Box2D 2.3.0 A 2D Physics Engine for Games

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b2Shape Class Referenceabstract

`#include <b2Shape.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.
Type | GetType () const
virtual int32 | GetChildCount () const =0
| Get the number of child primitives.
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, float32 density) const =0

## Public Attributes
Type | m_type
float32 | 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

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, b2PolygonShape, b2EdgeShape, and b2CircleShape.

virtual void b2Shape::ComputeMass | ( | b2MassData * | massData,
|  | float32 | 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, b2PolygonShape, b2EdgeShape, and b2CircleShape.

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.

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, b2PolygonShape, b2EdgeShape, and b2CircleShape.

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, b2PolygonShape, b2EdgeShape, and b2CircleShape.

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

- b2Shape.h