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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