ActsExamples/DetectorCommons/AlignmentContext.hpp

0001 // This file is part of the ACTS project.
0002 //
0003 // Copyright (C) 2016 CERN for the benefit of the ACTS project
0004 //
0005 // This Source Code Form is subject to the terms of the Mozilla Public
0006 // License, v. 2.0. If a copy of the MPL was not distributed with this
0007 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
0008
0009 #pragma once
0010
0011 #include "Acts/Definitions/Algebra.hpp"
0012 #include "Acts/Geometry/GeometryIdentifier.hpp"
0013 #include "Acts/Surfaces/Surface.hpp"
0014
0015 #include <unordered_map>
0016
0017 namespace ActsExamples {
0018
0019 /// @brief Base class for alignment stores which can retrieve contextual
0020 /// transforms from specific surfaces.
0021 ///
0022 /// Possible implementations may take the geometry identifier, access the
0023 /// detector element or use other means to identify which transform is being
0024 /// queried.
0025 class IAlignmentStore {
0026  public:
0027   /// @brief  Virtual destructor
0028   virtual ~IAlignmentStore() = default;
0029
0030   /// Clone the alignment store
0031   ///
0032   /// @return a unique pointer to the cloned store
0033   virtual std::shared_ptr<IAlignmentStore> clone() const = 0;
0034
0035   /// Retrieve the contextual transform for a given surface
0036   ///
0037   /// @param surface the  surface for which the contextual transform is requested
0038   /// @return a pointer to the transform if found, otherwise nullptr
0039   virtual const Acts::Transform3* contextualTransform(
0040       const Acts::Surface& surface) const = 0;
0041
0042   /// Visitor pattern to eventually generate an misalignment for demonstration
0043   /// purposes.
0044   /// @param visitor the visitor to be called with the store
0045   virtual void visitStore(
0046       const std::function<void(Acts::Transform3*)>& visitor) = 0;
0047 };
0048
0049 /// A simple struct holding a store raw pointer, ownership should not be in the
0050 /// Context as the store may expand lifetime beyond a context scope
0051 struct AlignmentContext {
0052   /// The store pointer
0053   const IAlignmentStore* store{nullptr};
0054 };
0055
0056 /// One possible implementation with a simple unordered map that relates a
0057 /// surface via its geometry identifier to a transform within the store
0058 ///
0059 /// To use this store, the GeometryContext of the corresponding geometry must
0060 /// be decorated with such a store and equipped to use it.
0061 class GeoIdAlignmentStore : public IAlignmentStore {
0062  public:
0063   /// Constructor from an unordered map of geometry ids and transforms
0064   /// @param transformMap the map of geometry ids and transforms
0065   explicit GeoIdAlignmentStore(
0066       std::unordered_map<Acts::GeometryIdentifier, Acts::Transform3>
0067           transformMap)
0068       : m_transformMap(std::move(transformMap)) {}
0069
0070   /// @copydoc IAlignmentStore::clone
0071   std::shared_ptr<IAlignmentStore> clone() const override {
0072     return std::make_shared<GeoIdAlignmentStore>(m_transformMap);
0073   }
0074
0075   /// @copydoc ITransformStore::contextualTransform
0076   const Acts::Transform3* contextualTransform(
0077       const Acts::Surface& surface) const override {
0078     auto it = m_transformMap.find(surface.geometryId());
0079     if (it != m_transformMap.end()) {
0080       return &(it->second);
0081     }
0082     return nullptr;
0083   }
0084
0085   /// @copydoc ITransformStore::visitStore
0086   void visitStore(
0087       const std::function<void(Acts::Transform3*)>& visitor) override {
0088     for (auto& [id, trf] : m_transformMap) {
0089       visitor(&trf);
0090     }
0091   }
0092
0093  private:
0094   /// The geometry id map
0095   std::unordered_map<Acts::GeometryIdentifier, Acts::Transform3> m_transformMap;
0096 };
0097
0098 }  // namespace ActsExamples