Polygon shape configuration. More...

#include <PolygonShapeConf.hpp>

Inheritance diagram for playrho::d2::PolygonShapeConf:

Collaboration diagram for playrho::d2::PolygonShapeConf:

Public Member Functions
	PolygonShapeConf (Length hx, Length hy, const PolygonShapeConf &conf=GetDefaultConf()) noexcept
	Initializing constructor for a 4-sided box polygon. More...

	PolygonShapeConf (Span< const Length2 > points, const PolygonShapeConf &conf=GetDefaultConf()) noexcept
	Creates a convex hull from the given array of local points. More...

PolygonShapeConf &	UseVertexRadius (NonNegative< Length > value) noexcept
	Uses the given vertex radius.

PolygonShapeConf &	UseVertices (const std::vector< Length2 > &verts) noexcept
	Uses the given vertices.

PolygonShapeConf &	SetAsBox (Length hx, Length hy) noexcept
	Sets the vertices to represent an axis-aligned box centered on the local origin. More...

PolygonShapeConf &	SetAsBox (Length hx, Length hy, Length2 center, Angle angle) noexcept
	Sets the vertices for the described box.

PolygonShapeConf &	Set (Span< const Length2 > verts) noexcept
	Sets the vertices to a convex hull of the given ones. More...

PolygonShapeConf &	Set (const VertexSet &points) noexcept
	Sets the vertices to a convex hull of the given ones. More...

PolygonShapeConf &	Transform (Transformation xfm) noexcept
	Transforms the vertices by the given transformation.

PolygonShapeConf &	Transform (const Mat22 &m) noexcept
	Transforms the vertices by the given transformation matrix. More...

VertexCounter	GetVertexCount () const noexcept
	Gets the vertex count. More...

Length2	GetVertex (VertexCounter index) const
	Gets a vertex by index. More...

UnitVec	GetNormal (VertexCounter index) const
	Gets a normal by index. More...

Span< const Length2 >	GetVertices () const noexcept
	Gets the span of vertices. More...

Span< const UnitVec >	GetNormals () const noexcept
	Gets the span of normals.

Length2	GetCentroid () const noexcept
	Gets the centroid.

Public Member Functions inherited from playrho::d2::ShapeBuilder< PolygonShapeConf >
constexpr	ShapeBuilder ()=default
	Default constructor.

constexpr	ShapeBuilder (const BaseShapeConf &value) noexcept
	Initializing constructor.

constexpr PolygonShapeConf &	UseFriction (NonNegative< Real > value) noexcept
	Uses the given friction.

constexpr PolygonShapeConf &	UseRestitution (Finite< Real > value) noexcept
	Uses the given restitution.

constexpr PolygonShapeConf &	UseDensity (NonNegative< AreaDensity > value) noexcept
	Uses the given density.

Static Public Member Functions
static constexpr NonNegative< Length >	GetDefaultVertexRadius () noexcept
	Gets the default vertex radius for the `PolygonShapeConf`.

static PolygonShapeConf	GetDefaultConf () noexcept
	Gets the default configuration for a `PolygonShapeConf`.

Public Attributes
NonNegative< Length >	vertexRadius = GetDefaultVertexRadius()
	Vertex radius. More...

Public Attributes inherited from playrho::d2::BaseShapeConf
NonNegative< Real >	friction = NonNegative<Real>{Real{2} / Real{10}}
	Friction coefficient. More...

Finite< Real >	restitution = Finite<Real>{0}
	Restitution (elasticity) of the associated shape. More...

NonNegative< AreaDensity >	density = NonNegative<AreaDensity>{0_kgpm2}
	Area density of the associated shape. More...

Private Attributes
std::vector< Length2 >	m_vertices
	Array of vertices. More...

std::vector< UnitVec >	m_normals
	Normals of edges. More...

Length2	m_centroid = GetInvalid<Length2>()
	Centroid of this shape.

Friends
bool	operator== (const PolygonShapeConf &lhs, const PolygonShapeConf &rhs) noexcept
	Equality operator.

bool	operator!= (const PolygonShapeConf &lhs, const PolygonShapeConf &rhs) noexcept
	Inequality operator.

Related Functions
(Note that these are not member functions.)
Length2	GetEdge (const PolygonShapeConf &shape, VertexCounter index)
	Gets the identified edge of the given polygon shape. More...

Detailed Description

Polygon shape configuration.

A convex polygon. The interior of the polygon is to the left of each edge. Polygons maximum number of vertices is defined by MaxShapeVertices. In most cases you should not need many vertices for a convex polygon.

Note: This data structure is 64-bytes large (with 4-byte Real).

Examples: HelloWorld.cpp, RevoluteJoint.cpp, Shape.cpp, World.cpp, and WorldBody.cpp.

Constructor & Destructor Documentation

◆ PolygonShapeConf() [1/2]

playrho::d2::PolygonShapeConf::PolygonShapeConf	(	Length	hx,
		Length	hy,
		const PolygonShapeConf &	conf = `GetDefaultConf()`
	)

noexcept

Initializing constructor for a 4-sided box polygon.

Parameters

hx	Half of the width.
hy	Half of the height.
conf	Additional configuration information.

See also: SetAsBox.

◆ PolygonShapeConf() [2/2]

playrho::d2::PolygonShapeConf::PolygonShapeConf	(	Span< const Length2 >	points,
		const PolygonShapeConf &	conf = `GetDefaultConf()`
	)

explicitnoexcept

Creates a convex hull from the given array of local points.

Note: The size of the span must be in the range [1, MaxShapeVertices].

Warning: the points may be re-ordered, even if they form a convex polygon; collinear points are handled but not removed. Collinear points may lead to poor stacking behavior.

Member Function Documentation

◆ GetNormal()

UnitVec playrho::d2::PolygonShapeConf::GetNormal ( VertexCounter index ) const

inline

Gets a normal by index.

These are 90-degree clockwise-rotated (outward-facing) unit-vectors of the edges defined by consecutive pairs of vertices starting with vertex 0.

Parameters

index Index of the normal to get.

Returns: Normal for the given index.

◆ GetVertex()

Length2 playrho::d2::PolygonShapeConf::GetVertex ( VertexCounter index ) const

inline

Gets a vertex by index.

Vertices go counter-clockwise.

Referenced by playrho::d2::GetEdge().

◆ GetVertexCount()

VertexCounter playrho::d2::PolygonShapeConf::GetVertexCount ( ) const

inlinenoexcept

Gets the vertex count.

Returns: value between 0 and MaxShapeVertices inclusive.

See also: MaxShapeVertices

Referenced by playrho::d2::GetChild(), playrho::d2::GetEdge(), GetNormal(), and GetVertex().

◆ GetVertices()

Span<const Length2> playrho::d2::PolygonShapeConf::GetVertices ( ) const

inlinenoexcept

Gets the span of vertices.

Vertices go counter-clockwise.

Referenced by playrho::d2::GetChild().

◆ Set() [1/2]

PolygonShapeConf & playrho::d2::PolygonShapeConf::Set ( const VertexSet & points )

noexcept

Sets the vertices to a convex hull of the given ones.

Note: The size of the span must be in the range [1, MaxShapeVertices].

Warning: Points may be re-ordered, even if they form a convex polygon; Collinear points are handled but not removed. Collinear points may lead to poor stacking behavior.

◆ Set() [2/2]

PolygonShapeConf & playrho::d2::PolygonShapeConf::Set ( Span< const Length2 > verts )

noexcept

Sets the vertices to a convex hull of the given ones.

Note: The size of the span must be in the range [1, MaxShapeVertices].

Warning: Points may be re-ordered, even if they form a convex polygon; Collinear points are handled but not removed. Collinear points may lead to poor stacking behavior.

◆ SetAsBox()

PolygonShapeConf & playrho::d2::PolygonShapeConf::SetAsBox	(	Length	hx,
		Length	hy
	)

noexcept

Sets the vertices to represent an axis-aligned box centered on the local origin.

Parameters

hx	the half-width.
hy	the half-height.

Examples: HelloWorld.cpp, RevoluteJoint.cpp, and World.cpp.

◆ Transform()

PolygonShapeConf & playrho::d2::PolygonShapeConf::Transform ( const Mat22 & m )

noexcept

Transforms the vertices by the given transformation matrix.

See also: https://en.wikipedia.org/wiki/Transformation_matrix

Friends And Related Function Documentation

◆ GetEdge()

Length2 GetEdge	(	const PolygonShapeConf &	shape,
		VertexCounter	index
	)

Note: This must not be called for shapes with less than 2 vertices.

Warning: Behavior is undefined if called for a shape with less than 2 vertices.

Member Data Documentation

◆ m_normals

std::vector<UnitVec> playrho::d2::PolygonShapeConf::m_normals

private

Normals of edges.

These are 90-degree clockwise-rotated unit-vectors of the vectors defined by consecutive pairs of elements of vertices.

Referenced by GetNormal(), and GetNormals().

◆ m_vertices

std::vector<Length2> playrho::d2::PolygonShapeConf::m_vertices

private

Array of vertices.

Consecutive vertices constitute "edges" of the polygon.

Referenced by GetNormals(), GetVertex(), GetVertexCount(), and GetVertices().

◆ vertexRadius

NonNegative<Length> playrho::d2::PolygonShapeConf::vertexRadius = GetDefaultVertexRadius()

Vertex radius.

This is the radius from the vertex that the shape's "skin" should extend outward by. While any edges — line segments between multiple vertices — are straight, corners between them (the vertices) are rounded and treated as rounded. Shapes with larger vertex radiuses compared to edge lengths therefore will be more prone to rolling or having other shapes more prone to roll off of them.

Note: This should be a non-negative value.

Referenced by playrho::d2::GetChild().

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

PolygonShapeConf.hpp
PolygonShapeConf.cpp

Public Member Functions

Static Public Member Functions

Public Attributes

Private Attributes

Friends

Related Functions

Detailed Description

Constructor & Destructor Documentation

◆ PolygonShapeConf() [1/2]

◆ PolygonShapeConf() [2/2]

Member Function Documentation

◆ GetNormal()

◆ GetVertex()

◆ GetVertexCount()

◆ GetVertices()

◆ Set() [1/2]

◆ Set() [2/2]

◆ SetAsBox()

◆ Transform()

Friends And Related Function Documentation

◆ GetEdge()

Member Data Documentation

◆ m_normals

◆ m_vertices

◆ vertexRadius