Ejemplo n.º 1
0
IGL_INLINE void igl::sort_vectors_ccw(
  const Eigen::PlainObjectBase<DerivedS>& P,
  const Eigen::PlainObjectBase<DerivedS>& N,
  Eigen::PlainObjectBase<DerivedI> &order)
{
  int half_degree = P.cols()/3;
  //local frame
  Eigen::Matrix<typename DerivedS::Scalar,1,3> e1 = P.head(3).normalized();
  Eigen::Matrix<typename DerivedS::Scalar,1,3> e3 = N.normalized();
  Eigen::Matrix<typename DerivedS::Scalar,1,3> e2 = e3.cross(e1);

  Eigen::Matrix<typename DerivedS::Scalar,3,3> F; F<<e1.transpose(),e2.transpose(),e3.transpose();

  Eigen::Matrix<typename DerivedS::Scalar,Eigen::Dynamic,1> angles(half_degree,1);
  for (int i=0; i<half_degree; ++i)
  {
    Eigen::Matrix<typename DerivedS::Scalar,1,3> Pl = F.colPivHouseholderQr().solve(P.segment(i*3,3).transpose()).transpose();
//    assert(fabs(Pl(2))/Pl.cwiseAbs().maxCoeff() <1e-5);
    angles[i] = atan2(Pl(1),Pl(0));
  }

  igl::sort( angles, 1, true, angles, order);
  //make sure that the first element is always  at the top
  while (order[0] != 0)
  {
    //do a circshift
    int temp = order[0];
    for (int i =0; i< half_degree-1; ++i)
      order[i] = order[i+1];
    order(half_degree-1) = temp;
  }
}