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 and of QinetiQ Ltd, * |
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20 | // * subject to DEFCON 705 IPR conditions. * |
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21 | // * By using, copying, modifying or distributing the software (or * |
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22 | // * any work based on the software) you agree to acknowledge its * |
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23 | // * use in resulting scientific publications, and indicate your * |
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24 | // * acceptance of all terms of the Geant4 Software license. * |
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25 | // ******************************************************************** |
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26 | // |
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27 | // $Id: G4TriangularFacet.cc,v 1.12 2008/11/13 08:25:07 gcosmo Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-03 $ |
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29 | // |
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30 | // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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31 | // |
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32 | // MODULE: G4TriangularFacet.cc |
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33 | // |
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34 | // Date: 15/06/2005 |
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35 | // Author: P R Truscott |
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36 | // Organisation: QinetiQ Ltd, UK |
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37 | // Customer: UK Ministry of Defence : RAO CRP TD Electronic Systems |
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38 | // Contract: C/MAT/N03517 |
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39 | // |
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40 | // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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41 | // |
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42 | // CHANGE HISTORY |
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43 | // -------------- |
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44 | // |
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45 | // 31 October 2004, P R Truscott, QinetiQ Ltd, UK - Created. |
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46 | // |
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47 | // 01 August 2007 P R Truscott, QinetiQ Ltd, UK |
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48 | // Significant modification to correct for errors and enhance |
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49 | // based on patches/observations kindly provided by Rickard |
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50 | // Holmberg |
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51 | // |
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52 | // 26 September 2007 |
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53 | // P R Truscott, QinetiQ Ltd, UK |
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54 | // Further chamges implemented to the Intersect member |
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55 | // function to correctly treat rays nearly parallel to the |
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56 | // plane of the triangle. |
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57 | // |
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58 | // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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59 | |
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60 | #include "G4TriangularFacet.hh" |
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61 | #include "G4TwoVector.hh" |
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62 | #include "globals.hh" |
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63 | #include "Randomize.hh" |
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64 | |
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65 | /////////////////////////////////////////////////////////////////////////////// |
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66 | // |
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67 | // Definition of triangular facet using absolute vectors to vertices. |
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68 | // From this for first vector is retained to define the facet location and |
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69 | // two relative vectors (E0 and E1) define the sides and orientation of |
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70 | // the outward surface normal. |
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71 | // |
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72 | G4TriangularFacet::G4TriangularFacet (const G4ThreeVector Pt0, |
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73 | const G4ThreeVector vt1, const G4ThreeVector vt2, |
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74 | G4FacetVertexType vertexType) |
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75 | : G4VFacet() |
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76 | { |
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77 | tGeomAlg = G4TessellatedGeometryAlgorithms::GetInstance(); |
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78 | P0 = Pt0; |
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79 | nVertices = 3; |
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80 | if (vertexType == ABSOLUTE) |
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81 | { |
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82 | P.push_back(vt1); |
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83 | P.push_back(vt2); |
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84 | |
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85 | E.push_back(vt1 - P0); |
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86 | E.push_back(vt2 - P0); |
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87 | } |
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88 | else |
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89 | { |
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90 | P.push_back(P0 + vt1); |
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91 | P.push_back(P0 + vt2); |
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92 | |
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93 | E.push_back(vt1); |
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94 | E.push_back(vt2); |
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95 | } |
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96 | |
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97 | G4double Emag1 = E[0].mag(); |
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98 | G4double Emag2 = E[1].mag(); |
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99 | G4double Emag3 = (E[1]-E[0]).mag(); |
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100 | |
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101 | if (Emag1 <= kCarTolerance || Emag2 <= kCarTolerance || |
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102 | Emag3 <= kCarTolerance) |
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103 | { |
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104 | G4Exception("G4TriangularFacet::G4TriangularFacet()", "InvalidSetup", |
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105 | JustWarning, "Length of sides of facet are too small."); |
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106 | G4cerr << G4endl; |
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107 | G4cerr << "P0 = " << P0 << G4endl; |
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108 | G4cerr << "P1 = " << P[0] << G4endl; |
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109 | G4cerr << "P2 = " << P[1] << G4endl; |
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110 | G4cerr << "Side lengths = P0->P1" << Emag1 << G4endl; |
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111 | G4cerr << "Side lengths = P0->P2" << Emag2 << G4endl; |
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112 | G4cerr << "Side lengths = P1->P2" << Emag3 << G4endl; |
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113 | G4cerr << G4endl; |
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114 | |
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115 | isDefined = false; |
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116 | geometryType = "G4TriangularFacet"; |
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117 | surfaceNormal = G4ThreeVector(0.0,0.0,0.0); |
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118 | a = 0.0; |
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119 | b = 0.0; |
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120 | c = 0.0; |
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121 | det = 0.0; |
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122 | } |
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123 | else |
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124 | { |
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125 | isDefined = true; |
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126 | geometryType = "G4TriangularFacet"; |
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127 | surfaceNormal = E[0].cross(E[1]).unit(); |
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128 | a = E[0].mag2(); |
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129 | b = E[0].dot(E[1]); |
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130 | c = E[1].mag2(); |
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131 | det = std::abs(a*c - b*b); |
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132 | |
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133 | sMin = -0.5*kCarTolerance/std::sqrt(a); |
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134 | sMax = 1.0 - sMin; |
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135 | tMin = -0.5*kCarTolerance/std::sqrt(c); |
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136 | |
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137 | area = 0.5 * (E[0].cross(E[1])).mag(); |
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138 | |
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139 | // G4ThreeVector vtmp = 0.25 * (E[0] + E[1]); |
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140 | G4double lambda0 = (a-b) * c / (8.0*area*area); |
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141 | G4double lambda1 = (c-b) * a / (8.0*area*area); |
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142 | circumcentre = P0 + lambda0*E[0] + lambda1*E[1]; |
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143 | radiusSqr = (circumcentre-P0).mag2(); |
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144 | radius = std::sqrt(radiusSqr); |
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145 | |
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146 | for (size_t i=0; i<3; i++) { I.push_back(0); } |
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147 | } |
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148 | } |
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149 | |
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150 | /////////////////////////////////////////////////////////////////////////////// |
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151 | // |
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152 | // ~G4TriangularFacet |
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153 | // |
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154 | // A pretty boring destructor indeed! |
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155 | // |
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156 | G4TriangularFacet::~G4TriangularFacet () |
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157 | { |
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158 | P.clear(); |
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159 | E.clear(); |
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160 | I.clear(); |
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161 | } |
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162 | |
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163 | /////////////////////////////////////////////////////////////////////////////// |
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164 | // |
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165 | // GetClone |
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166 | // |
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167 | // Simple member function to generate a diplicate of the triangular facet. |
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168 | // |
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169 | G4VFacet *G4TriangularFacet::GetClone () |
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170 | { |
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171 | G4TriangularFacet *fc = new G4TriangularFacet (P0, P[0], P[1], ABSOLUTE); |
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172 | G4VFacet *cc = 0; |
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173 | cc = fc; |
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174 | return cc; |
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175 | } |
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176 | |
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177 | /////////////////////////////////////////////////////////////////////////////// |
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178 | // |
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179 | // GetFlippedFacet |
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180 | // |
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181 | // Member function to generate an identical facet, but with the normal vector |
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182 | // pointing at 180 degrees. |
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183 | // |
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184 | G4TriangularFacet *G4TriangularFacet::GetFlippedFacet () |
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185 | { |
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186 | G4TriangularFacet *flipped = new G4TriangularFacet (P0, P[1], P[0], ABSOLUTE); |
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187 | return flipped; |
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188 | } |
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189 | |
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190 | /////////////////////////////////////////////////////////////////////////////// |
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191 | // |
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192 | // Distance (G4ThreeVector) |
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193 | // |
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194 | // Determines the vector between p and the closest point on the facet to p. |
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195 | // This is based on the algorithm published in "Geometric Tools for Computer |
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196 | // Graphics," Philip J Scheider and David H Eberly, Elsevier Science (USA), |
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197 | // 2003. at the time of writing, the algorithm is also available in a |
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198 | // technical note "Distance between point and triangle in 3D," by David Eberly |
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199 | // at http://www.geometrictools.com/Documentation/DistancePoint3Triangle3.pdf |
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200 | // |
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201 | // The by-product is the square-distance sqrDist, which is retained |
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202 | // in case needed by the other "Distance" member functions. |
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203 | // |
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204 | G4ThreeVector G4TriangularFacet::Distance (const G4ThreeVector &p) |
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205 | { |
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206 | G4ThreeVector D = P0 - p; |
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207 | G4double d = E[0].dot(D); |
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208 | G4double e = E[1].dot(D); |
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209 | G4double f = D.mag2(); |
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210 | G4double s = b*e - c*d; |
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211 | G4double t = b*d - a*e; |
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212 | |
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213 | sqrDist = 0.0; |
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214 | |
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215 | if (s+t <= det) |
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216 | { |
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217 | if (s < 0.0) |
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218 | { |
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219 | if (t < 0.0) |
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220 | { |
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221 | // |
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222 | // We are in region 4. |
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223 | // |
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224 | if (d < 0.0) |
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225 | { |
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226 | t = 0.0; |
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227 | if (-d >= a) {s = 1.0; sqrDist = a + 2.0*d + f;} |
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228 | else {s = -d/a; sqrDist = d*s + f;} |
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229 | } |
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230 | else |
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231 | { |
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232 | s = 0.0; |
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233 | if (e >= 0.0) {t = 0.0; sqrDist = f;} |
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234 | else if (-e >= c) {t = 1.0; sqrDist = c + 2.0*e + f;} |
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235 | else {t = -e/c; sqrDist = e*t + f;} |
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236 | } |
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237 | } |
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238 | else |
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239 | { |
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240 | // |
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241 | // We are in region 3. |
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242 | // |
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243 | s = 0.0; |
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244 | if (e >= 0.0) {t = 0.0; sqrDist = f;} |
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245 | else if (-e >= c) {t = 1.0; sqrDist = c + 2.0*e + f;} |
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246 | else {t = -e/c; sqrDist = e*t + f;} |
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247 | } |
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248 | } |
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249 | else if (t < 0.0) |
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250 | { |
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251 | // |
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252 | // We are in region 5. |
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253 | // |
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254 | t = 0.0; |
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255 | if (d >= 0.0) {s = 0.0; sqrDist = f;} |
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256 | else if (-d >= a) {s = 1.0; sqrDist = a + 2.0*d + f;} |
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257 | else {s = -d/a; sqrDist = d*s + f;} |
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258 | } |
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259 | else |
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260 | { |
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261 | // |
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262 | // We are in region 0. |
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263 | // |
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264 | s = s / det; |
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265 | t = t / det; |
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266 | sqrDist = s*(a*s + b*t + 2.0*d) + t*(b*s + c*t + 2.0*e) + f; |
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267 | } |
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268 | } |
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269 | else |
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270 | { |
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271 | if (s < 0.0) |
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272 | { |
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273 | // |
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274 | // We are in region 2. |
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275 | // |
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276 | G4double tmp0 = b + d; |
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277 | G4double tmp1 = c + e; |
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278 | if (tmp1 > tmp0) |
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279 | { |
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280 | G4double numer = tmp1 - tmp0; |
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281 | G4double denom = a - 2.0*b + c; |
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282 | if (numer >= denom) {s = 1.0; t = 0.0; sqrDist = a + 2.0*d + f;} |
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283 | else |
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284 | { |
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285 | s = numer/denom; |
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286 | t = 1.0 - s; |
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287 | sqrDist = s*(a*s + b*t +2.0*d) + t*(b*s + c*t + 2.0*e) + f; |
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288 | } |
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289 | } |
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290 | else |
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291 | { |
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292 | s = 0.0; |
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293 | if (tmp1 <= 0.0) {t = 1.0; sqrDist = c + 2.0*e + f;} |
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294 | else if (e >= 0.0) {t = 0.0; sqrDist = f;} |
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295 | else {t = -e/c; sqrDist = e*t + f;} |
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296 | } |
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297 | } |
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298 | else if (t < 0.0) |
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299 | { |
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300 | // |
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301 | // We are in region 6. |
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302 | // |
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303 | G4double tmp0 = b + e; |
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304 | G4double tmp1 = a + d; |
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305 | if (tmp1 > tmp0) |
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306 | { |
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307 | G4double numer = tmp1 - tmp0; |
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308 | G4double denom = a - 2.0*b + c; |
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309 | if (numer >= denom) {t = 1.0; s = 0.0; sqrDist = c + 2.0*e + f;} |
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310 | else |
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311 | { |
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312 | t = numer/denom; |
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313 | s = 1.0 - t; |
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314 | sqrDist = s*(a*s + b*t +2.0*d) + t*(b*s + c*t + 2.0*e) + f; |
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315 | } |
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316 | } |
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317 | else |
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318 | { |
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319 | t = 0.0; |
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320 | if (tmp1 <= 0.0) {s = 1.0; sqrDist = a + 2.0*d + f;} |
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321 | else if (d >= 0.0) {s = 0.0; sqrDist = f;} |
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322 | else {s = -d/a; sqrDist = d*s + f;} |
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323 | } |
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324 | } |
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325 | else |
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326 | // |
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327 | // We are in region 1. |
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328 | // |
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329 | { |
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330 | G4double numer = c + e - b - d; |
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331 | if (numer <= 0.0) |
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332 | { |
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333 | s = 0.0; |
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334 | t = 1.0; |
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335 | sqrDist = c + 2.0*e + f; |
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336 | } |
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337 | else |
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338 | { |
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339 | G4double denom = a - 2.0*b + c; |
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340 | if (numer >= denom) {s = 1.0; t = 0.0; sqrDist = a + 2.0*d + f;} |
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341 | else |
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342 | { |
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343 | s = numer/denom; |
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344 | t = 1.0 - s; |
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345 | sqrDist = s*(a*s + b*t + 2.0*d) + t*(b*s + c*t + 2.0*e) + f; |
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346 | } |
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347 | } |
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348 | } |
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349 | } |
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350 | // |
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351 | // |
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352 | // Do a heck for rounding errors in the distance-squared. |
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353 | // |
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354 | if (sqrDist < 0.0) { sqrDist = 0.0; } |
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355 | |
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356 | return D + s*E[0] + t*E[1]; |
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357 | } |
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358 | |
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359 | /////////////////////////////////////////////////////////////////////////////// |
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360 | // |
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361 | // Distance (G4ThreeVector, G4double) |
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362 | // |
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363 | // Determines the closest distance between point p and the facet. This makes |
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364 | // use of G4ThreeVector G4TriangularFacet::Distance, which stores the |
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365 | // square of the distance in variable sqrDist. If approximate methods show |
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366 | // the distance is to be greater than minDist, then forget about further |
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367 | // computation and return a very large number. |
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368 | // |
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369 | G4double G4TriangularFacet::Distance (const G4ThreeVector &p, |
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370 | const G4double minDist) |
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371 | { |
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372 | // |
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373 | // |
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374 | // Start with quicky test to determine if the surface of the sphere enclosing |
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375 | // the triangle is any closer to p than minDist. If not, then don't bother |
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376 | // about more accurate test. |
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377 | // |
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378 | G4double dist = kInfinity; |
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379 | if ((p-circumcentre).mag()-radius < minDist) |
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380 | { |
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381 | // |
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382 | // |
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383 | // It's possible that the triangle is closer than minDist, so do more accurate |
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384 | // assessment. |
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385 | // |
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386 | dist = Distance(p).mag(); |
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387 | // dist = std::sqrt(sqrDist); |
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388 | } |
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389 | |
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390 | return dist; |
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391 | } |
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392 | |
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393 | /////////////////////////////////////////////////////////////////////////////// |
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394 | // |
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395 | // Distance (G4ThreeVector, G4double, G4double) |
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396 | // |
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397 | // Determine the distance to point p. kInfinity is returned if either: |
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398 | // (1) outgoing is TRUE and the dot product of the normal vector to the facet |
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399 | // and the displacement vector from p to the triangle is negative. |
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400 | // (2) outgoing is FALSE and the dot product of the normal vector to the facet |
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401 | // and the displacement vector from p to the triangle is positive. |
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402 | // If approximate methods show the distance is to be greater than minDist, then |
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403 | // forget about further computation and return a very large number. |
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404 | // |
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405 | // This method has been heavily modified thanks to the valuable comments and |
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406 | // corrections of Rickard Holmberg. |
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407 | // |
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408 | G4double G4TriangularFacet::Distance (const G4ThreeVector &p, |
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409 | const G4double minDist, const G4bool outgoing) |
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410 | { |
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411 | // |
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412 | // |
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413 | // Start with quicky test to determine if the surface of the sphere enclosing |
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414 | // the triangle is any closer to p than minDist. If not, then don't bother |
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415 | // about more accurate test. |
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416 | // |
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417 | G4double dist = kInfinity; |
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418 | if ((p-circumcentre).mag()-radius < minDist) |
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419 | { |
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420 | // |
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421 | // |
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422 | // It's possible that the triangle is closer than minDist, so do more accurate |
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423 | // assessment. |
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424 | // |
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425 | G4ThreeVector v = Distance(p); |
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426 | G4double dist1 = std::sqrt(sqrDist); |
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427 | G4double dir = v.dot(surfaceNormal); |
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428 | G4bool wrongSide = (dir > 0.0 && !outgoing) || (dir < 0.0 && outgoing); |
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429 | if (dist1 <= kCarTolerance*0.5) |
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430 | { |
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431 | // |
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432 | // |
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433 | // Point p is very close to triangle. Check if it's on the wrong side, in |
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434 | // which case return distance of 0.0 otherwise . |
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435 | // |
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436 | if (wrongSide) dist = 0.0; |
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437 | else dist = dist1; |
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438 | } |
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439 | else if (!wrongSide) dist = dist1; |
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440 | } |
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441 | |
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442 | return dist; |
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443 | } |
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444 | |
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445 | /////////////////////////////////////////////////////////////////////////////// |
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446 | // |
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447 | // Extent |
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448 | // |
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449 | // Calculates the furthest the triangle extends in a particular direction |
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450 | // defined by the vector axis. |
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451 | // |
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452 | G4double G4TriangularFacet::Extent (const G4ThreeVector axis) |
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453 | { |
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454 | G4double s = P0.dot(axis); |
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455 | G4double sp = P[0].dot(axis); |
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456 | if (sp > s) s = sp; |
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457 | sp = P[1].dot(axis); |
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458 | if (sp > s) s = sp; |
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459 | |
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460 | return s; |
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461 | } |
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462 | |
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463 | /////////////////////////////////////////////////////////////////////////////// |
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464 | // |
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465 | // Intersect |
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466 | // |
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467 | // Member function to find the next intersection when going from p in the |
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468 | // direction of v. If: |
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469 | // (1) "outgoing" is TRUE, only consider the face if we are going out through |
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470 | // the face. |
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471 | // (2) "outgoing" is FALSE, only consider the face if we are going in through |
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472 | // the face. |
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473 | // Member functions returns TRUE if there is an intersection, FALSE otherwise. |
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474 | // Sets the distance (distance along w), distFromSurface (orthogonal distance) |
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475 | // and normal. |
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476 | // |
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477 | // Also considers intersections that happen with negative distance for small |
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478 | // distances of distFromSurface = 0.5*kCarTolerance in the wrong direction. |
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479 | // This is to detect kSurface without doing a full Inside(p) in |
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480 | // G4TessellatedSolid::Distance(p,v) calculation. |
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481 | // |
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482 | // This member function is thanks the valuable work of Rickard Holmberg. PT. |
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483 | // However, "gotos" are the Work of the Devil have been exorcised with |
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484 | // extreme prejudice!! |
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485 | // |
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486 | // IMPORTANT NOTE: These calculations are predicated on v being a unit |
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487 | // vector. If G4TessellatedSolid or other classes call this member function |
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488 | // with |v| != 1 then there will be errors. |
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489 | // |
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490 | G4bool G4TriangularFacet::Intersect (const G4ThreeVector &p, |
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491 | const G4ThreeVector &v, G4bool outgoing, G4double &distance, |
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492 | G4double &distFromSurface, G4ThreeVector &normal) |
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493 | { |
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494 | // |
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495 | // |
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496 | // Check whether the direction of the facet is consistent with the vector v |
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497 | // and the need to be outgoing or ingoing. If inconsistent, disregard and |
---|
498 | // return false. |
---|
499 | // |
---|
500 | G4double w = v.dot(surfaceNormal); |
---|
501 | if ((outgoing && (w <-dirTolerance)) || (!outgoing && (w > dirTolerance))) |
---|
502 | { |
---|
503 | distance = kInfinity; |
---|
504 | distFromSurface = kInfinity; |
---|
505 | normal = G4ThreeVector(0.0,0.0,0.0); |
---|
506 | return false; |
---|
507 | } |
---|
508 | // |
---|
509 | // |
---|
510 | // Calculate the orthogonal distance from p to the surface containing the |
---|
511 | // triangle. Then determine if we're on the right or wrong side of the |
---|
512 | // surface (at a distance greater than kCarTolerance) to be consistent with |
---|
513 | // "outgoing". |
---|
514 | // |
---|
515 | G4ThreeVector D = P0 - p; |
---|
516 | distFromSurface = D.dot(surfaceNormal); |
---|
517 | G4bool wrongSide = (outgoing && (distFromSurface < -0.5*kCarTolerance)) || |
---|
518 | (!outgoing && (distFromSurface > 0.5*kCarTolerance)); |
---|
519 | if (wrongSide) |
---|
520 | { |
---|
521 | distance = kInfinity; |
---|
522 | distFromSurface = kInfinity; |
---|
523 | normal = G4ThreeVector(0.0,0.0,0.0); |
---|
524 | return false; |
---|
525 | } |
---|
526 | |
---|
527 | wrongSide = (outgoing && (distFromSurface < 0.0)) || |
---|
528 | (!outgoing && (distFromSurface > 0.0)); |
---|
529 | if (wrongSide) |
---|
530 | { |
---|
531 | // |
---|
532 | // |
---|
533 | // We're slightly on the wrong side of the surface. Check if we're close |
---|
534 | // enough using a precise distance calculation. |
---|
535 | // |
---|
536 | G4ThreeVector u = Distance(p); |
---|
537 | if (std::sqrt(sqrDist) <= 0.5*kCarTolerance) |
---|
538 | { |
---|
539 | // |
---|
540 | // |
---|
541 | // We're very close. Therefore return a small negative number to pretend |
---|
542 | // we intersect. |
---|
543 | // |
---|
544 | distance = -0.5*kCarTolerance; |
---|
545 | normal = surfaceNormal; |
---|
546 | return true; |
---|
547 | } |
---|
548 | else |
---|
549 | { |
---|
550 | // |
---|
551 | // |
---|
552 | // We're close to the surface containing the triangle, but sufficiently |
---|
553 | // far from the triangle, and on the wrong side compared to the directions |
---|
554 | // of the surface normal and v. There is no intersection. |
---|
555 | // |
---|
556 | distance = kInfinity; |
---|
557 | distFromSurface = kInfinity; |
---|
558 | normal = G4ThreeVector(0.0,0.0,0.0); |
---|
559 | return false; |
---|
560 | } |
---|
561 | } |
---|
562 | if (w < dirTolerance && w > -dirTolerance) |
---|
563 | { |
---|
564 | // |
---|
565 | // |
---|
566 | // The ray is within the plane of the triangle. Project the problem into 2D |
---|
567 | // in the plane of the triangle. First try to create orthogonal unit vectors |
---|
568 | // mu and nu, where mu is E[0]/|E[0]|. This is kinda like |
---|
569 | // the original algorithm due to Rickard Holmberg, but with better mathematical |
---|
570 | // justification than the original method ... however, beware Rickard's was less |
---|
571 | // time-consuming. |
---|
572 | // |
---|
573 | // Note that vprime is not a unit vector. We need to keep it unnormalised |
---|
574 | // since the values of distance along vprime (s0 and s1) for intersection with |
---|
575 | // the triangle will be used to determine if we cut the plane at the same |
---|
576 | // time. |
---|
577 | // |
---|
578 | G4ThreeVector mu = E[0].unit(); |
---|
579 | G4ThreeVector nu = surfaceNormal.cross(mu); |
---|
580 | G4TwoVector pprime(p.dot(mu),p.dot(nu)); |
---|
581 | G4TwoVector vprime(v.dot(mu),v.dot(nu)); |
---|
582 | G4TwoVector P0prime(P0.dot(mu),P0.dot(nu)); |
---|
583 | G4TwoVector E0prime(E[0].mag(),0.0); |
---|
584 | G4TwoVector E1prime(E[1].dot(mu),E[1].dot(nu)); |
---|
585 | |
---|
586 | G4TwoVector loc[2]; |
---|
587 | if ( tGeomAlg->IntersectLineAndTriangle2D(pprime,vprime,P0prime, |
---|
588 | E0prime,E1prime,loc) ) |
---|
589 | { |
---|
590 | // |
---|
591 | // |
---|
592 | // There is an intersection between the line and triangle in 2D. Now check |
---|
593 | // which part of the line intersects with the plane containing the triangle |
---|
594 | // in 3D. |
---|
595 | // |
---|
596 | G4double vprimemag = vprime.mag(); |
---|
597 | G4double s0 = (loc[0] - pprime).mag()/vprimemag; |
---|
598 | G4double s1 = (loc[1] - pprime).mag()/vprimemag; |
---|
599 | G4double normDist0 = surfaceNormal.dot(s0*v) - distFromSurface; |
---|
600 | G4double normDist1 = surfaceNormal.dot(s1*v) - distFromSurface; |
---|
601 | |
---|
602 | if ((normDist0 < 0.0 && normDist1 < 0.0) || |
---|
603 | (normDist0 > 0.0 && normDist1 > 0.0)) |
---|
604 | { |
---|
605 | distance = kInfinity; |
---|
606 | distFromSurface = kInfinity; |
---|
607 | normal = G4ThreeVector(0.0,0.0,0.0); |
---|
608 | return false; |
---|
609 | } |
---|
610 | else |
---|
611 | { |
---|
612 | G4double dnormDist = normDist1-normDist0; |
---|
613 | if (std::abs(dnormDist) < DBL_EPSILON) |
---|
614 | { |
---|
615 | distance = s0; |
---|
616 | normal = surfaceNormal; |
---|
617 | if (!outgoing) distFromSurface = -distFromSurface; |
---|
618 | return true; |
---|
619 | } |
---|
620 | else |
---|
621 | { |
---|
622 | distance = s0 - normDist0*(s1-s0)/dnormDist; |
---|
623 | normal = surfaceNormal; |
---|
624 | if (!outgoing) distFromSurface = -distFromSurface; |
---|
625 | return true; |
---|
626 | } |
---|
627 | } |
---|
628 | |
---|
629 | // G4ThreeVector dloc = loc1 - loc0; |
---|
630 | // G4ThreeVector dlocXv = dloc.cross(v); |
---|
631 | // G4double dlocXvmag = dlocXv.mag(); |
---|
632 | // if (dloc.mag() <= 0.5*kCarTolerance || dlocXvmag <= DBL_EPSILON) |
---|
633 | // { |
---|
634 | // distance = loc0.mag(); |
---|
635 | // normal = surfaceNormal; |
---|
636 | // if (!outgoing) distFromSurface = -distFromSurface; |
---|
637 | // return true; |
---|
638 | // } |
---|
639 | |
---|
640 | // G4ThreeVector loc0Xv = loc0.cross(v); |
---|
641 | // G4ThreeVector loc1Xv = loc1.cross(v); |
---|
642 | // G4double sameDir = -loc0Xv.dot(loc1Xv); |
---|
643 | // if (sameDir < 0.0) |
---|
644 | // { |
---|
645 | // distance = kInfinity; |
---|
646 | // distFromSurface = kInfinity; |
---|
647 | // normal = G4ThreeVector(0.0,0.0,0.0); |
---|
648 | // return false; |
---|
649 | // } |
---|
650 | // else |
---|
651 | // { |
---|
652 | // distance = loc0.mag() + loc0Xv.mag() * dloc.mag()/dlocXvmag; |
---|
653 | // normal = surfaceNormal; |
---|
654 | // if (!outgoing) distFromSurface = -distFromSurface; |
---|
655 | // return true; |
---|
656 | // } |
---|
657 | } |
---|
658 | else |
---|
659 | { |
---|
660 | distance = kInfinity; |
---|
661 | distFromSurface = kInfinity; |
---|
662 | normal = G4ThreeVector(0.0,0.0,0.0); |
---|
663 | return false; |
---|
664 | } |
---|
665 | } |
---|
666 | // |
---|
667 | // |
---|
668 | // Use conventional algorithm to determine the whether there is an |
---|
669 | // intersection. This involves determining the point of intersection of the |
---|
670 | // line with the plane containing the triangle, and then calculating if the |
---|
671 | // point is within the triangle. |
---|
672 | // |
---|
673 | distance = distFromSurface / w; |
---|
674 | G4ThreeVector pp = p + v*distance; |
---|
675 | G4ThreeVector DD = P0 - pp; |
---|
676 | G4double d = E[0].dot(DD); |
---|
677 | G4double e = E[1].dot(DD); |
---|
678 | G4double s = b*e - c*d; |
---|
679 | G4double t = b*d - a*e; |
---|
680 | |
---|
681 | if (s < 0.0 || t < 0.0 || s+t > det) |
---|
682 | { |
---|
683 | // |
---|
684 | // |
---|
685 | // The intersection is outside of the triangle. |
---|
686 | // |
---|
687 | distance = kInfinity; |
---|
688 | distFromSurface = kInfinity; |
---|
689 | normal = G4ThreeVector(0.0,0.0,0.0); |
---|
690 | return false; |
---|
691 | } |
---|
692 | else |
---|
693 | { |
---|
694 | // |
---|
695 | // |
---|
696 | // There is an intersection. Now we only need to set the surface normal. |
---|
697 | // |
---|
698 | normal = surfaceNormal; |
---|
699 | if (!outgoing) distFromSurface = -distFromSurface; |
---|
700 | return true; |
---|
701 | } |
---|
702 | } |
---|
703 | |
---|
704 | //////////////////////////////////////////////////////////////////////// |
---|
705 | // |
---|
706 | // GetPointOnFace |
---|
707 | // |
---|
708 | // Auxiliary method for get a random point on surface |
---|
709 | |
---|
710 | G4ThreeVector G4TriangularFacet::GetPointOnFace() const |
---|
711 | { |
---|
712 | G4double alpha = CLHEP::RandFlat::shoot(0.,1.); |
---|
713 | G4double beta = CLHEP::RandFlat::shoot(0.,1); |
---|
714 | G4double lambda1=alpha*beta; |
---|
715 | G4double lambda0=alpha-lambda1; |
---|
716 | |
---|
717 | return (P0 + lambda0*E[0] + lambda1*E[1]); |
---|
718 | } |
---|
719 | |
---|
720 | //////////////////////////////////////////////////////////////////////// |
---|
721 | // |
---|
722 | // GetArea |
---|
723 | // |
---|
724 | // Auxiliary method for returning the surface area |
---|
725 | |
---|
726 | G4double G4TriangularFacet::GetArea() |
---|
727 | { |
---|
728 | return area; |
---|
729 | } |
---|