Box2D  2.4.0
A 2D physics engine for games
b2World Class Reference

#include <b2_world.h>

Public Member Functions

 b2World (const b2Vec2 &gravity)
 
 ~b2World ()
 Destruct the world. All physics entities are destroyed and all heap memory is released.
 
void SetDestructionListener (b2DestructionListener *listener)
 
void SetContactFilter (b2ContactFilter *filter)
 
void SetContactListener (b2ContactListener *listener)
 
void SetDebugDraw (b2Draw *debugDraw)
 
b2BodyCreateBody (const b2BodyDef *def)
 
void DestroyBody (b2Body *body)
 
b2JointCreateJoint (const b2JointDef *def)
 
void DestroyJoint (b2Joint *joint)
 
void Step (float timeStep, int32 velocityIterations, int32 positionIterations)
 
void ClearForces ()
 
void DrawDebugData ()
 Call this to draw shapes and other debug draw data. This is intentionally non-const.
 
void QueryAABB (b2QueryCallback *callback, const b2AABB &aabb) const
 
void RayCast (b2RayCastCallback *callback, const b2Vec2 &point1, const b2Vec2 &point2) const
 
b2BodyGetBodyList ()
 
const b2BodyGetBodyList () const
 
b2JointGetJointList ()
 
const b2JointGetJointList () const
 
b2ContactGetContactList ()
 
const b2ContactGetContactList () const
 
void SetAllowSleeping (bool flag)
 Enable/disable sleep.
 
bool GetAllowSleeping () const
 
void SetWarmStarting (bool flag)
 Enable/disable warm starting. For testing.
 
bool GetWarmStarting () const
 
void SetContinuousPhysics (bool flag)
 Enable/disable continuous physics. For testing.
 
bool GetContinuousPhysics () const
 
void SetSubStepping (bool flag)
 Enable/disable single stepped continuous physics. For testing.
 
bool GetSubStepping () const
 
int32 GetProxyCount () const
 Get the number of broad-phase proxies.
 
int32 GetBodyCount () const
 Get the number of bodies.
 
int32 GetJointCount () const
 Get the number of joints.
 
int32 GetContactCount () const
 Get the number of contacts (each may have 0 or more contact points).
 
int32 GetTreeHeight () const
 Get the height of the dynamic tree.
 
int32 GetTreeBalance () const
 Get the balance of the dynamic tree.
 
float GetTreeQuality () const
 
void SetGravity (const b2Vec2 &gravity)
 Change the global gravity vector.
 
b2Vec2 GetGravity () const
 Get the global gravity vector.
 
bool IsLocked () const
 Is the world locked (in the middle of a time step).
 
void SetAutoClearForces (bool flag)
 Set flag to control automatic clearing of forces after each time step.
 
bool GetAutoClearForces () const
 Get the flag that controls automatic clearing of forces after each time step.
 
void ShiftOrigin (const b2Vec2 &newOrigin)
 
const b2ContactManagerGetContactManager () const
 Get the contact manager for testing.
 
const b2ProfileGetProfile () const
 Get the current profile.
 
void Dump ()
 

Friends

class b2Body
 
class b2Fixture
 
class b2ContactManager
 
class b2Controller
 

Detailed Description

The world class manages all physics entities, dynamic simulation, and asynchronous queries. The world also contains efficient memory management facilities.

Constructor & Destructor Documentation

◆ b2World()

b2World::b2World ( const b2Vec2 gravity)

Construct a world object.

Parameters
gravitythe world gravity vector.

Member Function Documentation

◆ ClearForces()

void b2World::ClearForces ( )

Manually clear the force buffer on all bodies. By default, forces are cleared automatically after each call to Step. The default behavior is modified by calling SetAutoClearForces. The purpose of this function is to support sub-stepping. Sub-stepping is often used to maintain a fixed sized time step under a variable frame-rate. When you perform sub-stepping you will disable auto clearing of forces and instead call ClearForces after all sub-steps are complete in one pass of your game loop.

See also
SetAutoClearForces

◆ CreateBody()

b2Body* b2World::CreateBody ( const b2BodyDef def)

Create a rigid body given a definition. No reference to the definition is retained.

Warning
This function is locked during callbacks.

◆ CreateJoint()

b2Joint* b2World::CreateJoint ( const b2JointDef def)

Create a joint to constrain bodies together. No reference to the definition is retained. This may cause the connected bodies to cease colliding.

Warning
This function is locked during callbacks.

◆ DestroyBody()

void b2World::DestroyBody ( b2Body body)

Destroy a rigid body given a definition. No reference to the definition is retained. This function is locked during callbacks.

Warning
This automatically deletes all associated shapes and joints.
This function is locked during callbacks.

◆ DestroyJoint()

void b2World::DestroyJoint ( b2Joint joint)

Destroy a joint. This may cause the connected bodies to begin colliding.

Warning
This function is locked during callbacks.

◆ Dump()

void b2World::Dump ( )

Dump the world into the log file.

Warning
this should be called outside of a time step.

◆ GetBodyList()

const b2Body * b2World::GetBodyList ( )
inline

Get the world body list. With the returned body, use b2Body::GetNext to get the next body in the world list. A nullptr body indicates the end of the list.

Returns
the head of the world body list.

◆ GetContactList()

const b2Contact * b2World::GetContactList ( )
inline

Get the world contact list. With the returned contact, use b2Contact::GetNext to get the next contact in the world list. A nullptr contact indicates the end of the list.

Returns
the head of the world contact list.
Warning
contacts are created and destroyed in the middle of a time step. Use b2ContactListener to avoid missing contacts.

◆ GetJointList()

const b2Joint * b2World::GetJointList ( )
inline

Get the world joint list. With the returned joint, use b2Joint::GetNext to get the next joint in the world list. A nullptr joint indicates the end of the list.

Returns
the head of the world joint list.

◆ GetTreeQuality()

float b2World::GetTreeQuality ( ) const

Get the quality metric of the dynamic tree. The smaller the better. The minimum is 1.

◆ QueryAABB()

void b2World::QueryAABB ( b2QueryCallback callback,
const b2AABB aabb 
) const

Query the world for all fixtures that potentially overlap the provided AABB.

Parameters
callbacka user implemented callback class.
aabbthe query box.

◆ RayCast()

void b2World::RayCast ( b2RayCastCallback callback,
const b2Vec2 point1,
const b2Vec2 point2 
) const

Ray-cast the world for all fixtures in the path of the ray. Your callback controls whether you get the closest point, any point, or n-points. The ray-cast ignores shapes that contain the starting point.

Parameters
callbacka user implemented callback class.
point1the ray starting point
point2the ray ending point

◆ SetContactFilter()

void b2World::SetContactFilter ( b2ContactFilter filter)

Register a contact filter to provide specific control over collision. Otherwise the default filter is used (b2_defaultFilter). The listener is owned by you and must remain in scope.

◆ SetContactListener()

void b2World::SetContactListener ( b2ContactListener listener)

Register a contact event listener. The listener is owned by you and must remain in scope.

◆ SetDebugDraw()

void b2World::SetDebugDraw ( b2Draw debugDraw)

Register a routine for debug drawing. The debug draw functions are called inside with b2World::DrawDebugData method. The debug draw object is owned by you and must remain in scope.

◆ SetDestructionListener()

void b2World::SetDestructionListener ( b2DestructionListener listener)

Register a destruction listener. The listener is owned by you and must remain in scope.

◆ ShiftOrigin()

void b2World::ShiftOrigin ( const b2Vec2 newOrigin)

Shift the world origin. Useful for large worlds. The body shift formula is: position -= newOrigin

Parameters
newOriginthe new origin with respect to the old origin

◆ Step()

void b2World::Step ( float  timeStep,
int32  velocityIterations,
int32  positionIterations 
)

Take a time step. This performs collision detection, integration, and constraint solution.

Parameters
timeStepthe amount of time to simulate, this should not vary.
velocityIterationsfor the velocity constraint solver.
positionIterationsfor the position constraint solver.

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