include/DDCAD/Utilities.h

0001 //==========================================================================
0002 //  AIDA Detector description implementation
0003 //--------------------------------------------------------------------------
0004 // Copyright (C) Organisation europeenne pour la Recherche nucleaire (CERN)
0005 // All rights reserved.
0006 //
0007 // For the licensing terms see $DD4hepINSTALL/LICENSE.
0008 // For the list of contributors see $DD4hepINSTALL/doc/CREDITS.
0009 //
0010 // Author     : A. Sailer
0011 //
0012 //==========================================================================
0013 #ifndef DDCAD_UTILITIES_H
0014 #define DDCAD_UTILITIES_H
0015
0016 #include <vector>
0017 #include <cmath>
0018 #include <limits>
0019
0020 #include <TGeoTessellated.h>
0021 #include <TGeoVector3.h>
0022
0023 /// Namespace for the AIDA detector description toolkit
0024 namespace dd4hep {
0025
0026   /// Namespace for implementation details of the AIDA detector description toolkit
0027   namespace cad  {
0028
0029 #if ROOT_VERSION_CODE >= ROOT_VERSION(6,31,1)
0030     inline std::string streamFacet(TGeoFacet const& facet,
0031                                    TGeoTessellated const& shape) {
0032       using ::operator<<;
0033       std::stringstream str;
0034       str << "{";
0035       for (int i = 0; i < facet.GetNvert(); ++i) {
0036         str << shape.GetVertex(facet[i]);
0037         if (i != facet.GetNvert() - 1)
0038           str << ", ";
0039       }
0040       str << "}";
0041       return str.str();
0042     }
0043 #else
0044     inline std::string streamFacet(TGeoFacet const& facet,
0045                                    TGeoTessellated const& /* shape */) {
0046       using ::operator<<;
0047       std::stringstream str;
0048       str << facet;
0049       return str.str();
0050     }
0051 #endif
0052
0053     inline std::string streamVertices(ROOT::Geom::Vertex_t const& v1,
0054                         ROOT::Geom::Vertex_t const& v2,
0055                         ROOT::Geom::Vertex_t const& v3) {
0056       using ::operator<<;
0057       std::stringstream str;
0058       str << "{" << v1 << ", " << v2 <<  ", " << v3 << "}";
0059       return str.str();
0060     }
0061     // Determine if the facet is degenerated by calculating its determinant
0062     inline bool facetIsDegenerated(std::vector<ROOT::Geom::Vertex_t> const& vertices){
0063       using ROOT::Geom::Vertex_t;
0064       // Compute normal using non-zero segments
0065       constexpr double kTolerance = 1.e-20;
0066       bool degenerated = true;
0067       Vertex_t normal;
0068       int fNvert = int(vertices.size());
0069       for (int i = 0; i < fNvert - 1; ++i) {
0070         Vertex_t e1 = vertices[i + 1] - vertices[i];
0071         if (e1.Mag2() < kTolerance)
0072           continue;
0073         for (int j = i + 1; j < fNvert; ++j) {
0074           Vertex_t e2 = vertices[(j + 1) % fNvert] - vertices[j];
0075           if (e2.Mag2() < kTolerance)
0076             continue;
0077           normal = Vertex_t::Cross(e1, e2);
0078           // e1 and e2 may be colinear
0079           if (normal.Mag2() < kTolerance)
0080             continue;
0081           normal.Normalize();
0082           degenerated = false;
0083           break;
0084         }
0085         if (!degenerated)
0086           break;
0087       }
0088       return degenerated;
0089     }
0090   }
0091 }
0092 #endif