VecGeom/management/BooleanFactory.h

0001 // This file is part of VecGeom and is distributed under the
0002 // conditions in the file LICENSE.txt in the top directory.
0003
0004 /// @file BooleanFactory.h
0005 /// @brief Build equivalent Boolean solids with accelerated MultiUnion components.
0006
0007 #ifndef VECGEOM_MANAGEMENT_BOOLEANFACTORY_H_
0008 #define VECGEOM_MANAGEMENT_BOOLEANFACTORY_H_
0009
0010 #include "VecGeom/base/Global.h"
0011 #include <unordered_map>
0012
0013 namespace vecgeom {
0014 inline namespace VECGEOM_IMPL_NAMESPACE {
0015
0016 class LogicalVolume;
0017 class Transformation3D;
0018 class VPlacedVolume;
0019 class VUnplacedVolume;
0020
0021 /**
0022  * @brief Convert sufficiently large union groups and subtraction cutters to MultiUnions.
0023  * @details Input solids are unchanged. Repeated inputs share their replacement within
0024  * this factory. Created shapes, logical volumes, placements and transforms follow the
0025  * usual geometry lifetime; destroying the factory only releases its lookup tables.
0026  * Results can reuse input geometry; keep that geometry alive and unchanged
0027  * while using the factory or its results.
0028  * External adapters should call Create on the complete solid before publishing
0029  * their final logical volume or placement. This factory does not update existing
0030  * wrappers or make geometry compaction safe for externally retained placements.
0031  */
0032 class BooleanFactory {
0033   size_t fMinComponents;
0034   std::unordered_map<VUnplacedVolume const *, VUnplacedVolume const *> fResults;
0035   std::unordered_map<VUnplacedVolume const *, LogicalVolume *> fLogicalVolumes;
0036
0037   VPlacedVolume const *Place(VUnplacedVolume const *solid, Transformation3D const &transform);
0038   VPlacedVolume const *ConvertPlaced(VPlacedVolume const *placed);
0039
0040 public:
0041   /**
0042    * @brief Configure the minimum number of resulting MultiUnion components.
0043    * @param minComponents Minimum component count; zero disables conversion.
0044    * @details A MultiUnion always needs at least two components. This threshold
0045    * counts components, independently of the operand Inside-cost scores.
0046    */
0047   explicit BooleanFactory(size_t minComponents) : fMinComponents(minComponents) {}
0048
0049   /**
0050    * @brief Build an equivalent solid, reusing previous results for shared inputs.
0051    * @param solid Input solid, or null.
0052    * @return Replacement solid, the original pointer if unchanged, or null for null input.
0053    * @details Flatten union groups and left subtraction spines only when the
0054    * resulting union has enough finite components. Right subtraction and
0055    * intersection grouping are retained; their children can be converted.
0056    * Existing MultiUnions and scaled shapes retain their outer operation.
0057    */
0058   VUnplacedVolume const *Create(VUnplacedVolume const *solid);
0059 };
0060
0061 } // namespace VECGEOM_IMPL_NAMESPACE
0062 } // namespace vecgeom
0063
0064 #endif