GJK solver for convex geometries. More...

#include <solver_gjk_pp.hpp>

Inheritance diagram for netdem::SolverGJKPP:

Public Member Functions
	SolverGJKPP ()
	Default constructor for SolverGJKPP.

	SolverGJKPP (Particle const p1, Particle const p2)
	Constructor for SolverGJKPP.

CollisionSolverPP *	Clone () const override
	Creates a copy of this collision solver.

void	Init (Particle const p1, Particle const p2) override
	Initializes the collision solver with two particles.

bool	Detect () override
	Detects collisions between the two particles.

void	ResolveInit (ContactPP *const cnt, double timestep) override
	Initializes the contact point between two particles at time t = 0.

void	ResolveUpdate (ContactPP *const cnt, double timestep) override
	Updates the contact point between two particles at time t > 0.

void	ResolveInit (CollisionGeometries *const cnt_geoms, double timestep)
	Initializes the contact geometries between two particles at time t = 0.

void	ResolveUpdate (CollisionGeometries *const cnt_geoms, double timestep)
	Updates the contact geometries between two particles at time t > 0.

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

	CollisionSolverPP (Particle const p1, Particle const p2)

virtual bool	Detect (ContactPP *const cnt)

virtual	~CollisionSolverPP ()

Public Attributes
double	erosion_ratio_initial {0.01}
	< The initial ratio of erosion for the terrain.

double	erosion_ratio_increment {0.01}
	Whether to use erosion for the terrain or not.

bool	use_erosion {false}

bool	enable_logging {false}
	Flag to determine whether logging is enabled.

Public Attributes inherited from netdem::CollisionSolverPP
Particle *	particle_1 {nullptr}

Particle *	particle_2 {nullptr}

Protected Member Functions
bool	GJK ()
	Runs the Gilbert-Johnson-Keerthi algorithm.

std::tuple< double, Vec3d, Vec3d >	GJK_EROSION ()
	Runs the Gilbert-Johnson-Keerthi algorithm with erosion applied.

std::tuple< double, Vec3d, Vec3d >	EPA ()
	Runs the Expanding Polytope Algorithm.

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

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 of 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 used in the Gilbert-Johnson-Keerthi algorithm.

void	UpdateSimplexLine (Simplex const s, Vec3d const dir, double const min_dist, bool const cnt_flag)
	Updates the simplex when it contains a line segment.

void	UpdateSimplexTriangle (Simplex const s, Vec3d const dir, double const min_dist, bool const cnt_flag)
	Updates the simplex when it contains a triangle.

void	UpdateSimplexTetrahedron (Simplex const s, Vec3d const dir, double const min_dist, bool const cnt_flag)
	Updates the simplex when it contains a tetrahedron.

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

void	GetLooseEdges (VecXT< Vec2i > *const edges, Vec3i const &facet)
	Computes the edges of a triangle that could potentially be involved in a collision.

void	GetIntersections (VecXT< Vec3d > *const intersects, Vec3d const &dir_n, Vec3d const &l1_p1, Vec3d const &l1_p2, Vec3d const &l2_p1, Vec3d const &l2_p2)
	Computes the intersection points of two line segments.

void	GetIntersectionsAggresive (VecXT< Vec3d > *const intersects, Vec3d const &dir_n, Vec3d const &l1_p1, Vec3d const &l1_p2, Vec3d const &l2_p1, Vec3d const &l2_p2)
	Computes the intersection points of two line segments using a more aggressive algorithm.

void	SortVertices (VecXT< Vec3d > *const pos_vec, Vec3d const &dir_n)
	Sorts the vertices of a polygon based on their distance to a given point.

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

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

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

void	UpdateBasicGeoms (CollisionGeometries *const cnt_geoms, double timestep, Vec3d const &dir_n_old)
	Update the basic contact geometries associated with a collision.

Protected Attributes
Shape *	shape_1 {nullptr}

Shape *	shape_2 {nullptr}

double	bound_sphere_radius_1

double	bound_sphere_radius_2

Vec3d	dpos_12

Vec3d	dpos_12_ref

Vec4d	dquat_12

Vec4d	dquat_12_conj

Simplex	simplex_after_gjk

Detailed Description

GJK solver for convex geometries.

Examples: 0_demo_erosion_issue.cpp, 1_test_triaxial_comp.cpp, 2_ev_gjk_performance.cpp, 31_test_dataset_ellipsoid.cpp, 36_test_ann_vs_geom_ellipsoid.cpp, 37_test_ann_vs_geom_ellipsoid.cpp, and 81_voronoi_packing.cpp.

Constructor & Destructor Documentation

◆ SolverGJKPP() [1/2]

netdem::SolverGJKPP::SolverGJKPP ( )

Default constructor for SolverGJKPP.

◆ SolverGJKPP() [2/2]

netdem::SolverGJKPP::SolverGJKPP	(	Particle *const	p1,
		Particle *const	p2 )

Constructor for SolverGJKPP.

Parameters

p1	The first particle.
p2	The second particle.

Member Function Documentation

◆ Clone()

CollisionSolverPP * netdem::SolverGJKPP::Clone ( ) const

overridevirtual

Creates a copy of this collision solver.

Returns: A new instance of the collision solver.

Implements netdem::CollisionSolverPP.

◆ Detect()

bool netdem::SolverGJKPP::Detect ( )

overridevirtual

Detects collisions between the two particles.

Returns: True if a collision occurred, false otherwise.

Implements netdem::CollisionSolverPP.

Examples: 2_ev_gjk_performance.cpp, 31_test_dataset_ellipsoid.cpp, 36_test_ann_vs_geom_ellipsoid.cpp, and 37_test_ann_vs_geom_ellipsoid.cpp.

◆ EPA()

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

protected

Runs the Expanding Polytope Algorithm.

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

◆ GetContactPoint()

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

protected

Computes the contact point along a given direction.

Parameters

dir	The direction to compute the contact point along.

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

◆ GetContactPoint_PlaneCase()

tuple< Vec3d, bool > netdem::SolverGJKPP::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()

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

inlineprotected

Computes the normal and distance from origin of a facet defined by three vertices.

Parameters

a	The first vertex.
b	The second vertex.
c	The third vertex.

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

◆ GetIntersections()

void netdem::SolverGJKPP::GetIntersections	(	VecXT< Vec3d > *const	intersects,
		Vec3d const &	dir_n,
		Vec3d const &	l1_p1,
		Vec3d const &	l1_p2,
		Vec3d const &	l2_p1,
		Vec3d const &	l2_p2 )

protected

Computes the intersection points of two line segments.

Parameters

intersects	The output vector of intersection points.
dir_n	The direction of the line segments.
l1_p1	The starting point of the first line segment.
l1_p2	The ending point of the first line segment.
l2_p1	The starting point of the second line segment.
l2_p2	The ending point of the second line segment.

◆ GetIntersectionsAggresive()

void netdem::SolverGJKPP::GetIntersectionsAggresive	(	VecXT< Vec3d > *const	intersects,
		Vec3d const &	dir_n,
		Vec3d const &	l1_p1,
		Vec3d const &	l1_p2,
		Vec3d const &	l2_p1,
		Vec3d const &	l2_p2 )

protected

Computes the intersection points of two line segments using a more aggressive algorithm.

Parameters

intersects	The output vector of intersection points.
dir_n	The direction of the line segments.
l1_p1	The starting point of the first line segment.
l1_p2	The ending point of the first line segment.
l2_p1	The starting point of the second line segment.
l2_p2	The ending point of the second line segment.

◆ GetLooseEdges()

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

protected

Computes the edges of a triangle that could potentially be involved in a collision.

Parameters

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

◆ GetPolygonCentroid()

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

protected

Computes the centroid of a polygon.

Parameters

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

Returns: The centroid of the polygon.

◆ GJK()

bool netdem::SolverGJKPP::GJK ( )

protected

Runs the Gilbert-Johnson-Keerthi algorithm.

Returns: True if a collision occurred, false otherwise.

◆ GJK_EROSION()

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

protected

Runs the Gilbert-Johnson-Keerthi algorithm with erosion applied.

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

◆ Init()

void netdem::SolverGJKPP::Init	(	Particle *const	p1,
		Particle *const	p2 )

overridevirtual

Initializes the collision solver with two particles.

Parameters

p1	The first particle.
p2	The second particle.

Reimplemented from netdem::CollisionSolverPP.

Examples: 2_ev_gjk_performance.cpp, 31_test_dataset_ellipsoid.cpp, 36_test_ann_vs_geom_ellipsoid.cpp, and 37_test_ann_vs_geom_ellipsoid.cpp.

◆ IsInsidePolygon()

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

protected

Determines whether a point is inside a polygon.

Parameters

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

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

◆ MinkowskiDiff()

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

inlineprotected

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

Parameters

dir	The direction to compute the Minkowski difference along.
erosion_ratio	The erosion ratio to apply.

Returns: The Minkowski difference of the two shapes.

◆ ResolveInit() [1/2]

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

Initializes the contact geometries between two particles at time t = 0.

Parameters

cnt_geoms	The contact geometries.
timestep	The simulation timestep.

◆ ResolveInit() [2/2]

void netdem::SolverGJKPP::ResolveInit	(	ContactPP *const	cnt,
		double	timestep )

overridevirtual

Initializes the contact point between two particles at time t = 0.

Parameters

cnt	The contact point.
timestep	The simulation timestep.

Implements netdem::CollisionSolverPP.

Examples: 2_ev_gjk_performance.cpp, 31_test_dataset_ellipsoid.cpp, 36_test_ann_vs_geom_ellipsoid.cpp, and 37_test_ann_vs_geom_ellipsoid.cpp.

◆ ResolveUpdate() [1/2]

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

Updates the contact geometries between two particles at time t > 0.

Parameters

cnt_geoms	The contact geometries.
timestep	The simulation timestep.

◆ ResolveUpdate() [2/2]

void netdem::SolverGJKPP::ResolveUpdate	(	ContactPP *const	cnt,
		double	timestep )

overridevirtual

Updates the contact point between two particles at time t > 0.

Parameters

cnt	The contact point.
timestep	The simulation timestep.

Implements netdem::CollisionSolverPP.

◆ SortVertices()

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

protected

Sorts the vertices of a polygon based on their distance to a given point.

Parameters

pos_vec	The vector of vertices to sort.
dir_n	The direction to sort the vertices in.

◆ UpdateSimplex()

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

protected

Updates the simplex used in the Gilbert-Johnson-Keerthi algorithm.

Parameters

s	The simplex to update.
dir	The search direction.
min_dist	The minimum distance between the two shapes.
cnt_flag	A flag indicating whether a contact has been found.

◆ UpdateSimplexLine()

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

protected

Updates the simplex when it contains a line segment.

Parameters

s	The simplex to update.
dir	The search direction.
min_dist	The minimum distance between the two shapes.
cnt_flag	A flag indicating whether a contact has been found.

◆ UpdateSimplexTetrahedron()

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

protected

Updates the simplex when it contains a tetrahedron.

Parameters

s	The simplex to update.
dir	The search direction.
min_dist	The minimum distance between the two shapes.
cnt_flag	A flag indicating whether a contact has been found.

◆ UpdateSimplexTriangle()

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

protected

Updates the simplex when it contains a triangle.

Parameters

s	The simplex to update.
dir	The search direction.
min_dist	The minimum distance between the two shapes.
cnt_flag	A flag indicating whether a contact has been found.

Member Data Documentation

◆ bound_sphere_radius_1

double netdem::SolverGJKPP::bound_sphere_radius_1

protected

◆ bound_sphere_radius_2

double netdem::SolverGJKPP::bound_sphere_radius_2

protected

◆ dpos_12

Vec3d netdem::SolverGJKPP::dpos_12

protected

◆ dpos_12_ref

Vec3d netdem::SolverGJKPP::dpos_12_ref

protected

◆ dquat_12

Vec4d netdem::SolverGJKPP::dquat_12

protected

◆ dquat_12_conj

Vec4d netdem::SolverGJKPP::dquat_12_conj

protected

◆ enable_logging

bool netdem::SolverGJKPP::enable_logging {false}

Flag to determine whether logging is enabled.

◆ erosion_ratio_increment

double netdem::SolverGJKPP::erosion_ratio_increment {0.01}

Whether to use erosion for the terrain or not.

◆ erosion_ratio_initial

double netdem::SolverGJKPP::erosion_ratio_initial {0.01}

< The initial ratio of erosion for the terrain.

The increment ratio of erosion for the terrain.

Examples: 2_ev_gjk_performance.cpp.

◆ shape_1

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

protected

◆ shape_2

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

protected

◆ simplex_after_gjk

Simplex netdem::SolverGJKPP::simplex_after_gjk

protected

◆ use_erosion

bool netdem::SolverGJKPP::use_erosion {false}

Examples: 1_test_triaxial_comp.cpp, and 2_ev_gjk_performance.cpp.

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

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

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SolverGJKPP() [1/2]

◆ SolverGJKPP() [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