WIP: An example to decode the CellID using the DD4hep way.

Examples/CMakeLists.txt

@@ -6,6 +6,11 @@ find_package(podio REQUIRED)
 find_package(LCIO REQUIRED)
 find_package(EDM4HEP REQUIRED)
 find_package(K4FWCore REQUIRED)
+find_package(DD4hep COMPONENTS DDRec DDParsers REQUIRED)
+
+gaudi_depends_on_subdirs(
+    Detector/DetInterface
+)
 
 set(Examples_srcs
     src/HelloWorld/*.cpp
@@ -13,6 +18,7 @@ set(Examples_srcs
     src/SecondAlg/*.cpp
  #   src/PlcioTest/*.cpp
     src/Edm4hepTest/*.cpp
+    src/DumpIDAlg/*.cpp
 )
 
 # Headers and Libraries
@@ -23,6 +29,7 @@ gaudi_install_headers(Examples)
 gaudi_add_module(Examples ${Examples_srcs}
     INCLUDE_DIRS K4FWCore GaudiAlgLib GaudiKernel ${podio_INCLUDE_DIRS} ${LCIO_INCLUDE_DIRS}
     LINK_LIBRARIES K4FWCore GaudiAlgLib GaudiKernel ${LCIO_LIBRARIES} 
+      DD4hep ${DD4hep_COMPONENT_LIBRARIES}
       # Force loading the libraries.
       -Wl,--no-as-needed EDM4HEP::edm4hep EDM4HEP::edm4hepDict ${podio_LIBRARIES} podio::podioRootIO -Wl,--as-needed
 )

Examples/src/DumpIDAlg/DumpIDAlg.cpp

+#include "DumpIDAlg.h"
+#include "edm4hep/EventHeaderCollection.h"
+#include "edm4hep/MCParticleCollection.h"
+#include "edm4hep/SimCalorimeterHitCollection.h"
+#include "edm4hep/CaloHitContributionCollection.h"
+
+#include "DD4hep/Detector.h"
+#include "DD4hep/IDDescriptor.h"
+#include "DD4hep/Plugins.h"
+
+DECLARE_COMPONENT(DumpIDAlg)
+
+DumpIDAlg::DumpIDAlg(const std::string& name, ISvcLocator* svcLoc)
+: GaudiAlgorithm(name, svcLoc), m_dd4hep_geo(nullptr), m_decoder(nullptr)
+{
+
+}
+
+StatusCode DumpIDAlg::initialize()
+{
+    m_geosvc = service<IGeoSvc>("GeoSvc");
+    if (!m_geosvc) {
+        error() << "Failed to find GeoSvc." << endmsg;
+        return StatusCode::FAILURE;
+    }
+    m_dd4hep_geo = m_geosvc->lcdd();
+    if (!m_dd4hep_geo) {
+        error() << "failed to retrieve dd4hep_geo: " << m_dd4hep_geo << endmsg;
+        return StatusCode::FAILURE;
+    }
+
+    // get the DD4hep readout
+    auto readouts = m_dd4hep_geo->readouts();
+    const std::string name_readout = "EcalBarrelCollection";
+    if (readouts.find(name_readout) != readouts.end()) {
+        dd4hep::Readout readout = m_dd4hep_geo->readout(name_readout);
+
+        auto m_idspec = readout.idSpec();
+
+        info() << "The idspec is " << m_idspec.fieldDescription() << " for " << name_readout << endmsg;
+
+        dd4hep::DDSegmentation::BitFieldCoder* decoder = m_idspec.decoder();
+        
+        m_decoder = decoder;
+    }
+
+    if (!m_decoder) {
+        error() << "Failed to get the decoder. " << endmsg;
+        return StatusCode::FAILURE;
+    }
+
+    return GaudiAlgorithm::initialize();
+}
+
+StatusCode DumpIDAlg::execute()
+{
+
+
+    auto ecalBarrelCol = m_EcalBarrelCol.get();
+    for (auto calohit: *ecalBarrelCol) {
+        auto cellid = calohit.getCellID();
+
+        int id_system = m_decoder->get(cellid, "system");
+        int id_module = m_decoder->get(cellid, "module");
+        int id_stave = m_decoder->get(cellid, "stave");
+        int id_tower = m_decoder->get(cellid, "tower");
+        int id_layer = m_decoder->get(cellid, "layer");
+        int id_wafer = m_decoder->get(cellid, "wafer");
+        int id_cellX = m_decoder->get(cellid, "cellX");
+        int id_cellY = m_decoder->get(cellid, "cellY");
+
+        info() << "Calo hit cellid: " << cellid
+               << " system: " << id_system
+               << " module: " << id_module
+               << " stave: " << id_stave
+               << " tower: " << id_tower
+               << " layer: " << id_layer
+               << " wafer: " << id_wafer
+               << " cellX: " << id_cellX
+               << " cellY: " << id_cellY
+               << endmsg;
+    }
+    return StatusCode::SUCCESS;
+}
+
+StatusCode DumpIDAlg::finalize()
+{
+
+    return GaudiAlgorithm::finalize();
+}
+
+
+
+

Examples/src/DumpIDAlg/DumpIDAlg.h

+#ifndef DumpIDAlg_h
+#define DumpIDAlg_h
+
+#include "FWCore/DataHandle.h"
+#include "GaudiAlg/GaudiAlgorithm.h"
+
+#include "DetInterface/IGeoSvc.h"
+
+#include "DD4hep/Detector.h"
+
+namespace edm4hep {
+    class EventHeaderCollection;
+    class MCParticleCollection;
+    class SimCalorimeterHitCollection;
+    class CaloHitContributionCollection;
+}
+
+class DumpIDAlg: public GaudiAlgorithm
+{
+public:
+
+    DumpIDAlg(const std::string& name, ISvcLocator* svcLoc);
+
+    virtual StatusCode initialize();
+    virtual StatusCode execute();
+    virtual StatusCode finalize();
+
+private:
+    SmartIF<IGeoSvc> m_geosvc;
+    dd4hep::Detector* m_dd4hep_geo;
+    dd4hep::DDSegmentation::BitFieldCoder* m_decoder;
+
+    DataHandle<edm4hep::SimCalorimeterHitCollection> m_EcalBarrelCol{"EcalBarrelCollection", 
+            Gaudi::DataHandle::Reader, this};
+
+};
+
+
+#endif