java.lang.Object
- org.jbox2d.dynamics.contacts.Contact

Direct Known Subclasses:

ChainAndCircleContact, ChainAndPolygonContact, CircleContact, EdgeAndCircleContact, EdgeAndPolygonContact, PolygonAndCircleContact, PolygonContact
```
public abstract class Contact
extends java.lang.Object
```
The class manages contact between two shapes. A contact exists for each overlapping AABB in the broad-phase (except if filtered). Therefore a contact object may exist that has no contact points.

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`BULLET_HIT_FLAG`
`static int`	`ENABLED_FLAG`
`static int`	`FILTER_FLAG`
`static int`	`ISLAND_FLAG`
`Fixture`	`m_fixtureA`
`Fixture`	`m_fixtureB`
`int`	`m_flags`
`float`	`m_friction`
`int`	`m_indexA`
`int`	`m_indexB`
`Manifold`	`m_manifold`
`Contact`	`m_next`
`ContactEdge`	`m_nodeA`
`ContactEdge`	`m_nodeB`
`Contact`	`m_prev`
`float`	`m_restitution`
`float`	`m_tangentSpeed`
`float`	`m_toi`
`float`	`m_toiCount`
`private Manifold`	`oldManifold`
`protected IWorldPool`	`pool`
`static int`	`TOI_FLAG`
`static int`	`TOUCHING_FLAG`

Constructor Summary

Constructors
Modifier Constructor Description

protected Contact(IWorldPool argPool)

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract void`	`evaluate(Manifold manifold, Transform xfA, Transform xfB)`
`void`	`flagForFiltering()`	Flag this contact for filtering.
`int`	`getChildIndexA()`
`int`	`getChildIndexB()`
`Fixture`	`getFixtureA()`	Get the first fixture in this contact.
`Fixture`	`getFixtureB()`	Get the second fixture in this contact.
`float`	`getFriction()`
`Manifold`	`getManifold()`	Get the contact manifold.
`Contact`	`getNext()`	Get the next contact in the world's contact list.
`float`	`getRestitution()`
`float`	`getTangentSpeed()`
`void`	`getWorldManifold(WorldManifold worldManifold)`	Get the world manifold.
`void`	`init(Fixture fA, int indexA, Fixture fB, int indexB)`	initialization for pooling
`boolean`	`isEnabled()`	Has this contact been disabled?
`boolean`	`isTouching()`	Is this contact touching
`static float`	`mixFriction(float friction1, float friction2)`	Friction mixing law.
`static float`	`mixRestitution(float restitution1, float restitution2)`	Restitution mixing law.
`void`	`resetFriction()`
`void`	`resetRestitution()`
`void`	`setEnabled(boolean flag)`	Enable/disable this contact.
`void`	`setFriction(float friction)`
`void`	`setRestitution(float restitution)`
`void`	`setTangentSpeed(float speed)`
`void`	`update(ContactListener listener)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ISLAND_FLAG
```
public static final int ISLAND_FLAG
```
See Also:

Constant Field Values

TOUCHING_FLAG
```
public static final int TOUCHING_FLAG
```
See Also:

Constant Field Values

ENABLED_FLAG
```
public static final int ENABLED_FLAG
```
See Also:

Constant Field Values

FILTER_FLAG
```
public static final int FILTER_FLAG
```
See Also:

Constant Field Values

BULLET_HIT_FLAG
```
public static final int BULLET_HIT_FLAG
```
See Also:

Constant Field Values

TOI_FLAG
```
public static final int TOI_FLAG
```
See Also:

Constant Field Values

m_flags
```
public int m_flags
```

m_prev
```
public Contact m_prev
```

m_next
```
public Contact m_next
```

m_nodeA
```
public ContactEdge m_nodeA
```

m_nodeB
```
public ContactEdge m_nodeB
```

m_fixtureA
```
public Fixture m_fixtureA
```

m_fixtureB
```
public Fixture m_fixtureB
```

m_indexA
```
public int m_indexA
```

m_indexB
```
public int m_indexB
```

m_manifold
```
public final Manifold m_manifold
```

m_toiCount
```
public float m_toiCount
```

m_toi
```
public float m_toi
```

m_friction
```
public float m_friction
```

m_restitution
```
public float m_restitution
```

m_tangentSpeed
```
public float m_tangentSpeed
```

pool
```
protected final IWorldPool pool
```

oldManifold
```
private final Manifold oldManifold
```

Constructor Detail

Contact

protected Contact(IWorldPool argPool)

Method Detail

init

public void init(Fixture fA,
                 int indexA,
                 Fixture fB,
                 int indexB)

initialization for pooling

getManifold
```
public Manifold getManifold()
```
Get the contact manifold. Do not set the point count to zero. Instead call Disable.

getWorldManifold

public void getWorldManifold(WorldManifold worldManifold)

Get the world manifold.

isTouching
```
public boolean isTouching()
```
Is this contact touching

Returns:

setEnabled
```
public void setEnabled(boolean flag)
```
Enable/disable this contact. This can be used inside the pre-solve contact listener. The contact is only disabled for the current time step (or sub-step in continuous collisions).

Parameters:

flag -

isEnabled
```
public boolean isEnabled()
```
Has this contact been disabled?

Returns:

getNext
```
public Contact getNext()
```
Get the next contact in the world's contact list.

Returns:

getFixtureA
```
public Fixture getFixtureA()
```
Get the first fixture in this contact.

Returns:

getChildIndexA
```
public int getChildIndexA()
```

getFixtureB
```
public Fixture getFixtureB()
```
Get the second fixture in this contact.

Returns:

getChildIndexB
```
public int getChildIndexB()
```

setFriction

public void setFriction(float friction)

getFriction
```
public float getFriction()
```

resetFriction
```
public void resetFriction()
```

setRestitution

public void setRestitution(float restitution)

getRestitution
```
public float getRestitution()
```

resetRestitution
```
public void resetRestitution()
```

setTangentSpeed

public void setTangentSpeed(float speed)

getTangentSpeed
```
public float getTangentSpeed()
```

evaluate

public abstract void evaluate(Manifold manifold,
                              Transform xfA,
                              Transform xfB)

flagForFiltering
```
public void flagForFiltering()
```
Flag this contact for filtering. Filtering will occur the next time step.

update

public void update(ContactListener listener)

mixFriction
```
public static final float mixFriction(float friction1,
                                      float friction2)
```
Friction mixing law. The idea is to allow either fixture to drive the restitution to zero. For example, anything slides on ice.

Parameters:

friction1 -

friction2 -

Returns:

mixRestitution
```
public static final float mixRestitution(float restitution1,
                                         float restitution2)
```
Restitution mixing law. The idea is allow for anything to bounce off an inelastic surface. For example, a superball bounces on anything.

Parameters:

restitution1 -

restitution2 -

Returns:

Class Contact

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ISLAND_FLAG

TOUCHING_FLAG

ENABLED_FLAG

FILTER_FLAG

BULLET_HIT_FLAG

TOI_FLAG

m_flags

m_prev

m_next

m_nodeA

m_nodeB

m_fixtureA

m_fixtureB

m_indexA

m_indexB

m_manifold

m_toiCount

m_toi

m_friction

m_restitution

m_tangentSpeed

pool

oldManifold

Constructor Detail

Contact

Method Detail

init

getManifold

getWorldManifold

isTouching

setEnabled

isEnabled

getNext

getFixtureA

getChildIndexA

getFixtureB

getChildIndexB

setFriction

getFriction

resetFriction

setRestitution

getRestitution

resetRestitution

setTangentSpeed

getTangentSpeed

evaluate

flagForFiltering

update

mixFriction

mixRestitution