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

```
public class DistanceJoint
extends Joint
```
A distance joint constrains two points on two bodies to remain at a fixed distance from each other. You can view this as a massless, rigid rod.

Field Summary

Fields
Modifier and Type	Field	Description
`private float`	`m_bias`
`private float`	`m_dampingRatio`
`private float`	`m_frequencyHz`
`private float`	`m_gamma`
`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 Vec2`	`m_rA`
`private Vec2`	`m_rB`
`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 DistanceJoint(IWorldPool argWorld, DistanceJointDef 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.
`float`	`getDampingRatio()`
`float`	`getFrequency()`
`float`	`getLength()`
`Vec2`	`getLocalAnchorA()`
`Vec2`	`getLocalAnchorB()`
`void`	`getReactionForce(float inv_dt, Vec2 argOut)`	Get the reaction force given the inverse time step.
`float`	`getReactionTorque(float inv_dt)`	Get the reaction torque given the inverse time step.
`void`	`initVelocityConstraints(SolverData data)`
`void`	`setDampingRatio(float damp)`
`void`	`setFrequency(float hz)`
`void`	`setLength(float argLength)`
`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_frequencyHz
```
private float m_frequencyHz
```

m_dampingRatio
```
private float m_dampingRatio
```

m_bias
```
private float m_bias
```

m_localAnchorA
```
private final Vec2 m_localAnchorA
```

m_localAnchorB
```
private final Vec2 m_localAnchorB
```

m_gamma
```
private float m_gamma
```

m_impulse
```
private float m_impulse
```

m_length
```
private float m_length
```

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
```

Constructor Detail

DistanceJoint

protected DistanceJoint(IWorldPool argWorld,
                        DistanceJointDef def)

Method Detail
- setFrequency
```
public void setFrequency(float hz)
```
- getFrequency
```
public float getFrequency()
```
- getLength
```
public float getLength()
```
- setLength
```
public void setLength(float argLength)
```
- setDampingRatio
```
public void setDampingRatio(float damp)
```
- getDampingRatio
```
public float getDampingRatio()
```
- 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
- getLocalAnchorA
```
public Vec2 getLocalAnchorA()
```
- getLocalAnchorB
```
public Vec2 getLocalAnchorB()
```
- getReactionForce
```
public void getReactionForce(float inv_dt,
                             Vec2 argOut)
```
  Get the reaction force given the inverse time step. Unit is N.
  
  Specified by:
  
  getReactionForce in class Joint
- getReactionTorque
```
public float getReactionTorque(float inv_dt)
```
  Get the reaction torque given the inverse time step. Unit is N*m. This is always zero for a distance joint.
  
  Specified by:
  
  getReactionTorque in class Joint
  
  Returns:
- 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:

Class DistanceJoint

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_frequencyHz

m_dampingRatio

m_bias

m_localAnchorA

m_localAnchorB

m_gamma

m_impulse

m_length

m_indexA

m_indexB

m_u

m_rA

m_rB

m_localCenterA

m_localCenterB

m_invMassA

m_invMassB

m_invIA

m_invIB

m_mass

Constructor Detail

DistanceJoint

Method Detail

setFrequency

getFrequency

getLength

setLength

setDampingRatio

getDampingRatio

getAnchorA

getAnchorB

getLocalAnchorA

getLocalAnchorB

getReactionForce

getReactionTorque

initVelocityConstraints

solveVelocityConstraints

solvePositionConstraints