java.lang.Object
- org.jbox2d.dynamics.joints.Joint
- - org.jbox2d.dynamics.joints.RopeJoint

```
public class RopeJoint
extends Joint
```
A rope joint enforces a maximum distance between two points on two bodies. It has no other effect. Warning: if you attempt to change the maximum length during the simulation you will get some non-physical behavior. A model that would allow you to dynamically modify the length would have some sponginess, so I chose not to implement it that way. See DistanceJoint if you want to dynamically control length.

Field Summary

Fields
Modifier and Type	Field	Description
`private float`	`m_impulse`
`private int`	`m_indexA`
`private int`	`m_indexB`
`private float`	`m_invIA`
`private float`	`m_invIB`
`private float`	`m_invMassA`
`private float`	`m_invMassB`
`private float`	`m_length`
`private Vec2`	`m_localAnchorA`
`private Vec2`	`m_localAnchorB`
`private Vec2`	`m_localCenterA`
`private Vec2`	`m_localCenterB`
`private float`	`m_mass`
`private float`	`m_maxLength`
`private Vec2`	`m_rA`
`private Vec2`	`m_rB`
`private LimitState`	`m_state`
`private Vec2`	`m_u`

Fields inherited from class org.jbox2d.dynamics.joints.Joint
m_bodyA, m_bodyB, m_edgeA, m_edgeB, m_islandFlag, m_next, m_prev, m_userData, pool

Constructor Summary

Constructors
Modifier Constructor Description

protected RopeJoint(IWorldPool worldPool, RopeJointDef def)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`getAnchorA(Vec2 argOut)`	get the anchor point on bodyA in world coordinates.
`void`	`getAnchorB(Vec2 argOut)`	get the anchor point on bodyB in world coordinates.
`LimitState`	`getLimitState()`
`Vec2`	`getLocalAnchorA()`
`Vec2`	`getLocalAnchorB()`
`float`	`getMaxLength()`
`void`	`getReactionForce(float inv_dt, Vec2 argOut)`	get the reaction force on body2 at the joint anchor in Newtons.
`float`	`getReactionTorque(float inv_dt)`	get the reaction torque on body2 in N*m.
`void`	`initVelocityConstraints(SolverData data)`
`void`	`setMaxLength(float maxLength)`
`boolean`	`solvePositionConstraints(SolverData data)`	This returns true if the position errors are within tolerance.
`void`	`solveVelocityConstraints(SolverData data)`

Methods inherited from class org.jbox2d.dynamics.joints.Joint
create, destroy, destructor, getBodyA, getBodyB, getCollideConnected, getNext, getType, getUserData, isActive, setUserData

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

Field Detail

m_localAnchorA
```
private final Vec2 m_localAnchorA
```

m_localAnchorB
```
private final Vec2 m_localAnchorB
```

m_maxLength
```
private float m_maxLength
```

m_length
```
private float m_length
```

m_impulse
```
private float m_impulse
```

m_indexA
```
private int m_indexA
```

m_indexB
```
private int m_indexB
```

m_u
```
private final Vec2 m_u
```

m_rA
```
private final Vec2 m_rA
```

m_rB
```
private final Vec2 m_rB
```

m_localCenterA
```
private final Vec2 m_localCenterA
```

m_localCenterB
```
private final Vec2 m_localCenterB
```

m_invMassA
```
private float m_invMassA
```

m_invMassB
```
private float m_invMassB
```

m_invIA
```
private float m_invIA
```

m_invIB
```
private float m_invIB
```

m_mass
```
private float m_mass
```

m_state
```
private LimitState m_state
```

Constructor Detail

RopeJoint

protected RopeJoint(IWorldPool worldPool,
                    RopeJointDef def)

Method Detail
- initVelocityConstraints
```
public void initVelocityConstraints(SolverData data)
```
  Specified by:
  
  initVelocityConstraints in class Joint
- solveVelocityConstraints
```
public void solveVelocityConstraints(SolverData data)
```
  Specified by:
  
  solveVelocityConstraints in class Joint
- solvePositionConstraints
```
public boolean solvePositionConstraints(SolverData data)
```
  Description copied from class: Joint
  
  This returns true if the position errors are within tolerance.
  
  Specified by:
  
  solvePositionConstraints in class Joint
  
  Returns:
- getAnchorA
```
public void getAnchorA(Vec2 argOut)
```
  Description copied from class: Joint
  
  get the anchor point on bodyA in world coordinates.
  
  Specified by:
  
  getAnchorA in class Joint
- getAnchorB
```
public void getAnchorB(Vec2 argOut)
```
  Description copied from class: Joint
  
  get the anchor point on bodyB in world coordinates.
  
  Specified by:
  
  getAnchorB in class Joint
- getReactionForce
```
public void getReactionForce(float inv_dt,
                             Vec2 argOut)
```
  Description copied from class: Joint
  
  get the reaction force on body2 at the joint anchor in Newtons.
  
  Specified by:
  
  getReactionForce in class Joint
- getReactionTorque
```
public float getReactionTorque(float inv_dt)
```
  Description copied from class: Joint
  
  get the reaction torque on body2 in N*m.
  
  Specified by:
  
  getReactionTorque in class Joint
  
  Returns:
- getLocalAnchorA
```
public Vec2 getLocalAnchorA()
```
- getLocalAnchorB
```
public Vec2 getLocalAnchorB()
```
- getMaxLength
```
public float getMaxLength()
```
- setMaxLength
```
public void setMaxLength(float maxLength)
```
- getLimitState
```
public LimitState getLimitState()
```

Class RopeJoint

Field Summary

Fields inherited from class org.jbox2d.dynamics.joints.Joint

Constructor Summary

Method Summary

Methods inherited from class org.jbox2d.dynamics.joints.Joint

Methods inherited from class java.lang.Object

Field Detail

m_localAnchorA

m_localAnchorB

m_maxLength

m_length

m_impulse

m_indexA

m_indexB

m_u

m_rA

m_rB

m_localCenterA

m_localCenterB

m_invMassA

m_invMassB

m_invIA

m_invIB

m_mass

m_state

Constructor Detail

RopeJoint

Method Detail

initVelocityConstraints

solveVelocityConstraints

solvePositionConstraints

getAnchorA

getAnchorB

getReactionForce

getReactionTorque

getLocalAnchorA

getLocalAnchorB

getMaxLength

setMaxLength

getLimitState