feat: Mockup builder class with a cpp script for test (#2008)

This PR creates the mockup  geometry with the chambers from a gdml file and extends the sector with the three chambers at phi.  The picture `barrel_chambers000.png` shows the geometry in an obj file obtained by running the `TestMockupBuilder.cpp` script, which is also in the PR in order to reproduce the geometry.

There is also some work in progress (e.g. python bindings)

@noemina  @asalzburger 

Co-authored-by: Andreas Stefl <487211+andiwand@users.noreply.github.com>

Examples/Detectors/Geant4Detector/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_library(
   ActsExamplesDetectorGeant4 SHARED
-  src/Geant4Detector.cpp)
+  src/Geant4Detector.cpp
+  src/MockupSectorBuilder.cpp)
 target_include_directories(
     ActsExamplesDetectorGeant4
   PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>)
@@ -11,4 +12,4 @@ target_link_libraries(
 install(
   TARGETS ActsExamplesDetectorGeant4
   LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})
-
+

Examples/Detectors/Geant4Detector/include/ActsExamples/Geant4Detector/MockupSectorBuilder.hpp

@@ -0,0 +1,85 @@
+// This file is part of the Acts project.
+//
+// Copyright (C) 2022-2023 CERN for the benefit of the Acts project
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#pragma once
+
+#include "Acts/Detector/DetectorVolume.hpp"
+#include "Acts/Geometry/GeometryContext.hpp"
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "G4VPhysicalVolume.hh"
+
+namespace ActsExamples {
+
+///@class MockupsectorBuilder
+///
+/// This is a class that builds a chamber by reading a gdml file
+
+class MockupSectorBuilder {
+ public:
+  /// Nested configuration struct
+  struct Config {
+    // The path of the gdml file that holds the mockup geometry
+    std::string gdmlPath = "";
+
+    // The number of sectors we want to create
+    int NumberOfSectors = 1;
+
+    float toleranceOverlap = 10.;
+  };
+
+  /// Nested configuration struct for chamber
+  struct ChamberConfig {
+    // The name of the chamber
+    std::string name;
+
+    // The names of the sensitive surfaces
+    std::vector<std::string> SensitiveNames;
+
+    // The names of the passive surfaces
+    std::vector<std::string> PassiveNames;
+  };
+
+  /// Constructor
+  ///@param config The configuration struct
+  MockupSectorBuilder(const Config& config);
+
+  /// Destructor
+  ~MockupSectorBuilder() = default;
+
+  /// Build chamber
+  /// @param gctx The current geometry context object
+  /// @param chamber_config The configuration chamber struct
+  std::shared_ptr<Acts::Experimental::DetectorVolume> buildChamber(
+      const ChamberConfig& chamberConfig);
+
+  /// Build Sector
+  /// @param det_volumes The vector that contains the detector volumes of the Sector
+  /// @param gctx The current geometry context object
+  std::shared_ptr<Acts::Experimental::DetectorVolume> buildSector(
+      std::vector<std::shared_ptr<Acts::Experimental::DetectorVolume>>
+          detVolumes);
+
+  /// Draw the sector in an obj file
+  /// @param nameObjFile The name of the obj file where the sector will be saved
+  void drawSector(const std::shared_ptr<Acts::Experimental::DetectorVolume>&
+                      detectorVolumeSector,
+                  const std::string& nameObjFile);
+
+ private:
+  Config mCfg;
+
+  G4VPhysicalVolume* g4World = nullptr;
+
+  int maxNumberOfSectors = 8;
+};
+
+}  // namespace ActsExamples