1 | /* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield |
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2 | * |
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3 | * This library is open source and may be redistributed and/or modified under |
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4 | * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or |
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5 | * (at your option) any later version. The full license is in LICENSE file |
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6 | * included with this distribution, and on the openscenegraph.org website. |
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7 | * |
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8 | * This library is distributed in the hope that it will be useful, |
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9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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11 | * OpenSceneGraph Public License for more details. |
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12 | */ |
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13 | |
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14 | #ifndef OSG_BOUNDINGSPHERE |
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15 | #define OSG_BOUNDINGSPHERE 1 |
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16 | |
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17 | #include <osg/Config> |
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18 | #include <osg/Export> |
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19 | #include <osg/Vec3f> |
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20 | #include <osg/Vec3d> |
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21 | |
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22 | namespace osg { |
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23 | |
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24 | template<typename VT> |
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25 | class BoundingBoxImpl; |
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26 | |
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27 | /** General purpose bounding sphere class for enclosing nodes/objects/vertices. |
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28 | * Bounds internal osg::Nodes in the scene, assists in view frustum culling, |
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29 | * etc. Similar in function to BoundingBox, it's quicker for evaluating |
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30 | * culling but generally will not cull as aggressively because it encloses a |
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31 | * greater volume. |
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32 | */ |
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33 | template<typename VT> |
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34 | class BoundingSphereImpl |
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35 | { |
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36 | public: |
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37 | typedef VT vec_type; |
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38 | typedef typename VT::value_type value_type; |
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39 | |
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40 | vec_type _center; |
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41 | value_type _radius; |
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42 | |
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43 | /** Construct a default bounding sphere with radius to -1.0f, representing an invalid/unset bounding sphere.*/ |
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44 | BoundingSphereImpl() : _center(0.0,0.0,0.0),_radius(-1.0) {} |
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45 | |
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46 | /** Creates a bounding sphere initialized to the given extents. */ |
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47 | BoundingSphereImpl(const vec_type& center, value_type radius) : _center(center),_radius(radius) {} |
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48 | |
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49 | /** Creates a bounding sphere initialized to the given extents. */ |
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50 | BoundingSphereImpl(const BoundingSphereImpl& bs) : _center(bs._center),_radius(bs._radius) {} |
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51 | |
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52 | /** Creates a bounding sphere initialized to the given extents. */ |
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53 | BoundingSphereImpl(const BoundingBoxImpl<VT>& bb) : _center(0.0,0.0,0.0),_radius(-1.0) { expandBy(bb); } |
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54 | |
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55 | /** Clear the bounding sphere. Reset to default values. */ |
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56 | inline void init() |
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57 | { |
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58 | _center.set(0.0,0.0,0.0); |
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59 | _radius = -1.0; |
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60 | } |
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61 | |
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62 | /** Returns true of the bounding sphere extents are valid, false |
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63 | * otherwise. */ |
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64 | inline bool valid() const { return _radius>=0.0; } |
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65 | |
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66 | /** Set the bounding sphere to the given center/radius using floats. */ |
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67 | inline void set(const vec_type& center,value_type radius) |
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68 | { |
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69 | _center = center; |
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70 | _radius = radius; |
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71 | } |
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72 | |
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73 | /** Returns the center of the bounding sphere. */ |
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74 | inline vec_type& center() { return _center; } |
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75 | |
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76 | /** Returns the const center of the bounding sphere. */ |
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77 | inline const vec_type& center() const { return _center; } |
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78 | |
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79 | /** Returns the radius of the bounding sphere. */ |
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80 | inline value_type& radius() { return _radius; } |
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81 | /** Returns the const radius of the bounding sphere. */ |
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82 | inline value_type radius() const { return _radius; } |
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83 | |
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84 | /** Returns the squared length of the radius. Note, For performance |
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85 | * reasons, the calling method is responsible for checking to make |
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86 | * sure the sphere is valid. */ |
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87 | inline value_type radius2() const { return _radius*_radius; } |
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88 | |
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89 | /** Expands the sphere to encompass the given point. Repositions the |
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90 | * sphere center to minimize the radius increase. If the sphere is |
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91 | * uninitialized, set its center to v and radius to zero. */ |
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92 | template<typename vector_type> |
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93 | void expandBy(const vector_type& v); |
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94 | |
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95 | /** Expands the sphere to encompass the given point. Does not |
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96 | * reposition the sphere center. If the sphere is |
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97 | * uninitialized, set its center to v and radius to zero. */ |
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98 | template<typename vector_type> |
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99 | void expandRadiusBy(const vector_type& v); |
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100 | |
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101 | /** Expands the sphere to encompass the given sphere. Repositions the |
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102 | * sphere center to minimize the radius increase. If the sphere is |
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103 | * uninitialized, set its center and radius to match sh. */ |
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104 | void expandBy(const BoundingSphereImpl& sh); |
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105 | |
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106 | /** Expands the sphere to encompass the given sphere. Does not |
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107 | * repositions the sphere center. If the sphere is |
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108 | * uninitialized, set its center and radius to match sh. */ |
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109 | void expandRadiusBy(const BoundingSphereImpl& sh); |
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110 | |
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111 | /** Expands the sphere to encompass the given box. Repositions the |
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112 | * sphere center to minimize the radius increase. */ |
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113 | void expandBy(const BoundingBoxImpl<VT>& bb); |
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114 | |
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115 | /** Expands the sphere to encompass the given box. Does not |
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116 | * repositions the sphere center. */ |
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117 | void expandRadiusBy(const BoundingBoxImpl<VT>& bb); |
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118 | |
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119 | /** Returns true if v is within the sphere. */ |
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120 | inline bool contains(const vec_type& v) const |
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121 | { |
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122 | return valid() && ((v-_center).length2()<=radius2()); |
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123 | } |
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124 | |
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125 | |
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126 | /** Returns true if there is a non-empty intersection with the given |
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127 | * bounding sphere. */ |
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128 | inline bool intersects( const BoundingSphereImpl& bs ) const |
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129 | { |
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130 | return valid() && bs.valid() && |
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131 | ((_center - bs._center).length2() <= (_radius + bs._radius)*(_radius + bs._radius)); |
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132 | } |
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133 | |
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134 | }; |
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135 | |
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136 | |
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137 | template<typename VT> |
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138 | template<typename vector_type> |
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139 | void BoundingSphereImpl<VT>::expandBy(const vector_type& v) |
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140 | { |
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141 | if (valid()) |
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142 | { |
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143 | vec_type dv = v-_center; |
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144 | value_type r = dv.length(); |
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145 | if (r>_radius) |
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146 | { |
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147 | value_type dr = (r-_radius)*0.5; |
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148 | _center += dv*(dr/r); |
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149 | _radius += dr; |
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150 | } // else do nothing as vertex is within sphere. |
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151 | } |
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152 | else |
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153 | { |
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154 | _center = v; |
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155 | _radius = 0.0; |
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156 | } |
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157 | } |
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158 | |
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159 | template<typename VT> |
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160 | template<typename vector_type> |
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161 | void BoundingSphereImpl<VT>::expandRadiusBy(const vector_type& v) |
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162 | { |
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163 | if (valid()) |
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164 | { |
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165 | value_type r = (v-_center).length(); |
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166 | if (r>_radius) _radius = r; |
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167 | // else do nothing as vertex is within sphere. |
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168 | } |
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169 | else |
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170 | { |
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171 | _center = v; |
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172 | _radius = 0.0; |
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173 | } |
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174 | } |
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175 | |
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176 | template<typename VT> |
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177 | void BoundingSphereImpl<VT>::expandBy(const BoundingSphereImpl& sh) |
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178 | { |
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179 | // ignore operation if incomming BoundingSphere is invalid. |
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180 | if (!sh.valid()) return; |
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181 | |
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182 | // This sphere is not set so use the inbound sphere |
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183 | if (!valid()) |
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184 | { |
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185 | _center = sh._center; |
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186 | _radius = sh._radius; |
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187 | |
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188 | return; |
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189 | } |
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190 | |
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191 | |
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192 | // Calculate d == The distance between the sphere centers |
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193 | double d = ( _center - sh.center() ).length(); |
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194 | |
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195 | // New sphere is already inside this one |
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196 | if ( d + sh.radius() <= _radius ) |
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197 | { |
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198 | return; |
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199 | } |
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200 | |
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201 | // New sphere completely contains this one |
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202 | if ( d + _radius <= sh.radius() ) |
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203 | { |
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204 | _center = sh._center; |
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205 | _radius = sh._radius; |
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206 | return; |
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207 | } |
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208 | |
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209 | |
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210 | // Build a new sphere that completely contains the other two: |
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211 | // |
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212 | // The center point lies halfway along the line between the furthest |
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213 | // points on the edges of the two spheres. |
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214 | // |
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215 | // Computing those two points is ugly - so we'll use similar triangles |
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216 | double new_radius = (_radius + d + sh.radius() ) * 0.5; |
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217 | double ratio = ( new_radius - _radius ) / d ; |
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218 | |
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219 | _center[0] += ( sh.center()[0] - _center[0] ) * ratio; |
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220 | _center[1] += ( sh.center()[1] - _center[1] ) * ratio; |
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221 | _center[2] += ( sh.center()[2] - _center[2] ) * ratio; |
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222 | |
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223 | _radius = new_radius; |
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224 | |
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225 | } |
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226 | |
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227 | template<typename VT> |
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228 | void BoundingSphereImpl<VT>::expandRadiusBy(const BoundingSphereImpl& sh) |
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229 | { |
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230 | if (sh.valid()) |
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231 | { |
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232 | if (valid()) |
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233 | { |
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234 | value_type r = (sh._center-_center).length()+sh._radius; |
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235 | if (r>_radius) _radius = r; |
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236 | // else do nothing as vertex is within sphere. |
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237 | } |
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238 | else |
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239 | { |
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240 | _center = sh._center; |
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241 | _radius = sh._radius; |
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242 | } |
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243 | } |
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244 | } |
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245 | |
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246 | template<typename VT> |
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247 | void BoundingSphereImpl<VT>::expandBy(const BoundingBoxImpl<VT>& bb) |
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248 | { |
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249 | if (bb.valid()) |
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250 | { |
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251 | if (valid()) |
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252 | { |
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253 | BoundingBoxImpl<vec_type> newbb(bb); |
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254 | |
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255 | for(unsigned int c=0;c<8;++c) |
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256 | { |
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257 | vec_type v = bb.corner(c)-_center; // get the direction vector from corner |
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258 | v.normalize(); // normalise it. |
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259 | v *= -_radius; // move the vector in the opposite direction distance radius. |
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260 | v += _center; // move to absolute position. |
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261 | newbb.expandBy(v); // add it into the new bounding box. |
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262 | } |
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263 | |
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264 | _center = newbb.center(); |
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265 | _radius = newbb.radius(); |
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266 | |
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267 | } |
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268 | else |
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269 | { |
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270 | _center = bb.center(); |
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271 | _radius = bb.radius(); |
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272 | } |
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273 | } |
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274 | } |
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275 | |
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276 | template<typename VT> |
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277 | void BoundingSphereImpl<VT>::expandRadiusBy(const BoundingBoxImpl<VT>& bb) |
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278 | { |
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279 | if (bb.valid()) |
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280 | { |
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281 | if (valid()) |
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282 | { |
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283 | for(unsigned int c=0;c<8;++c) |
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284 | { |
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285 | expandRadiusBy(bb.corner(c)); |
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286 | } |
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287 | } |
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288 | else |
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289 | { |
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290 | _center = bb.center(); |
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291 | _radius = bb.radius(); |
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292 | } |
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293 | } |
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294 | } |
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295 | |
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296 | typedef BoundingSphereImpl<Vec3f> BoundingSpheref; |
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297 | typedef BoundingSphereImpl<Vec3d> BoundingSphered; |
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298 | |
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299 | #ifdef OSG_USE_FLOAT_BOUNDINGSPHERE |
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300 | typedef BoundingSpheref BoundingSphere; |
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301 | #else |
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302 | typedef BoundingSphered BoundingSphere; |
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303 | #endif |
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304 | } |
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305 | |
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306 | #endif |
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