UPolyPhiFace.icc

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//
// ********************************************************************
// * This Software is part of the AIDA Unified Solids Library package *
// * See: https://aidasoft.web.cern.ch/USolids                        *
// ********************************************************************
//
// $Id:$
//
// --------------------------------------------------------------------
//
// UPolyPhiFace.icc
//
// 19.10.12 Marek Gayer
//          Created from original implementation in Geant4
// --------------------------------------------------------------------

inline
UVCSGface* UPolyPhiFace::Clone()
{
  return new UPolyPhiFace(*this);
}

// ExactZOrder
//
// Decide precisely whether a trajectory passes to the left, right, or exactly
// passes through the z position of a vertex point in our face.
//
// Result is only determined within an arbitrary (positive) factor.
//      > 0 to the right
//      < 0 to the left
//      = 0 exactly on top of
// In 99.9999% of the cases, a trivial calculation is used. In difficult
// cases, a precise, compliant calculation is relied on.
//
inline
double UPolyPhiFace::ExactZOrder(double z,
                                 double qx, double qy, double qz,
                                 const UVector3& v,
                                 double normSign,
                                 const UPolyPhiFaceVertex* vert) const
{
  double answer = vert->z - z;
  if (std::fabs(answer) < VUSolid::Tolerance())
  {
    UVector3 qa(qx - vert->x + radial.x,
                qy - vert->y + radial.y, qz - vert->z),
                   qb(qx - vert->x, qy - vert->y, qz - vert->z);
    UVector3 qacb = qa.Cross(qb);

    answer = normSign * qacb.Dot(v) * (normal.y * radial.x - normal.x * radial.y);
  }

  return answer;
}