box2d::Simplex Class Reference

Simplex. More...

#include <Simplex.hpp>

Classes
class	Cache
	Simplex cache. More...

Public Types
using	Edges = ArrayList< SimplexEdge, MaxEdges, std::remove_const< decltype(MaxEdges)>::type >
	Simplex edge collection. More...
using	size_type = Edges::size_type
	Size type. More...
using	Coefficients = ArrayList< RealNum, MaxEdges, std::remove_const< decltype(MaxEdges)>::type >
	Coefficients. More...
using	IndexPairs = ArrayList< IndexPair, MaxEdges, std::remove_const< decltype(MaxEdges)>::type >
	Index pairs. More...

Public Member Functions
	Simplex ()=default
BOX2D_CONSTEXPR Edges	GetEdges () const noexcept
const SimplexEdge &	GetSimplexEdge (size_type index) const noexcept
BOX2D_CONSTEXPR RealNum	GetCoefficient (size_type index) const noexcept
BOX2D_CONSTEXPR size_type	GetSize () const noexcept

Static Public Member Functions
static Cache	GetCache (const Simplex::Edges &edges) noexcept
static IndexPairs	GetIndexPairs (const Edges &collection) noexcept
	Gets index pairs for the given edges collection. More...
static BOX2D_CONSTEXPR Length2D	CalcSearchDirection (const Edges &simplexEdges) noexcept
	Calculates the "search direction" for the given simplex edge list. More...
static RealNum	CalcMetric (const Edges &simplexEdges)
	Gets the given simplex's "metric". More...
static Simplex	Get (const SimplexEdge &s0) noexcept
static Simplex	Get (const SimplexEdge &s0, const SimplexEdge &s1) noexcept
	Gets the simplex for the given 2 edges. More...
static Simplex	Get (const SimplexEdge &s0, const SimplexEdge &s1, const SimplexEdge &s2) noexcept
	Gets the simplex for the given 3 edges. More...
static Simplex	Get (const Edges &edges) noexcept
	Gets the simplex for the given collection of vertices. More...

Static Public Attributes
static constexpr auto	MaxEdges = std::uint8_t{3}
	Maximum number of supportable edges in a simplex. More...

Detailed Description

Simplex.

An encapsulation of a point, line segment, or triangle. These are defined respectively as: a 0-simplex, a 1-simplex, and a 2-simplex. Used in doing GJK collision detection.

Note

This data structure is 104-bytes large.

Invariant

Vertex's for the same index must have the same point locations.

There may not be more than one entry for the same index pair.

See also

https://en.wikipedia.org/wiki/Simplex

https://en.wikipedia.org/wiki/Gilbert%2DJohnson%2DKeerthi_distance_algorithm

Member Typedef Documentation

Coefficients

using box2d::Simplex::Coefficients = ArrayList<RealNum, MaxEdges, std::remove_const<decltype(MaxEdges)>::type>

Coefficients.

Collection of coefficient values.

Note

This data structure is 4 * 3 + 4 = 16-bytes large.

Edges

using box2d::Simplex::Edges = ArrayList<SimplexEdge, MaxEdges, std::remove_const<decltype(MaxEdges)>::type>

Simplex edge collection.

Note

This data is 28 * 3 + 4 = 88-bytes large (on at least one 64-bit platform).

IndexPairs

using box2d::Simplex::IndexPairs = ArrayList<IndexPair, MaxEdges, std::remove_const<decltype(MaxEdges)>::type>

Index pairs.

Note

This data type is 7-bytes large (on at least one 64-bit platform).

size_type

using box2d::Simplex::size_type = Edges::size_type

Size type.

Note

This data type is explicitly set to 1-byte large.

Constructor & Destructor Documentation

Simplex()

box2d::Simplex::Simplex ( )

default

Member Function Documentation

CalcMetric()

RealNum box2d::Simplex::CalcMetric ( const Edges &  simplexEdges )

inlinestatic

Gets the given simplex's "metric".

CalcSearchDirection()

BOX2D_CONSTEXPR Length2D box2d::Simplex::CalcSearchDirection ( const Edges &  simplexEdges )

inlinestaticnoexcept

Calculates the "search direction" for the given simplex edge list.

Parameters

simplexEdges

A one or two edge list.

Warning

Behavior is undefined if the given edge list has zero edges.

Returns

"search direction" vector.

Get() [1/4]

Simplex Simplex::Get ( const SimplexEdge &  s0 )

staticnoexcept

Get() [2/4]

Simplex Simplex::Get ( const SimplexEdge &  s0, const SimplexEdge &  s1  )

staticnoexcept

Gets the simplex for the given 2 edges.

Note

The given simplex vertices must have different index pairs or be of the same values.

Warning

Behavior is undefined if the given simplex edges index pairs are the same and the whole edges values are not also the same.

Parameters

s0	Simplex edge 0.
s1	Simplex edge 1.

Returns

One or two edge simplex.

Get() [3/4]

Simplex Simplex::Get ( const SimplexEdge &  s0, const SimplexEdge &  s1, const SimplexEdge &  s2  )

staticnoexcept

Gets the simplex for the given 3 edges.

Returns

One, two, or three edge simplex.

Get() [4/4]

Simplex Simplex::Get ( const Edges &  edges )

staticnoexcept

Gets the simplex for the given collection of vertices.

Parameters

edges

Collection of zero, one, two, or three simplex edges.

Warning

Behavior is undefined if the given collection has more than 3 edges.

Returns

Zero, one, two, or three edge simplex.

GetCache()

Simplex::Cache box2d::Simplex::GetCache ( const Simplex::Edges &  edges )

inlinestaticnoexcept

GetCoefficient()

BOX2D_CONSTEXPR RealNum box2d::Simplex::GetCoefficient ( size_type  index ) const

inlinenoexcept

GetEdges()

BOX2D_CONSTEXPR Simplex::Edges box2d::Simplex::GetEdges ( ) const

inlinenoexcept

GetIndexPairs()

Simplex::IndexPairs box2d::Simplex::GetIndexPairs ( const Edges &  collection )

inlinestaticnoexcept

Gets index pairs for the given edges collection.

GetSimplexEdge()

const SimplexEdge & box2d::Simplex::GetSimplexEdge ( size_type  index ) const

inlinenoexcept

GetSize()

BOX2D_CONSTEXPR Simplex::size_type box2d::Simplex::GetSize ( ) const

inlinenoexcept

Member Data Documentation

MaxEdges

constexpr auto box2d::Simplex::MaxEdges = std::uint8_t{3}

static

Maximum number of supportable edges in a simplex.

---

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

• Simplex.hpp
• Simplex.cpp