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//=============================================================================
//
//  CLASS CatmullClarkT - IMPLEMENTATION
//
//=============================================================================

#define OPENMESH_SUBDIVIDER_UNIFORM_CATMULLCLARK_CC

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

#include "CatmullClarkT.hh"
#include <OpenMesh/Tools/Utils/MeshCheckerT.hh>

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

namespace OpenMesh   { // BEGIN_NS_OPENMESH
namespace Subdivider { // BEGIN_NS_SUBVIDER
namespace Uniform    { // BEGIN_NS_UNIFORM

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

template <typename MeshType, typename RealType>
bool
CatmullClarkT< MeshType, RealType >::prepare( MeshType& _m  )
{
  _m.add_property( vp_pos_ );
  _m.add_property( ep_pos_ );
  _m.add_property( fp_pos_ );
  _m.add_property( creaseWeights_ );

  // initialize all weights to 0 (= smooth edge)
  for( EdgeIter e_it = _m.edges_begin(); e_it != _m.edges_end(); ++e_it)
     _m.property(creaseWeights_, *e_it ) = 0.0;

  return true;
}

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

template <typename MeshType, typename RealType>
bool
CatmullClarkT<MeshType,RealType>::cleanup( MeshType& _m  )
{
  _m.remove_property( vp_pos_ );
  _m.remove_property( ep_pos_ );
  _m.remove_property( fp_pos_ );
  _m.remove_property( creaseWeights_ );
  return true;
}

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

template <typename MeshType, typename RealType>
bool
CatmullClarkT<MeshType,RealType>::subdivide( MeshType& _m , size_t _n , const bool _update_points)
{
  // Do _n subdivisions
  for ( size_t i = 0; i < _n; ++i)
  {

    // Compute face centroid
    for ( auto fh : _m.faces())
    {
      Point centroid;
      _m.calc_face_centroid( fh, centroid);
      _m.property( fp_pos_, fh ) = centroid;
    }

    // Compute position for new (edge-) vertices and store them in the edge property
    for ( auto eh : _m.edges())
      compute_midpoint( _m, eh, _update_points );

    // position updates activated?
    if(_update_points)
    {
      // compute new positions for old vertices
      for ( auto vh : _m.vertices())
        update_vertex( _m, vh );

      // Commit changes in geometry
      for ( auto vh : _m.vertices())
        _m.set_point(vh, _m.property( vp_pos_, vh ) );
    }

    // Split each edge at midpoint stored in edge property ep_pos_;
    // Attention! Creating new edges, hence make sure the loop ends correctly.
    for ( auto eh : _m.edges())
      split_edge( _m, eh );

    // Commit changes in topology and reconsitute consistency
    // Attention! Creating new faces, hence make sure the loop ends correctly.
    for ( auto fh : _m.faces())
      split_face( _m, fh);


#if defined(_DEBUG) || defined(DEBUG)
    // Now we have an consistent mesh!
    assert( OpenMesh::Utils::MeshCheckerT<MeshType>(_m).check() );
#endif
  }

  _m.update_normals();

  return true;
}

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

template <typename MeshType, typename RealType>
void
CatmullClarkT<MeshType,RealType>::split_face( MeshType& _m, const FaceHandle& _fh)
{
  /*
     Split an n-gon into n quads by connecting
     each vertex of fh to vh.

     - _fh will remain valid (it will become one of the quads)
     - the halfedge handles of the new quads will
     point to the old halfedges
   */

  // Since edges already refined (valence*2)
  size_t valence = _m.valence(_fh)/2;

  // new mesh vertex from face centroid
  VertexHandle vh = _m.add_vertex(_m.property( fp_pos_, _fh ));

  HalfedgeHandle hend = _m.halfedge_handle(_fh);
  HalfedgeHandle hh = _m.next_halfedge_handle(hend);

  HalfedgeHandle hold = _m.new_edge(_m.to_vertex_handle(hend), vh);

  _m.set_next_halfedge_handle(hend, hold);
  _m.set_face_handle(hold, _fh);

  hold = _m.opposite_halfedge_handle(hold);

  for(size_t i = 1; i < valence; i++)
  {
    HalfedgeHandle hnext = _m.next_halfedge_handle(hh);

    FaceHandle fnew = _m.new_face();

    _m.set_halfedge_handle(fnew, hh);

    HalfedgeHandle hnew = _m.new_edge(_m.to_vertex_handle(hnext), vh);

    _m.set_face_handle(hnew,  fnew);
    _m.set_face_handle(hold,  fnew);
    _m.set_face_handle(hh,    fnew);
    _m.set_face_handle(hnext, fnew);

    _m.set_next_halfedge_handle(hnew, hold);
    _m.set_next_halfedge_handle(hold, hh);
    _m.set_next_halfedge_handle(hh, hnext);
    hh = _m.next_halfedge_handle(hnext);
    _m.set_next_halfedge_handle(hnext, hnew);

    hold = _m.opposite_halfedge_handle(hnew);
  }

  _m.set_next_halfedge_handle(hold, hh);
  _m.set_next_halfedge_handle(hh, hend);
  hh = _m.next_halfedge_handle(hend);
  _m.set_next_halfedge_handle(hend, hh);
  _m.set_next_halfedge_handle(hh, hold);

  _m.set_face_handle(hold, _fh);

  _m.set_halfedge_handle(vh, hold);
}

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

template <typename MeshType, typename RealType>
void
CatmullClarkT<MeshType,RealType>::split_edge( MeshType& _m, const EdgeHandle& _eh)
{
  HalfedgeHandle heh     = _m.halfedge_handle(_eh, 0);
  HalfedgeHandle opp_heh = _m.halfedge_handle(_eh, 1);

  HalfedgeHandle new_heh, opp_new_heh, t_heh;
  VertexHandle   vh;
  VertexHandle   vh1( _m.to_vertex_handle(heh));
  Point          zero(0,0,0);

  // new vertex
  vh                = _m.new_vertex( zero );
  _m.set_point( vh, _m.property( ep_pos_, _eh ) );

  // Re-link mesh entities
  if (_m.is_boundary(_eh))
  {
    for (t_heh = heh;
        _m.next_halfedge_handle(t_heh) != opp_heh;
        t_heh = _m.opposite_halfedge_handle(_m.next_halfedge_handle(t_heh)))
    {}
  }
  else
  {
    for (t_heh = _m.next_halfedge_handle(opp_heh);
        _m.next_halfedge_handle(t_heh) != opp_heh;
        t_heh = _m.next_halfedge_handle(t_heh) )
    {}
  }

  new_heh     = _m.new_edge(vh, vh1);
  opp_new_heh = _m.opposite_halfedge_handle(new_heh);
  _m.set_vertex_handle( heh, vh );

  _m.set_next_halfedge_handle(t_heh, opp_new_heh);
  _m.set_next_halfedge_handle(new_heh, _m.next_halfedge_handle(heh));
  _m.set_next_halfedge_handle(heh, new_heh);
  _m.set_next_halfedge_handle(opp_new_heh, opp_heh);

  if (_m.face_handle(opp_heh).is_valid())
  {
    _m.set_face_handle(opp_new_heh, _m.face_handle(opp_heh));
    _m.set_halfedge_handle(_m.face_handle(opp_new_heh), opp_new_heh);
  }

  if( _m.face_handle(heh).is_valid())
  {
    _m.set_face_handle( new_heh, _m.face_handle(heh) );
    _m.set_halfedge_handle( _m.face_handle(heh), heh );
  }

  _m.set_halfedge_handle( vh, new_heh);
  _m.set_halfedge_handle( vh1, opp_new_heh );

  // Never forget this, when playing with the topology
  _m.adjust_outgoing_halfedge( vh );
  _m.adjust_outgoing_halfedge( vh1 );
}

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

template <typename MeshType, typename RealType>
void
CatmullClarkT<MeshType,RealType>::compute_midpoint( MeshType& _m, const EdgeHandle& _eh, const bool _update_points)
{
  HalfedgeHandle heh, opp_heh;

  heh      = _m.halfedge_handle( _eh, 0);
  opp_heh  = _m.halfedge_handle( _eh, 1);

  Point pos( _m.point( _m.to_vertex_handle( heh)));

  pos +=  _m.point( _m.to_vertex_handle( opp_heh));

  // boundary edge: just average vertex positions
  // this yields the [1/2 1/2] mask
  if (_m.is_boundary(_eh) || !_update_points)
  {
    pos *= static_cast<RealType>(0.5);
  }
//  else if (_m.status(_eh).selected() )
//  {
//    pos *= 0.5; // change this
//  }

  else // inner edge: add neighbouring Vertices to sum
    // this yields the [1/16 1/16; 3/8 3/8; 1/16 1/16] mask
  {
    pos += _m.property(fp_pos_, _m.face_handle(heh));
    pos += _m.property(fp_pos_, _m.face_handle(opp_heh));
    pos *= static_cast<RealType>(0.25);
  }
  _m.property( ep_pos_, _eh ) = pos;
}

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

template <typename MeshType, typename RealType>
void
CatmullClarkT<MeshType,RealType>::update_vertex( MeshType& _m, const VertexHandle& _vh)
{
  Point            pos(0.0,0.0,0.0);

  // TODO boundary, Extraordinary Vertex and  Creased Surfaces
  // see "A Factored Approach to Subdivision Surfaces"
  // http://faculty.cs.tamu.edu/schaefer/research/tutorial.pdf
  // and http://www.cs.utah.edu/~lacewell/subdeval
  if ( _m.is_boundary( _vh))
  {
    pos = _m.point(_vh);
    VertexEdgeIter   ve_itr;
    for ( ve_itr = _m.ve_iter( _vh); ve_itr.is_valid(); ++ve_itr)
      if ( _m.is_boundary( *ve_itr))
        pos += _m.property( ep_pos_, *ve_itr);
    pos /= static_cast<typename vector_traits<typename MeshType::Point>::value_type>(3.0);
  }
  else // inner vertex
  {
    /* For each (non boundary) vertex V, introduce a new vertex whose
       position is F/n + 2E/n + (n-3)V/n where F is the average of
       the new face vertices of all faces adjacent to the old vertex
       V, E is the average of the midpoints of all edges incident
       on the old vertex V, and n is the number of edges incident on
       the vertex.
       */

    /*
    Normal           Vec;
    VertexEdgeIter   ve_itr;
    double           valence(0.0);

    // R = Calculate Valence and sum of edge midpoints
    for ( ve_itr = _m.ve_iter( _vh); ve_itr; ++ve_itr)
    {
      valence+=1.0;
      pos += _m.property(ep_pos_, *ve_itr);
    }
    pos /= valence*valence;
    */

    RealType       valence(0.0);
    VOHIter voh_it = _m.voh_iter( _vh );
    for( ; voh_it.is_valid(); ++voh_it )
    {
      pos += _m.point( _m.to_vertex_handle( *voh_it ) );
      valence+=1.0;
    }
    pos /= valence*valence;

    VertexFaceIter vf_itr;
    Point          Q(0, 0, 0);

    for ( vf_itr = _m.vf_iter( _vh); vf_itr.is_valid(); ++vf_itr) //, neigboring_faces += 1.0 )
    {
      Q += _m.property(fp_pos_, *vf_itr);
    }

    Q /= valence*valence;//neigboring_faces;

    pos += _m.point(_vh) * (valence - RealType(2.0) )/valence + Q;
    //      pos = vector_cast<Vec>(_m.point(_vh));
  }

  _m.property( vp_pos_, _vh ) = pos;
}

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

//=============================================================================
} // END_NS_UNIFORM
} // END_NS_SUBDIVIDER
} // END_NS_OPENMESH
//=============================================================================
