Example3DSystem3.cxx

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/*
  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
*/
 
//                                                                     //
//  Implementation of class Example3DSystem3                           //
//                                                                     //
//  Author: Thomas Kittelmann <Thomas.Kittelmann@cern.ch>              //
//                                                                     //
//  Initial version: June 2007                                         //
//                                                                     //
 
#include "VP1TestSystems/Example3DSystem3.h"
 
#include <Inventor/nodes/SoSeparator.h>
#include <Inventor/nodes/SoLineSet.h>
#include <Inventor/nodes/SoVertexProperty.h>
 
#include "StoreGate/StoreGateSvc.h"
#include "TrkTrack/Track.h"
#include "TrkTrack/TrackCollection.h"
#include "TrkParameters/TrackParameters.h"
//#include "CLHEP/Units/SystemOfUnits.h"
#include "GaudiKernel/SystemOfUnits.h"
 
 
//_____________________________________________________________________________________
Example3DSystem3::Example3DSystem3()
  : IVP13DSystemSimple("Ex3DSys3",
               "This is an illustration of a very basic 3D system.\n"
               "It transforms track information found in storegate"
               " into relevant 3D objects (SoLineSet's), and displays track information when tracks are selected by the cursor.",
               "Thomas.Kittelmann@cern.ch")
{
}
 
//_____________________________________________________________________________________
void Example3DSystem3::buildEventSceneGraph(StoreGateSvc* sg, SoSeparator *root)
{
  //Clear node2Track info:
  m_nodeToTrack.clear();
 
  //1) Try to get the collection of (InDet) tracks from storegate:
 
  //Sanity check:
  if (!sg) {
    message("Error: Got null storegate pointer");
    return;
  }
 
  const TrackCollection *trackColl;
  std::string trackname="Tracks";
  StatusCode status = sg->retrieve(trackColl, trackname);
  if (status != StatusCode::SUCCESS || !trackColl) {
    message("Error: Could not retrieve track collection (used key="+QString(trackname.c_str())+")");
    return;
  }
 
  //2) Loop over the tracks and construct a relevant 3D object for each of them (a SoLineSet):
 
  TrackCollection::const_iterator trackItr, trackItrEnd = trackColl->end();
 
  for ( trackItr = trackColl->begin() ; trackItr != trackItrEnd; ++trackItr) {
      const Trk::Track *track = (*trackItr);
      const DataVector<const Trk::TrackParameters> *params = track->trackParameters();
 
      //Just a sanity check (we need at least two points on the track):
      if ( !params || params->size()<2 )
    continue;
 
      //The list of points on this track should be set in a so-called
      //SoVertexProperty (which one realises by reading the
      //documentation for SoLineSet at http://doc.coin3d.org/Coin/):
 
      SoVertexProperty *vertices = new SoVertexProperty();
 
      int iver(0);
      DataVector<const Trk::TrackParameters>::const_iterator it, itE = params->end();
      for (it = params->begin();it!=itE;++it) {
    vertices->vertex.set1Value(iver++,(*it)->position().x(),(*it)->position().y(),(*it)->position().z());
      }
 
      //Create a set of lines from these vertices:
      SoLineSet * line = new SoLineSet();
      line->numVertices = iver;
      line->vertexProperty = vertices;
 
      //Add to the tree:
      root->addChild(line);
 
      //Bookkeep which track this 3D object corresponds to (we will need this to display track info when the user clicks):
      m_nodeToTrack[line] = track;
 
      //To avoid GUI freeze-ups:
      updateGUI();
 
  }
 
}
 
//_____________________________________________________________________________________
void Example3DSystem3::userPickedNode(SoNode* pickedNode, SoPath * /*pickedPath*/) {
 
  //User clicked on "pickedNode". We should know which track this belongs to:
  if (m_nodeToTrack.find(pickedNode)==m_nodeToTrack.end()) {
    message("Error: Does not have track information for picked node");
    return;
  }
 
  //Get parameters:
  const DataVector<const Trk::TrackParameters> *params = m_nodeToTrack[pickedNode]->trackParameters();
  if ( !params || params->empty() ) {
    message("Error: Track has no trackparameters");
    return;
  }
 
  //Show some interesting information (from the first trackparameter):
  message("===> Track info:");
  message("  |p| = "+QString::number(params->front()->momentum().mag()/Gaudi::Units::GeV)+" GeV");
  message("   pT = "+QString::number(params->front()->pT()/Gaudi::Units::GeV)+" GeV");
  message("   Q  = "+QString::number(params->front()->charge()));
  message("  eta = "+QString::number(params->front()->eta()));
 
}