text: // This file is part of libigl, a simple c++ geometry processing library.
  //
  // Copyright (C) 2014 Nico Pietroni <nico.pietroni@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_LINE_FIELD_MISSMATCH_H
  #define IGL_LINE_FIELD_MISSMATCH_H
  #include "igl_inline.h"
  
  namespace igl
  {
    // Calculates the mismatch (integer), at each face edge, of a cross field defined on the mesh faces.
    // The integer mismatch is a multiple of pi/2 that transforms the cross on one side of the edge to
    // the cross on the other side. It represents the deviation from a Lie connection across the edge.
  
    // Inputs:
    //   V         #V by 3 eigen Matrix of mesh vertex 3D positions
    //   F         #F by 3 eigen Matrix of face (quad) indices
    //   PD1       #F by 3 eigen Matrix of the first per face cross field vector
    //   PD2       #F by 3 eigen Matrix of the second per face cross field vector
    //   isCombed  boolean, specifying whether the field is combed (i.e. matching has been precomputed.
    //             If not, the field is combed first.
    // Output:
    //   mismatch  #F by 3 eigen Matrix containing the integer mismatch of the cross field
    //             across all face edges
    //
  
      template <typename DerivedV, typename DerivedF, typename DerivedO>
      IGL_INLINE void line_field_mismatch(const Eigen::PlainObjectBase<DerivedV> &V,
                                          const Eigen::PlainObjectBase<DerivedF> &F,
                                          const Eigen::PlainObjectBase<DerivedV> &PD1,
                                          const bool isCombed,
                                          Eigen::PlainObjectBase<DerivedO> &mismatch);
  }
  #ifndef IGL_STATIC_LIBRARY
  #include "line_field_mismatch.cpp"
  #endif
  
  #endif
  