//
// ********************************************************************
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//
// $Id: G4AuxiliaryNavServices.icc,v 1.2 2003/11/03 17:15:20 gcosmo Exp $
// GEANT4 tag $Name: geant4-06-00-patch-01 $
//
//
// class G4AuxiliaryNavServices Inline implementation
//
// --------------------------------------------------------------------

inline G4bool
G4AuxiliaryNavServices::
CheckPointOnSurface( const G4VSolid* sampleSolid, 
                     const G4ThreeVector& localPoint, 
                     const G4ThreeVector* globalDirection, 
                     const G4AffineTransform& sampleTransform,
                     const G4bool locatedOnEdge)
{
  G4ThreeVector localDirection, sampleNormal;
  G4bool        enter = false;

  EInside insideSolid = sampleSolid->Inside(localPoint); 
  if ( insideSolid!=kOutside ) 
  {
    G4bool checkDirection= locatedOnEdge && (globalDirection!=0);
    if( (insideSolid==kSurface) && checkDirection)
    {
      // We are probably located on an edge.
      //
      localDirection= sampleTransform.TransformAxis(*globalDirection); 

      // Check whether we enter the volume
      // 
      sampleNormal = sampleSolid->SurfaceNormal(localPoint);
      if ( sampleNormal.dot(localDirection) <= 0 )
      {
        if( sampleNormal.dot(localDirection) == 0 )
        {
          // We can't decide yet, let's make sure we're entering the solid.
          // If by a confusion we entered the next solid we find out now
          // whether to leave or to enter.
          // This happens when we're on the surface or edge shared by two
          // solids
          //
          G4double distanceToIn =
                   sampleSolid->DistanceToIn( localPoint, localDirection );
          if( distanceToIn != kInfinity )
          {
            enter = true;
          } 
        }
        else
        {
          enter = true;
        }
      }
    }
    else
    {
      enter = true;
    }
  }
  return enter;
}