Convert Geant4 geometry to VecGeom in memory

CMakeLists.txt

@@ -180,12 +180,7 @@ elseif(CELERITAS_USE_HIP)
 endif()
 
 if(CELERITAS_USE_Geant4 AND NOT Geant4_FOUND)
-  # Geant4 calls `include_directories` for CLHEP :( which is not what we want!
-  # Save and restore include directories around the call -- even though as a
-  # standalone project Celeritas will never have directory-level includes
-  get_directory_property(_include_dirs INCLUDE_DIRECTORIES)
   find_package(Geant4 REQUIRED)
-  set_directory_properties(PROPERTIES INCLUDE_DIRECTORIES "${_include_dirs}")
 endif()
 
 if(CELERITAS_USE_HepMC3 AND NOT HepMC3_FOUND)
@@ -227,8 +222,7 @@ endif()
 if(CELERITAS_USE_VecGeom)
   find_package(VecGeom 1.1.17 REQUIRED)
 
-  if((CELERITAS_USE_CUDA AND NOT VecGeom_CUDA_FOUND)
-      OR (NOT CELERITAS_USE_CUDA AND VecGeom_CUDA_FOUND))
+  if((CELERITAS_USE_CUDA AND NOT VecGeom_CUDA_FOUND))
     message(SEND_ERROR "CUDA mismatch between the VecGeom installation "
       "at ${VECGEOM_INSTALL_DIR} (VecGeom_CUDA_FOUND=${VecGeom_CUDA_FOUND}) "
       "and Celeritas (CELERITAS_USE_CUDA=${CELERITAS_USE_CUDA})"

app/geo-check/geo-check.cc

@@ -22,6 +22,7 @@
 #include "corecel/cont/Label.hh"
 #include "corecel/cont/Range.hh"
 #include "corecel/io/Logger.hh"
+#include "corecel/math/ArrayUtils.hh"
 #include "corecel/sys/Device.hh"
 #include "orange/Types.hh"
 #include "celeritas/geo/GeoParamsFwd.hh"
@@ -57,6 +58,7 @@ void run(std::istream& is, bool use_cuda)
         pos[i] = inp.at("track_origin")[i].get<real_type>();
         dir[i] = inp.at("track_direction")[i].get<real_type>();
     }
+    normalize_direction(&dir);
     GeoTrackInitializer trkinit{pos, dir};
 
     CELER_ASSERT(geo_params);

cmake/FindGeant4.cmake

@@ -11,10 +11,21 @@ Find the Geant4 HEP library.
 
 #]=======================================================================]
 
+# Save and restore global settings changed by Geant's find script
+get_directory_property(_include_dirs INCLUDE_DIRECTORIES)
+
 find_package(Geant4 QUIET CONFIG)
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(Geant4 CONFIG_MODE)
 
+if(Geant4_FOUND)
+  # Geant4 calls `include_directories` for CLHEP :( which is not what we want!
+  # Save and restore include directories around the call -- even though as a
+  # standalone project Celeritas will never have directory-level includes
+  set_directory_properties(PROPERTIES INCLUDE_DIRECTORIES "${_include_dirs}")
+endif()
+unset(_include_dirs)
+
 if(Geant4_FOUND AND Geant4_VERSION VERSION_GREATER_EQUAL 11 AND CELERITAS_USE_CUDA)
   foreach(_tgt Geant4::G4global Geant4::G4global-static)
     if(TARGET ${_tgt})

doc/appendices/license.rst

@@ -32,10 +32,15 @@ Additional licenses
 
 Small portions of Celeritas are derived from other open source projects.
 
-BVHNavigator
-------------
+CERN Apache 2.0
+---------------
 
-Derived from AdePT_ under the following license::
+The following VecGeom-related components are derivative works:
+
+- BVHNavigator: from AdePT_
+- GenericSolid, GenericPlacedVolume, GeantGeometryImporter: from VecGeomG4Solid_
+
+with portions distributed under the following license::
 
    Copyright 2020 CERN
 
@@ -52,3 +57,4 @@ Derived from AdePT_ under the following license::
    limitations under the License.
 
 .. _AdePT: https://github.com/apt-sim/AdePT
+.. _VecGeomG4Solid: https://gitlab.cern.ch/VecGeom/g4vecgeomnav/-/raw/ce4a0bb2f777a6728e59dee96c764fd61fa8b785/include/VecGeomG4Solid.h

src/celeritas/CMakeLists.txt

@@ -97,7 +97,8 @@ if(CELERITAS_RNG STREQUAL "CURAND")
 endif()
 
 if(CELERITAS_USE_Geant4)
-  celeritas_add_object_library(celeritas_geant4
+  set(_cg4_libs Celeritas::corecel XercesC::XercesC ${Geant4_LIBRARIES})
+  set(_cg4_sources
     ext/LoadGdml.cc
     ext/GeantImporter.cc
     ext/GeantSetup.cc
@@ -111,9 +112,15 @@ if(CELERITAS_USE_Geant4)
     ext/detail/GeantProcessImporter.cc
     ext/detail/GeantVolumeVisitor.cc
   )
-  target_link_libraries(celeritas_geant4
-    PRIVATE Celeritas::corecel XercesC::XercesC ${Geant4_LIBRARIES}
-  )
+  if(CELERITAS_USE_VecGeom)
+    list(APPEND _cg4_sources
+      ext/detail/GeantGeometryImporter.cc
+    )
+    list(APPEND _cg4_libs VecGeom::vecgeom)
+  endif()
+  celeritas_add_object_library(celeritas_geant4 ${_cg4_sources})
+
+  target_link_libraries(celeritas_geant4 PRIVATE ${_cg4_libs})
   list(APPEND SOURCES $<TARGET_OBJECTS:celeritas_geant4>)
   list(APPEND PRIVATE_DEPS celeritas_geant4)
 endif()

src/celeritas/ext/VecgeomParams.cc

@@ -31,6 +31,7 @@
 
 #include "VecgeomData.hh"  // IWYU pragma: associated
 #include "detail/GeantGeoExporter.hh"
+#include "detail/GeantGeometryImporter.hh"
 
 namespace celeritas
 {
@@ -40,7 +41,7 @@ namespace celeritas
  */
 VecgeomParams::VecgeomParams(std::string const& filename)
 {
-    CELER_LOG(info) << "Loading VecGeom geometry from GDML at " << filename;
+    CELER_LOG(status) << "Loading VecGeom geometry from GDML at " << filename;
     if (!ends_with(filename, ".gdml"))
     {
         CELER_LOG(warning) << "Expected '.gdml' extension for GDML input";
@@ -62,25 +63,17 @@ VecgeomParams::VecgeomParams(std::string const& filename)
 //---------------------------------------------------------------------------//
 /*!
  * Translate a geometry from Geant4.
- *
- * At present this just exports the geometry to GDML, then loads it through the
- * VGDML reader.
  */
 VecgeomParams::VecgeomParams(G4VPhysicalVolume const* world)
 {
     CELER_EXPECT(world);
+
+    // Convert the geometry to VecGeom
 #if CELERITAS_USE_GEANT4
-    auto filename = detail::GeantGeoExporter::make_tmpfile_name();
-    CELER_LOG(debug) << "Temporary file for Geant4 export: " << filename;
-    {
-        // Export file from Geant4
-        detail::GeantGeoExporter export_to(world);
-        export_to(filename);
-    }
     {
-        // Import file into VecGeom
-        ScopedTimeAndRedirect time_and_output_("vgdml::Frontend");
-        vgdml::Frontend::Load(filename, /* validate_xml_schema = */ false);
+        detail::GeantGeometryImporter convert;
+        convert(world);
+        CELER_ASSERT(vecgeom::GeoManager::Instance().GetWorld());
     }
 #else
     CELER_NOT_CONFIGURED("Geant4");

src/celeritas/ext/VecgeomParams.hh

@@ -88,7 +88,7 @@ class VecgeomParams
     //! Access geometry data on host
     inline HostRef const& host_ref() const;
 
-    //! Access geometry data on host
+    //! Access geometry data on device
     inline DeviceRef const& device_ref() const;
 
   private: