b2ChainShape Class Reference

#include <b2_chain_shape.h>

Inheritance diagram for b2ChainShape:

Public Member Functions
	~b2ChainShape ()
	The destructor frees the vertices using b2Free.
void	Clear ()
	Clear all data.
void	CreateLoop (const b2Vec2 *vertices, int32 count)
void	CreateChain (const b2Vec2 *vertices, int32 count, const b2Vec2 &prevVertex, const b2Vec2 &nextVertex)
b2Shape *	Clone (b2BlockAllocator *allocator) const override
	Implement b2Shape. Vertices are cloned using b2Alloc. More...
int32	GetChildCount () const override
void	GetChildEdge (b2EdgeShape *edge, int32 index) const
	Get a child edge.
bool	TestPoint (const b2Transform &transform, const b2Vec2 &p) const override
bool	RayCast (b2RayCastOutput *output, const b2RayCastInput &input, const b2Transform &transform, int32 childIndex) const override
	Implement b2Shape. More...
void	ComputeAABB (b2AABB *aabb, const b2Transform &transform, int32 childIndex) const override
void	ComputeMass (b2MassData *massData, float density) const override
Public Member Functions inherited from b2Shape
virtual b2Shape *	Clone (b2BlockAllocator *allocator) const =0
	Clone the concrete shape using the provided allocator. More...
Type	GetType () const
virtual int32	GetChildCount () const =0
	Get the number of child primitives. More...
virtual bool	TestPoint (const b2Transform &xf, const b2Vec2 &p) const =0
virtual bool	RayCast (b2RayCastOutput *output, const b2RayCastInput &input, const b2Transform &transform, int32 childIndex) const =0
virtual void	ComputeAABB (b2AABB *aabb, const b2Transform &xf, int32 childIndex) const =0
virtual void	ComputeMass (b2MassData *massData, float density) const =0

Public Attributes
b2Vec2 *	m_vertices
	The vertices. Owned by this class.
int32	m_count
	The vertex count.
b2Vec2	m_prevVertex
b2Vec2	m_nextVertex
Public Attributes inherited from b2Shape
Type	m_type
float	m_radius

Additional Inherited Members
Public Types inherited from b2Shape
enum	Type {   e_circle = 0 , e_edge = 1 , e_polygon = 2 , e_chain = 3 ,   e_typeCount = 4 }

Detailed Description

A chain shape is a free form sequence of line segments. The chain has one-sided collision, with the surface normal pointing to the right of the edge. This provides a counter-clockwise winding like the polygon shape. Connectivity information is used to create smooth collisions.

Warning

the chain will not collide properly if there are self-intersections.

Member Function Documentation

Clone()

b2Shape * b2ChainShape::Clone ( b2BlockAllocator *  allocator ) const

overridevirtual

Implement b2Shape. Vertices are cloned using b2Alloc.

Implements b2Shape.

ComputeAABB()

void b2ChainShape::ComputeAABB ( b2AABB *  aabb, const b2Transform &  transform, int32  childIndex  ) const

overridevirtual

See also

b2Shape::ComputeAABB

Implements b2Shape.

ComputeMass()

void b2ChainShape::ComputeMass ( b2MassData *  massData, float  density  ) const

overridevirtual

Chains have zero mass.

See also

b2Shape::ComputeMass

Implements b2Shape.

CreateChain()

void b2ChainShape::CreateChain	(	const b2Vec2 *	vertices,
		int32	count,
		const b2Vec2 &	prevVertex,
		const b2Vec2 &	nextVertex
	)

Create a chain with ghost vertices to connect multiple chains together.

Parameters

vertices	an array of vertices, these are copied
count	the vertex count
prevVertex	previous vertex from chain that connects to the start
nextVertex	next vertex from chain that connects to the end

CreateLoop()

void b2ChainShape::CreateLoop	(	const b2Vec2 *	vertices,
		int32	count
	)

Create a loop. This automatically adjusts connectivity.

Parameters

vertices	an array of vertices, these are copied
count	the vertex count

GetChildCount()

int32 b2ChainShape::GetChildCount ( ) const

overridevirtual

See also

b2Shape::GetChildCount

Implements b2Shape.

RayCast()

bool b2ChainShape::RayCast ( b2RayCastOutput *  output, const b2RayCastInput &  input, const b2Transform &  transform, int32  childIndex  ) const

overridevirtual

Implement b2Shape.

Implements b2Shape.

TestPoint()

bool b2ChainShape::TestPoint ( const b2Transform &  transform, const b2Vec2 &  p  ) const

overridevirtual

This always return false.

See also

b2Shape::TestPoint

Implements b2Shape.

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

• include/box2d/b2_chain_shape.h