walberla::mesa_pd::collision_detection::GJK Class Reference

Detailed Description

Implementation of the Gilbert-Johnson-Keerthi Algorithm.

#include <GJK.h>

Public Member Functions
Constructor
	GJK ()
Query functions
real_t	doGJK (const Support &geom1, const Support &geom2, Vec3 &normal, Vec3 &contactPoint)
	Calculate an upper bound for the distance of two Geometries.
bool	doGJKmargin (const Support &geom1, const Support &geom2, const real_t margin=real_t(0))
	Compute if two geometries intersect.
Get functions
const std::vector< Vec3 > &	getSimplex () const
size_t	getSimplexSize () const
const std::vector< Vec3 > &	getSupportA () const
const std::vector< Vec3 > &	getSupportB () const

Private Member Functions
Utility functions
bool	simplex2 (Vec3 &d)
	Process a simplex with two nodes.
bool	simplex3 (Vec3 &d)
	Process a simplex with three nodes.
bool	simplex4 (Vec3 &d)
	Process a simplex with four nodes.
bool	sameDirection (const Vec3 &vec1, const Vec3 &vec2) const
	Checks if two vectors roughly point in the same direction.
bool	zeroLengthVector (const Vec3 &vec) const
	Checks if the length of a vector is zero or as close to zero that it can not be distinguished form zero.
real_t	calcDistance (Vec3 &normal, Vec3 &contactPoint)
	Calculate closest Point in the simplex and its distance to the origin.
Vec3	putSupport (const Support &geom1, const Support &geom2, const Vec3 &dir, const real_t margin, std::vector< Vec3 > &simplex, std::vector< Vec3 > &supportA, std::vector< Vec3 > &supportB, size_t index)
	Calculate a support point of a particle extended by a threshold.

Private Attributes
Member variables
std::vector< Vec3 >	simplex_
	Container to hold the simplex.
std::vector< Vec3 >	supportA_
	Container to hold the support points generated in triangle mesh mA.
std::vector< Vec3 >	supportB_
	Container to hold the support points generated in triangle mesh mB.
unsigned char	numPoints_
	Current number of points in the simplex.
Vec3	d_
	The next search direction.

Constructor & Destructor Documentation

GJK()

walberla::mesa_pd::collision_detection::GJK::GJK ( )

explicit

Member Function Documentation

calcDistance()

real_t walberla::mesa_pd::collision_detection::GJK::calcDistance ( Vec3 & normal, Vec3 & contactPoint )

inlineprivate

Calculate closest Point in the simplex and its distance to the origin.

doGJK()

real_t walberla::mesa_pd::collision_detection::GJK::doGJK	(	const Support &	geom1,
		const Support &	geom2,
		Vec3 &	normal,
		Vec3 &	contactPoint )

Calculate an upper bound for the distance of two Geometries.

Returns

Distance between geom1 and geom2 or 0.0 if they are intersecting.

doGJKmargin()

bool walberla::mesa_pd::collision_detection::GJK::doGJKmargin	(	const Support &	geom1,
		const Support &	geom2,
		const real_t	margin = real_t(0) )

Compute if two geometries intersect.

Both can be enlarged by a specified margin.

Parameters

geom1	support function for the first particle
geom2	support function for the second particle
margin	The margin by which the objects will be enlarged.

Returns

true, if an intersection is found.

getSimplex()

const std::vector< Vec3 > & walberla::mesa_pd::collision_detection::GJK::getSimplex ( ) const

inline

getSimplexSize()

size_t walberla::mesa_pd::collision_detection::GJK::getSimplexSize ( ) const

inline

getSupportA()

const std::vector< Vec3 > & walberla::mesa_pd::collision_detection::GJK::getSupportA ( ) const

inline

getSupportB()

const std::vector< Vec3 > & walberla::mesa_pd::collision_detection::GJK::getSupportB ( ) const

inline

putSupport()

Vec3 walberla::mesa_pd::collision_detection::GJK::putSupport ( const Support & geom1, const Support & geom2, const Vec3 & dir, const real_t margin, std::vector< Vec3 > & simplex, std::vector< Vec3 > & supportA, std::vector< Vec3 > & supportB, size_t index )

inlineprivate

Calculate a support point of a particle extended by a threshold.

Parameters

geom1	The body A.
geom2	The body B.
dir	The support point direction.
margin	The margin by which the objects will be enlarged.

sameDirection()

bool walberla::mesa_pd::collision_detection::GJK::sameDirection ( const Vec3 & vec1, const Vec3 & vec2 ) const

inlineprivate

Checks if two vectors roughly point in the same direction.

simplex2()

bool walberla::mesa_pd::collision_detection::GJK::simplex2 ( Vec3 & d )

private

Process a simplex with two nodes.

simplex3()

bool walberla::mesa_pd::collision_detection::GJK::simplex3 ( Vec3 & d )

private

Process a simplex with three nodes.

simplex4()

bool walberla::mesa_pd::collision_detection::GJK::simplex4 ( Vec3 & d )

private

Process a simplex with four nodes.

zeroLengthVector()

bool walberla::mesa_pd::collision_detection::GJK::zeroLengthVector ( const Vec3 & vec ) const

inlineprivate

Checks if the length of a vector is zero or as close to zero that it can not be distinguished form zero.

Member Data Documentation

d_

Vec3 walberla::mesa_pd::collision_detection::GJK::d_

private

The next search direction.

numPoints_

unsigned char walberla::mesa_pd::collision_detection::GJK::numPoints_

private

Current number of points in the simplex.

simplex_

std::vector<Vec3> walberla::mesa_pd::collision_detection::GJK::simplex_

private

Container to hold the simplex.

supportA_

std::vector<Vec3> walberla::mesa_pd::collision_detection::GJK::supportA_

private

Container to hold the support points generated in triangle mesh mA.

supportB_

std::vector<Vec3> walberla::mesa_pd::collision_detection::GJK::supportB_

private

Container to hold the support points generated in triangle mesh mB.

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The documentation for this class was generated from the following files:

• /builds/administration/walberla-website/walberla/src/mesa_pd/collision_detection/GJK.h
• /builds/administration/walberla-website/walberla/src/mesa_pd/collision_detection/GJK.cpp