1 | #ifndef _ViewCellBsp_H__ |
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2 | #define _ViewCellBsp_H__ |
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3 | |
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4 | #include "Mesh.h" |
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5 | #include "Containers.h" |
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6 | #include <stack> |
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7 | |
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8 | class ViewCell; |
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9 | class Plane3; |
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10 | class BspTree; |
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11 | class BspInterior; |
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12 | class Polygon3; |
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13 | class AxisAlignedBox3; |
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14 | class Ray; |
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15 | |
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16 | struct BspRayTraversalData |
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17 | { |
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18 | BspNode *mNode; |
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19 | Vector3 mExitPoint; |
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20 | float mMaxT; |
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21 | |
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22 | BspRayTraversalData() {} |
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23 | |
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24 | BspRayTraversalData(BspNode *n, const Vector3 &extp, const float maxt): |
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25 | mNode(n), mExitPoint(extp), mMaxT(maxt) |
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26 | {} |
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27 | }; |
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28 | |
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29 | class BspTreeStatistics |
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30 | { |
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31 | public: |
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32 | // total number of nodes |
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33 | int nodes; |
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34 | // number of splits |
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35 | int splits; |
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36 | // totals number of rays |
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37 | int rays; |
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38 | // maximal reached depth |
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39 | int maxDepth; |
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40 | // minimal depth |
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41 | int minDepth; |
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42 | // max depth nodes |
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43 | int maxDepthNodes; |
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44 | // max number of rays per node |
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45 | int maxObjectRefs; |
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46 | // accumulated depth (used to compute average) |
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47 | int accumDepth; |
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48 | // number of initial polygons |
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49 | int polys; |
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50 | /// number of view cells different to the view cell representing unbounded space. |
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51 | int viewCells; |
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52 | |
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53 | // Constructor |
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54 | BspTreeStatistics() |
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55 | { |
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56 | Reset(); |
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57 | } |
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58 | |
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59 | int Nodes() const {return nodes;} |
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60 | int Interior() const { return nodes / 2; } |
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61 | int Leaves() const { return (nodes / 2) + 1; } |
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62 | double AvgDepth() const { return accumDepth / (double)Leaves();}; // TODO: computation wrong |
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63 | |
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64 | void Reset() |
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65 | { |
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66 | nodes = 0; |
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67 | splits = 0; |
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68 | maxDepthNodes = 0; |
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69 | maxDepth = 0; |
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70 | minDepth = 99999; |
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71 | polys = 0; |
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72 | accumDepth = 0; |
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73 | viewCells = 0; |
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74 | } |
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75 | |
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76 | void |
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77 | Print(ostream &app) const; |
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78 | |
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79 | friend ostream &operator<<(ostream &s, const BspTreeStatistics &stat) { |
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80 | stat.Print(s); |
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81 | return s; |
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82 | } |
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83 | |
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84 | }; |
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85 | |
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86 | /** |
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87 | BspNode abstract class serving for interior and leaf node implementation |
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88 | */ |
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89 | class BspNode |
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90 | { |
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91 | friend BspTree; |
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92 | |
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93 | public: |
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94 | BspNode(); |
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95 | virtual ~BspNode(); |
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96 | BspNode(BspInterior *parent); |
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97 | |
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98 | /** Determines whether this node is a leaf or not |
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99 | @return true if leaf |
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100 | */ |
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101 | virtual bool IsLeaf() const = 0; |
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102 | |
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103 | /** Determines whether this node is a root |
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104 | @return true if root |
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105 | */ |
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106 | virtual bool IsRoot() const; |
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107 | |
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108 | /** Returns parent node. |
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109 | */ |
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110 | BspInterior *GetParent(); |
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111 | /** Sets parent node. |
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112 | */ |
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113 | void SetParent(BspInterior *parent); |
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114 | |
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115 | /** Returns pointer to polygons. |
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116 | */ |
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117 | PolygonContainer *GetPolygons(); |
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118 | /** Stores polygons in node or discards them according to storePolys. |
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119 | */ |
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120 | void ProcessPolygons(PolygonContainer *polys, const bool storePolys); |
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121 | |
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122 | //int mViewCellIdx; |
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123 | protected: |
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124 | |
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125 | /// parent of this node |
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126 | BspInterior *mParent; |
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127 | |
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128 | /// store polygons created during BSP splits |
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129 | PolygonContainer *mPolygons; |
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130 | }; |
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131 | |
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132 | /** BSP interior node implementation |
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133 | */ |
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134 | class BspInterior : public BspNode |
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135 | { |
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136 | friend BspTree; |
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137 | public: |
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138 | /** Standard contructor taking split plane as argument. |
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139 | */ |
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140 | BspInterior(const Plane3 &plane); |
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141 | /** @return false since it is an interior node |
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142 | */ |
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143 | bool IsLeaf() const; |
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144 | |
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145 | BspNode *GetBack(); |
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146 | BspNode *GetFront(); |
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147 | |
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148 | Plane3 *GetPlane(); |
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149 | |
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150 | void ReplaceChildLink(BspNode *oldChild, BspNode *newChild); |
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151 | void SetupChildLinks(BspNode *b, BspNode *f); |
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152 | |
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153 | /** Splits polygons with respect to the split plane. |
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154 | @param polys the polygons to be split. the polygons are consumed and |
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155 | distributed to the containers frontPolys, backPolys, coincident. |
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156 | @param frontPolys returns the polygons in the front of the split plane |
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157 | @param backPolys returns the polygons in the back of the split plane |
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158 | @param coincident returns the polygons coincident to the split plane |
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159 | @param splits returns the splits number of splits |
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160 | @param storePolys if the polygons should be stored in the node |
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161 | */ |
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162 | void SplitPolygons(PolygonContainer &polys, |
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163 | PolygonContainer &frontPolys, |
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164 | PolygonContainer &backPolys, |
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165 | PolygonContainer &coincident, |
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166 | int &splits, |
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167 | bool storePolys = false); |
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168 | |
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169 | /** Stores polygon in node or discards them according to storePolys. |
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170 | @param polys the polygons |
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171 | @param storePolys if the polygons should be stored or discarded |
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172 | */ |
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173 | void ProcessPolygon(Polygon3 **poly, const bool storePolys); |
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174 | |
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175 | friend ostream &operator<<(ostream &s, const BspInterior &A) |
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176 | { |
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177 | return s << A.mPlane; |
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178 | } |
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179 | |
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180 | protected: |
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181 | |
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182 | /// Splitting plane corresponding to this node |
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183 | Plane3 mPlane; |
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184 | /// back node |
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185 | BspNode *mBack; |
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186 | /// front node |
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187 | BspNode *mFront; |
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188 | }; |
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189 | |
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190 | /** BSP leaf node implementation. |
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191 | */ |
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192 | class BspLeaf : public BspNode |
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193 | { |
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194 | friend BspTree; |
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195 | |
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196 | public: |
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197 | BspLeaf(); |
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198 | BspLeaf(ViewCell *viewCell); |
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199 | BspLeaf(BspInterior *parent); |
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200 | BspLeaf(BspInterior *parent, ViewCell *viewCell); |
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201 | |
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202 | /** @return true since it is an interior node |
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203 | */ |
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204 | bool IsLeaf() const; |
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205 | /** Returns pointer from view cell. |
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206 | */ |
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207 | ViewCell *GetViewCell(); |
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208 | /** Sets pointer to view cell. |
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209 | */ |
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210 | void SetViewCell(ViewCell *viewCell); |
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211 | |
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212 | protected: |
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213 | |
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214 | /// if NULL this does not correspond to feasible viewcell |
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215 | ViewCell *mViewCell; |
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216 | }; |
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217 | |
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218 | /** Implementation of the view cell BSP tree. |
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219 | */ |
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220 | class BspTree |
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221 | { |
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222 | public: |
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223 | |
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224 | /** Additional data which is passed down the BSP tree during traversal. |
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225 | */ |
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226 | struct BspTraversalData |
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227 | { |
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228 | /// the current node |
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229 | BspNode *mNode; |
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230 | /// polygonal data for splitting |
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231 | PolygonContainer *mPolygons; |
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232 | /// current depth |
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233 | int mDepth; |
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234 | /// the view cell associated with this subdivsion |
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235 | ViewCell *mViewCell; |
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236 | |
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237 | BspTraversalData(): |
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238 | mNode(NULL), |
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239 | mPolygons(NULL), |
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240 | mDepth(0), |
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241 | mViewCell(NULL) |
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242 | {} |
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243 | |
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244 | BspTraversalData(BspNode *node, |
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245 | PolygonContainer *polys, |
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246 | const int depth, |
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247 | ViewCell *viewCell): |
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248 | mNode(node), |
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249 | mPolygons(polys), |
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250 | mDepth(depth), |
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251 | mViewCell(viewCell) |
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252 | {} |
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253 | }; |
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254 | |
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255 | typedef std::stack<BspTraversalData> BspTraversalStack; |
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256 | |
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257 | /** Default constructor creating an empty tree. |
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258 | @param viewCell view cell corresponding to unbounded space |
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259 | */ |
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260 | BspTree(ViewCell *viewCell); |
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261 | |
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262 | ~BspTree(); |
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263 | |
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264 | const BspTreeStatistics &GetStatistics() const; |
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265 | |
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266 | /** Constructs tree using the given list of view cells. |
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267 | For this type of construction we filter all view cells down the |
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268 | tree. If there is no polygon left, the last split plane |
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269 | decides inside or outside of the viewcell. A pointer to the |
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270 | appropriate view cell is stored within each leaf. |
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271 | Many leafs can point to the same viewcell. |
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272 | */ |
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273 | void Construct(const ViewCellContainer &viewCells); |
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274 | |
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275 | /** Constructs tree using the given list of objects. |
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276 | @note the objects are not taken as view cells, but the view cells are |
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277 | constructed from the subdivision: Each leaf is taken as one viewcell. |
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278 | |
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279 | @param objects list of objects |
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280 | @returns list of view cells. |
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281 | */ |
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282 | void Construct(const ObjectContainer &objects, ViewCellContainer *viewCells); |
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283 | |
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284 | /** Constructs the tree from the given list of polygons. |
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285 | @param viewCells if not NULL, new view cells are |
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286 | created in the leafs and stored in the conatainer |
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287 | */ |
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288 | void Construct(PolygonContainer *polys, ViewCellContainer *viewCells = NULL); |
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289 | |
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290 | /** Constructs the tree from a list of scene geometry and a |
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291 | given bundle of rays. |
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292 | @param objects list of objects |
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293 | @param rays the bundle of sample rays |
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294 | @param viewCells if not NULL, new view cells are |
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295 | created in the leafs and stored in the conatainer |
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296 | */ |
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297 | void Construct(const ObjectContainer &objects, |
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298 | const RayContainer &rays, |
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299 | ViewCellContainer *viewCells = NULL); |
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300 | |
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301 | /** Returns list of BSP leaves. |
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302 | */ |
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303 | void CollectLeaves(vector<BspLeaf *> &leaves); |
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304 | |
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305 | /** Returns box which bounds the whole tree. |
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306 | */ |
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307 | AxisAlignedBox3 GetBoundingBox()const; |
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308 | |
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309 | /** Returns root of BSP tree. |
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310 | */ |
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311 | BspNode *GetRoot() const; |
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312 | |
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313 | /** Exports Bsp tree to file. |
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314 | */ |
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315 | bool Export(const string filename); |
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316 | |
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317 | void CollectViewCells(BspNode *n, ViewCellContainer &viewCells); |
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318 | |
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319 | /** A ray is cast possible intersecting the tree. |
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320 | @param the ray that is cast. |
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321 | @returns the number of intersections with objects stored in the tree. |
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322 | */ |
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323 | int CastRay(Ray &ray); |
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324 | |
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325 | /// bsp tree construction types |
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326 | enum {FROM_INPUT_VIEW_CELLS, FROM_SCENE_GEOMETRY, FROM_RAYS}; |
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327 | |
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328 | protected: |
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329 | |
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330 | // -------------------------------------------------------------- |
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331 | // For sorting objects |
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332 | // -------------------------------------------------------------- |
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333 | struct SortableEntry |
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334 | { |
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335 | enum {POLY_MIN, POLY_MAX}; |
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336 | |
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337 | int type; |
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338 | float value; |
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339 | Polygon3 *poly; |
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340 | SortableEntry() {} |
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341 | SortableEntry(const int t, const float v, Polygon3 *poly): |
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342 | type(t), value(v), poly(poly) {} |
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343 | |
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344 | bool operator<(const SortableEntry &b) const |
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345 | { |
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346 | return value < b.value; |
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347 | } |
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348 | }; |
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349 | |
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350 | /** Evaluates the contribution of the candidate split plane. |
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351 | @note the polygons can be reordered in the process. |
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352 | @returns the cost of the candidate split plane |
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353 | */ |
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354 | float SplitPlaneCost(PolygonContainer &polys, |
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355 | const Plane3 &candidatePlane); |
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356 | |
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357 | /** Evaluates tree stats in the BSP tree leafs. |
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358 | */ |
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359 | void EvaluateLeafStats(const BspTraversalData &data); |
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360 | |
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361 | /** Subdivides node with respect to the traversal data. |
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362 | @param tStack current traversal stack |
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363 | @param tData traversal data also holding node to be subdivided |
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364 | @returns new root of the subtree |
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365 | */ |
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366 | BspNode *Subdivide(BspTraversalStack &tStack, BspTraversalData &tData); |
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367 | |
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368 | /** Selects the best possible splitting plane. |
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369 | @param leaf the leaf to be split |
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370 | @param polys the polygon list on which the split decition is based |
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371 | @Returns the split plane |
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372 | */ |
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373 | Plane3 SelectPlane(BspLeaf *leaf, |
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374 | PolygonContainer &polys); |
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375 | |
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376 | /** Filters next view cell down the tree and inserts it into the appropriate leaves |
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377 | (i.e., possibly more than one leaf). |
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378 | */ |
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379 | void InsertViewCell(ViewCell *viewCell); |
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380 | /** Inserts polygons down the tree. The polygons are filtered until a leaf is reached, |
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381 | then further subdivided. |
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382 | @param viewCellContainer if not null, a new viewcell is created and stored in the container |
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383 | */ |
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384 | void InsertPolygons(PolygonContainer *polys, ViewCellContainer *viewCells = NULL); |
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385 | |
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386 | /** Subdivide leaf. |
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387 | @param leaf the leaf to be subdivided |
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388 | @param polys the input polygons |
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389 | @param frontPolys returns the polygons in the front of the split plane |
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390 | @param backPolys returns the polygons in the back of the split plane |
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391 | @param coincident returns the polygons coincident to the split plane |
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392 | @returns the root of the subdivision |
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393 | */ |
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394 | BspInterior *SubdivideNode(BspLeaf *leaf, |
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395 | PolygonContainer &polys, |
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396 | PolygonContainer &frontPolys, |
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397 | PolygonContainer &backPolys, |
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398 | PolygonContainer &coincident); |
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399 | |
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400 | /** Filters polygons down the tree. |
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401 | @param node the current BSP node |
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402 | @param polys the polygons to be filtered |
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403 | @param frontPolys returns the polygons in front of the split plane |
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404 | @param backPolys returns the polygons in the back of the split plane |
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405 | */ |
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406 | void FilterPolygons(BspInterior *node, |
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407 | PolygonContainer *polys, |
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408 | PolygonContainer *frontPolys, |
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409 | PolygonContainer *backPolys); |
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410 | |
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411 | /** Selects the split plane in order to construct a tree with |
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412 | certain characteristics (e.g., balanced tree, least splits, |
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413 | 2.5d aligned) |
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414 | @param polygons container of polygons |
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415 | @param maxTests the maximal number of candidate tests |
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416 | */ |
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417 | Plane3 SelectPlaneHeuristics(PolygonContainer &polys, |
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418 | const int maxTests); |
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419 | |
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420 | /** Extracts the meshes of the objects and adds them to polygons. |
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421 | Adds object aabb to the aabb of the tree. |
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422 | @param maxPolys the maximal number of objects to be stored as polygons |
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423 | @returns the number of polygons |
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424 | */ |
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425 | int AddToPolygonSoup(const ObjectContainer &objects, |
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426 | PolygonContainer &polys, |
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427 | int maxObjects = 0); |
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428 | |
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429 | /** Extracts the meshes of the view cells and and adds them to polygons. |
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430 | Adds view cell aabb to the aabb of the tree. |
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431 | @param maxPolys the maximal number of objects to be stored as polygons |
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432 | @returns the number of polygons |
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433 | */ |
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434 | int AddToPolygonSoup(const ViewCellContainer &viewCells, |
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435 | PolygonContainer &polys, |
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436 | int maxObjects = 0); |
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437 | |
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438 | /** Extract polygons of this mesh and add to polygon container. |
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439 | @param mesh the mesh that drives the polygon construction |
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440 | @param parent the parent intersectable this polygon is constructed from |
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441 | @returns number of polygons |
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442 | */ |
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443 | int AddMeshToPolygons(Mesh *mesh, PolygonContainer &polys, MeshInstance *parent); |
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444 | |
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445 | /** returns next candidate index and reorders polygons so no candidate is chosen two times |
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446 | @param the current candidate index |
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447 | @param max the range of candidates |
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448 | */ |
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449 | int GetNextCandidateIdx(int currentIdx, PolygonContainer &polys); |
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450 | |
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451 | /** Helper function which extracts a view cell on the front and the back |
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452 | of the split plane. |
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453 | @param backViewCell returns view cell on the back of the split plane |
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454 | @param frontViewCell returns a view cell on the front of the split plane |
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455 | @param coincident container of polygons coincident to the split plane |
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456 | @param splitPlane the split plane which decides about back and front |
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457 | @param extractBack if a back view cell is extracted |
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458 | @param extractFront if a front view cell is extracted |
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459 | */ |
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460 | void ExtractViewCells(ViewCell **backViewCell, |
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461 | ViewCell **frontViewCell, |
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462 | const PolygonContainer &coincident, |
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463 | const Plane3 splitPlane, |
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464 | const bool extractBack, |
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465 | const bool extractFront) const; |
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466 | |
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467 | /** Computes best cost ratio for the suface area heuristics for axis aligned |
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468 | splits. This heuristics minimizes the cost for ray traversal. |
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469 | @param polys the polygons guiding the ratio computation |
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470 | @param box the bounding box of the leaf |
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471 | @param axis the current split axis |
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472 | @param position returns the split position |
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473 | @param objectsBack the number of objects in the back of the split plane |
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474 | @param objectsFront the number of objects in the front of the split plane |
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475 | */ |
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476 | float BestCostRatio(const PolygonContainer &polys, |
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477 | const AxisAlignedBox3 &box, |
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478 | const int axis, |
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479 | float &position, |
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480 | int &objectsBack, |
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481 | int &objectsFront) const; |
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482 | |
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483 | /** Sorts split candidates for surface area heuristics for axis aligned splits. |
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484 | @param polys the input for choosing split candidates |
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485 | @param axis the current split axis |
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486 | @param splitCandidates returns sorted list of split candidates |
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487 | */ |
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488 | void SortSplitCandidates(const PolygonContainer &polys, |
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489 | const int axis, |
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490 | vector<SortableEntry> &splitCandidates) const; |
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491 | |
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492 | /// Pointer to the root of the tree |
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493 | BspNode *mRoot; |
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494 | |
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495 | /// Pointer to the root cell of the viewspace |
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496 | // ViewCell *mRootCell; |
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497 | |
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498 | BspTreeStatistics mStat; |
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499 | |
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500 | /// Strategies for choosing next split plane. |
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501 | enum {NO_STRATEGY = 0, |
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502 | RANDOM_POLYGON = 1, |
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503 | AXIS_ALIGNED = 2, |
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504 | LEAST_SPLITS = 4, |
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505 | BALANCED_POLYS = 8, |
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506 | BALANCED_VIEW_CELLS = 16, |
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507 | LARGEST_POLY_AREA = 32, |
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508 | VERTICAL_AXIS = 64, |
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509 | BLOCKED_RAYS = 128 |
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510 | }; |
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511 | |
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512 | /// box around the whole view domain |
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513 | AxisAlignedBox3 mBox; |
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514 | |
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515 | /// view cell corresponding to unbounded space |
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516 | ViewCell *mRootCell; |
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517 | |
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518 | public: |
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519 | /// Parses the environment and stores the global BSP tree parameters |
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520 | static void ParseEnvironment(); |
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521 | |
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522 | /// maximal number of polygons where tree construction is terminated |
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523 | static int sTermMaxPolygons; |
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524 | /// maximal possible depth |
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525 | static int sTermMaxDepth; |
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526 | /// strategy to get the best split plane |
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527 | static int sSplitPlaneStrategy; |
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528 | /// number of candidates evaluated for the next split plane |
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529 | static int sMaxCandidates; |
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530 | /// BSP tree construction method |
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531 | static int sConstructionMethod; |
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532 | /// maximal number of polygons where we do axis aligned splits |
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533 | static int sTermMaxPolysForAxisAligned; |
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534 | |
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535 | static float sCt_div_ci; |
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536 | static float sSplitBorder; |
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537 | static float sMaxCostRatio; |
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538 | |
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539 | // factors to guid the split plane heuristics |
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540 | static float sLeastSplitsFactor; |
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541 | static float sBalancedPolysFactor; |
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542 | static float sBalancedViewCellsFactor; |
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543 | static float sVerticalSplitsFactor; |
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544 | static float sLargestPolyAreaFactor; |
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545 | static float sBlockedRaysFactor; |
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546 | |
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547 | /// if polygons should be stored in the tree |
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548 | static bool sStoreSplitPolys; |
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549 | |
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550 | private: |
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551 | /** Evaluates split plane classification with respect to the plane's |
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552 | contribution for a balanced tree. |
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553 | */ |
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554 | static float sLeastSplitsTable[4]; |
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555 | /** Evaluates split plane classification with respect to the plane's |
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556 | contribution for a minimum number splits in the tree. |
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557 | */ |
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558 | static float sBalancedPolysTable[4]; |
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559 | }; |
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560 | |
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561 | //}; // GtpVisibilityPreprocessor |
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562 | |
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563 | #endif |
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