#include "btConcaveShape.h"
#include "LinearMath/btAlignedObjectArray.h"

Functions
virtual btScalar	getRawHeightFieldValue (int x, int y) const

void	quantizeWithClamp (int *out, const btVector3 &point, int isMax) const
	given input vector, return quantized version

void	initialize (int heightStickWidth, int heightStickLength, const void *heightfieldData, btScalar heightScale, btScalar minHeight, btScalar maxHeight, int upAxis, PHY_ScalarType heightDataType, bool flipQuadEdges)
	protected initialization

	BT_DECLARE_ALIGNED_ALLOCATOR ()

	btHeightfieldTerrainShape (int heightStickWidth, int heightStickLength, const void *heightfieldData, btScalar heightScale, btScalar minHeight, btScalar maxHeight, int upAxis, PHY_ScalarType heightDataType, bool flipQuadEdges)
	preferred constructor

	btHeightfieldTerrainShape (int heightStickWidth, int heightStickLength, const void *heightfieldData, btScalar maxHeight, int upAxis, bool useFloatData, bool flipQuadEdges)
	legacy constructor

virtual	~btHeightfieldTerrainShape ()

void	setUseDiamondSubdivision (bool useDiamondSubdivision=true)

void	setUseZigzagSubdivision (bool useZigzagSubdivision=true)
	could help compatibility with Ogre heightfields. See https://code.google.com/p/bullet/issues/detail?id=625

void	setFlipTriangleWinding (bool flipTriangleWinding)

virtual void	getAabb (const btTransform &t, btVector3 &aabbMin, btVector3 &aabbMax) const
	getAabb returns the axis aligned bounding box in the coordinate frame of the given transform t.

virtual void	processAllTriangles (btTriangleCallback *callback, const btVector3 &aabbMin, const btVector3 &aabbMax) const

virtual void	calculateLocalInertia (btScalar mass, btVector3 &inertia) const
	CollisionShape Interface.

virtual void	setLocalScaling (const btVector3 &scaling)
	in case we receive negative scaling

virtual const btVector3 &	getLocalScaling () const

void	getVertex (int x, int y, btVector3 &vertex) const

void	performRaycast (btTriangleCallback *callback, const btVector3 &raySource, const btVector3 &rayTarget) const

void	buildAccelerator (int chunkSize=16)

void	clearAccelerator ()

int	getUpAxis () const

virtual const char *	getName () const

void	setUserIndex2 (int index)

int	getUserIndex2 () const

void	setUserValue3 (btScalar value)

btScalar	getUserValue3 () const

const struct btTriangleInfoMap *	getTriangleInfoMap () const

void	setTriangleInfoMap (btTriangleInfoMap *map)

const unsigned char *	getHeightfieldRawData () const

Variables
btHeightfieldTerrainShape	__pad0__
	btHeightfieldTerrainShape simulates a 2D heightfield terrain

btScalar	max

btVector3	m_localAabbMin

btVector3	m_localAabbMax

btVector3	m_localOrigin

int	m_heightStickWidth
	terrain data

int	m_heightStickLength

btScalar	m_minHeight

btScalar	m_maxHeight

btScalar	m_width

btScalar	m_length

btScalar	m_heightScale

union {

const unsigned char * m_heightfieldDataUnsignedChar

const short * m_heightfieldDataShort

const btScalar * m_heightfieldDataFloat

const void * m_heightfieldDataUnknown

};

PHY_ScalarType	m_heightDataType

bool	m_flipQuadEdges

bool	m_useDiamondSubdivision

bool	m_useZigzagSubdivision

bool	m_flipTriangleWinding

int	m_upAxis

btVector3	m_localScaling

btAlignedObjectArray< Range >	m_vboundsGrid

int	m_vboundsGridWidth

int	m_vboundsGridLength

int	m_vboundsChunkSize

int	m_userIndex2

btScalar	m_userValue3

struct btTriangleInfoMap *	m_triangleInfoMap

Function Documentation

◆ BT_DECLARE_ALIGNED_ALLOCATOR()

BT_DECLARE_ALIGNED_ALLOCATOR ( )

◆ btHeightfieldTerrainShape() [1/2]

btHeightfieldTerrainShape::btHeightfieldTerrainShape	(	int	heightStickWidth,
		int	heightStickLength,
		const void *	heightfieldData,
		btScalar	heightScale,
		btScalar	minHeight,
		btScalar	maxHeight,
		int	upAxis,
		PHY_ScalarType	heightDataType,
		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.

Definition at line 20 of file btHeightfieldTerrainShape.cpp.

References initialize().

Referenced by btAdjustInternalEdgeContacts(), and btCollisionWorld::rayTestSingleInternal().

◆ btHeightfieldTerrainShape() [2/2]

btHeightfieldTerrainShape::btHeightfieldTerrainShape	(	int	heightStickWidth,
		int	heightStickLength,
		const void *	heightfieldData,
		btScalar	maxHeight,
		int	upAxis,
		bool	useFloatData,
		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).

Definition at line 33 of file btHeightfieldTerrainShape.cpp.

References initialize(), PHY_FLOAT, and PHY_UCHAR.

◆ buildAccelerator()

void btHeightfieldTerrainShape::buildAccelerator ( int chunkSize = 16 )

Builds a grid data structure storing the min and max heights of the terrain in chunks. if chunkSize is zero, that accelerator is removed. If you modify the heights, you need to rebuild this accelerator.

Definition at line 750 of file btHeightfieldTerrainShape.cpp.

References clearAccelerator(), getRawHeightFieldValue(), m_heightStickLength, m_heightStickWidth, m_vboundsChunkSize, m_vboundsGrid, m_vboundsGridLength, m_vboundsGridWidth, x, and z().

◆ calculateLocalInertia()

virtual void calculateLocalInertia	(	btScalar	mass,
		btVector3 &	inertia ) const

virtual

CollisionShape Interface.

Definition at line 54 of file btConeShape.h.

◆ clearAccelerator()

void btHeightfieldTerrainShape::clearAccelerator ( )

Definition at line 848 of file btHeightfieldTerrainShape.cpp.

References m_vboundsGrid.

Referenced by buildAccelerator(), and ~btHeightfieldTerrainShape().

◆ getAabb()

virtual void getAabb	(	const btTransform &	t,
		btVector3 &	aabbMin,
		btVector3 &	aabbMax ) const

virtual

getAabb returns the axis aligned bounding box in the coordinate frame of the given transform t.

getAabb's default implementation is brute force, expected derived classes to implement a fast dedicated version

getAabb returns the axis aligned bounding box in the coordinate frame of the given transform t.

Definition at line 54 of file btCapsuleShape.h.

◆ getHeightfieldRawData()

const unsigned char * getHeightfieldRawData ( ) const

Definition at line 223 of file btHeightfieldTerrainShape.h.

References m_heightfieldDataUnsignedChar.

◆ getLocalScaling()

virtual const btVector3 & getLocalScaling ( ) const

virtual

Definition at line 126 of file btCompoundShape.h.

◆ getName()

virtual const char * getName ( ) const

virtual

Definition at line 192 of file btHeightfieldTerrainShape.h.

◆ getRawHeightFieldValue()

btScalar btHeightfieldTerrainShape::getRawHeightFieldValue	(	int	x,
		int	y ) const

protectedvirtual

This returns the "raw" (user's initial) height, not the actual height. The actual height needs to be adjusted to be relative to the center of the heightfield's AABB.

Definition at line 146 of file btHeightfieldTerrainShape.cpp.

References btAssert, m_heightDataType, m_heightfieldDataFloat, m_heightfieldDataShort, m_heightfieldDataUnsignedChar, m_heightScale, m_heightStickWidth, PHY_FLOAT, PHY_SHORT, and PHY_UCHAR.

Referenced by buildAccelerator().

◆ getTriangleInfoMap()

const struct btTriangleInfoMap * getTriangleInfoMap ( ) const

Definition at line 211 of file btHeightfieldTerrainShape.h.

References m_triangleInfoMap.

◆ getUpAxis()

int getUpAxis ( ) const

Definition at line 187 of file btHeightfieldTerrainShape.h.

References m_upAxis.

◆ getUserIndex2()

int getUserIndex2 ( ) const

Definition at line 199 of file btHeightfieldTerrainShape.h.

References m_userIndex2.

◆ getUserValue3()

btScalar getUserValue3 ( ) const

Definition at line 207 of file btHeightfieldTerrainShape.h.

References m_userValue3.

◆ getVertex()

void getVertex	(	int	x,
		int	y,
		btVector3 &	vertex ) const

◆ initialize()

void initialize	(	int	heightStickWidth,
		int	heightStickLength,
		const void *	heightfieldData,
		btScalar	heightScale,
		btScalar	minHeight,
		btScalar	maxHeight,
		int	upAxis,
		PHY_ScalarType	heightDataType,
		bool	flipQuadEdges )

protected

protected initialization

Handles the work of constructors so that public constructors can be backwards-compatible without a lot of copy/paste.

◆ performRaycast()

void performRaycast	(	btTriangleCallback *	callback,
		const btVector3 &	raySource,
		const btVector3 &	rayTarget ) const

◆ processAllTriangles()

virtual void processAllTriangles	(	btTriangleCallback *	callback,
		const btVector3 &	aabbMin,
		const btVector3 &	aabbMax ) const

virtual

Definition at line 57 of file btEmptyShape.h.

◆ quantizeWithClamp()

void btHeightfieldTerrainShape::quantizeWithClamp	(	int *	out,
		const btVector3 &	point,
		int	isMax ) const

protected

given input vector, return quantized version

This routine is basically determining the gridpoint indices for a given input vector, answering the question: "which gridpoint is closest to the provided point?".

"with clamp" means that we restrict the point to be in the heightfield's axis-aligned bounding box.

Definition at line 246 of file btHeightfieldTerrainShape.cpp.

References getQuantized(), m_localAabbMax, and m_localAabbMin.

◆ setFlipTriangleWinding()

void setFlipTriangleWinding ( bool flipTriangleWinding )

Definition at line 166 of file btHeightfieldTerrainShape.h.

References m_flipTriangleWinding.

◆ setLocalScaling()

virtual void setLocalScaling ( const btVector3 & scaling )

virtual

in case we receive negative scaling

Definition at line 120 of file btBox2dShape.h.

◆ setTriangleInfoMap()

void setTriangleInfoMap ( btTriangleInfoMap * map )

Definition at line 219 of file btHeightfieldTerrainShape.h.

References m_triangleInfoMap.

◆ setUseDiamondSubdivision()

void setUseDiamondSubdivision ( bool useDiamondSubdivision = true )

Definition at line 161 of file btHeightfieldTerrainShape.h.

References m_useDiamondSubdivision.

◆ setUserIndex2()

void setUserIndex2 ( int index )

Definition at line 195 of file btHeightfieldTerrainShape.h.

References m_userIndex2.

◆ setUserValue3()

void setUserValue3 ( btScalar value )

Definition at line 203 of file btHeightfieldTerrainShape.h.

References m_userValue3.

◆ setUseZigzagSubdivision()

void setUseZigzagSubdivision ( bool useZigzagSubdivision = true )

could help compatibility with Ogre heightfields. See https://code.google.com/p/bullet/issues/detail?id=625

Definition at line 164 of file btHeightfieldTerrainShape.h.

References m_useZigzagSubdivision.

◆ ~btHeightfieldTerrainShape()

btHeightfieldTerrainShape::~btHeightfieldTerrainShape ( )

virtual

Definition at line 120 of file btHeightfieldTerrainShape.cpp.

References clearAccelerator().

Variable Documentation

◆ [union]

union { ... }

◆ pad0

btHeightfieldTerrainShape __pad0__

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).

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.

Definition at line 73 of file btHeightfieldTerrainShape.h.