PackageBox2D.Dynamics
Classpublic class b2ContactListener
Sourceb2ContactListener.as

Implement this class to get contact information. You can use these results for things like sounds and game logic. You can also get contact results by traversing the contact lists after the time step. However, you might miss some contacts because continuous physics leads to sub-stepping. Additionally you may receive multiple callbacks for the same contact in a single time step. You should strive to make your callbacks efficient because there may be many callbacks per time step.

Warning: You cannot create/destroy Box2D entities inside these callbacks.


Public Methods
 MethodDefined by
  
BeginContact(contact:b2Contact):void
Called when two fixtures begin to touch.
b2ContactListener
  
EndContact(contact:b2Contact):void
Called when two fixtures cease to touch.
b2ContactListener
  
PostSolve(contact:b2Contact, impulse:b2ContactImpulse):void
This lets you inspect a contact after the solver is finished.
b2ContactListener
  
PreSolve(contact:b2Contact, oldManifold:b2Manifold):void
This is called after a contact is updated.
b2ContactListener
Method detail
BeginContact()method
public function BeginContact(contact:b2Contact):void

Called when two fixtures begin to touch.

Parameters
contact:b2Contact
EndContact()method 
public function EndContact(contact:b2Contact):void

Called when two fixtures cease to touch.

Parameters
contact:b2Contact
PostSolve()method 
public function PostSolve(contact:b2Contact, impulse:b2ContactImpulse):void

This lets you inspect a contact after the solver is finished. This is useful for inspecting impulses. Note: the contact manifold does not include time of impact impulses, which can be arbitrarily large if the sub-step is small. Hence the impulse is provided explicitly in a separate data structure. Note: this is only called for contacts that are touching, solid, and awake.

Parameters
contact:b2Contact
 
impulse:b2ContactImpulse
PreSolve()method 
public function PreSolve(contact:b2Contact, oldManifold:b2Manifold):void

This is called after a contact is updated. This allows you to inspect a contact before it goes to the solver. If you are careful, you can modify the contact manifold (e.g. disable contact). A copy of the old manifold is provided so that you can detect changes. Note: this is called only for awake bodies. Note: this is called even when the number of contact points is zero. Note: this is not called for sensors. Note: if you set the number of contact points to zero, you will not get an EndContact callback. However, you may get a BeginContact callback the next step.

Parameters
contact:b2Contact
 
oldManifold:b2Manifold



Box2DFlash 2.1a