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geant4/source/geometry/management/include/G4BoundingEnvelope.hh
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2018-12-07 15:15:39 +01:00

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//
// ********************************************************************
// * License and Disclaimer *
// * *
// * The Geant4 software is copyright of the Copyright Holders of *
// * the Geant4 Collaboration. It is provided under the terms and *
// * conditions of the Geant4 Software License, included in the file *
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// * This code implementation is the result of the scientific and *
// * technical work of the GEANT4 collaboration. *
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//
//
//
//
// class G4BoundingEnvelope
//
// Class description:
//
// Helper class to facilitate calculation of the extent of a solid
// within the limits defined by a G4VoxelLimits object.
//
// The function CalculateExtent() of a particular solid can create
// a G4BoundingEnvelope object that bounds the solid and then call
// CalculateExtent() of the G4BoundingEnvelope object.
//
// Calculation of extent uses G4Transform3D, thus takes into account
// scaling and reflection, if any.
// History:
//
// 2016.05.25 E.Tcherniaev - initial version
//
// --------------------------------------------------------------------
#ifndef G4BOUNDINGENVELOPE_HH
#define G4BOUNDINGENVELOPE_HH
#include <vector>
#include "geomdefs.hh"
#include "G4ThreeVector.hh"
#include "G4VoxelLimits.hh"
#include "G4Transform3D.hh"
#include "G4Point3D.hh"
#include "G4Plane3D.hh"
typedef std::vector<G4ThreeVector> G4ThreeVectorList;
typedef std::vector<G4Point3D> G4Polygon3D;
typedef std::pair<G4Point3D,G4Point3D> G4Segment3D;
class G4BoundingEnvelope
{
public:
G4BoundingEnvelope(const G4ThreeVector& pMin,
const G4ThreeVector& pMax);
// Constructor from an axis aligned bounding box (AABB)
G4BoundingEnvelope(const std::vector<const G4ThreeVectorList*>& polygons);
// Constructor from a sequence of convex polygons, the polygons
// should have equal numbers of vertices except first and last
// polygons which may consist of a single vertex
G4BoundingEnvelope(const G4ThreeVector& pMin,
const G4ThreeVector& pMax,
const std::vector<const G4ThreeVectorList*>& polygons);
// Constructor from AABB and a sequence of polygons
~G4BoundingEnvelope();
// Destructor
G4bool BoundingBoxVsVoxelLimits(const EAxis pAxis,
const G4VoxelLimits& pVoxelLimits,
const G4Transform3D& pTransform3D,
G4double& pMin, G4double& pMax) const;
// Analyse the position of the bounding box relative to the voxel.
// It returns "true" in the case where the value of the extent can be
// figured out directly from the dimensions of the bounding box, or
// it is clear that the bounding box and the voxel do not intersect.
// The reply "false" means that further calculations are needed.
G4bool CalculateExtent(const EAxis pAxis,
const G4VoxelLimits& pVoxelLimits,
const G4Transform3D& pTransform3D,
G4double& pMin, G4double& pMax) const;
// Calculate extent of the bounding envelope
private:
void CheckBoundingBox();
// Check correctness of the AABB (axis aligned bounding box)
void CheckBoundingPolygons();
// Check correctness of the sequence of convex polygonal bases
G4double FindScaleFactor(const G4Transform3D& pTransform3D) const;
// Find max scale factor of the transformation
void TransformVertices(const G4Transform3D& pTransform3D,
std::vector<G4Polygon3D*>& pBases) const;
// Create list of transformed polygons
void GetPrismAABB(const G4Polygon3D& pBaseA,
const G4Polygon3D& pBaseB,
G4Segment3D& pAABB) const;
// Find bounding box of a prism
void CreateListOfEdges(const G4Polygon3D& baseA,
const G4Polygon3D& baseB,
std::vector<G4Segment3D>& pEdges) const;
// Create list of edges of a prism
void CreateListOfPlanes(const G4Polygon3D& baseA,
const G4Polygon3D& baseB,
std::vector<G4Plane3D>& pPlanes) const;
// Create list of planes bounding a prism
G4bool ClipEdgesByVoxel(const std::vector<G4Segment3D>& pEdges,
const G4VoxelLimits& pLimits,
G4Segment3D& pExtent) const;
// Clip set of edges by G4VoxelLimits
void ClipVoxelByPlanes(G4int pBits,
const G4VoxelLimits& pLimits,
const std::vector<G4Plane3D>& pPlanes,
const G4Segment3D& pAABB,
G4Segment3D& pExtent) const;
// Clip G4VoxelLimits by set of planes bounding a prism
private:
G4ThreeVector fMin, fMax;
// original bounding box
const std::vector<const G4ThreeVectorList*>* fPolygons;
// ref to original sequence of polygonal bases
};
#endif // G4BOUNDINGENVELOPE_HH