        dfs.push(*f_it);

        while (!dfs.empty()) {
            const typename MeshT::FaceHandle fh = dfs.top(); dfs.pop();

            component[fh] = current_component;

            /*
             * Visit neighbors, push them onto stack if they
             * haven't been visited yet.
             */
            for (typename MeshT::CFFIter ff_it = mesh.cff_begin(fh),
                    ff_end = mesh.cff_end(fh); ff_it != ff_end; ++ff_it) {

                if (component[*ff_it] == 0)
                    dfs.push(*ff_it);
            }
        }
    }
    std::cout << "\x1b[33mmark_components: Mesh has " << current_component
            << " components.\x1b[0m" << std::endl;

}

template <class PointT>
template<class MeshT, class SpatialSearchT>
unsigned int PolyLineT<PointT>::component_of(
        const OpenMesh::PropertyManager<
            OpenMesh::FPropHandleT<unsigned int>,
            MeshT> &component,
        const PointT &pt,
        SpatialSearchT &_ssearch) {

    typename MeshT::FaceHandle fh;
    find_nearest_point(component.getMesh(), pt, fh, _ssearch);
//#ifndef NDEBUG
//    std::cout << "Point(" << pt << ") on fh " << fh.idx() << std::endl;
//#endif
    return component[fh];
}

template <class PointT>
template <class MeshT, class SpatialSearchT>
bool PolyLineT<PointT>::
on_multiple_components(MeshT &_mesh,
                       SpatialSearchT &_ssearch) {

    if (points_.empty()) return false;

    OpenMesh::PropertyManager<OpenMesh::FPropHandleT<unsigned int>, MeshT>
        component(_mesh,
                  "component.on_multiple_components.objecttypes.polyline"
                  ".i8.informatik.rwth-aachen.de");


    mark_components(component);

    const unsigned int first_component =
            component_of(component, points_.front(), _ssearch);

    for (typename std::vector<PointT>::iterator pt_it = ++points_.begin(),
            pt_end = points_.end(); pt_it != pt_end; ++pt_it) {

        if (first_component != component_of(component, *pt_it, _ssearch))
            return true;
    }

    return false;
}

template <class PointT>
template <class MeshT, class SpatialSearchT>
void PolyLineT<PointT>::
split_into_one_per_component(MeshT &_mesh,
                             SpatialSearchT &_ssearch,
                             std::vector<PolyLineT> &out_polylines) {

    if (points_.size() < 2) return;

    OpenMesh::PropertyManager<OpenMesh::FPropHandleT<unsigned int>, MeshT>
        component(_mesh,
                  "component.split_into_one_per_component.objecttypes.polyline"
                  ".i8.informatik.rwth-aachen.de");

    mark_components(component);

    PolyLineT<PointT> current_polyLine;
    current_polyLine.add_point(points_.front());
    unsigned int current_component =
            component_of(component, points_.front(), _ssearch);

    for (typename std::vector<PointT>::iterator pt_it = ++points_.begin(),
            pt_end = points_.end(); pt_it != pt_end; ++pt_it) {

        /*
         * The easy case: next point is on the same component as
         * the previous one.
         */
        const unsigned int next_comp = component_of(component, *pt_it, _ssearch);
        if (next_comp == current_component) {
            current_polyLine.add_point(*pt_it);
            continue;
        }

        /*
         * The hard case: next point is on different component
         * than the previous one.
         */

        PointT p0 = current_polyLine.back();
        const PointT p1 = *pt_it;
        unsigned int comp = next_comp;

        do {
            const double dist = (p0 - p1).norm();
            double lastIn = 0;
            double firstOut = 1;

            /*
             * Perform binary search to determine reasonable lastIn and firstOut.
             */
            static const double EPSILON = 1e-12;
            while ((firstOut - lastIn) * dist > EPSILON) {
                const double new_pos = .5 * (lastIn + firstOut);
                const PointT new_pt = p0 * (1.0 - new_pos) + p1 * new_pos;
                const unsigned int new_comp =
                        component_of(component, new_pt, _ssearch);

                if (new_comp == current_component) {
                    lastIn = new_pos;
                } else {
                    firstOut = new_pos;
                    comp = new_comp;
                }
            }

            if (lastIn != 0)
                current_polyLine.add_point(p0 * (1.0 - lastIn) + p1 * lastIn);
            if (current_polyLine.n_vertices() >= 2)
                out_polylines.push_back(current_polyLine);
            current_polyLine.clear();
            current_polyLine.add_point(p0 * (1.0 - firstOut) + p1 * firstOut);
            current_component = comp;

            // Update
            p0 = p0 * (1.0 - firstOut) + p1 * firstOut;
        } while (comp != next_comp);

        if (current_polyLine.back() != *pt_it)
            current_polyLine.add_point(*pt_it);
    }

    if (current_polyLine.n_vertices() >= 2)
      out_polylines.push_back(current_polyLine);

    // hack! if no splitting return original polyline
    if(out_polylines.size() <= 1)
    {
      out_polylines.clear();
      out_polylines.push_back(*this);
    }
}

template <class PointT>
typename PolyLineT<PointT>::CustomPropertyHandle PolyLineT<PointT>::custom_prop_handle(const CustomProperty* _prop) const {
  size_t n = cprop_enum.size();
  for (int i = 0; i < n; ++i)
    if (cprop_enum[i] == _prop)
      return i;
  return -1;
}

template <class PointT>
typename PolyLineT<PointT>::CustomProperty* PolyLineT<PointT>::custom_prop(CustomPropertyHandle _handle) {
  return (_handle >= 0 && _handle < int(get_num_custom_properties()) ? cprop_enum[_handle] : NULL);
}

template <class PointT>
const typename PolyLineT<PointT>::CustomProperty* PolyLineT<PointT>::custom_prop(CustomPropertyHandle _handle) const {
  return (_handle >= 0 && _handle < int(get_num_custom_properties()) ? cprop_enum[_handle] : NULL);
}

template <class PointT>
typename PolyLineT<PointT>::CustomPropertyHandle PolyLineT<PointT>::
  request_custom_property(const std::string& _name,
  unsigned int _prop_size) {

  CustomPropertyHandle h = get_custom_property_handle(_name);
  CustomProperty* pcontainer = custom_prop(h);

  if (!pcontainer) {

    // create new property container
    pcontainer = new CustomProperty;

    pcontainer->name = _name;
    pcontainer->ref_count = 1;
    pcontainer->prop_size = _prop_size;

    pcontainer->datatype = 0;

    pcontainer->prop_data.resize(n_vertices() * _prop_size, 0);

    custom_properties[_name] = pcontainer;

    cprop_enum.push_back(pcontainer);
  } else {

    if (++pcontainer->ref_count < 1)
      pcontainer->ref_count = 1;
  }

  return custom_prop_handle(pcontainer);
}

template <class PointT>
void PolyLineT<PointT>::
  release_custom_property(CustomPropertyHandle _prop_handle) {

  CustomProperty* p = custom_prop(_prop_handle);

  if (p && --(p->ref_count) <= 0)
    p->prop_data.clear();
}

template <class PointT>
void PolyLineT<PointT>::
  release_custom_property(const std::string& _name) {

  CustomPropertyHandle h = get_custom_property_handle(_name);
  release_custom_property(h);
}

template <class PointT>
typename PolyLineT<PointT>::CustomPropertyHandle PolyLineT<PointT>::
  get_custom_property_handle(const std::string& _name) const {

  typename CustomPropertyMap::const_iterator it = custom_properties.find(_name);

  if (it == custom_properties.end())
    return -1;

  return custom_prop_handle(it->second);
}

template <class PointT>
const std::string PolyLineT<PointT>::
  get_custom_property_name(CustomPropertyHandle _property_handle) const {

  const CustomProperty* p = custom_prop(_property_handle);

  if (p)
    return p->name;

  std::cerr << "PolyLineT::get_custom_property_name - invalid handle" << std::endl;

  return "";
}


template <class PointT>
void PolyLineT<PointT>::
  set_custom_property(CustomPropertyHandle _property_handle,
  unsigned int _i,
  const void* _data) {

  if (!_data) {
    std::cerr << "PolyLineT::set_custom_property - invalid data" << std::endl;
    return;
  }

  CustomProperty* p = custom_prop(_property_handle);

  if (p) {
    unsigned int offset = p->prop_size * _i;

    // check out of range
    if (offset + p->prop_size > p->prop_data.size()) {
      std::cerr << "PolyLineT::set_custom_property - out of range access" << std::endl;
      return;
    }


    // copy data byte-wise
    memcpy(p->buffer() + offset, _data, p->prop_size);
  }
  else
    std::cerr << "PolyLineT::set_custom_property - invalid handle" << std::endl;
}

template <class PointT>
void PolyLineT<PointT>::
  set_custom_property(const std::string& _name,
  unsigned int _i,
  const void* _data) {

  CustomPropertyHandle h = get_custom_property_handle(_name);
  set_custom_property(h, _i, _data);
}

template <class PointT>
void PolyLineT<PointT>::
  get_custom_property(CustomPropertyHandle _property_handle,
  unsigned int _i,
  void* _dst) const {

  if (!_dst) {
    std::cerr << "PolyLineT::get_custom_property - invalid destination address" << std::endl;
    return;
  }

  const CustomProperty* p = custom_prop(_property_handle);

  if (p) {

    unsigned int offset = p->prop_size * _i;

    // check out of range
    if (offset + p->prop_size > p->prop_data.size()) {
      std::cerr << "PolyLineT::get_custom_property - out of range access" << std::endl;
      return;
    }

    // copy data byte-wise
    memcpy(_dst, p->buffer() + offset, p->prop_size);
  }
  else
    std::cerr << "PolyLineT::get_custom_property - invalid handle" << std::endl;
}

template <class PointT>
void PolyLineT<PointT>::
  get_custom_property(const std::string& _name,
  unsigned int _i,
  void* _data) const {

  CustomPropertyHandle h = get_custom_property_handle(_name);
  get_custom_property(h, _i, _data);
}


template <class PointT>
bool PolyLineT<PointT>::
  custom_property_available(CustomPropertyHandle _property_handle) const {

  const CustomProperty* p = custom_prop(_property_handle);

  if (p)
    return p->ref_count > 0;
  
  return false;
}


template <class PointT>
bool PolyLineT<PointT>::
  custom_property_available(const std::string& _name) const {

  CustomPropertyHandle h = get_custom_property_handle(_name);
  return custom_property_available(h);
}


template <class PointT>
void PolyLineT<PointT>::
  bind_custom_property_to_shader(CustomPropertyHandle _property_handle, const std::string& _shader_input_name, unsigned int _datatype) {

  CustomProperty* p = custom_prop(_property_handle);

  if (p) {
    
    p->datatype = _datatype;
    p->shader_binding = _shader_input_name;

  } else
    std::cerr << "PolyLineT::bind_custom_property_to_shader - invalid handle" << std::endl;
}


template <class PointT>
bool PolyLineT<PointT>::
  get_custom_property_shader_binding(CustomPropertyHandle _property_handle, unsigned int* _propsize, const char** _input_name, unsigned int* _datatype) const {

  const CustomProperty* p = custom_prop(_property_handle);

  if (p) {
    
    if (_propsize)
      *_propsize = p->prop_size;

    if (_input_name)
      *_input_name = p->shader_binding.c_str();

    if (_datatype)
      *_datatype = p->datatype;

    return !p->shader_binding.empty() && p->datatype;
  } 
  else
    std::cerr << "PolyLineT::get_custom_property_shader_binding - invalid handle" << std::endl;

  return false;
}

template <class PointT>
const void* PolyLineT<PointT>::
  get_custom_property_buffer(CustomPropertyHandle _property_handle) const {

  const CustomProperty* p = custom_prop(_property_handle);

  if (p)
    return p->buffer();
  else
    std::cerr << "PolyLineT::get_custom_property_buffer - invalid handle" << std::endl;

  return NULL;
}

template <class PointT>
unsigned int PolyLineT<PointT>::
  get_num_custom_properties() const {
  return custom_properties.size();
}

template <class PointT>
typename PolyLineT<PointT>::CustomPropertyHandle PolyLineT<PointT>::
  enumerate_custom_property_handles(unsigned int _i) const {

  if (_i < get_num_custom_properties())
    return CustomPropertyHandle(_i);
  else
    return -1;
}

//=============================================================================
} // namespace ACG
//=============================================================================