/home/hauberg/Dokumenter/Capture/humim-tracker-0.1/src/OpenTissue/OpenTissue/core/containers/mesh/common/util/mesh_compute_angle_weighted_vertex_normals.h

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#ifndef OPENTISSUE_CORE_CONTAINERS_MESH_COMMON_UTIL_COMPUTE_ANGLE_WEIGHTED_VERTEX_NORMALS_H
#define OPENTISSUE_CORE_CONTAINERS_MESH_COMMON_UTIL_COMPUTE_ANGLE_WEIGHTED_VERTEX_NORMALS_H
//
// OpenTissue Template Library
// - A generic toolbox for physics-based modeling and simulation.
// Copyright (C) 2008 Department of Computer Science, University of Copenhagen.
//
// OTTL is licensed under zlib: http://opensource.org/licenses/zlib-license.php
//
#include <OpenTissue/configuration.h>

#include <cassert>
#include <cmath>
#include <vector>

namespace OpenTissue
{
  namespace mesh
  {

    template<typename mesh_type>
    void compute_angle_weighted_vertex_normals(mesh_type & mesh)
    {
      typedef typename mesh_type::math_types                        math_types;
      typedef typename math_types::value_traits                     value_traits;
      typedef typename math_types::vector3_type                     vector3_type;
      typedef typename math_types::real_type                        real_type;

      typedef typename mesh_type::vertex_iterator         vertex_iterator;
      typedef typename mesh_type::face_iterator           face_iterator;
      typedef typename mesh_type::face_vertex_circulator  face_vertex_circulator;
      {
        vertex_iterator end = mesh.vertex_end();
        vertex_iterator v   = mesh.vertex_begin();
        for(;v!=end;++v)
          v->m_normal.clear();
      }
      {
        face_iterator end = mesh.face_end();
        face_iterator   f = mesh.face_begin();
        for(;f!=end;++f)
        {
          face_vertex_circulator i ( *f ),vend;
          face_vertex_circulator j ( *f );++j;
          face_vertex_circulator k ( *f );++k;++k;
          for(;i!=vend;++i,++j,++k)
          {
            vector3_type u0 =  normalize(j->m_coord - i->m_coord);
            vector3_type u1 =  normalize(k->m_coord - j->m_coord);
            real_type dot = -( u0*u1 );
            if(dot<-1)
              dot = -1;
            if(dot>1)
              dot = 1;
            real_type alpha = std::acos( dot );
            vector3_type n = normalize(u0 % u1);
            j->m_normal += alpha*n;
          }
        }
      }
      {
        vertex_iterator end = mesh.vertex_end();
        vertex_iterator v   = mesh.vertex_begin();
        for(;v!=end;++v)
          v->m_normal = normalize(v->m_normal);
      }
    }


  } // namespace mesh
} // namespace OpenTissue

//OPENTISSUE_CORE_CONTAINERS_MESH_COMMON_UTIL_COMPUTE_ANGLE_WEIGHTED_VERTEX_NORMALS_H
#endif