libigl_Martin/include/igl/project_to_line.cpp

// This file is part of libigl, a simple c++ geometry processing library.
//
// Copyright (C) 2013 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/.
#include "project_to_line.h"
#include <cassert>
#include <Eigen/Core>

template <
  typename DerivedP, 
  typename DerivedS, 
  typename DerivedD, 
  typename Derivedt, 
  typename DerivedsqrD>
IGL_INLINE void igl::project_to_line(
  const Eigen::MatrixBase<DerivedP> & P,
  const Eigen::MatrixBase<DerivedS> & S,
  const Eigen::MatrixBase<DerivedD> & D,
  Eigen::PlainObjectBase<Derivedt> & t,
  Eigen::PlainObjectBase<DerivedsqrD> & sqrD)
{
  // http://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html

  // number of dimensions
#ifndef NDEBUG
  int dim = P.cols();
  assert(dim == S.size());
  assert(dim == D.size());
#endif
  // number of points
  int np  = P.rows();
  // vector from source to destination
  DerivedD DmS = D-S;
  double v_sqrlen = (double)(DmS.squaredNorm());
  assert(v_sqrlen != 0);
  // resize output
  t.resize(np,1);
  sqrD.resize(np,1);
  // loop over points
#pragma omp parallel for if (np>10000)
  for(int i = 0;i<np;i++)
  {
    const typename DerivedP::ConstRowXpr Pi = P.row(i);
    // vector from point i to source
    const DerivedD SmPi = S-Pi;
    t(i) = -(DmS.array()*SmPi.array()).sum() / v_sqrlen;
    // P projected onto line
    const DerivedD projP = (1-t(i))*S + t(i)*D;
    sqrD(i) = (Pi-projP).squaredNorm();
  }
}

template <typename Scalar>
IGL_INLINE void igl::project_to_line(
  const Scalar px,
  const Scalar py,
  const Scalar pz,
  const Scalar sx,
  const Scalar sy,
  const Scalar sz,
  const Scalar dx,
  const Scalar dy,
  const Scalar dz,
  Scalar & projpx,
  Scalar & projpy,
  Scalar & projpz,
  Scalar & t,
  Scalar & sqrd)
{
  // vector from source to destination
  Scalar dms[3];
  dms[0] = dx-sx;
  dms[1] = dy-sy;
  dms[2] = dz-sz;
  Scalar v_sqrlen = dms[0]*dms[0] + dms[1]*dms[1] + dms[2]*dms[2];
  // line should have some length
  assert(v_sqrlen != 0);
  // vector from point to source
  Scalar smp[3];
  smp[0] = sx-px;
  smp[1] = sy-py;
  smp[2] = sz-pz;
  t = -(dms[0]*smp[0]+dms[1]*smp[1]+dms[2]*smp[2])/v_sqrlen;
  // P projectred onto line
  projpx = (1.0-t)*sx + t*dx;
  projpy = (1.0-t)*sy + t*dy;
  projpz = (1.0-t)*sz + t*dz;
  // vector from projected point to p
  Scalar pmprojp[3];
  pmprojp[0] = px-projpx;
  pmprojp[1] = py-projpy;
  pmprojp[2] = pz-projpz;
  sqrd = pmprojp[0]*pmprojp[0] + pmprojp[1]*pmprojp[1] + pmprojp[2]*pmprojp[2];
}

template <typename Scalar>
IGL_INLINE void igl::project_to_line(
  const Scalar px,
  const Scalar py,
  const Scalar pz,
  const Scalar sx,
  const Scalar sy,
  const Scalar sz,
  const Scalar dx,
  const Scalar dy,
  const Scalar dz,
  Scalar & t,
  Scalar & sqrd)
{
  Scalar projpx;
  Scalar projpy;
  Scalar projpz;
  return igl::project_to_line(
    px, py, pz, sx, sy, sz, dx, dy, dz,
    projpx, projpy, projpz, t, sqrd);
}

#ifdef IGL_STATIC_LIBRARY
// Explicit template specialization
// generated by autoexplicit.sh
template void igl::project_to_line<Eigen::Matrix<double, 1, 2, 1, 1, 2>, Eigen::Matrix<double, 1, 2, 1, 1, 2>, Eigen::Matrix<double, 1, 2, 1, 1, 2>, Eigen::Matrix<double, 1, 1, 0, 1, 1>, Eigen::Matrix<double, 1, 1, 0, 1, 1> >(Eigen::MatrixBase<Eigen::Matrix<double, 1, 2, 1, 1, 2> > const&, Eigen::MatrixBase<Eigen::Matrix<double, 1, 2, 1, 1, 2> > const&, Eigen::MatrixBase<Eigen::Matrix<double, 1, 2, 1, 1, 2> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, 1, 1, 0, 1, 1> >&, Eigen::PlainObjectBase<Eigen::Matrix<double, 1, 1, 0, 1, 1> >&);
template void igl::project_to_line<double>(double, double, double, double, double, double, double, double, double, double&, double&);
template void igl::project_to_line<double>(double, double, double, double, double, double, double, double, double, double&, double&,double&,double&, double&);
template void igl::project_to_line<Eigen::Matrix<double, 1, 3, 1, 1, 3>, Eigen::Matrix<double, 1, 3, 1, 1, 3>, Eigen::Matrix<double, 1, 3, 1, 1, 3>, Eigen::Matrix<double, 1, 1, 0, 1, 1>, Eigen::Matrix<double, 1, 1, 0, 1, 1> >(Eigen::MatrixBase<Eigen::Matrix<double, 1, 3, 1, 1, 3> > const&, Eigen::MatrixBase<Eigen::Matrix<double, 1, 3, 1, 1, 3> > const&, Eigen::MatrixBase<Eigen::Matrix<double, 1, 3, 1, 1, 3> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, 1, 1, 0, 1, 1> >&, Eigen::PlainObjectBase<Eigen::Matrix<double, 1, 1, 0, 1, 1> >&);
template void igl::project_to_line<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<double, -1, 1, 0, -1, 1>, Eigen::Matrix<double, -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<double, -1, -1, 0, -1, -1> > const&, Eigen::MatrixBase<Eigen::Matrix<double, -1, 1, 0, -1, 1> > const&, Eigen::MatrixBase<Eigen::Matrix<double, -1, 1, 0, -1, 1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, 1, 0, -1, 1> >&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, 1, 0, -1, 1> >&);
#endif