GJK solver for convex geometries. More...

#include <solver_gjk_pw.hpp>

Inheritance diagram for netdem::SolverGJKPW:

Public Member Functions
	SolverGJKPW ()
	Default constructor for the SolverGJKPW class.

	SolverGJKPW (Particle const p, Wall const w)
	Constructor for the SolverGJKPW class.

CollisionSolverPW *	Clone () const override
	Creates a copy of the current collision solver.

void	Init (Particle const p, Wall const w) override
	Initializes the collision solver with a particle and a wall.

bool	Detect () override
	Detects collisions between a particle and a wall.

void	ResolveInit (ContactPW *const cnt, double timestep) override
	Initializes the contact resolution for a contact point.

void	ResolveUpdate (ContactPW *const cnt, double timestep) override
	Updates the contact resolution for a contact point.

void	ResolveInit (CollisionGeometries *const cnt_geoms, double timestep)
	Initializes the contact resolution for a set of collision geometries.

void	ResolveUpdate (CollisionGeometries *const cnt_geoms, double timestep)
	Updates the contact resolution for a set of collision geometries.

Public Member Functions inherited from netdem::CollisionSolverPW
	CollisionSolverPW ()

	CollisionSolverPW (Particle const p, Wall const w)

virtual bool	Detect (ContactPW *const cnt)

virtual	~CollisionSolverPW ()

Public Attributes
double	erosion_ratio_initial {0.01}
	< The initial erosion ratio used by the solver.

double	erosion_ratio_increment {0.01}
	Whether to use erosion during collision detection.

bool	use_erosion {false}
	Whether to print debug logs during collision detection.

bool	enable_logging {false}

Public Attributes inherited from netdem::CollisionSolverPW
Particle *	particle {nullptr}

Wall *	wall {nullptr}

Protected Member Functions
bool	GJK ()
	Implements the Gilbert-Johnson-Keerthi algorithm for collision detection.

std::tuple< double, Vec3d, Vec3d >	GJK_EROSION ()
	Implements the Gilbert-Johnson-Keerthi algorithm with erosion for collision detection.

std::tuple< double, Vec3d, Vec3d >	EPA ()
	Implements the Expanding Polytope Algorithm for collision resolution.

std::tuple< Vec3d, bool >	GetContactPoint (Vec3d const &dir)
	Computes the contact point given the contact normal.

std::tuple< Vec3d, bool >	GetContactPoint_PlaneCase (Vec3d const &dir, const VecXT< Vec3d > &pos_vec_1, const VecXT< Vec3d > &pos_vec_2)
	Computes the contact point in the case where one of the shapes is a plane.

Vec3d	MinkowskiDiff (Vec3d const &dir, double erosion_ratio=0)
	Computes the Minkowski difference between the two shapes along a given direction.

void	UpdateSimplex (Simplex const s, Vec3d const dir, double const min_dist, bool const cnt_flag)
	Updates the simplex after each GJK iteration based on the distance computed.

void	UpdateSimplexLine (Simplex const s, Vec3d const dir, double const min_dist, bool const cnt_flag)
	Updates the simplex for the line case.

void	UpdateSimplexTriangle (Simplex const s, Vec3d const dir, double const min_dist, bool const cnt_flag)
	Updates the simplex for the triangle case.

void	UpdateSimplexTetrahedron (Simplex const s, Vec3d const dir, double const min_dist, bool const cnt_flag)
	Updates the simplex for the tetrahedron case.

std::tuple< Vec3d, double >	GetFacetNormal (Vec3d const &a, Vec3d const &b, Vec3d const &c)
	Computes the normal and distance of a facet defined by three points.

void	GetLooseEdges (VecXT< Vec2i > *const edges, Vec3i const &facet)
	Computes the edges of a polygon defined by a set of vertices.

void	GetIntersections (VecXT< Vec3d > *const intersects, Vec3d const &dir_n, Vec3d const &l1_p, Vec3d const &l1_w, Vec3d const &l2_p, Vec3d const &l2_w)
	Computes the intersection points between two 3D line segments.

void	GetIntersectionsAggresive (VecXT< Vec3d > *const intersects, Vec3d const &dir_n, Vec3d const &l1_p, Vec3d const &l1_w, Vec3d const &l2_p, Vec3d const &l2_w)
	Same as GetInter sections, but uses a more aggressive intersection algorithm.

void	SortVertices (VecXT< Vec3d > *const pos_vec, Vec3d const &dir_n)
	Sorts the vertices of a polygon in counter-clockwise order relative to a given direction.

bool	IsInsidePolygon (VecXT< Vec3d > const &pos_vec, Vec3d const &dir_n, Vec3d const &pos)
	Determines whether a point is inside a polygon defined by a set of vertices.

Vec3d	GetPolygonCentroid (VecXT< Vec3d > const &pos_vec, Vec3d const &dir_n)
	Computes the centroid of a polygon defined by a set of vertices.

Protected Member Functions inherited from netdem::CollisionSolverPW
void	InitBasicGeoms (CollisionGeometries *const cnt_geoms, double timestep)

void	UpdateBasicGeoms (CollisionGeometries *const cnt_geoms, double timestep, Vec3d const &dir_n_old)

Protected Attributes
Shape *	shape_1 {nullptr}
	< The shapes involved in the collision.

Shape *	shape_2 {nullptr}
	The radii of the bounding spheres around the shapes.

double	bound_sphere_radius_1

double	bound_sphere_radius_2
	The position difference between the particles.

Vec3d	dpos_12

Vec3d	dpos_12_ref
	The orientation difference between the particles.

Vec4d	dquat_12

Vec4d	dquat_12_conj
	The simplex computed during GJK collision detection.

Simplex	simplex_after_gjk

Detailed Description

GJK solver for convex geometries.

This class is a collision solver that uses the Gilbert-Johnson-Keerthi (GJK) algorithm to detect collisions between particles and walls with convex geometries. It extends the CollisionSolverPW class.

Examples: 1_test_triaxial_comp.cpp, 21_test_dataset_ellipsoid_plane.cpp, and 26_test_ann_vs_geom_ellipsoid_plane.cpp.

Constructor & Destructor Documentation

◆ SolverGJKPW() [1/2]

netdem::SolverGJKPW::SolverGJKPW ( )

Default constructor for the SolverGJKPW class.

◆ SolverGJKPW() [2/2]

netdem::SolverGJKPW::SolverGJKPW	(	Particle *const	p,
		Wall *const	w )

Constructor for the SolverGJKPW class.

Parameters

p	The particle involved in the collision.
w	The wall involved in the collision.

Member Function Documentation

◆ Clone()

CollisionSolverPW * netdem::SolverGJKPW::Clone ( ) const

overridevirtual

Creates a copy of the current collision solver.

Returns: A pointer to the cloned CollisionSolverPW object.

Implements netdem::CollisionSolverPW.

◆ Detect()

bool netdem::SolverGJKPW::Detect ( )

overridevirtual

Detects collisions between a particle and a wall.

Returns: True if a collision is detected, false otherwise.

Implements netdem::CollisionSolverPW.

Examples: 21_test_dataset_ellipsoid_plane.cpp, and 26_test_ann_vs_geom_ellipsoid_plane.cpp.

◆ EPA()

tuple< double, Vec3d, Vec3d > netdem::SolverGJKPW::EPA ( )

protected

Implements the Expanding Polytope Algorithm for collision resolution.

Returns: A tuple containing the contact position and a flag indicating whether the algorithm succeeded.

◆ GetContactPoint()

tuple< Vec3d, bool > netdem::SolverGJKPW::GetContactPoint ( Vec3d const & dir )

protected

Computes the contact point given the contact normal.

Parameters

dir	The contact normal.

Returns: A tuple containing the contact position and a flag indicating whether the algorithm succeeded.

◆ GetContactPoint_PlaneCase()

tuple< Vec3d, bool > netdem::SolverGJKPW::GetContactPoint_PlaneCase	(	Vec3d const &	dir,
		const VecXT< Vec3d > &	pos_vec_1,
		const VecXT< Vec3d > &	pos_vec_2 )

protected

Computes the contact point in the case where one of the shapes is a plane.

Parameters

dir	The contact normal.
pos_vec_1	The positions of the vertices of shape 1.
pos_vec_2	The positions of the vertices of shape 2.

Returns: A tuple containing the contact position and a flag indicating whether the algorithm succeeded.

◆ GetFacetNormal()

tuple< Vec3d, double > netdem::SolverGJKPW::GetFacetNormal	(	Vec3d const &	a,
		Vec3d const &	b,
		Vec3d const &	c )

inlineprotected

Computes the normal and distance of a facet defined by three points.

Parameters

a	The first point of the facet.
b	The second point of the facet.
c	The third point of the facet.

Returns: A tuple containing the normal vector and the distance from the origin.

◆ GetIntersections()

void netdem::SolverGJKPW::GetIntersections	(	VecXT< Vec3d > *const	intersects,
		Vec3d const &	dir_n,
		Vec3d const &	l1_p,
		Vec3d const &	l1_w,
		Vec3d const &	l2_p,
		Vec3d const &	l2_w )

protected

Computes the intersection points between two 3D line segments.

Parameters

intersects	The output vector of intersection points.
dir_n	The direction of the line segments.
l1_p	The starting point of the first line segment.
l1_w	The ending point of the first line segment.
l2_p	The starting point of the second line segment.
l2_w	The ending point of the second line segment.

◆ GetIntersectionsAggresive()

void netdem::SolverGJKPW::GetIntersectionsAggresive	(	VecXT< Vec3d > *const	intersects,
		Vec3d const &	dir_n,
		Vec3d const &	l1_p,
		Vec3d const &	l1_w,
		Vec3d const &	l2_p,
		Vec3d const &	l2_w )

protected

Same as GetInter sections, but uses a more aggressive intersection algorithm.

Parameters

intersects	The output vector of intersection points.
dir_n	The direction of the line segments.
l1_p	The starting point of the first line segment.
l1_w	The ending point of the first line segment.
l2_p	The starting point of the second line segment.
l2_w	The ending point of the second line segment.

◆ GetLooseEdges()

void netdem::SolverGJKPW::GetLooseEdges	(	VecXT< Vec2i > *const	edges,
		Vec3i const &	facet )

protected

Computes the edges of a polygon defined by a set of vertices.

Parameters

edges	The output vector of edges.
facet	The indices of the vertices defining the polygon.

◆ GetPolygonCentroid()

Vec3d netdem::SolverGJKPW::GetPolygonCentroid	(	VecXT< Vec3d > const &	pos_vec,
		Vec3d const &	dir_n )

protected

Computes the centroid of a polygon defined by a set of vertices.

Parameters

pos_vec	The vertices defining the polygon.
dir_n	The normal vector of the polygon.

Returns: The centroid of the polygon.

◆ GJK()

bool netdem::SolverGJKPW::GJK ( )

protected

Implements the Gilbert-Johnson-Keerthi algorithm for collision detection.

Returns: True if a collision is detected, false otherwise.

◆ GJK_EROSION()

tuple< double, Vec3d, Vec3d > netdem::SolverGJKPW::GJK_EROSION ( )

protected

Implements the Gilbert-Johnson-Keerthi algorithm with erosion for collision detection.

Returns: A tuple containing the length and direction of the contact normal, and the contact position.

◆ Init()

void netdem::SolverGJKPW::Init	(	Particle *const	p,
		Wall *const	w )

overridevirtual

Initializes the collision solver with a particle and a wall.

Parameters

p	The particle involved in the collision.
w	The wall involved in the collision.

Reimplemented from netdem::CollisionSolverPW.

Examples: 21_test_dataset_ellipsoid_plane.cpp, and 26_test_ann_vs_geom_ellipsoid_plane.cpp.

◆ IsInsidePolygon()

bool netdem::SolverGJKPW::IsInsidePolygon	(	VecXT< Vec3d > const &	pos_vec,
		Vec3d const &	dir_n,
		Vec3d const &	pos )

protected

Determines whether a point is inside a polygon defined by a set of vertices.

Parameters

pos_vec	The vertices defining the polygon.
dir_n	The normal vector of the polygon.
pos	The point to test for containment.

Returns: True if the point is inside the polygon, false otherwise.

◆ MinkowskiDiff()

Vec3d netdem::SolverGJKPW::MinkowskiDiff	(	Vec3d const &	dir,
		double	erosion_ratio = 0 )

inlineprotected

Computes the Minkowski difference between the two shapes along a given direction.

Parameters

dir	The direction to compute the Minkowski difference along.
erosion_ratio	The amount of erosion to apply to the shapes.

Returns: The Minkowski difference.

◆ ResolveInit() [1/2]

void netdem::SolverGJKPW::ResolveInit	(	CollisionGeometries *const	cnt_geoms,
		double	timestep )

Initializes the contact resolution for a set of collision geometries.

Parameters

cnt_geoms	The collision geometries to resolve.
timestep	The simulation time step size.

◆ ResolveInit() [2/2]

void netdem::SolverGJKPW::ResolveInit	(	ContactPW *const	cnt,
		double	timestep )

overridevirtual

Initializes the contact resolution for a contact point.

Parameters

cnt	The contact point to resolve.
timestep	The simulation time step size.

Implements netdem::CollisionSolverPW.

Examples: 21_test_dataset_ellipsoid_plane.cpp, and 26_test_ann_vs_geom_ellipsoid_plane.cpp.

◆ ResolveUpdate() [1/2]

void netdem::SolverGJKPW::ResolveUpdate	(	CollisionGeometries *const	cnt_geoms,
		double	timestep )

Updates the contact resolution for a set of collision geometries.

Parameters

cnt_geoms	The collision geometries to resolve.
timestep	The simulation time step size.

◆ ResolveUpdate() [2/2]

void netdem::SolverGJKPW::ResolveUpdate	(	ContactPW *const	cnt,
		double	timestep )

overridevirtual

Updates the contact resolution for a contact point.

Parameters

cnt	The contact point to resolve.
timestep	The simulation time step size.

Implements netdem::CollisionSolverPW.

◆ SortVertices()

void netdem::SolverGJKPW::SortVertices	(	VecXT< Vec3d > *const	pos_vec,
		Vec3d const &	dir_n )

protected

Sorts the vertices of a polygon in counter-clockwise order relative to a given direction.

Parameters

pos_vec	The input and output vector of vertices.
dir_n	The direction to sort the vertices relative to.

◆ UpdateSimplex()

void netdem::SolverGJKPW::UpdateSimplex	(	Simplex *const	s,
		Vec3d *const	dir,
		double *const	min_dist,
		bool *const	cnt_flag )

protected

Updates the simplex after each GJK iteration based on the distance computed.

Parameters

s	The current simplex.
dir	The search direction for the next iteration.
min_dist	The minimum distance between the shapes.
cnt_flag	A flag indicating whether a contact has been detected.

◆ UpdateSimplexLine()

void netdem::SolverGJKPW::UpdateSimplexLine	(	Simplex *const	s,
		Vec3d *const	dir,
		double *const	min_dist,
		bool *const	cnt_flag )

protected

Updates the simplex for the line case.

Parameters

s	The current simplex.
dir	The search direction for the next iteration.
min_dist	The minimum distance between the shapes.
cnt_flag	A flag indicating whether a contact has been detected.

◆ UpdateSimplexTetrahedron()

void netdem::SolverGJKPW::UpdateSimplexTetrahedron	(	Simplex *const	s,
		Vec3d *const	dir,
		double *const	min_dist,
		bool *const	cnt_flag )

protected

Updates the simplex for the tetrahedron case.

Parameters

s	The current simplex.
dir	The search direction for the next iteration.
min_dist	The minimum distance between the shapes.
cnt_flag	A flag indicating whether a contact has been detected.

◆ UpdateSimplexTriangle()

void netdem::SolverGJKPW::UpdateSimplexTriangle	(	Simplex *const	s,
		Vec3d *const	dir,
		double *const	min_dist,
		bool *const	cnt_flag )

protected

Updates the simplex for the triangle case.

Parameters

s	The current simplex.
dir	The search direction for the next iteration.
min_dist	The minimum distance between the shapes.
cnt_flag	A flag indicating whether a contact has been detected.

Member Data Documentation

◆ bound_sphere_radius_1

double netdem::SolverGJKPW::bound_sphere_radius_1

protected

◆ bound_sphere_radius_2

double netdem::SolverGJKPW::bound_sphere_radius_2

protected

The position difference between the particles.

◆ dpos_12

Vec3d netdem::SolverGJKPW::dpos_12

protected

◆ dpos_12_ref

Vec3d netdem::SolverGJKPW::dpos_12_ref

protected

The orientation difference between the particles.

◆ dquat_12

Vec4d netdem::SolverGJKPW::dquat_12

protected

◆ dquat_12_conj

Vec4d netdem::SolverGJKPW::dquat_12_conj

protected

The simplex computed during GJK collision detection.

◆ enable_logging

bool netdem::SolverGJKPW::enable_logging {false}

◆ erosion_ratio_increment

double netdem::SolverGJKPW::erosion_ratio_increment {0.01}

Whether to use erosion during collision detection.

◆ erosion_ratio_initial

double netdem::SolverGJKPW::erosion_ratio_initial {0.01}

< The initial erosion ratio used by the solver.

The incremental change in erosion ratio.

◆ shape_1

Shape* netdem::SolverGJKPW::shape_1 {nullptr}

protected

< The shapes involved in the collision.

◆ shape_2

Shape * netdem::SolverGJKPW::shape_2 {nullptr}

protected

The radii of the bounding spheres around the shapes.

◆ simplex_after_gjk

Simplex netdem::SolverGJKPW::simplex_after_gjk

protected

◆ use_erosion

bool netdem::SolverGJKPW::use_erosion {false}

Whether to print debug logs during collision detection.

Examples: 1_test_triaxial_comp.cpp.

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

/Users/lzhshou/Documents/Research/myProjects/apaam/repo/netdem/src/dem/solver_gjk_pw.hpp
/Users/lzhshou/Documents/Research/myProjects/apaam/repo/netdem/src/dem/solver_gjk_pw.cpp

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SolverGJKPW() [1/2]

◆ SolverGJKPW() [2/2]

Member Function Documentation

◆ Clone()

◆ Detect()

◆ EPA()

◆ GetContactPoint()

◆ GetContactPoint_PlaneCase()

◆ GetFacetNormal()

◆ GetIntersections()

◆ GetIntersectionsAggresive()

◆ GetLooseEdges()

◆ GetPolygonCentroid()

◆ GJK()

◆ GJK_EROSION()

◆ Init()

◆ IsInsidePolygon()

◆ MinkowskiDiff()

◆ ResolveInit() [1/2]

◆ ResolveInit() [2/2]

◆ ResolveUpdate() [1/2]

◆ ResolveUpdate() [2/2]

◆ SortVertices()

◆ UpdateSimplex()

◆ UpdateSimplexLine()

◆ UpdateSimplexTetrahedron()

◆ UpdateSimplexTriangle()

Member Data Documentation

◆ bound_sphere_radius_1

◆ bound_sphere_radius_2

◆ dpos_12

◆ dpos_12_ref

◆ dquat_12

◆ dquat_12_conj

◆ enable_logging

◆ erosion_ratio_increment

◆ erosion_ratio_initial

◆ shape_1

◆ shape_2

◆ simplex_after_gjk

◆ use_erosion