1 | /* |
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2 | Bullet Continuous Collision Detection and Physics Library |
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3 | Copyright (c) 2003-2009 Erwin Coumans http://bulletphysics.org |
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4 | |
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5 | This software is provided 'as-is', without any express or implied warranty. |
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6 | In no event will the authors be held liable for any damages arising from the use of this software. |
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7 | Permission is granted to anyone to use this software for any purpose, |
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8 | including commercial applications, and to alter it and redistribute it freely, |
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9 | subject to the following restrictions: |
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10 | |
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11 | 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. |
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12 | 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. |
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13 | 3. This notice may not be removed or altered from any source distribution. |
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14 | */ |
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15 | |
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16 | #ifndef HEIGHTFIELD_TERRAIN_SHAPE_H |
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17 | #define HEIGHTFIELD_TERRAIN_SHAPE_H |
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18 | |
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19 | #include "btConcaveShape.h" |
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20 | |
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21 | ///btHeightfieldTerrainShape simulates a 2D heightfield terrain |
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22 | /** |
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23 | The caller is responsible for maintaining the heightfield array; this |
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24 | class does not make a copy. |
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25 | |
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26 | The heightfield can be dynamic so long as the min/max height values |
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27 | capture the extremes (heights must always be in that range). |
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28 | |
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29 | The local origin of the heightfield is assumed to be the exact |
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30 | center (as determined by width and length and height, with each |
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31 | axis multiplied by the localScaling). |
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32 | |
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33 | \b NOTE: be careful with coordinates. If you have a heightfield with a local |
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34 | min height of -100m, and a max height of +500m, you may be tempted to place it |
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35 | at the origin (0,0) and expect the heights in world coordinates to be |
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36 | -100 to +500 meters. |
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37 | Actually, the heights will be -300 to +300m, because bullet will re-center |
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38 | the heightfield based on its AABB (which is determined by the min/max |
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39 | heights). So keep in mind that once you create a btHeightfieldTerrainShape |
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40 | object, the heights will be adjusted relative to the center of the AABB. This |
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41 | is different to the behavior of many rendering engines, but is useful for |
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42 | physics engines. |
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43 | |
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44 | Most (but not all) rendering and heightfield libraries assume upAxis = 1 |
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45 | (that is, the y-axis is "up"). This class allows any of the 3 coordinates |
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46 | to be "up". Make sure your choice of axis is consistent with your rendering |
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47 | system. |
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48 | |
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49 | The heightfield heights are determined from the data type used for the |
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50 | heightfieldData array. |
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51 | |
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52 | - PHY_UCHAR: height at a point is the uchar value at the |
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53 | grid point, multipled by heightScale. uchar isn't recommended |
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54 | because of its inability to deal with negative values, and |
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55 | low resolution (8-bit). |
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56 | |
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57 | - PHY_SHORT: height at a point is the short int value at that grid |
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58 | point, multipled by heightScale. |
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59 | |
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60 | - PHY_FLOAT: height at a point is the float value at that grid |
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61 | point. heightScale is ignored when using the float heightfield |
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62 | data type. |
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63 | |
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64 | Whatever the caller specifies as minHeight and maxHeight will be honored. |
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65 | The class will not inspect the heightfield to discover the actual minimum |
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66 | or maximum heights. These values are used to determine the heightfield's |
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67 | axis-aligned bounding box, multiplied by localScaling. |
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68 | |
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69 | For usage and testing see the TerrainDemo. |
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70 | */ |
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71 | class btHeightfieldTerrainShape : public btConcaveShape |
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72 | { |
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73 | protected: |
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74 | btVector3 m_localAabbMin; |
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75 | btVector3 m_localAabbMax; |
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76 | btVector3 m_localOrigin; |
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77 | |
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78 | ///terrain data |
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79 | int m_heightStickWidth; |
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80 | int m_heightStickLength; |
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81 | btScalar m_minHeight; |
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82 | btScalar m_maxHeight; |
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83 | btScalar m_width; |
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84 | btScalar m_length; |
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85 | btScalar m_heightScale; |
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86 | union |
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87 | { |
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88 | unsigned char* m_heightfieldDataUnsignedChar; |
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89 | short* m_heightfieldDataShort; |
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90 | btScalar* m_heightfieldDataFloat; |
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91 | void* m_heightfieldDataUnknown; |
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92 | }; |
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93 | |
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94 | PHY_ScalarType m_heightDataType; |
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95 | bool m_flipQuadEdges; |
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96 | bool m_useDiamondSubdivision; |
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97 | |
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98 | int m_upAxis; |
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99 | |
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100 | btVector3 m_localScaling; |
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101 | |
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102 | virtual btScalar getRawHeightFieldValue(int x,int y) const; |
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103 | void quantizeWithClamp(int* out, const btVector3& point,int isMax) const; |
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104 | void getVertex(int x,int y,btVector3& vertex) const; |
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105 | |
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106 | |
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107 | |
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108 | /// protected initialization |
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109 | /** |
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110 | Handles the work of constructors so that public constructors can be |
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111 | backwards-compatible without a lot of copy/paste. |
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112 | */ |
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113 | void initialize(int heightStickWidth, int heightStickLength, |
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114 | void* heightfieldData, btScalar heightScale, |
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115 | btScalar minHeight, btScalar maxHeight, int upAxis, |
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116 | PHY_ScalarType heightDataType, bool flipQuadEdges); |
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117 | |
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118 | public: |
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119 | /// preferred constructor |
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120 | /** |
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121 | This constructor supports a range of heightfield |
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122 | data types, and allows for a non-zero minimum height value. |
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123 | heightScale is needed for any integer-based heightfield data types. |
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124 | */ |
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125 | btHeightfieldTerrainShape(int heightStickWidth,int heightStickLength, |
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126 | void* heightfieldData, btScalar heightScale, |
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127 | btScalar minHeight, btScalar maxHeight, |
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128 | int upAxis, PHY_ScalarType heightDataType, |
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129 | bool flipQuadEdges); |
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130 | |
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131 | /// legacy constructor |
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132 | /** |
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133 | The legacy constructor assumes the heightfield has a minimum height |
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134 | of zero. Only unsigned char or floats are supported. For legacy |
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135 | compatibility reasons, heightScale is calculated as maxHeight / 65535 |
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136 | (and is only used when useFloatData = false). |
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137 | */ |
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138 | btHeightfieldTerrainShape(int heightStickWidth,int heightStickLength,void* heightfieldData, btScalar maxHeight,int upAxis,bool useFloatData,bool flipQuadEdges); |
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139 | |
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140 | virtual ~btHeightfieldTerrainShape(); |
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141 | |
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142 | |
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143 | void setUseDiamondSubdivision(bool useDiamondSubdivision=true) { m_useDiamondSubdivision = useDiamondSubdivision;} |
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144 | |
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145 | |
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146 | virtual void getAabb(const btTransform& t,btVector3& aabbMin,btVector3& aabbMax) const; |
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147 | |
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148 | virtual void processAllTriangles(btTriangleCallback* callback,const btVector3& aabbMin,const btVector3& aabbMax) const; |
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149 | |
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150 | virtual void calculateLocalInertia(btScalar mass,btVector3& inertia) const; |
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151 | |
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152 | virtual void setLocalScaling(const btVector3& scaling); |
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153 | |
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154 | virtual const btVector3& getLocalScaling() const; |
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155 | |
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156 | //debugging |
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157 | virtual const char* getName()const {return "HEIGHTFIELD";} |
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158 | |
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159 | }; |
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160 | |
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161 | #endif //HEIGHTFIELD_TERRAIN_SHAPE_H |
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