// This file is part of libigl, a simple c++ geometry processing library.
// 
// Copyright (C) 2018 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_INTRINSIC_DELAUNAY_COTMATRIX_H
#define IGL_INTRINSIC_DELAUNAY_COTMATRIX_H
#include "igl_inline.h"
#include <Eigen/Core>
#include <Eigen/Sparse>
namespace igl
{
  // INTRINSIC_DELAUNAY_COTMATRIX Computes the discrete cotangent Laplacian of a
  // mesh after converting it into its intrinsic Delaunay triangulation (see,
  // e.g., [Fisher et al. 2007].
  //
  // Inputs:
  //   V  #V by dim list of mesh vertex positions
  //   F  #F by 3 list of mesh elements (triangles or tetrahedra)
  // Outputs: 
  //   L  #V by #V cotangent matrix, each row i corresponding to V(i,:)
  //   l_intrinsic  #F by 3 list of intrinsic edge-lengths used to compute L
  //   F_intrinsic  #F by 3 list of intrinsic face indices used to compute L
  //
  // See also: intrinsic_delaunay_triangulation, cotmatrix, cotmatrix_intrinsic
  template <
    typename DerivedV, 
    typename DerivedF, 
    typename Scalar,
    typename Derivedl_intrinsic,
    typename DerivedF_intrinsic>
  IGL_INLINE void intrinsic_delaunay_cotmatrix(
    const Eigen::MatrixBase<DerivedV> & V, 
    const Eigen::MatrixBase<DerivedF> & F, 
    Eigen::SparseMatrix<Scalar>& L,
    Eigen::PlainObjectBase<Derivedl_intrinsic> & l_intrinsic,
    Eigen::PlainObjectBase<DerivedF_intrinsic> & F_intrinsic);
  template <typename DerivedV, typename DerivedF, typename Scalar>
  IGL_INLINE void intrinsic_delaunay_cotmatrix(
    const Eigen::MatrixBase<DerivedV> & V, 
    const Eigen::MatrixBase<DerivedF> & F, 
    Eigen::SparseMatrix<Scalar>& L);
}

#ifndef IGL_STATIC_LIBRARY
#  include "intrinsic_delaunay_cotmatrix.cpp"
#endif

#endif