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

```
public class MouseJoint
extends Joint
```
A mouse joint is used to make a point on a body track a specified world point. This a soft constraint with a maximum force. This allows the constraint to stretch and without applying huge forces. NOTE: this joint is not documented in the manual because it was developed to be used in the testbed. If you want to learn how to use the mouse joint, look at the testbed.

Field Summary

Fields
Modifier and Type	Field	Description
`private float`	`m_beta`
`private Vec2`	`m_C`
`private float`	`m_dampingRatio`
`private float`	`m_frequencyHz`
`private float`	`m_gamma`
`private Vec2`	`m_impulse`
`private int`	`m_indexB`
`private float`	`m_invIB`
`private float`	`m_invMassB`
`private Vec2`	`m_localAnchorB`
`private Vec2`	`m_localCenterB`
`private Mat22`	`m_mass`
`private float`	`m_maxForce`
`private Vec2`	`m_rB`
`private Vec2`	`m_targetA`

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 MouseJoint(IWorldPool argWorld, MouseJointDef 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`	`getMaxForce()`
`void`	`getReactionForce(float invDt, Vec2 argOut)`	get the reaction force on body2 at the joint anchor in Newtons.
`float`	`getReactionTorque(float invDt)`	get the reaction torque on body2 in N*m.
`Vec2`	`getTarget()`
`void`	`initVelocityConstraints(SolverData data)`
`void`	`setDampingRatio(float ratio)`
`void`	`setFrequency(float hz)`
`void`	`setMaxForce(float force)`
`void`	`setTarget(Vec2 target)`
`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_localAnchorB
```
private final Vec2 m_localAnchorB
```

m_targetA
```
private final Vec2 m_targetA
```

m_frequencyHz
```
private float m_frequencyHz
```

m_dampingRatio
```
private float m_dampingRatio
```

m_beta
```
private float m_beta
```

m_impulse
```
private final Vec2 m_impulse
```

m_maxForce
```
private float m_maxForce
```

m_gamma
```
private float m_gamma
```

m_indexB
```
private int m_indexB
```

m_rB
```
private final Vec2 m_rB
```

m_localCenterB
```
private final Vec2 m_localCenterB
```

m_invMassB
```
private float m_invMassB
```

m_invIB
```
private float m_invIB
```

m_mass
```
private final Mat22 m_mass
```

m_C
```
private final Vec2 m_C
```

Constructor Detail

MouseJoint

protected MouseJoint(IWorldPool argWorld,
                     MouseJointDef def)

Method Detail
- 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 invDt,
                             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 invDt)
```
  Description copied from class: Joint
  
  get the reaction torque on body2 in N*m.
  
  Specified by:
  
  getReactionTorque in class Joint
  
  Returns:
- setTarget
```
public void setTarget(Vec2 target)
```
- getTarget
```
public Vec2 getTarget()
```
- setMaxForce
```
public void setMaxForce(float force)
```
- getMaxForce
```
public float getMaxForce()
```
- setFrequency
```
public void setFrequency(float hz)
```
- getFrequency
```
public float getFrequency()
```
- setDampingRatio
```
public void setDampingRatio(float ratio)
```
- getDampingRatio
```
public float getDampingRatio()
```
- initVelocityConstraints
```
public void initVelocityConstraints(SolverData data)
```
  Specified by:
  
  initVelocityConstraints 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:
- solveVelocityConstraints
```
public void solveVelocityConstraints(SolverData data)
```
  Specified by:
  
  solveVelocityConstraints in class Joint

Class MouseJoint

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_localAnchorB

m_targetA

m_frequencyHz

m_dampingRatio

m_beta

m_impulse

m_maxForce

m_gamma

m_indexB

m_rB

m_localCenterB

m_invMassB

m_invIB

m_mass

m_C

Constructor Detail

MouseJoint

Method Detail

getAnchorA

getAnchorB

getReactionForce

getReactionTorque

setTarget

getTarget

setMaxForce

getMaxForce

setFrequency

getFrequency

setDampingRatio

getDampingRatio

initVelocityConstraints

solvePositionConstraints

solveVelocityConstraints