Box2D: b2Shape Class Reference

Box2D

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b2Shape Class Reference

A shape is used for collision detection. More...

Inheritance diagram for b2Shape:

b2CircleShape b2PolygonShape

List of all members.

Public Member Functions

b2ShapeType GetType () const
 Get the type of this shape.
bool IsSensor () const
 Is this shape a sensor (non-solid)?
void SetFilterData (const b2FilterData &filter)
 Set the contact filtering data.
const b2FilterData & GetFilterData () const
 Get the contact filtering data.
b2Body * GetBody ()
 Get the parent body of this shape.
b2Shape * GetNext ()
 Get the next shape in the parent body's shape list.
void * GetUserData ()
 Get the user data that was assigned in the shape definition.
void SetUserData (void *data)
 Set the user data. Use this to store your application specific data.
virtual bool TestPoint (const b2XForm &xf, const b2Vec2 &p) const =0
 Test a point for containment in this shape.
virtual bool TestSegment (const b2XForm &xf, float32 *lambda, b2Vec2 *normal, const b2Segment &segment, float32 maxLambda) const =0
 Perform a ray cast against this shape.
virtual void ComputeAABB (b2AABB *aabb, const b2XForm &xf) const =0
 Given a transform, compute the associated axis aligned bounding box for this shape.
virtual void ComputeSweptAABB (b2AABB *aabb, const b2XForm &xf1, const b2XForm &xf2) const =0
 Given two transforms, compute the associated swept axis aligned bounding box for this shape.
virtual void ComputeMass (b2MassData *massData) const =0
 Compute the mass properties of this shape using its dimensions and density.
float32 GetSweepRadius () const
 Get the maximum radius about the parent body's center of mass.
float32 GetFriction () const
 Get the coefficient of friction.
float32 GetRestitution () const
 Get the coefficient of restitution.

Friends

class b2Body
class b2World

Detailed Description

A shape is used for collision detection.

Shapes are created in b2World. You can use shape for collision detection before they are attached to the world.

Warning:
you cannot reuse shapes.

Member Function Documentation

b2ShapeType 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.

bool b2Shape::IsSensor (  )  const [inline]

Is this shape a sensor (non-solid)?

Returns:
the true if the shape is a sensor.

void b2Shape::SetFilterData ( const b2FilterData &  filter  )  [inline]

Set the contact filtering data.

You must call b2World::Refilter to correct existing contacts/non-contacts.

b2Body * b2Shape::GetBody (  )  [inline]

Get the parent body of this shape.

This is NULL if the shape is not attached.

Returns:
the parent body.

b2Shape * b2Shape::GetNext (  )  [inline]

Get the next shape in the parent body's shape list.

Returns:
the next shape.

void * b2Shape::GetUserData (  )  [inline]

Get the user data that was assigned in the shape definition.

Use this to store your application specific data.

virtual bool b2Shape::TestPoint ( const b2XForm &  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 b2CircleShape, and b2PolygonShape.

virtual bool b2Shape::TestSegment ( const b2XForm &  xf,
float32 *  lambda,
b2Vec2 *  normal,
const b2Segment &  segment,
float32  maxLambda 
) const [pure virtual]

Perform a ray cast against this shape.

Parameters:
xf the shape world transform.
lambda returns the hit fraction. You can use this to compute the contact point p = (1 - lambda) * segment.p1 + lambda * segment.p2.
normal returns the normal at the contact point. If there is no intersection, the normal is not set.
segment defines the begin and end point of the ray cast.
maxLambda a number typically in the range [0,1].
Returns:
true if there was an intersection.

Implemented in b2CircleShape, and b2PolygonShape.

virtual void b2Shape::ComputeAABB ( b2AABB *  aabb,
const b2XForm &  xf 
) const [pure virtual]

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

Parameters:
aabb returns the axis aligned box.
xf the world transform of the shape.

Implemented in b2CircleShape, and b2PolygonShape.

virtual void b2Shape::ComputeSweptAABB ( b2AABB *  aabb,
const b2XForm &  xf1,
const b2XForm &  xf2 
) const [pure virtual]

Given two transforms, compute the associated swept axis aligned bounding box for this shape.

Parameters:
aabb returns the axis aligned box.
xf1 the starting shape world transform.
xf2 the ending shape world transform.

Implemented in b2CircleShape, and b2PolygonShape.

virtual void b2Shape::ComputeMass ( b2MassData *  massData  )  const [pure virtual]

Compute the mass properties of this shape using its dimensions and density.

The inertia tensor is computed about the local origin, not the centroid.

Parameters:
massData returns the mass data for this shape.

Implemented in b2CircleShape, and b2PolygonShape.

The documentation for this class was generated from the following files:
  • b2Shape.h
  • b2Shape.cpp
Generated on Sun Apr 13 15:21:27 2008 for Box2D by  doxygen 1.5.4

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