VolumeIntersection.h

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/

// VolumeIntersection.h, (c) ATLAS Detector software
 
#ifndef TRKDETDESCRGEOMODELCNV_VOLUMEINTERSECTION_H
#define TRKDETDESCRGEOMODELCNV_VOLUMEINTERSECTION_H
 
#include <memory>
#include <utility>  //for std::pair
#include <vector>
 
#include "TrkDetDescrGeoModelCnv/GeoShapeConverter.h"
 
namespace Trk {
class Volume;
}
 
namespace Trk {
 
struct PolygonCache {
    double hZ{0.};
    double minZ{0.};
    double maxZ{0.};
    Amg::Vector3D center{Amg::Vector3D::Zero()};
    int nVtx{0};
    std::vector<Amg::Vector3D> vertices{};
    std::vector<std::pair<double, double>> xyVertices{};  // size+1
    std::vector<bool> commonVertices{};
    std::vector<std::pair<double, double>> edges{};
    PolygonCache() = default;
};
 
struct EdgeCross {
 
    std::pair<int, int> edge_id{};
    std::pair<double, double> edge_pos{};
    bool used{false};
    EdgeCross(std::pair<int, int> ei, std::pair<double, double> ep)
        : edge_id(std::move(ei)), edge_pos(std::move(ep)){};
};

 
class VolumeIntersection {
 
   public:
    static std::pair<bool, std::unique_ptr<Trk::Volume>> intersect(
        const Volume& volA, const Volume& volB) ;
 
    static std::pair<bool, std::unique_ptr<Trk::Volume>> intersectApproximative(
        const Volume& volA, const Volume& volB) ;
 
   private:
    static PolygonCache polygonXY(const Volume& inVol, int swap = 0) ;
    static Trk::PolygonCache intersectPgon(Trk::PolygonCache&,
                                    Trk::PolygonCache&) ;
 
    static bool inside(const std::pair<double, double>& vtx,
                const std::vector<std::pair<double, double>>& pgon) ;
 
    static double det(const std::pair<double, double>& a,
               const std::pair<double, double>& b, bool) ;
};
 
}  // end of namespace Trk
 
#endif