| 1 | //
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| 2 | // ********************************************************************
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| 3 | // * License and Disclaimer *
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| 4 | // * *
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of *
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and *
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| 7 | // * conditions of the Geant4 Software License, included in the file *
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These *
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| 9 | // * include a list of copyright holders. *
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| 10 | // * *
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| 11 | // * Neither the authors of this software system, nor their employing *
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| 12 | // * institutes,nor the agencies providing financial support for this *
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| 13 | // * work make any representation or warranty, express or implied, *
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| 14 | // * regarding this software system or assume any liability for its *
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| 15 | // * use. Please see the license in the file LICENSE and URL above *
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| 16 | // * for the full disclaimer and the limitation of liability. *
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| 17 | // * *
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| 18 | // * This code implementation is the result of the scientific and *
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| 19 | // * technical work of the GEANT4 collaboration. *
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| 20 | // * By using, copying, modifying or distributing the software (or *
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| 21 | // * any work based on the software) you agree to acknowledge its *
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| 22 | // * use in resulting scientific publications, and indicate your *
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| 23 | // * acceptance of all terms of the Geant4 Software license. *
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| 24 | // ********************************************************************
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| 25 | //
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| 26 | //
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| 27 | // $Id: G4LineSection.cc,v 1.10 2006/06/29 18:24:16 gunter Exp $
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| 28 | // GEANT4 tag $Name: HEAD $
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| 29 | //
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| 30 | // --------------------------------------------------------------------
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| 31 |
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| 32 | #include "G4LineSection.hh"
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| 33 |
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| 34 | G4LineSection::G4LineSection( const G4ThreeVector& PntA,
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| 35 | const G4ThreeVector& PntB )
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| 36 | : EndpointA(PntA),
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| 37 | VecAtoB(PntB-PntA)
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| 38 | {
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| 39 | fABdistanceSq = VecAtoB.mag2() ;
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| 40 | /*
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| 41 | G4double distABsquared = VecAtoB.mag2() ;
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| 42 | if ( distABsquared == 0.0)
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| 43 | {
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| 44 | G4Exception("G4LineSection::G4LineSection()", "WrongArgumentValue",
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| 45 | FatalException, "Equal points in input (line->point) ?") ;
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| 46 | }
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| 47 | else
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| 48 | {
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| 49 | inverse_square_distAB=1.0 / distABsquared ;
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| 50 | }
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| 51 | */
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| 52 | }
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| 53 |
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| 54 | G4double G4LineSection::Dist( G4ThreeVector OtherPnt ) const
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| 55 | {
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| 56 | G4double dist_sq;
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| 57 | G4ThreeVector VecAZ;
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| 58 | G4double sq_VecAZ, inner_prod, unit_projection ;
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| 59 |
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| 60 | VecAZ= OtherPnt - EndpointA;
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| 61 | sq_VecAZ = VecAZ.mag2();
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| 62 |
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| 63 | inner_prod= VecAtoB.dot( VecAZ );
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| 64 |
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| 65 | // Determine Projection(AZ on AB) / Length(AB)
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| 66 | //
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| 67 | if( fABdistanceSq != 0.0 )
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| 68 | {
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| 69 | // unit_projection= inner_prod * InvsqDistAB();
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| 70 | unit_projection = inner_prod/fABdistanceSq;
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| 71 |
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| 72 | if( (0. <= unit_projection ) && (unit_projection <= 1.0 ) )
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| 73 | {
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| 74 | dist_sq= sq_VecAZ - unit_projection * inner_prod ;
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| 75 | }
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| 76 | else
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| 77 | {
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| 78 | // The perpendicular from the point to the line AB meets the line
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| 79 | // in a point outside the line segment!
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| 80 |
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| 81 | if( unit_projection < 0. ) // A is the closest point
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| 82 | {
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| 83 | dist_sq= sq_VecAZ;
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| 84 | }
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| 85 | else // B is the closest point
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| 86 | {
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| 87 | G4ThreeVector EndpointB = EndpointA + VecAtoB;
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| 88 | G4ThreeVector VecBZ = OtherPnt - EndpointB;
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| 89 | dist_sq = VecBZ.mag2();
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| 90 | }
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| 91 | }
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| 92 | }
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| 93 | else
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| 94 | {
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| 95 | dist_sq = (OtherPnt - EndpointA).mag2() ;
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| 96 | }
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| 97 | if( dist_sq < 0.0 ) dist_sq = 0.0 ;
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| 98 |
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| 99 | return std::sqrt(dist_sq) ;
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| 100 | }
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| 101 |
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| 102 | G4double G4LineSection::Distline( const G4ThreeVector& OtherPnt,
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| 103 | const G4ThreeVector& LinePntA,
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| 104 | const G4ThreeVector& LinePntB )
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| 105 | {
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| 106 | G4LineSection LineAB( LinePntA, LinePntB ); // Line from A to B
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| 107 |
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| 108 | return LineAB.Dist( OtherPnt );
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| 109 | }
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