| Geant4 Cross Reference |
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25 //
26 // class G4BoundingEnvelope
27 //
28 // Class description:
29 //
30 // Helper class to facilitate calculation of the extent of a solid
31 // within the limits defined by a G4VoxelLimits object.
32 //
33 // The function CalculateExtent() of a particular solid can create
34 // a G4BoundingEnvelope object that bounds the solid and then call
35 // CalculateExtent() of the G4BoundingEnvelope object.
36 //
37 // Calculation of extent uses G4Transform3D, thus takes into account
38 // scaling and reflection, if any.
39
40 // 2016.05.25, E.Tcherniaev - initial version
41 // --------------------------------------------------------------------
42 #ifndef G4BOUNDINGENVELOPE_HH
43 #define G4BOUNDINGENVELOPE_HH
44
45 #include <vector>
46 #include "geomdefs.hh"
47
48 #include "G4ThreeVector.hh"
49 #include "G4VoxelLimits.hh"
50 #include "G4Transform3D.hh"
51 #include "G4Point3D.hh"
52 #include "G4Plane3D.hh"
53
54 using G4ThreeVectorList = std::vector<G4ThreeVector>;
55 using G4Polygon3D = std::vector<G4Point3D>;
56 using G4Segment3D = std::pair<G4Point3D,G4Point3D>;
57
58 class G4BoundingEnvelope
59 {
60 public:
61
62 G4BoundingEnvelope(const G4ThreeVector& pMin,
63 const G4ThreeVector& pMax);
64 // Constructor from an axis aligned bounding box (AABB)
65
66 G4BoundingEnvelope(const std::vector<const G4ThreeVectorList*>& polygons);
67 // Constructor from a sequence of convex polygons, the polygons
68 // should have equal numbers of vertices except first and last
69 // polygons which may consist of a single vertex
70
71 G4BoundingEnvelope(const G4ThreeVector& pMin,
72 const G4ThreeVector& pMax,
73 const std::vector<const G4ThreeVectorList*>& polygons);
74 // Constructor from AABB and a sequence of polygons
75
76 ~G4BoundingEnvelope() = default;
77 // Destructor
78
79 G4bool BoundingBoxVsVoxelLimits(const EAxis pAxis,
80 const G4VoxelLimits& pVoxelLimits,
81 const G4Transform3D& pTransform3D,
82 G4double& pMin, G4double& pMax) const;
83 // Analyse the position of the bounding box relative to the voxel.
84 // It returns "true" in the case where the value of the extent can be
85 // figured out directly from the dimensions of the bounding box, or
86 // it is clear that the bounding box and the voxel do not intersect.
87 // The reply "false" means that further calculations are needed.
88
89 G4bool CalculateExtent(const EAxis pAxis,
90 const G4VoxelLimits& pVoxelLimits,
91 const G4Transform3D& pTransform3D,
92 G4double& pMin, G4double& pMax) const;
93 // Calculate extent of the bounding envelope
94
95 private:
96
97 void CheckBoundingBox();
98 // Check correctness of the AABB (axis aligned bounding box)
99
100 void CheckBoundingPolygons();
101 // Check correctness of the sequence of convex polygonal bases
102
103 G4double FindScaleFactor(const G4Transform3D& pTransform3D) const;
104 // Find max scale factor of the transformation
105
106 void TransformVertices(const G4Transform3D& pTransform3D,
107 std::vector<G4Point3D>& pVertices,
108 std::vector<std::pair<G4int,G4int>>& pBases) const;
109 // Create list of transformed polygons
110
111 void GetPrismAABB(const G4Polygon3D& pBaseA,
112 const G4Polygon3D& pBaseB,
113 G4Segment3D& pAABB) const;
114 // Find bounding box of a prism
115
116 void CreateListOfEdges(const G4Polygon3D& baseA,
117 const G4Polygon3D& baseB,
118 std::vector<G4Segment3D>& pEdges) const;
119 // Create list of edges of a prism
120
121 void CreateListOfPlanes(const G4Polygon3D& baseA,
122 const G4Polygon3D& baseB,
123 std::vector<G4Plane3D>& pPlanes) const;
124 // Create list of planes bounding a prism
125
126 G4bool ClipEdgesByVoxel(const std::vector<G4Segment3D>& pEdges,
127 const G4VoxelLimits& pLimits,
128 G4Segment3D& pExtent) const;
129 // Clip set of edges by G4VoxelLimits
130
131 void ClipVoxelByPlanes(G4int pBits,
132 const G4VoxelLimits& pLimits,
133 const std::vector<G4Plane3D>& pPlanes,
134 const G4Segment3D& pAABB,
135 G4Segment3D& pExtent) const;
136 // Clip G4VoxelLimits by set of planes bounding a prism
137
138 private:
139
140 G4ThreeVector fMin, fMax;
141 // original bounding box
142
143 const std::vector<const G4ThreeVectorList*>* fPolygons = nullptr;
144 // ref to original sequence of polygonal bases
145 };
146
147 #endif // G4BOUNDINGENVELOPE_HH
148