b2Shape Class Reference

#include <b2_shape.h>

Inheritance diagram for b2Shape:

Public Types
enum	Type {   e_circle = 0 , e_edge = 1 , e_polygon = 2 , e_chain = 3 ,   e_typeCount = 4 }

Public Member Functions
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
Type	m_type
float	m_radius

Detailed Description

A shape is used for collision detection. You can create a shape however you like. Shapes used for simulation in b2World are created automatically when a b2Fixture is created. Shapes may encapsulate a one or more child shapes.

Member Function Documentation

Clone()

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

pure virtual

Clone the concrete shape using the provided allocator.

Implemented in b2ChainShape, b2CircleShape, b2EdgeShape, and b2PolygonShape.

ComputeAABB()

virtual void b2Shape::ComputeAABB ( b2AABB *  aabb, const b2Transform &  xf, int32  childIndex  ) const

pure virtual

Given a transform, compute the associated axis aligned bounding box for a child shape.

Parameters

aabb	returns the axis aligned box.
xf	the world transform of the shape.
childIndex	the child shape

Implemented in b2ChainShape, b2CircleShape, b2EdgeShape, and b2PolygonShape.

ComputeMass()

virtual void b2Shape::ComputeMass ( b2MassData *  massData, float  density  ) const

pure virtual

Compute the mass properties of this shape using its dimensions and density. The inertia tensor is computed about the local origin.

Parameters

massData	returns the mass data for this shape.
density	the density in kilograms per meter squared.

Implemented in b2ChainShape, b2CircleShape, b2EdgeShape, and b2PolygonShape.

GetChildCount()

virtual int32 b2Shape::GetChildCount ( ) const

pure virtual

Get the number of child primitives.

Implemented in b2ChainShape, b2CircleShape, b2EdgeShape, and b2PolygonShape.

GetType()

b2Shape::Type b2Shape::GetType ( ) const

inline

Get the type of this shape. You can use this to down cast to the concrete shape.

Returns

the shape type.

RayCast()

virtual bool b2Shape::RayCast ( b2RayCastOutput *  output, const b2RayCastInput &  input, const b2Transform &  transform, int32  childIndex  ) const

pure virtual

Cast a ray against a child shape.

Parameters

output	the ray-cast results.
input	the ray-cast input parameters.
transform	the transform to be applied to the shape.
childIndex	the child shape index

Implemented in b2ChainShape, b2CircleShape, b2EdgeShape, and b2PolygonShape.

TestPoint()

virtual bool b2Shape::TestPoint ( const b2Transform &  xf, const b2Vec2 &  p  ) const

pure virtual

Test a point for containment in this shape. This only works for convex shapes.

Parameters

xf	the shape world transform.
p	a point in world coordinates.

Implemented in b2ChainShape, b2CircleShape, b2EdgeShape, and b2PolygonShape.

Member Data Documentation

m_radius

float b2Shape::m_radius

Radius of a shape. For polygonal shapes this must be b2_polygonRadius. There is no support for making rounded polygons.

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

• include/box2d/b2_shape.h