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: G4ClippablePolygon.cc,v 1.12 2007/05/11 13:54:28 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 | // GEANT 4 class source file |
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33 | // |
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34 | // |
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35 | // G4ClippablePolygon.cc |
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36 | // |
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37 | // Includes code from G4VSolid (P.Kent, V.Grichine, J.Allison) |
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38 | // |
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39 | // -------------------------------------------------------------------- |
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40 | |
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41 | #include "G4ClippablePolygon.hh" |
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42 | |
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43 | #include "G4VoxelLimits.hh" |
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44 | #include "G4GeometryTolerance.hh" |
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45 | |
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46 | // |
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47 | // Constructor |
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48 | // |
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49 | G4ClippablePolygon::G4ClippablePolygon() |
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50 | : normal(0.,0.,0.) |
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51 | { |
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52 | kCarTolerance = G4GeometryTolerance::GetInstance()->GetSurfaceTolerance(); |
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53 | } |
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54 | |
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55 | |
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56 | // |
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57 | // Destructor |
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58 | // |
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59 | G4ClippablePolygon::~G4ClippablePolygon() |
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60 | { |
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61 | } |
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62 | |
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63 | |
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64 | // |
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65 | // AddVertexInOrder |
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66 | // |
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67 | void G4ClippablePolygon::AddVertexInOrder( const G4ThreeVector vertex ) |
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68 | { |
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69 | vertices.push_back( vertex ); |
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70 | } |
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71 | |
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72 | |
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73 | // |
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74 | // ClearAllVertices |
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75 | // |
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76 | void G4ClippablePolygon::ClearAllVertices() |
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77 | { |
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78 | vertices.clear(); |
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79 | } |
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80 | |
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81 | |
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82 | // |
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83 | // Clip |
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84 | // |
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85 | G4bool G4ClippablePolygon::Clip( const G4VoxelLimits &voxelLimit ) |
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86 | { |
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87 | if (voxelLimit.IsLimited()) { |
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88 | ClipAlongOneAxis( voxelLimit, kXAxis ); |
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89 | ClipAlongOneAxis( voxelLimit, kYAxis ); |
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90 | ClipAlongOneAxis( voxelLimit, kZAxis ); |
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91 | } |
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92 | |
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93 | return (vertices.size() > 0); |
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94 | } |
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95 | |
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96 | |
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97 | // |
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98 | // PartialClip |
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99 | // |
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100 | // Clip, while ignoring the indicated axis |
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101 | // |
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102 | G4bool G4ClippablePolygon::PartialClip( const G4VoxelLimits &voxelLimit, |
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103 | const EAxis IgnoreMe ) |
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104 | { |
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105 | if (voxelLimit.IsLimited()) { |
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106 | if (IgnoreMe != kXAxis) ClipAlongOneAxis( voxelLimit, kXAxis ); |
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107 | if (IgnoreMe != kYAxis) ClipAlongOneAxis( voxelLimit, kYAxis ); |
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108 | if (IgnoreMe != kZAxis) ClipAlongOneAxis( voxelLimit, kZAxis ); |
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109 | } |
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110 | |
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111 | return (vertices.size() > 0); |
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112 | } |
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113 | |
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114 | |
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115 | // |
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116 | // GetExtent |
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117 | // |
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118 | G4bool G4ClippablePolygon::GetExtent( const EAxis axis, |
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119 | G4double &min, |
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120 | G4double &max ) const |
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121 | { |
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122 | // |
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123 | // Okay, how many entries do we have? |
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124 | // |
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125 | G4int noLeft = vertices.size(); |
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126 | |
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127 | // |
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128 | // Return false if nothing is left |
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129 | // |
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130 | if (noLeft == 0) return false; |
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131 | |
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132 | // |
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133 | // Initialize min and max to our first vertex |
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134 | // |
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135 | min = max = vertices[0].operator()( axis ); |
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136 | |
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137 | // |
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138 | // Compare to the rest |
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139 | // |
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140 | G4int i; |
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141 | for( i=1; i<noLeft; i++ ) |
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142 | { |
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143 | G4double component = vertices[i].operator()( axis ); |
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144 | if (component < min ) |
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145 | min = component; |
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146 | else if (component > max ) |
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147 | max = component; |
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148 | } |
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149 | |
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150 | return true; |
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151 | } |
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152 | |
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153 | |
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154 | // |
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155 | // GetMinPoint |
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156 | // |
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157 | // Returns pointer to minimum point along the specified axis. |
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158 | // Take care! Do not use pointer after destroying parent polygon. |
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159 | // |
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160 | const G4ThreeVector *G4ClippablePolygon::GetMinPoint( const EAxis axis ) const |
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161 | { |
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162 | G4int noLeft = vertices.size(); |
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163 | if (noLeft==0) |
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164 | G4Exception("G4ClippablePolygon::GetMinPoint()", |
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165 | "InvalidSetup", FatalException, "Empty polygon."); |
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166 | |
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167 | const G4ThreeVector *answer = &(vertices[0]); |
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168 | G4double min = answer->operator()(axis); |
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169 | |
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170 | G4int i; |
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171 | for( i=1; i<noLeft; i++ ) |
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172 | { |
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173 | G4double component = vertices[i].operator()( axis ); |
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174 | if (component < min) |
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175 | { |
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176 | answer = &(vertices[i]); |
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177 | min = component; |
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178 | } |
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179 | } |
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180 | |
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181 | return answer; |
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182 | } |
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183 | |
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184 | |
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185 | // |
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186 | // GetMaxPoint |
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187 | // |
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188 | // Returns pointer to maximum point along the specified axis. |
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189 | // Take care! Do not use pointer after destroying parent polygon. |
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190 | // |
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191 | const G4ThreeVector *G4ClippablePolygon::GetMaxPoint( const EAxis axis ) const |
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192 | { |
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193 | G4int noLeft = vertices.size(); |
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194 | if (noLeft==0) |
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195 | G4Exception("G4ClippablePolygon::GetMaxPoint()", |
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196 | "InvalidSetup", FatalException, "Empty polygon."); |
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197 | |
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198 | const G4ThreeVector *answer = &(vertices[0]); |
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199 | G4double max = answer->operator()(axis); |
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200 | |
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201 | G4int i; |
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202 | for( i=1; i<noLeft; i++ ) |
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203 | { |
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204 | G4double component = vertices[i].operator()( axis ); |
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205 | if (component > max) |
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206 | { |
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207 | answer = &(vertices[i]); |
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208 | max = component; |
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209 | } |
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210 | } |
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211 | |
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212 | return answer; |
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213 | } |
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214 | |
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215 | |
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216 | // |
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217 | // InFrontOf |
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218 | // |
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219 | // Decide if this polygon is in "front" of another when |
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220 | // viewed along the specified axis. For our purposes here, |
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221 | // it is sufficient to use the minimum extent of the |
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222 | // polygon along the axis to determine this. |
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223 | // |
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224 | // In case the minima of the two polygons are equal, |
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225 | // we use a more sophisticated test. |
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226 | // |
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227 | // Note that it is possible for the two following |
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228 | // statements to both return true or both return false: |
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229 | // polygon1.InFrontOf(polygon2) |
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230 | // polygon2.BehindOf(polygon1) |
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231 | // |
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232 | G4bool G4ClippablePolygon::InFrontOf( const G4ClippablePolygon &other, |
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233 | EAxis axis ) const |
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234 | { |
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235 | // |
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236 | // If things are empty, do something semi-sensible |
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237 | // |
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238 | G4int noLeft = vertices.size(); |
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239 | if (noLeft==0) return false; |
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240 | |
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241 | if (other.Empty()) return true; |
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242 | |
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243 | // |
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244 | // Get minimum of other polygon |
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245 | // |
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246 | const G4ThreeVector *minPointOther = other.GetMinPoint( axis ); |
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247 | const G4double minOther = minPointOther->operator()(axis); |
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248 | |
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249 | // |
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250 | // Get minimum of this polygon |
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251 | // |
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252 | const G4ThreeVector *minPoint = GetMinPoint( axis ); |
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253 | const G4double min = minPoint->operator()(axis); |
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254 | |
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255 | // |
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256 | // Easy decision |
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257 | // |
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258 | if (min < minOther-kCarTolerance) return true; // Clear winner |
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259 | |
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260 | if (minOther < min-kCarTolerance) return false; // Clear loser |
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261 | |
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262 | // |
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263 | // We have a tie (this will not be all that rare since our |
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264 | // polygons are connected) |
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265 | // |
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266 | // Check to see if there is a vertex in the other polygon |
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267 | // that is behind this one (or vice versa) |
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268 | // |
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269 | G4bool answer; |
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270 | G4ThreeVector normalOther = other.GetNormal(); |
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271 | |
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272 | if (std::fabs(normalOther(axis)) > std::fabs(normal(axis))) |
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273 | { |
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274 | G4double minP, maxP; |
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275 | GetPlanerExtent( *minPointOther, normalOther, minP, maxP ); |
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276 | |
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277 | answer = (normalOther(axis) > 0) ? (minP < -kCarTolerance) |
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278 | : (maxP > +kCarTolerance); |
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279 | } |
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280 | else |
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281 | { |
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282 | G4double minP, maxP; |
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283 | other.GetPlanerExtent( *minPoint, normal, minP, maxP ); |
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284 | |
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285 | answer = (normal(axis) > 0) ? (maxP > +kCarTolerance) |
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286 | : (minP < -kCarTolerance); |
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287 | } |
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288 | return answer; |
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289 | } |
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290 | |
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291 | // |
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292 | // BehindOf |
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293 | // |
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294 | // Decide if this polygon is behind another. |
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295 | // See notes in method "InFrontOf" |
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296 | // |
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297 | G4bool G4ClippablePolygon::BehindOf( const G4ClippablePolygon &other, |
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298 | EAxis axis ) const |
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299 | { |
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300 | // |
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301 | // If things are empty, do something semi-sensible |
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302 | // |
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303 | G4int noLeft = vertices.size(); |
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304 | if (noLeft==0) return false; |
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305 | |
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306 | if (other.Empty()) return true; |
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307 | |
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308 | // |
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309 | // Get minimum of other polygon |
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310 | // |
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311 | const G4ThreeVector *maxPointOther = other.GetMaxPoint( axis ); |
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312 | const G4double maxOther = maxPointOther->operator()(axis); |
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313 | |
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314 | // |
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315 | // Get minimum of this polygon |
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316 | // |
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317 | const G4ThreeVector *maxPoint = GetMaxPoint( axis ); |
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318 | const G4double max = maxPoint->operator()(axis); |
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319 | |
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320 | // |
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321 | // Easy decision |
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322 | // |
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323 | if (max > maxOther+kCarTolerance) return true; // Clear winner |
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324 | |
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325 | if (maxOther > max+kCarTolerance) return false; // Clear loser |
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326 | |
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327 | // |
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328 | // We have a tie (this will not be all that rare since our |
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329 | // polygons are connected) |
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330 | // |
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331 | // Check to see if there is a vertex in the other polygon |
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332 | // that is in front of this one (or vice versa) |
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333 | // |
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334 | G4bool answer; |
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335 | G4ThreeVector normalOther = other.GetNormal(); |
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336 | |
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337 | if (std::fabs(normalOther(axis)) > std::fabs(normal(axis))) |
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338 | { |
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339 | G4double minP, maxP; |
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340 | GetPlanerExtent( *maxPointOther, normalOther, minP, maxP ); |
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341 | |
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342 | answer = (normalOther(axis) > 0) ? (maxP > +kCarTolerance) |
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343 | : (minP < -kCarTolerance); |
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344 | } |
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345 | else |
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346 | { |
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347 | G4double minP, maxP; |
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348 | other.GetPlanerExtent( *maxPoint, normal, minP, maxP ); |
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349 | |
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350 | answer = (normal(axis) > 0) ? (minP < -kCarTolerance) |
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351 | : (maxP > +kCarTolerance); |
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352 | } |
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353 | return answer; |
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354 | } |
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355 | |
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356 | |
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357 | // |
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358 | // GetPlanerExtent |
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359 | // |
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360 | // Get min/max distance in or out of a plane |
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361 | // |
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362 | G4bool G4ClippablePolygon::GetPlanerExtent( const G4ThreeVector &pointOnPlane, |
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363 | const G4ThreeVector &planeNormal, |
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364 | G4double &min, |
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365 | G4double &max ) const |
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366 | { |
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367 | // |
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368 | // Okay, how many entries do we have? |
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369 | // |
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370 | G4int noLeft = vertices.size(); |
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371 | |
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372 | // |
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373 | // Return false if nothing is left |
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374 | // |
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375 | if (noLeft == 0) return false; |
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376 | |
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377 | // |
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378 | // Initialize min and max to our first vertex |
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379 | // |
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380 | min = max = planeNormal.dot(vertices[0]-pointOnPlane); |
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381 | |
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382 | // |
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383 | // Compare to the rest |
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384 | // |
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385 | G4int i; |
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386 | for( i=1; i<noLeft; i++ ) |
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387 | { |
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388 | G4double component = planeNormal.dot(vertices[i] - pointOnPlane); |
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389 | if (component < min ) |
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390 | min = component; |
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391 | else if (component > max ) |
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392 | max = component; |
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393 | } |
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394 | |
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395 | return true; |
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396 | } |
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397 | |
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398 | |
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399 | // |
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400 | // Clip along just one axis, as specified in voxelLimit |
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401 | // |
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402 | void G4ClippablePolygon::ClipAlongOneAxis( const G4VoxelLimits &voxelLimit, |
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403 | const EAxis axis ) |
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404 | { |
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405 | if (!voxelLimit.IsLimited(axis)) return; |
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406 | |
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407 | G4ThreeVectorList tempPolygon; |
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408 | |
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409 | // |
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410 | // Build a "simple" voxelLimit that includes only the min extent |
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411 | // and apply this to our vertices, producing result in tempPolygon |
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412 | // |
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413 | G4VoxelLimits simpleLimit1; |
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414 | simpleLimit1.AddLimit( axis, voxelLimit.GetMinExtent(axis), kInfinity ); |
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415 | ClipToSimpleLimits( vertices, tempPolygon, simpleLimit1 ); |
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416 | |
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417 | // |
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418 | // If nothing is left from the above clip, we might as well return now |
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419 | // (but with an empty vertices) |
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420 | // |
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421 | if (tempPolygon.size() == 0) |
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422 | { |
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423 | vertices.clear(); |
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424 | return; |
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425 | } |
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426 | |
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427 | // |
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428 | // Now do the same, but using a "simple" limit that includes only the max |
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429 | // extent. Apply this to out tempPolygon, producing result in vertices. |
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430 | // |
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431 | G4VoxelLimits simpleLimit2; |
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432 | simpleLimit2.AddLimit( axis, -kInfinity, voxelLimit.GetMaxExtent(axis) ); |
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433 | ClipToSimpleLimits( tempPolygon, vertices, simpleLimit2 ); |
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434 | |
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435 | // |
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436 | // If nothing is left, return now |
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437 | // |
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438 | if (vertices.size() == 0) return; |
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439 | } |
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440 | |
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441 | |
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442 | // |
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443 | // pVoxelLimits must be only limited along one axis, and either the maximum |
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444 | // along the axis must be +kInfinity, or the minimum -kInfinity |
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445 | // |
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446 | void G4ClippablePolygon::ClipToSimpleLimits( G4ThreeVectorList& pPolygon, |
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447 | G4ThreeVectorList& outputPolygon, |
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448 | const G4VoxelLimits& pVoxelLimit ) |
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449 | { |
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450 | G4int i; |
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451 | G4int noVertices=pPolygon.size(); |
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452 | G4ThreeVector vEnd,vStart; |
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453 | |
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454 | outputPolygon.clear(); |
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455 | |
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456 | for (i=0;i<noVertices;i++) |
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457 | { |
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458 | vStart=pPolygon[i]; |
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459 | if (i==noVertices-1) |
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460 | { |
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461 | vEnd=pPolygon[0]; |
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462 | } |
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463 | else |
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464 | { |
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465 | vEnd=pPolygon[i+1]; |
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466 | } |
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467 | |
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468 | if (pVoxelLimit.Inside(vStart)) |
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469 | { |
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470 | if (pVoxelLimit.Inside(vEnd)) |
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471 | { |
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472 | // vStart and vEnd inside -> output end point |
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473 | // |
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474 | outputPolygon.push_back(vEnd); |
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475 | } |
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476 | else |
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477 | { |
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478 | // vStart inside, vEnd outside -> output crossing point |
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479 | // |
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480 | pVoxelLimit.ClipToLimits(vStart,vEnd); |
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481 | outputPolygon.push_back(vEnd); |
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482 | } |
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483 | } |
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484 | else |
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485 | { |
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486 | if (pVoxelLimit.Inside(vEnd)) |
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487 | { |
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488 | // vStart outside, vEnd inside -> output inside section |
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489 | // |
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490 | pVoxelLimit.ClipToLimits(vStart,vEnd); |
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491 | outputPolygon.push_back(vStart); |
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492 | outputPolygon.push_back(vEnd); |
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493 | } |
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494 | else // Both point outside -> no output |
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495 | { |
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496 | } |
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497 | } |
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498 | } |
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499 | } |
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