libigl/include/igl/edge_crossings.cpp

#include "edge_crossings.h"
#include "list_to_matrix.h"

template <
  typename DeriveduE,
  typename DerivedS,
  typename DerivedT>
void igl::edge_crossings(
  const Eigen::MatrixBase<DeriveduE> & uE,
  const Eigen::MatrixBase<DerivedS> & S,
  const typename DerivedS::Scalar val,
  std::unordered_map<int,int> & uE2I,
  Eigen::PlainObjectBase<DerivedT> & T)
{
  using Scalar = typename DerivedS::Scalar;
  {
    std::vector<Scalar> vT;
    for(int u = 0;u<uE.rows();u++)
    {
      // Does edge cross isovalue?
      const int i = uE(u,0);
      const int j = uE(u,1);
      const Scalar Si = S(i);
      const Scalar Sj = S(j);
      // Specifically do not include endpoints
      if( (Si-val)*(Sj-val) >= 0)
      {
        continue;
      }
      // find crossing point
      const Scalar t = (val-Si)/(Sj-Si);
      uE2I[u] = vT.size();
      vT.emplace_back(t);
    }
    igl::list_to_matrix(vT,T);
  }
}

#ifdef IGL_STATIC_LIBRARY
// Explicit template instantiation
// generated by autoexplicit.sh
template void igl::edge_crossings<Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<double, -1, 1, 0, -1, 1>, Eigen::Matrix<double, -1, 1, 0, -1, 1> >(Eigen::MatrixBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::MatrixBase<Eigen::Matrix<double, -1, 1, 0, -1, 1> > const&, Eigen::Matrix<double, -1, 1, 0, -1, 1>::Scalar, std::unordered_map<int, int, std::hash<int>, std::equal_to<int>, std::allocator<std::pair<int const, int> > >&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, 1, 0, -1, 1> >&);
#endif