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

```
public class PulleyJoint
extends Joint
```
The pulley joint is connected to two bodies and two fixed ground points. The pulley supports a ratio such that: length1 + ratio * length2 <= constant Yes, the force transmitted is scaled by the ratio. Warning: the pulley joint can get a bit squirrelly by itself. They often work better when combined with prismatic joints. You should also cover the the anchor points with static shapes to prevent one side from going to zero length.

Field Summary

Fields
Modifier and Type	Field	Description
`private float`	`m_constant`
`private Vec2`	`m_groundAnchorA`
`private Vec2`	`m_groundAnchorB`
`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_lengthA`
`private float`	`m_lengthB`
`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 float`	`m_ratio`
`private Vec2`	`m_rB`
`private Vec2`	`m_uA`
`private Vec2`	`m_uB`
`static float`	`MIN_PULLEY_LENGTH`

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 PulleyJoint(IWorldPool argWorldPool, PulleyJointDef 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`	`getCurrentLengthA()`
`float`	`getCurrentLengthB()`
`Vec2`	`getGroundAnchorA()`
`Vec2`	`getGroundAnchorB()`
`float`	`getLength1()`
`float`	`getLength2()`
`float`	`getLengthA()`
`float`	`getLengthB()`
`Vec2`	`getLocalAnchorA()`
`Vec2`	`getLocalAnchorB()`
`float`	`getRatio()`
`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)`
`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

MIN_PULLEY_LENGTH
```
public static final float MIN_PULLEY_LENGTH
```
See Also:

Constant Field Values

m_groundAnchorA
```
private final Vec2 m_groundAnchorA
```

m_groundAnchorB
```
private final Vec2 m_groundAnchorB
```

m_lengthA
```
private float m_lengthA
```

m_lengthB
```
private float m_lengthB
```

m_localAnchorA
```
private final Vec2 m_localAnchorA
```

m_localAnchorB
```
private final Vec2 m_localAnchorB
```

m_constant
```
private float m_constant
```

m_ratio
```
private float m_ratio
```

m_impulse
```
private float m_impulse
```

m_indexA
```
private int m_indexA
```

m_indexB
```
private int m_indexB
```

m_uA
```
private final Vec2 m_uA
```

m_uB
```
private final Vec2 m_uB
```

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

PulleyJoint

protected PulleyJoint(IWorldPool argWorldPool,
                      PulleyJointDef def)

Method Detail
- getLengthA
```
public float getLengthA()
```
- getLengthB
```
public float getLengthB()
```
- getCurrentLengthA
```
public float getCurrentLengthA()
```
- getCurrentLengthB
```
public float getCurrentLengthB()
```
- getLocalAnchorA
```
public Vec2 getLocalAnchorA()
```
- getLocalAnchorB
```
public Vec2 getLocalAnchorB()
```
- 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:
- getGroundAnchorA
```
public Vec2 getGroundAnchorA()
```
- getGroundAnchorB
```
public Vec2 getGroundAnchorB()
```
- getLength1
```
public float getLength1()
```
- getLength2
```
public float getLength2()
```
- getRatio
```
public float getRatio()
```
- 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 PulleyJoint

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

MIN_PULLEY_LENGTH

m_groundAnchorA

m_groundAnchorB

m_lengthA

m_lengthB

m_localAnchorA

m_localAnchorB

m_constant

m_ratio

m_impulse

m_indexA

m_indexB

m_uA

m_uB

m_rA

m_rB

m_localCenterA

m_localCenterB

m_invMassA

m_invMassB

m_invIA

m_invIB

m_mass

Constructor Detail

PulleyJoint

Method Detail

getLengthA

getLengthB

getCurrentLengthA

getCurrentLengthB

getLocalAnchorA

getLocalAnchorB

getAnchorA

getAnchorB

getReactionForce

getReactionTorque

getGroundAnchorA

getGroundAnchorB

getLength1

getLength2

getRatio

initVelocityConstraints

solveVelocityConstraints

solvePositionConstraints