ContactListener interface
Implement this interface 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.
interface ContactListener { /** * Called when two fixtures begin to touch. */ void beginContact(Contact contact); /** * Called when two fixtures cease to touch. */ void endContact(Contact contact); /** * 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. * Note: the oldManifold parameter is pooled, so it will be the same object * for every callback for each thread. */ void preSolve(Contact contact, Manifold oldManifold); /** * 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. */ void postSolve(Contact contact, ContactImpulse impulse); }
Properties
final Type runtimeType #
A representation of the runtime type of the object.
external Type get runtimeType;
Operators
bool operator ==(other) #
The equality operator.
The default behavior for all Object
s is to return true if and
only if this
and
other are the same object.
If a subclass overrides the equality operator it should override
the hashCode
method as well to maintain consistency.
bool operator ==(other) => identical(this, other);
Methods
void beginContact(Contact contact) #
Called when two fixtures begin to touch.
void beginContact(Contact contact);
void endContact(Contact contact) #
Called when two fixtures cease to touch.
void endContact(Contact contact);
int hashCode() #
Get a hash code for this object.
All objects have hash codes. Hash codes are guaranteed to be the
same for objects that are equal when compared using the equality
operator ==
. Other than that there are no guarantees about
the hash codes. They will not be consistent between runs and
there are no distribution guarantees.
If a subclass overrides hashCode
it should override the
equality operator as well to maintain consistency.
external int hashCode();
noSuchMethod(String name, List args) #
noSuchMethod
is invoked when users invoke a non-existant method
on an object. The name of the method and the arguments of the
invocation are passed to noSuchMethod
. If noSuchMethod
returns a value, that value becomes the result of the original
invocation.
The default behavior of noSuchMethod
is to throw a
noSuchMethodError
.
external Dynamic noSuchMethod(String name, List args);
const Object() #
Creates a new Object
instance.
Object
instances have no meaningful state, and are only useful
through their identity. An Object
instance is equal to itself
only.
const Object();
void postSolve(Contact contact, ContactImpulse impulse) #
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.
void postSolve(Contact contact, ContactImpulse impulse);
void preSolve(Contact contact, Manifold oldManifold) #
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. Note: the oldManifold parameter is pooled, so it will be the same object for every callback for each thread.
void preSolve(Contact contact, Manifold oldManifold);
String toString() #
Returns a string representation of this object.
external String toString();