diff options
Diffstat (limited to 'extern/bullet2/src/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h')
| -rw-r--r-- | extern/bullet2/src/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h | 108 |
1 files changed, 89 insertions, 19 deletions
diff --git a/extern/bullet2/src/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h b/extern/bullet2/src/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h index d6890fe6b97..36489a0ebc3 100644 --- a/extern/bullet2/src/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h +++ b/extern/bullet2/src/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h @@ -18,28 +18,80 @@ subject to the following restrictions: #include "btConcaveShape.h" -///The btHeightfieldTerrainShape simulates a 2D heightfield terrain collision shape. You can also use the more general btBvhTriangleMeshShape instead. -///An example implementation of btHeightfieldTerrainShape is provided in Demos/VehicleDemo/VehicleDemo.cpp +///btHeightfieldTerrainShape simulates a 2D heightfield terrain +/** + The caller is responsible for maintaining the heightfield array; this + class does not make a copy. + + The heightfield can be dynamic so long as the min/max height values + capture the extremes (heights must always be in that range). + + The local origin of the heightfield is assumed to be the exact + center (as determined by width and length and height, with each + axis multiplied by the localScaling). + + \b NOTE: be careful with coordinates. If you have a heightfield with a local + min height of -100m, and a max height of +500m, you may be tempted to place it + at the origin (0,0) and expect the heights in world coordinates to be + -100 to +500 meters. + Actually, the heights will be -300 to +300m, because bullet will re-center + the heightfield based on its AABB (which is determined by the min/max + heights). So keep in mind that once you create a btHeightfieldTerrainShape + object, the heights will be adjusted relative to the center of the AABB. This + is different to the behavior of many rendering engines, but is useful for + physics engines. + + Most (but not all) rendering and heightfield libraries assume upAxis = 1 + (that is, the y-axis is "up"). This class allows any of the 3 coordinates + to be "up". Make sure your choice of axis is consistent with your rendering + system. + + The heightfield heights are determined from the data type used for the + heightfieldData array. + + - PHY_UCHAR: height at a point is the uchar value at the + grid point, multipled by heightScale. uchar isn't recommended + because of its inability to deal with negative values, and + low resolution (8-bit). + + - PHY_SHORT: height at a point is the short int value at that grid + point, multipled by heightScale. + + - PHY_FLOAT: height at a point is the float value at that grid + point. heightScale is ignored when using the float heightfield + data type. + + Whatever the caller specifies as minHeight and maxHeight will be honored. + The class will not inspect the heightfield to discover the actual minimum + or maximum heights. These values are used to determine the heightfield's + axis-aligned bounding box, multiplied by localScaling. + + For usage and testing see the TerrainDemo. + */ class btHeightfieldTerrainShape : public btConcaveShape { protected: btVector3 m_localAabbMin; btVector3 m_localAabbMax; - + btVector3 m_localOrigin; + ///terrain data int m_heightStickWidth; int m_heightStickLength; + btScalar m_minHeight; btScalar m_maxHeight; btScalar m_width; btScalar m_length; + btScalar m_heightScale; union { unsigned char* m_heightfieldDataUnsignedChar; + short* m_heightfieldDataShort; btScalar* m_heightfieldDataFloat; void* m_heightfieldDataUnknown; }; - - bool m_useFloatData; + + PHY_ScalarType m_heightDataType; bool m_flipQuadEdges; bool m_useDiamondSubdivision; @@ -47,31 +99,49 @@ protected: btVector3 m_localScaling; - virtual btScalar getHeightFieldValue(int x,int y) const; + virtual btScalar getRawHeightFieldValue(int x,int y) const; void quantizeWithClamp(int* out, const btVector3& point,int isMax) const; void getVertex(int x,int y,btVector3& vertex) const; - inline bool testQuantizedAabbAgainstQuantizedAabb(int* aabbMin1, int* aabbMax1,const int* aabbMin2,const int* aabbMax2) const - { - bool overlap = true; - overlap = (aabbMin1[0] > aabbMax2[0] || aabbMax1[0] < aabbMin2[0]) ? false : overlap; - overlap = (aabbMin1[2] > aabbMax2[2] || aabbMax1[2] < aabbMin2[2]) ? false : overlap; - overlap = (aabbMin1[1] > aabbMax2[1] || aabbMax1[1] < aabbMin2[1]) ? false : overlap; - return overlap; - } + + + /// protected initialization + /** + Handles the work of constructors so that public constructors can be + backwards-compatible without a lot of copy/paste. + */ + void initialize(int heightStickWidth, int heightStickLength, + void* heightfieldData, btScalar heightScale, + btScalar minHeight, btScalar maxHeight, int upAxis, + PHY_ScalarType heightDataType, bool flipQuadEdges); public: - btHeightfieldTerrainShape(int heightStickWidth,int heightStickHeight,void* heightfieldData, btScalar maxHeight,int upAxis,bool useFloatData,bool flipQuadEdges); + /// preferred constructor + /** + This constructor supports a range of heightfield + data types, and allows for a non-zero minimum height value. + heightScale is needed for any integer-based heightfield data types. + */ + btHeightfieldTerrainShape(int heightStickWidth,int heightStickLength, + void* heightfieldData, btScalar heightScale, + btScalar minHeight, btScalar maxHeight, + int upAxis, PHY_ScalarType heightDataType, + bool flipQuadEdges); + + /// legacy constructor + /** + The legacy constructor assumes the heightfield has a minimum height + of zero. Only unsigned char or floats are supported. For legacy + compatibility reasons, heightScale is calculated as maxHeight / 65535 + (and is only used when useFloatData = false). + */ + btHeightfieldTerrainShape(int heightStickWidth,int heightStickLength,void* heightfieldData, btScalar maxHeight,int upAxis,bool useFloatData,bool flipQuadEdges); virtual ~btHeightfieldTerrainShape(); void setUseDiamondSubdivision(bool useDiamondSubdivision=true) { m_useDiamondSubdivision = useDiamondSubdivision;} - virtual int getShapeType() const - { - return TERRAIN_SHAPE_PROXYTYPE; - } virtual void getAabb(const btTransform& t,btVector3& aabbMin,btVector3& aabbMax) const; |