Calorimeter Truth partial fix

Currently uses the first hit as the truth. This should be fixed in the future.

src/dd4pod/plugins/Geant4Output2Podio.cxx

@@ -200,10 +200,8 @@ namespace dd4hep::sim {
 
             auto cal_hit =
                 dynamic_cast<dd4hep::sim::Geant4Calorimeter::Hit*>(h);
-
             //Geant4HitData::Contributions& c = cal_hit->truth;
-            //for (Geant4HitData::Contributions::iterator j = c.begin();
-            //     j != c.end(); ++j) {
+            //for (Geant4HitData::Contributions::iterator j = c.begin(); j != c.end(); ++j) {
             //  Geant4HitData::Contribution& t       = *j;
             //  int                          trackID = t.trackID;
             //  t.trackID = m_truth->particleID(trackID);
@@ -215,6 +213,16 @@ namespace dd4hep::sim {
               phit.g4ID(cal_hit->g4ID);
               phit.position({cal_hit->position.x(), cal_hit->position.y(),
                              cal_hit->position.z(), 0.0});
+              const auto& first_truth = cal_hit->truth[0];
+              phit.truth(dd4pod::MonteCarloContrib({
+                (int)first_truth.trackID, 
+                (int)first_truth.pdgID,
+                (double)first_truth.deposit,
+                (double)first_truth.time, 
+                (double)first_truth.length,
+                (double)first_truth.x, 
+                (double)first_truth.y,
+                (double)first_truth.z}));
               //phit.truth({cal_hit->truth.trackID, cal_hit->truth.pdgID, cal_hit->truth.deposit, cal_hit->truth.time,
               //            cal_hit->truth.length, cal_hit->truth.x, cal_hit->truth.y, cal_hit->truth.z});
               phit.energyDeposit(cal_hit->energyDeposit);