// This file is part of libigl, a simple c++ geometry processing library.
// 
// Copyright (C) 2015 Alec Jacobson <alecjacobson@gmail.com>
// 
// This Source Code Form is subject to the terms of the Mozilla Public License 
// v. 2.0. If a copy of the MPL was not distributed with this file, You can 
// obtain one at http://mozilla.org/MPL/2.0/.
#ifndef IGL_UNIQUE_EDGE_MAP_H
#define IGL_UNIQUE_EDGE_MAP_H
#include "igl_inline.h"
#include <Eigen/Dense>
#include <vector>
namespace igl
{
  // Construct relationships between facet "half"-(or rather "viewed")-edges E
  // to unique edges of the mesh seen as a graph.
  //
  // Inputs:
  //   F  #F by 3  list of simplices
  // Outputs:
  //   E  #F*3 by 2 list of all directed edges, such that E.row(f+#F*c) is the
  //     edge opposite F(f,c)
  //   uE  #uE by 2 list of unique undirected edges
  //   EMAP #F*3 list of indices into uE, mapping each directed edge to unique
  //     undirected edge so that uE(EMAP(f+#F*c)) is the unique edge
  //     corresponding to E.row(f+#F*c)
  //   uE2E  #uE list of lists of indices into E of coexisting edges, so that
  //     E.row(uE2E[i][j]) corresponds to uE.row(i) for all j in
  //     0..uE2E[i].size()-1.
  template <
    typename DerivedF,
    typename DerivedE,
    typename DeriveduE,
    typename DerivedEMAP,
    typename uE2EType>
  IGL_INLINE void unique_edge_map(
    const Eigen::MatrixBase<DerivedF> & F,
    Eigen::PlainObjectBase<DerivedE> & E,
    Eigen::PlainObjectBase<DeriveduE> & uE,
    Eigen::PlainObjectBase<DerivedEMAP> & EMAP,
    std::vector<std::vector<uE2EType> > & uE2E);

}
#ifndef IGL_STATIC_LIBRARY
#  include "unique_edge_map.cpp"
#endif

#endif