include/Geant4/G4VFieldModel.hh

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0025 //
0026 // Michael Kelsey  31 January 2019
0027 //
0028 // Class Description:
0029 //
0030 // Abstract base class to implement drawing vector field geometries
0031 // (e.g., electric, magnetic or gravity).  Implementation extracted
0032 // from G4MagneticFieldModel, with field-value access left pure
0033 // virtual for implementation by base classes.
0034
0035 #ifndef G4VFIELDMODEL_HH
0036 #define G4VFIELDMODEL_HH
0037
0038 #include "G4VModel.hh"
0039 #include "G4Point3D.hh"
0040 #include "G4PhysicalVolumesSearchScene.hh"
0041
0042 #include <vector>
0043
0044 class G4Field;
0045
0046 class G4VFieldModel: public G4VModel {
0047
0048 public: // With description
0049
0050   enum Representation {fullArrow, lightArrow};
0051
0052   G4VFieldModel
0053   (const G4String& typeOfField, const G4String& symbol="",
0054    const G4VisExtent& extentForField = G4VisExtent(),
0055    const std::vector<G4PhysicalVolumesSearchScene::Findings>& pvFindings
0056    = std::vector<G4PhysicalVolumesSearchScene::Findings>(),
0057    G4int nDataPointsPerHalfScene = 10,
0058    Representation representation = Representation::fullArrow,
0059    G4int arrow3DLineSegmentsPerCircle = 6);
0060   // typeOfField is "Electric" or "Magnetic" etc.
0061   // symbol is "E" or "B" etc.
0062
0063   virtual ~G4VFieldModel();
0064
0065   virtual void DescribeYourselfTo(G4VGraphicsScene& sceneHandler);
0066   // The main task of a model is to describe itself to the graphics scene.
0067   // Note: It is in this function that the extent for drawing the filed must
0068   // be calcualted. If fExtentForField is null, pick up the extent from
0069   // the sceneHandler.
0070
0071 protected:
0072
0073   // Subclasses MUST implement this for their particular kind of field
0074   virtual void GetFieldAtLocation(const G4Field* field,
0075                   const G4Point3D& position, G4double time,
0076                   G4Point3D& result) const = 0;
0077   // The appropriate output from GetFieldValue should be filled into result.
0078   // If (field==0), the function should do nothing; returning without error.
0079
0080 private:
0081
0082   // Private copy contructor and assignment to forbid use...
0083   G4VFieldModel(const G4VFieldModel&);
0084   G4VFieldModel& operator=(const G4VFieldModel&);
0085
0086   G4VisExtent fExtentForField;
0087   // If null, get extent from scene handler in DescribeYourselfTo.
0088
0089   std::vector<G4PhysicalVolumesSearchScene::Findings> fPVFindings;
0090   // If empty, use fExtentForField alone for sampling and drawing.
0091   // If non-empty, use fExtentForField alone for sampling, but only
0092   // draw if sampling point is in the specified physical volume(s).
0093
0094   G4int fNDataPointsPerMaxHalfExtent;
0095   // No. of data points sampled per maximum half extent.
0096   // Note that total number of sampling points can be as high as
0097   // (2*n+1)^3, which can get very big. However, fields are usually
0098   // confined to only parts of the scene, so this may not be a problem.
0099   // Sampling can be further limited with fExtentForField and/or fPVFindings.
0100
0101   Representation fRepresentation;       // Big arrows or just lines
0102   G4int fArrow3DLineSegmentsPerCircle;
0103   G4String fTypeOfField;                // "Electric" or "Magnetic" etc.
0104   G4String fArrowPrefix;                // For attaching text label to arrows
0105 };
0106
0107 #endif