include/Geant4/G4TessellatedGeometryAlgorithms.hh

0001 //
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0026 //
0027 // G4TessellatedGeometryAlgorithms
0028 //
0029 // Class description:
0030 //
0031 // The G4TessellatedGeometryAlgorithms class is used to contain standard
0032 // routines to determine whether (and if so where) simple geometric shapes
0033 // intersect.
0034 //
0035 // The constructor doesn't need to do anything, and neither does the
0036 // destructor.
0037 //
0038 // IntersectLineAndTriangle2D
0039 //   Determines whether there is an intersection between a line defined
0040 //   by r = p + s.v and a triangle defined by verticies P0, P0+E0 and P0+E1.
0041 //   Here:
0042 //        p = 2D vector
0043 //        s = scaler on [0,infinity)
0044 //        v = 2D vector
0045 //        P0, E0 and E1 are 2D vectors
0046 //   Information about where the intersection occurs is returned in the
0047 //   variable location.
0048 //
0049 // IntersectLineAndLineSegment2D
0050 //   Determines whether there is an intersection between a line defined
0051 //   by r = P0 + s.D0 and a line-segment with endpoints P1 and P1+D1.
0052 //   Here:
0053 //        P0 = 2D vector
0054 //        s  = scaler on [0,infinity)
0055 //        D0 = 2D vector
0056 //        P1 and D1 are 2D vectors
0057 //   Information about where the intersection occurs is returned in the
0058 //   variable location.
0059
0060 // Author: P.R.Truscott (QinetiQ Ltd, UK), 07.08.2007 - Created, with member
0061 //                            functions based on the work of Rickard Holmberg.
0062 //         M.Gayer (CERN), 12.10.2012 - Reviewed and optimized implementation.
0063 // --------------------------------------------------------------------
0064 #ifndef G4TESSELLATEDGEOMETRYALGORITHMS_HH
0065 #define G4TESSELLATEDGEOMETRYALGORITHMS_HH
0066
0067 #include "G4TwoVector.hh"
0068
0069 /**
0070  * @brief G4TessellatedGeometryAlgorithms contains standard methods to
0071  * determine whether (and if so where) simple geometric shapes intersect.
0072  */
0073
0074 class G4TessellatedGeometryAlgorithms
0075 {
0076   public:
0077
0078     /**
0079      * Determines whether there is an intersection between a line defined
0080      * by r = p + s.v and a triangle defined by vertices p0, p0+e0 and p0+e1.
0081      *  @param[in] p Coefficient of line equation.
0082      *  @param[in] v Coefficient of line equation.
0083      *  @param[in] p0 First vertex of triangle.
0084      *  @param[in] e0 Second vertex of triangle.
0085      *  @param[in] e1 Third vertex of triangle.
0086      *  @param[out] location The returned location of the intersection.
0087      *  @returns false if no intersection occours.
0088      */
0089     static G4bool IntersectLineAndTriangle2D (const G4TwoVector& p,
0090                                               const G4TwoVector& v,
0091                                               const G4TwoVector& p0,
0092                                               const G4TwoVector& e0,
0093                                               const G4TwoVector& e1,
0094                                                     G4TwoVector location[2]);
0095
0096     /**
0097      * Determines whether there is an intersection between a line defined
0098      * by r = p0 + s.d0 and a line-segment with endpoints p1 and p1+d1.
0099      *  @param[in] p0 Coefficient of line equation.
0100      *  @param[in] d0 Coefficient of line equation.
0101      *  @param[in] p1 First line-segment end-point..
0102      *  @param[in] d1 Delta line-segment end-point.
0103      *  @param[out] location The returned location of the intersection.
0104      *  @returns false if no intersection occours.
0105      */
0106     static G4int IntersectLineAndLineSegment2D (const G4TwoVector& p0,
0107                                                 const G4TwoVector& d0,
0108                                                 const G4TwoVector& p1,
0109                                                 const G4TwoVector& d1,
0110                                                       G4TwoVector location[2]);
0111
0112     /**
0113      * Ficticious "cross-product" function for two 2D vectors.
0114      *  @param[in] v1 First 2D vector.
0115      *  @param[in] v2 Second 2D vector.
0116      *  @returns The cross-product of v1 and v2.
0117      */
0118     static G4double cross(const G4TwoVector& v1, const G4TwoVector& v2);
0119 };
0120
0121 #endif