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: G4ReduciblePolygon.cc,v 1.11 2006/06/29 18:48:53 gunter Exp $ |
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28 | // GEANT4 tag $Name: HEAD $ |
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29 | // |
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30 | // |
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31 | // -------------------------------------------------------------------- |
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32 | // GEANT 4 class source file |
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33 | // |
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34 | // |
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35 | // G4ReduciblePolygon.cc |
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36 | // |
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37 | // Implementation of a utility class used to specify, test, reduce, |
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38 | // and/or otherwise manipulate a 2D polygon. |
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39 | // |
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40 | // See G4ReduciblePolygon.hh for more info. |
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41 | // |
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42 | // -------------------------------------------------------------------- |
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43 | |
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44 | #include "G4ReduciblePolygon.hh" |
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45 | #include "globals.hh" |
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46 | |
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47 | // |
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48 | // Constructor: with simple arrays |
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49 | // |
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50 | G4ReduciblePolygon::G4ReduciblePolygon( const G4double a[], |
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51 | const G4double b[], |
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52 | G4int n ) |
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53 | : aMin(0.), aMax(0.), bMin(0.), bMax(0.), |
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54 | vertexHead(0) |
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55 | { |
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56 | // |
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57 | // Do all of the real work in Create |
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58 | // |
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59 | Create( a, b, n ); |
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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 | // Constructor: special PGON/PCON case |
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65 | // |
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66 | G4ReduciblePolygon::G4ReduciblePolygon( const G4double rmin[], |
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67 | const G4double rmax[], |
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68 | const G4double z[], G4int n ) |
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69 | : aMin(0.), aMax(0.), bMin(0.), bMax(0.), |
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70 | vertexHead(0) |
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71 | { |
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72 | // |
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73 | // Translate |
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74 | // |
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75 | G4double *a = new G4double[n*2]; |
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76 | G4double *b = new G4double[n*2]; |
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77 | |
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78 | G4double *rOut = a + n, |
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79 | *zOut = b + n, |
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80 | *rIn = rOut-1, |
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81 | *zIn = zOut-1; |
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82 | |
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83 | G4int i; |
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84 | for( i=0; i < n; i++, rOut++, zOut++, rIn--, zIn-- ) |
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85 | { |
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86 | *rOut = rmax[i]; |
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87 | *rIn = rmin[i]; |
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88 | *zOut = *zIn = z[i]; |
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89 | } |
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90 | |
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91 | Create( a, b, n*2 ); |
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92 | |
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93 | delete [] a; |
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94 | delete [] b; |
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95 | } |
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96 | |
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97 | |
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98 | // |
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99 | // Create |
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100 | // |
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101 | // To be called by constructors, fill in the list and statistics for a new |
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102 | // polygon |
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103 | // |
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104 | void G4ReduciblePolygon::Create( const G4double a[], |
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105 | const G4double b[], G4int n ) |
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106 | { |
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107 | if (n<3) |
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108 | G4Exception("G4ReduciblePolygon::Create()", "WrongArgumentValue", |
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109 | FatalException, "Less than 3 vertices specified."); |
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110 | |
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111 | const G4double *anext = a, *bnext = b; |
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112 | ABVertex *prev = 0; |
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113 | do |
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114 | { |
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115 | ABVertex *newVertex = new ABVertex; |
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116 | newVertex->a = *anext; |
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117 | newVertex->b = *bnext; |
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118 | newVertex->next = 0; |
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119 | if (prev==0) |
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120 | { |
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121 | vertexHead = newVertex; |
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122 | } |
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123 | else |
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124 | { |
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125 | prev->next = newVertex; |
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126 | } |
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127 | |
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128 | prev = newVertex; |
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129 | } while( ++anext, ++bnext < b+n ); |
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130 | |
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131 | numVertices = n; |
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132 | |
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133 | CalculateMaxMin(); |
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134 | } |
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135 | |
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136 | |
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137 | // |
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138 | // Fake default constructor - sets only member data and allocates memory |
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139 | // for usage restricted to object persistency. |
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140 | // |
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141 | G4ReduciblePolygon::G4ReduciblePolygon( __void__& ) |
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142 | : aMin(0.), aMax(0.), bMin(0.), bMax(0.), vertexHead(0) |
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143 | { |
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144 | } |
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145 | |
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146 | |
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147 | // |
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148 | // Destructor |
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149 | // |
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150 | G4ReduciblePolygon::~G4ReduciblePolygon() |
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151 | { |
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152 | ABVertex *curr = vertexHead; |
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153 | while( curr ) |
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154 | { |
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155 | ABVertex *toDelete = curr; |
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156 | curr = curr->next; |
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157 | delete toDelete; |
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158 | } |
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159 | } |
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160 | |
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161 | |
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162 | // |
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163 | // CopyVertices |
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164 | // |
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165 | // Copy contents into simple linear arrays. |
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166 | // ***** CAUTION ***** Be care to declare the arrays to a large |
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167 | // enough size! |
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168 | // |
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169 | void G4ReduciblePolygon::CopyVertices( G4double a[], G4double b[] ) const |
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170 | { |
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171 | G4double *anext = a, *bnext = b; |
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172 | ABVertex *curr = vertexHead; |
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173 | while( curr ) |
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174 | { |
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175 | *anext++ = curr->a; |
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176 | *bnext++ = curr->b; |
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177 | curr = curr->next; |
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178 | } |
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179 | } |
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180 | |
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181 | |
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182 | // |
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183 | // ScaleA |
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184 | // |
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185 | // Multiply all a values by a common scale |
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186 | // |
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187 | void G4ReduciblePolygon::ScaleA( G4double scale ) |
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188 | { |
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189 | ABVertex *curr = vertexHead; |
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190 | while( curr ) |
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191 | { |
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192 | curr->a *= scale; |
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193 | curr = curr->next; |
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194 | } |
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195 | } |
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196 | |
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197 | |
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198 | // |
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199 | // ScaleB |
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200 | // |
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201 | // Multiply all b values by a common scale |
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202 | // |
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203 | void G4ReduciblePolygon::ScaleB( G4double scale ) |
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204 | { |
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205 | ABVertex *curr = vertexHead; |
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206 | while( curr ) |
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207 | { |
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208 | curr->b *= scale; |
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209 | curr = curr->next; |
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210 | } |
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211 | } |
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212 | |
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213 | |
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214 | // |
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215 | // RemoveDuplicateVertices |
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216 | // |
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217 | // Remove adjacent vertices that are equal. Returns "false" if there |
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218 | // is a problem (too few vertices remaining). |
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219 | // |
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220 | G4bool G4ReduciblePolygon::RemoveDuplicateVertices( G4double tolerance ) |
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221 | { |
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222 | ABVertex *curr = vertexHead, |
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223 | *prev = 0, |
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224 | *next = curr->next; // A little dangerous |
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225 | while( curr ) |
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226 | { |
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227 | next = curr->next; |
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228 | if (next == 0) next = vertexHead; |
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229 | |
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230 | if (std::fabs(curr->a-next->a) < tolerance && |
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231 | std::fabs(curr->b-next->b) < tolerance ) |
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232 | { |
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233 | // |
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234 | // Duplicate found: do we have > 3 vertices? |
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235 | // |
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236 | if (numVertices <= 3) |
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237 | { |
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238 | CalculateMaxMin(); |
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239 | return false; |
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240 | } |
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241 | |
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242 | // |
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243 | // Delete |
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244 | // |
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245 | ABVertex *toDelete = curr; |
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246 | curr = curr->next; |
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247 | delete toDelete; |
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248 | |
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249 | numVertices--; |
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250 | |
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251 | if (prev) prev->next = curr; else vertexHead = curr; |
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252 | } |
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253 | else |
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254 | { |
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255 | prev = curr; |
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256 | curr = curr->next; |
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257 | } |
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258 | } |
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259 | |
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260 | // |
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261 | // In principle, this is not needed, but why not just play it safe? |
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262 | // |
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263 | CalculateMaxMin(); |
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264 | |
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265 | return true; |
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266 | } |
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267 | |
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268 | |
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269 | // |
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270 | // RemoveRedundantVertices |
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271 | // |
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272 | // Remove any unneeded vertices, i.e. those vertices which |
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273 | // are on the line connecting the previous and next vertices. |
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274 | // |
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275 | G4bool G4ReduciblePolygon::RemoveRedundantVertices( G4double tolerance ) |
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276 | { |
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277 | // |
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278 | // Under these circumstances, we can quit now! |
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279 | // |
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280 | if (numVertices <= 2) return false; |
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281 | |
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282 | G4double tolerance2 = tolerance*tolerance; |
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283 | |
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284 | // |
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285 | // Loop over all vertices |
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286 | // |
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287 | ABVertex *curr = vertexHead, |
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288 | *next = curr->next; // A little dangerous |
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289 | while( curr ) |
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290 | { |
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291 | next = curr->next; |
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292 | if (next == 0) next = vertexHead; |
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293 | |
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294 | G4double da = next->a - curr->a, |
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295 | db = next->b - curr->b; |
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296 | |
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297 | // |
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298 | // Loop over all subsequent vertices, up to curr |
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299 | // |
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300 | for(;;) |
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301 | { |
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302 | // |
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303 | // Get vertex after next |
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304 | // |
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305 | ABVertex *test = next->next; |
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306 | if (test == 0) test = vertexHead; |
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307 | |
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308 | // |
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309 | // If we are back to the original vertex, stop |
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310 | // |
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311 | if (test==curr) break; |
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312 | |
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313 | // |
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314 | // Test for parallel line segments |
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315 | // |
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316 | G4double dat = test->a - curr->a, |
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317 | dbt = test->b - curr->b; |
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318 | |
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319 | if (std::fabs(dat*db-dbt*da)>tolerance2) break; |
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320 | |
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321 | // |
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322 | // Redundant vertex found: do we have > 3 vertices? |
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323 | // |
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324 | if (numVertices <= 3) |
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325 | { |
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326 | CalculateMaxMin(); |
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327 | return false; |
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328 | } |
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329 | |
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330 | // |
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331 | // Delete vertex pointed to by next. Carefully! |
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332 | // |
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333 | if (curr->next) |
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334 | { // next is not head |
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335 | if (next->next) |
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336 | curr->next = test; // next is not tail |
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337 | else |
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338 | curr->next = 0; // New tail |
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339 | } |
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340 | else |
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341 | vertexHead = test; // New head |
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342 | |
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343 | delete next; |
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344 | |
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345 | numVertices--; |
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346 | |
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347 | // |
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348 | // Replace next by the vertex we just tested, |
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349 | // and keep on going... |
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350 | // |
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351 | next = test; |
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352 | da = dat; db = dbt; |
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353 | } |
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354 | curr = curr->next; |
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355 | } |
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356 | |
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357 | // |
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358 | // In principle, this is not needed, but why not just play it safe? |
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359 | // |
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360 | CalculateMaxMin(); |
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361 | |
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362 | return true; |
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363 | } |
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364 | |
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365 | |
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366 | // |
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367 | // ReverseOrder |
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368 | // |
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369 | // Reverse the order of the vertices |
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370 | // |
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371 | void G4ReduciblePolygon::ReverseOrder() |
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372 | { |
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373 | // |
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374 | // Loop over all vertices |
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375 | // |
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376 | ABVertex *prev = vertexHead; |
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377 | if (prev==0) return; // No vertices |
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378 | |
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379 | ABVertex *curr = prev->next; |
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380 | if (curr==0) return; // Just one vertex |
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381 | |
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382 | // |
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383 | // Our new tail |
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384 | // |
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385 | vertexHead->next = 0; |
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386 | |
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387 | for(;;) |
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388 | { |
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389 | // |
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390 | // Save pointer to next vertex (in original order) |
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391 | // |
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392 | ABVertex *save = curr->next; |
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393 | |
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394 | // |
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395 | // Replace it with a pointer to the previous one |
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396 | // (in original order) |
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397 | // |
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398 | curr->next = prev; |
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399 | |
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400 | // |
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401 | // Last vertex? |
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402 | // |
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403 | if (save == 0) break; |
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404 | |
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405 | // |
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406 | // Next vertex |
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407 | // |
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408 | prev = curr; |
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409 | curr = save; |
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410 | } |
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411 | |
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412 | // |
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413 | // Our new head |
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414 | // |
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415 | vertexHead = curr; |
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416 | } |
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417 | |
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418 | |
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419 | // |
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420 | // CrossesItself |
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421 | // |
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422 | // Return "true" if the polygon crosses itself |
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423 | // |
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424 | // Warning: this routine is not very fast (runs as N**2) |
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425 | // |
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426 | G4bool G4ReduciblePolygon::CrossesItself( G4double tolerance ) |
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427 | { |
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428 | G4double tolerance2 = tolerance*tolerance; |
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429 | G4double one = 1.0-tolerance, |
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430 | zero = tolerance; |
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431 | // |
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432 | // Top loop over line segments. By the time we finish |
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433 | // with the second to last segment, we're done. |
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434 | // |
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435 | ABVertex *curr1 = vertexHead, *next1=0; |
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436 | while (curr1->next) { |
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437 | next1 = curr1->next; |
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438 | G4double da1 = next1->a-curr1->a, |
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439 | db1 = next1->b-curr1->b; |
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440 | |
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441 | // |
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442 | // Inner loop over subsequent line segments |
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443 | // |
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444 | ABVertex *curr2 = next1->next; |
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445 | while( curr2 ) { |
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446 | ABVertex *next2 = curr2->next; |
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447 | if (next2==0) next2 = vertexHead; |
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448 | G4double da2 = next2->a-curr2->a, |
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449 | db2 = next2->b-curr2->b; |
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450 | G4double a12 = curr2->a-curr1->a, |
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451 | b12 = curr2->b-curr1->b; |
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452 | |
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453 | // |
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454 | // Calculate intersection of the two lines |
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455 | // |
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456 | G4double deter = da1*db2 - db1*da2; |
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457 | if (std::fabs(deter) > tolerance2) { |
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458 | G4double s1, s2; |
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459 | s1 = (a12*db2-b12*da2)/deter; |
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460 | |
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461 | if (s1 >= zero && s1 < one) { |
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462 | s2 = -(da1*b12-db1*a12)/deter; |
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463 | if (s2 >= zero && s2 < one) return true; |
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464 | } |
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465 | } |
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466 | curr2 = curr2->next; |
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467 | } |
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468 | curr1 = next1; |
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469 | } |
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470 | return false; |
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471 | } |
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472 | |
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473 | |
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474 | |
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475 | // |
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476 | // BisectedBy |
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477 | // |
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478 | // Decide if a line through two points crosses the polygon, within tolerance |
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479 | // |
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480 | G4bool G4ReduciblePolygon::BisectedBy( G4double a1, G4double b1, |
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481 | G4double a2, G4double b2, |
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482 | G4double tolerance ) |
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483 | { |
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484 | G4int nNeg = 0, nPos = 0; |
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485 | |
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486 | G4double a12 = a2-a1, b12 = b2-b1; |
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487 | G4double len12 = std::sqrt( a12*a12 + b12*b12 ); |
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488 | a12 /= len12; b12 /= len12; |
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489 | |
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490 | ABVertex *curr = vertexHead; |
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491 | do |
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492 | { |
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493 | G4double av = curr->a - a1, |
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494 | bv = curr->b - b1; |
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495 | |
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496 | G4double cross = av*b12 - bv*a12; |
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497 | |
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498 | if (cross < -tolerance) |
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499 | { |
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500 | if (nPos) return true; |
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501 | nNeg++; |
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502 | } |
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503 | else if (cross > tolerance) |
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504 | { |
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505 | if (nNeg) return true; |
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506 | nPos++; |
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507 | } |
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508 | curr = curr->next; |
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509 | } while( curr ); |
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510 | |
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511 | return false; |
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512 | } |
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513 | |
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514 | |
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515 | |
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516 | // |
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517 | // Area |
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518 | // |
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519 | // Calculated signed polygon area, where polygons specified in a |
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520 | // clockwise manner (where x==a, y==b) have negative area |
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521 | // |
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522 | // References: [O' Rourke (C)] pp. 18-27; [Gems II] pp. 5-6: |
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523 | // "The Area of a Simple Polygon", Jon Rokne. |
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524 | // |
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525 | G4double G4ReduciblePolygon::Area() |
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526 | { |
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527 | G4double answer = 0; |
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528 | |
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529 | ABVertex *curr = vertexHead, *next; |
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530 | do |
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531 | { |
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532 | next = curr->next; |
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533 | if (next==0) next = vertexHead; |
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534 | |
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535 | answer += curr->a*next->b - curr->b*next->a; |
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536 | curr = curr->next; |
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537 | } while( curr ); |
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538 | |
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539 | return 0.5*answer; |
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540 | } |
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541 | |
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542 | |
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543 | // |
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544 | // Print |
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545 | // |
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546 | void G4ReduciblePolygon::Print() |
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547 | { |
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548 | ABVertex *curr = vertexHead; |
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549 | do |
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550 | { |
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551 | G4cerr << curr->a << " " << curr->b << G4endl; |
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552 | curr = curr->next; |
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553 | } while( curr ); |
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554 | } |
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555 | |
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556 | |
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557 | // |
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558 | // CalculateMaxMin |
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559 | // |
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560 | // To be called when the vertices are changed, this |
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561 | // routine re-calculates global values |
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562 | // |
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563 | void G4ReduciblePolygon::CalculateMaxMin() |
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564 | { |
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565 | ABVertex *curr = vertexHead; |
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566 | aMin = aMax = curr->a; |
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567 | bMin = bMax = curr->b; |
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568 | curr = curr->next; |
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569 | while( curr ) |
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570 | { |
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571 | if (curr->a < aMin) |
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572 | aMin = curr->a; |
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573 | else if (curr->a > aMax) |
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574 | aMax = curr->a; |
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575 | |
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576 | if (curr->b < bMin) |
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577 | bMin = curr->b; |
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578 | else if (curr->b > bMax) |
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579 | bMax = curr->b; |
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580 | |
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581 | curr = curr->next; |
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582 | } |
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583 | } |
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