1 | #include <stack>
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2 | #include <algorithm>
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3 | #include <queue>
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4 | #include "Environment.h"
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5 | #include "Mesh.h"
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6 | #include "MeshKdTree.h"
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7 |
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8 | using namespace std;
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9 |
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10 | namespace GtpVisibilityPreprocessor {
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11 |
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12 |
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13 | float MeshKdTree::mSplitBorder;
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14 | int MeshKdTree::mTermMaxDepth;
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15 | int MeshKdTree::mTermMinCost;
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16 | float MeshKdTree::mMaxCostRatio;
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17 | float MeshKdTree::mCt_div_ci;
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18 | int MeshKdTree::mSplitMethod;
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19 |
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20 | MeshKdTree::MeshKdTree(Mesh *mesh):mMesh(mesh)
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21 | {
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22 | mRoot = new MeshKdLeaf;
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23 | mSubdivisionCandidates = NULL;
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24 | }
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25 |
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26 | void
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27 | MeshKdTree::ParseEnvironment()
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28 | {
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29 | Environment::GetSingleton()->GetIntValue("MeshKdTree.Termination.maxDepth", mTermMaxDepth);
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30 | Environment::GetSingleton()->GetIntValue("MeshKdTree.Termination.minCost", mTermMinCost);
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31 | Environment::GetSingleton()->GetFloatValue("MeshKdTree.Termination.maxCostRatio", mMaxCostRatio);
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32 | Environment::GetSingleton()->GetFloatValue("MeshKdTree.Termination.ct_div_ci", mCt_div_ci);
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33 | Environment::GetSingleton()->GetFloatValue("MeshKdTree.splitBorder", mSplitBorder);
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34 |
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35 | char splitType[64];
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36 | Environment::GetSingleton()->GetStringValue("MeshKdTree.splitMethod", splitType);
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37 |
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38 | mSplitMethod = SPLIT_SPATIAL_MEDIAN;
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39 | if (strcmp(splitType, "spatialMedian") == 0)
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40 | mSplitMethod = SPLIT_SPATIAL_MEDIAN;
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41 | else
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42 | if (strcmp(splitType, "objectMedian") == 0)
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43 | mSplitMethod = SPLIT_OBJECT_MEDIAN;
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44 | else
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45 | if (strcmp(splitType, "SAH") == 0)
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46 | mSplitMethod = SPLIT_SAH;
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47 | else {
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48 | cerr<<"Wrong kd split type "<<splitType<<endl;
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49 | exit(1);
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50 | }
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51 | }
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52 |
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53 |
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54 |
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55 | int
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56 | MeshKdTree::SelectPlane(MeshKdLeaf *leaf,
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57 | const AxisAlignedBox3 &box,
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58 | float &position
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59 | )
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60 | {
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61 | int axis = -1;
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62 |
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63 | switch (mSplitMethod)
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64 | {
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65 | case SPLIT_SPATIAL_MEDIAN: {
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66 | axis = box.Size().DrivingAxis();
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67 | position = (box.Min()[axis] + box.Max()[axis])*0.5f;
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68 | break;
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69 | }
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70 | case SPLIT_SAH: {
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71 | int objectsBack, objectsFront;
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72 | float costRatio;
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73 | bool mOnlyDrivingAxis = false;
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74 | if (mOnlyDrivingAxis) {
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75 | axis = box.Size().DrivingAxis();
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76 | costRatio = BestCostRatio(leaf,
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77 | box,
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78 | axis,
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79 | position,
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80 | objectsBack,
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81 | objectsFront);
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82 | } else {
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83 | costRatio = MAX_FLOAT;
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84 | for (int i=0; i < 3; i++) {
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85 | float p;
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86 | float r = BestCostRatio(leaf,
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87 | box,
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88 | i,
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89 | p,
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90 | objectsBack,
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91 | objectsFront);
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92 | if (r < costRatio) {
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93 | costRatio = r;
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94 | axis = i;
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95 | position = p;
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96 | }
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97 | }
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98 | }
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99 |
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100 | if (costRatio > mMaxCostRatio) {
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101 | // cout<<"Too big cost ratio "<<costRatio<<endl;
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102 | axis = -1;
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103 | }
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104 | break;
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105 | }
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106 |
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107 | }
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108 | return axis;
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109 | }
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110 |
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111 | MeshKdNode *
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112 | MeshKdTree::SubdivideNode(
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113 | MeshKdLeaf *leaf,
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114 | MeshKdInterior *parent,
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115 | const AxisAlignedBox3 &box,
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116 | const int depth,
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117 | AxisAlignedBox3 &backBBox,
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118 | AxisAlignedBox3 &frontBBox
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119 | )
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120 | {
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121 |
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122 | if (TerminationCriteriaMet(leaf, depth))
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123 | return leaf;
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124 |
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125 | float position;
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126 | // select subdivision axis
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127 | int axis = SelectPlane( leaf, box, position );
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128 |
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129 | if (axis == -1) {
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130 | return leaf;
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131 | }
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132 |
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133 | // add the new nodes to the tree
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134 | MeshKdInterior *node = new MeshKdInterior;
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135 |
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136 | node->mAxis = axis;
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137 | node->mPosition = position;
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138 |
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139 | backBBox = box;
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140 | frontBBox = box;
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141 |
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142 | // first count ray sides
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143 |
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144 | backBBox.SetMax(axis, position);
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145 | frontBBox.SetMin(axis, position);
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146 |
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147 | vector<int>::const_iterator fi;
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148 | vector<int> objectsFront, objectsBack;
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149 |
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150 | for ( fi = leaf->mFaces.begin(); fi != leaf->mFaces.end(); fi++)
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151 | {
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152 | // determine the side of this ray with respect to the plane
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153 | AxisAlignedBox3 box = mMesh->GetFaceBox(*fi);
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154 |
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155 | if (box.Max(axis) > position )
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156 | objectsFront.push_back(*fi);
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157 |
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158 | if (box.Min(axis) < position )
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159 | objectsBack.push_back(*fi);
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160 | }
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161 |
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162 | MeshKdLeaf *back = new MeshKdLeaf(objectsBack);
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163 | MeshKdLeaf *front = new MeshKdLeaf(objectsFront);
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164 |
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165 | // replace a link from node's parent
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166 | if ( parent )
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167 | parent->ReplaceChildLink(leaf, node);
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168 |
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169 | // and setup child links
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170 | node->SetupChildLinks(back, front);
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171 |
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172 | delete leaf;
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173 | return node;
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174 | }
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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 | void
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180 | MeshKdTree::SortSubdivisionCandidates(
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181 | MeshKdLeaf *node,
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182 | const int axis
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183 | )
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184 | {
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185 | mSubdivisionCandidates->clear();
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186 |
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187 | int requestedSize = 2*(int)node->mFaces.size();
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188 | // creates a sorted split candidates array
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189 | if (mSubdivisionCandidates->capacity() > 500000 &&
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190 | requestedSize < (int)(mSubdivisionCandidates->capacity()/10) ) {
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191 | delete mSubdivisionCandidates;
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192 | mSubdivisionCandidates = new vector<SortableEntry>;
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193 | }
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194 |
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195 | mSubdivisionCandidates->reserve(requestedSize);
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196 |
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197 | vector<int>::const_iterator fi;
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198 | // insert all queries
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199 | for(fi = node->mFaces.begin();
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200 | fi < node->mFaces.end();
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201 | fi++) {
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202 |
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203 | AxisAlignedBox3 box = mMesh->GetFaceBox(*fi);
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204 |
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205 | mSubdivisionCandidates->push_back(SortableEntry(SortableEntry::FACE_MIN,
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206 | box.Min(axis),
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207 | *fi)
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208 | );
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209 |
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210 |
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211 | mSubdivisionCandidates->push_back(SortableEntry(SortableEntry::FACE_MAX,
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212 | box.Max(axis),
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213 | *fi)
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214 | );
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215 | }
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216 |
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217 | stable_sort(mSubdivisionCandidates->begin(), mSubdivisionCandidates->end());
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218 | }
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219 |
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220 |
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221 | float
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222 | MeshKdTree::BestCostRatio(
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223 | MeshKdLeaf *node,
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224 | const AxisAlignedBox3 &box,
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225 | const int axis,
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226 | float &position,
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227 | int &objectsBack,
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228 | int &objectsFront
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229 | )
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230 | {
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231 |
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232 | SortSubdivisionCandidates(node, axis);
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233 |
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234 | // go through the lists, count the number of objects left and right
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235 | // and evaluate the following cost funcion:
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236 | // C = ct_div_ci + (ol + or)/queries
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237 |
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238 | int objectsLeft = 0, objectsRight = (int)node->mFaces.size();
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239 |
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240 | float minBox = box.Min(axis);
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241 | float maxBox = box.Max(axis);
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242 | float boxArea = box.SurfaceArea();
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243 |
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244 | float minBand = minBox + mSplitBorder*(maxBox - minBox);
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245 | float maxBand = minBox + (1.0f - mSplitBorder)*(maxBox - minBox);
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246 |
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247 | float minSum = 1e20f;
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248 | vector<SortableEntry>::const_iterator ci;
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249 |
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250 | for(ci = mSubdivisionCandidates->begin();
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251 | ci != mSubdivisionCandidates->end();
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252 | ci++) {
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253 | switch ((*ci).type) {
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254 | case SortableEntry::FACE_MIN:
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255 | objectsLeft++;
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256 | break;
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257 | case SortableEntry::FACE_MAX:
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258 | objectsRight--;
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259 | break;
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260 | }
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261 |
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262 | if ((*ci).value > minBand && (*ci).value < maxBand) {
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263 | AxisAlignedBox3 lbox = box;
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264 | AxisAlignedBox3 rbox = box;
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265 | lbox.SetMax(axis, (*ci).value);
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266 | rbox.SetMin(axis, (*ci).value);
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267 |
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268 | float sum = objectsLeft*lbox.SurfaceArea() + objectsRight*rbox.SurfaceArea();
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269 |
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270 | // cout<<"pos="<<(*ci).value<<"\t q=("<<ql<<","<<qr<<")\t r=("<<rl<<","<<rr<<")"<<endl;
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271 | // cout<<"cost= "<<sum<<endl;
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272 |
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273 | if (sum < minSum) {
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274 | minSum = sum;
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275 | position = (*ci).value;
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276 |
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277 | objectsBack = objectsLeft;
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278 | objectsFront = objectsRight;
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279 | }
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280 | }
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281 | }
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282 |
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283 | float oldCost = (float)node->mFaces.size();
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284 | float newCost = mCt_div_ci + minSum/boxArea;
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285 | float ratio = newCost/oldCost;
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286 |
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287 | #if 0
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288 | cout<<"===================="<<endl;
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289 | cout<<"costRatio="<<ratio<<" pos="<<position<<" t="<<(position - minBox)/(maxBox - minBox)
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290 | <<"\t o=("<<objectsBack<<","<<objectsFront<<")"<<endl;
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291 | #endif
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292 | return ratio;
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293 | }
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294 |
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295 | int
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296 | MeshKdTree::CastRay(
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297 | Ray &ray,
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298 | MeshInstance *instance
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299 | )
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300 | {
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301 | int hits = 0;
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302 |
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303 | stack<RayTraversalData> tStack;
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304 |
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305 | float maxt = 1e6;
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306 | float mint = 0;
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307 |
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308 | AxisAlignedBox3 box = GetBox();
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309 |
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310 | if (!box.GetMinMaxT(ray, &mint, &maxt))
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311 | return 0;
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312 |
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313 | if (mint < 0)
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314 | mint = 0;
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315 |
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316 |
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317 | if (ray.GetType() == Ray::LOCAL_RAY &&
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318 | ray.intersections.size() && ray.intersections[0].mT < mint) {
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319 | return 0;
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320 | }
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321 |
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322 | maxt += Limits::Threshold;
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323 |
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324 | Vector3 entp = ray.Extrap(mint);
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325 | Vector3 extp = ray.Extrap(maxt);
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326 |
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327 | MeshKdNode *node = mRoot;
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328 | MeshKdNode *farChild;
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329 | float position;
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330 | int axis;
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331 |
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332 | while (1) {
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333 | if (!node->IsLeaf()) {
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334 | MeshKdInterior *in = (MeshKdInterior *) node;
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335 | position = in->mPosition;
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336 | axis = in->mAxis;
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337 |
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338 | if (entp[axis] <= position) {
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339 | if (extp[axis] <= position) {
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340 | node = in->mBack;
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341 | // cases N1,N2,N3,P5,Z2,Z3
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342 | continue;
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343 | } else {
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344 | // case N4
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345 | node = in->mBack;
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346 | farChild = in->mFront;
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347 | }
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348 | }
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349 | else {
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350 | if (position <= extp[axis]) {
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351 | node = in->mFront;
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352 | // cases P1,P2,P3,N5,Z1
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353 | continue;
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354 | } else {
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355 | node = in->mFront;
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356 | farChild = in->mBack;
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357 | // case P4
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358 | }
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359 | }
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360 | // $$ modification 3.5.2004 - hints from Kamil Ghais
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361 | // case N4 or P4
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362 | float tdist = (position - ray.GetLoc(axis)) / ray.GetDir(axis);
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363 | tStack.push(RayTraversalData(farChild, extp, maxt));
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364 | extp = ray.GetLoc() + ray.GetDir()*tdist;
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365 | maxt = tdist;
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366 | } else {
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367 | // compute intersection with all objects in this leaf
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368 | MeshKdLeaf *leaf = (MeshKdLeaf *) node;
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369 | // cout<<"leaf mfaces size="<<leaf->mFaces.size()<<endl<<flush;
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370 | hits += instance->CastRay(ray, leaf->mFaces);
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371 |
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372 | if (ray.GetType() == Ray::LOCAL_RAY && ray.intersections.size())
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373 | if (ray.intersections[0].mT <= maxt) {
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374 | break;
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375 | }
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376 |
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377 | // get the next node from the stack
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378 | if (tStack.empty())
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379 | break;
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380 |
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381 | entp = extp;
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382 | mint = maxt;
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383 |
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384 | if (ray.GetType() == Ray::LINE_SEGMENT && mint > 1.0f)
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385 | break;
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386 |
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387 | RayTraversalData &s = tStack.top();
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388 | node = s.mNode;
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389 | extp = s.mExitPoint;
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390 | maxt = s.mMaxT;
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391 | tStack.pop();
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392 | }
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393 | }
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394 |
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395 |
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396 | return hits;
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397 | }
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398 |
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399 | bool
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400 | MeshKdTree::TerminationCriteriaMet(const MeshKdLeaf *leaf, const int depth)
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401 | {
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402 | // cerr<<"\n OBJECTS="<<leaf->mObjects.size()<<endl;
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403 | return
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404 | (leaf->mFaces.size() <= mTermMinCost) ||
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405 | (depth >= mTermMaxDepth);
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406 |
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407 | }
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408 |
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409 | bool
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410 | MeshKdTree::Construct()
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411 | {
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412 | if (!mSubdivisionCandidates)
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413 | mSubdivisionCandidates = new vector<SortableEntry>;
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414 |
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415 | // first construct a leaf that will get subdivide
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416 | MeshKdLeaf *leaf = (MeshKdLeaf *) mRoot;
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417 |
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418 | mRoot = Subdivide(TraversalData(leaf, NULL, GetBox(), 0));
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419 |
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420 | cout << "created " << endl;
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421 | // remove the allocated array
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422 | delete mSubdivisionCandidates;
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423 | mSubdivisionCandidates = NULL;
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424 |
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425 | return true;
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426 | }
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427 |
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428 |
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429 | MeshKdNode *
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430 | MeshKdTree::Subdivide(const TraversalData &tdata)
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431 | {
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432 | MeshKdNode *result = NULL;
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433 |
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434 | priority_queue<TraversalData> tStack;
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435 | // stack<STraversalData> tStack;
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436 |
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437 | tStack.push(tdata);
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438 | AxisAlignedBox3 backBox, frontBox;
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439 |
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440 |
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441 | while (!tStack.empty()) {
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442 |
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443 | TraversalData data = tStack.top();
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444 | tStack.pop();
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445 |
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446 | MeshKdNode *node = SubdivideNode((MeshKdLeaf *) data.mNode,
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447 | data.mParent,
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448 | data.mBox,
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449 | data.mDepth,
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450 | backBox,
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451 | frontBox
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452 | );
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453 | if (result == NULL)
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454 | result = node;
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455 |
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456 | if (!node->IsLeaf()) {
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457 |
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458 | MeshKdInterior *interior = (MeshKdInterior *) node;
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459 | // push the children on the stack
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460 | tStack.push(TraversalData(interior->mBack, interior, backBox, data.mDepth+1));
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461 | tStack.push(TraversalData(interior->mFront, interior, frontBox, data.mDepth+1));
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462 |
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463 | }
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464 | }
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465 |
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466 | return result;
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467 | }
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468 |
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469 |
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470 | AxisAlignedBox3 MeshKdTree::GetBox() const
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471 | {
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472 | return mMesh->mBox;
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473 | }
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474 |
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475 |
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476 | MeshKdTree::~MeshKdTree()
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477 | {
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478 | if (mSubdivisionCandidates)
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479 | delete mSubdivisionCandidates;
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480 |
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481 | if (mRoot)
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482 | delete mRoot;
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483 | }
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484 |
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485 |
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486 | MeshKdNode *MeshKdTree::GetRoot() const
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487 | {
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488 | return mRoot;
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489 | }
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490 |
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491 |
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492 | }
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