In This Package:

GtTransformTool.cc

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#include "GtTransformTool.h"

#include "DetDesc/ILVolume.h"
#include "DetDesc/IDetectorElement.h"
#include "DetDesc/IGeometryInfo.h"

#include "GaudiKernel/Point3DTypes.h"

#include "HepMC/GenEvent.h"
#include "HepMC/GenVertex.h"
// This may need to change when move to HepMC v2.
#include "CLHEP/Vector/LorentzVector.h"

GtTransformTool::GtTransformTool(const std::string& type,
                                 const std::string& name, 
                                 const IInterface* parent)
    : GaudiTool(type,name,parent)
    , m_offset(3,0)
    , m_detelem(0)
{
    declareInterface<IHepMCEventMutator>(this);

    declareProperty("Volume",m_volume="",
                    "Name of the DetectorElement to provide the local coordinate system.");

    declareProperty("Offset",m_offset,
                    "Spatial offset to apply to vertices before transformation");

    declareProperty("IgnorePosition",m_ignorePosition = false,
                    "Do not transform the position.");

    declareProperty("IgnoreDirection",m_ignoreDirection = false,
                    "Do not transform the direction.");
}

const IDetectorElement* GtTransformTool::detelem()
{
    if (m_detelem) return m_detelem;

    if ("" == m_volume) return 0;

    if (!existDet<IDetectorElement>(m_volume)) return 0;

    m_detelem = getDet<IDetectorElement>(m_volume);
    return m_detelem;
}

GtTransformTool::~GtTransformTool()
{
}

StatusCode GtTransformTool::initialize()
{
    this->GaudiTool::initialize();

    const IDetectorElement* detelem = this->detelem();
    if (!detelem) {
        fatal() << "Could not get detector element: \"" << m_volume << "\"" << endreq;
        return StatusCode::FAILURE;
    }

    return StatusCode::SUCCESS;
}

#include "CLHEP/Units/SystemOfUnits.h"

StatusCode GtTransformTool::mutate(HepMC::GenEvent& event)
{
    if (!m_ignorePosition) {

        debug() << "Transforming " << event.vertices_size() << " vertices:\n";
        HepMC::GenEvent::vertex_iterator vtx, done = event.vertices_end();
        for (vtx = event.vertices_begin(); vtx != done; ++vtx) {
            HepMC::FourVector pos = (*vtx)->position();

            // Note XYZPoint, not XYZVector
            Gaudi::XYZPoint local_point(pos.x()+m_offset[0],pos.y()+m_offset[1],pos.z()+m_offset[2]);
            Gaudi::XYZPoint global_point = m_detelem->geometry()->toGlobal(local_point);

            debug() << "\ttransform("<< pos.x()<<","<<pos.y()<<","<<pos.z() << ")\n"
                    << "\tlocal: " << local_point 
                    << "\tglobal: " << global_point << '\n'
                    << "\t detelem: " << *m_detelem << "\n"
                //<< "\t with lvolume: " << *(m_detelem->geometry()->lvolume())  
                    << "\n";

            pos.setX(global_point.x()); 
            pos.setY(global_point.y()); 
            pos.setZ(global_point.z());
            (*vtx)->set_position(pos);
            debug() << "\tvertex @ " << "("
                    << (*vtx)->position().x()/CLHEP::cm << ","
                    << (*vtx)->position().y()/CLHEP::cm << ","
                    << (*vtx)->position().z()/CLHEP::cm << ","
                    << (*vtx)->position().t()/CLHEP::second << ") [cm,cm,cm,second]";
        }
        debug () << endreq;
    }

    if (!m_ignoreDirection) {

        HepMC::GenEvent::particle_iterator pit, pdone = event.particles_end();
        for (pit = event.particles_begin(); pit != pdone; ++pit) {
            HepMC::FourVector mom = (*pit)->momentum();

            // Note XYZVector, not XYZPoint
            Gaudi::XYZVector lmom(mom.px(),mom.py(),mom.pz());
            Gaudi::XYZVector gmom = m_detelem->geometry()->toGlobal(lmom);
            mom.set(gmom.x(),gmom.y(),gmom.z(),mom.e());

            (*pit)->set_momentum(mom);
        }
    }

    return StatusCode::SUCCESS;
}

StatusCode GtTransformTool::finalize()
{

    return this->GaudiTool::finalize();
}

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