Object
- Joint<T>
- - RevoluteJoint<T>

Type Parameters:

T - the PhysicsBody type

All Implemented Interfaces:

DataContainer, Shiftable, Ownable
```
public class RevoluteJoint<T extends PhysicsBody>
extends Joint<T>
implements Shiftable, DataContainer
```
Implementation of a pivot joint.
A pivot joint allows two bodies to rotate freely about a common point, but does not allow them to translate relative to one another. The system as a whole can translate and rotate freely.
By default the lower and upper limit angles are set to the current angle between the bodies. When the lower and upper limits are equal, the bodies rotate together and are not allowed rotate relative to one another. By default the limits are disabled.
If the lower and upper limits are set explicitly, the values must follow these restrictions:
- lower limit ≤ upper limit
- lower limit > -180
- upper limit < 180
To create a joint with limits outside of this range use the setReferenceAngle(double) method. This method sets the baseline angle for the joint, which represents 0 radians in the context of the limits. For example:
```
 // we would like the joint limits to be [30, 260]
 // this is the same as the limits [-60, 170] if the reference angle is 90
 joint.setLimits(Math.toRadians(-60), Math.toRadians(170));
 joint.setReferenceAngle(Math.toRadians(90));
 
```
This joint also supports a motor. The motor is an angular motor about the anchor point. The motor speed can be positive or negative to indicate a clockwise or counter-clockwise rotation. The maximum motor torque must be greater than zero for the motor to apply any motion.
Since:

1.0.0

Version:

4.0.1

Author:

William Bittle

See Also:

Documentation, Point-to-Point Constraint

Constructor Summary

Constructors
Constructor Description

RevoluteJoint(T body1, T body2, Vector2 anchor)
Minimal constructor.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`Vector2`	`getAnchor1()`	Returns the anchor point on the first `PhysicsBody` in world coordinates.
`Vector2`	`getAnchor2()`	Returns the anchor point on the second `PhysicsBody` in world coordinates.
`double`	`getJointAngle()`	Returns the relative angle between the two `PhysicsBody`s in radians in the range [-π, π].
`double`	`getJointSpeed()`	Returns the relative speed at which the `PhysicsBody`s are rotating in radians/second.
`LimitState`	`getLimitState()`	Deprecated. Deprecated in 4.0.0.
`double`	`getLowerLimit()`	Returns the lower rotational limit in radians.
`double`	`getMaximumMotorTorque()`	Returns the maximum torque this motor will apply in newton-meters.
`double`	`getMotorSpeed()`	Returns the desired motor speed in radians/second.
`double`	`getMotorTorque()`	Returns the motor torque in newton-meters.
`Vector2`	`getReactionForce(double invdt)`	Returns the force applied to the `PhysicsBody`s in order to satisfy the constraint in newtons.
`double`	`getReactionTorque(double invdt)`	Returns the torque applied to the `PhysicsBody`s in order to satisfy the constraint in newton-meters.
`double`	`getReferenceAngle()`	Returns the reference angle.
`double`	`getUpperLimit()`	Returns the upper rotational limit in radians.
`void`	`initializeConstraints(TimeStep step, Settings settings)`	Performs any initialization of the velocity and position constraints.
`boolean`	`isLimitEnabled()`	Returns true if the rotational limit is enabled.
`boolean`	`isMotorEnabled()`	Returns true if this motor is enabled.
`void`	`setLimitEnabled(boolean flag)`	Enables or disables the rotational limit.
`void`	`setLimits(double lowerLimit, double upperLimit)`	Sets the upper and lower rotational limits.
`void`	`setLowerLimit(double lowerLimit)`	Sets the lower rotational limit.
`void`	`setMaximumMotorTorque(double maximumMotorTorque)`	Sets the maximum torque this motor will apply in newton-meters.
`void`	`setMotorEnabled(boolean flag)`	Sets whether the motor for this joint is enabled or not.
`void`	`setMotorSpeed(double motorSpeed)`	Sets the target motor speed in radians/second.
`void`	`setReferenceAngle(double angle)`	Sets the reference angle.
`void`	`setUpperLimit(double upperLimit)`	Sets the upper rotational limit.
`void`	`shift(Vector2 shift)`	Translates the object to match the given coordinate shift.
`boolean`	`solvePositionConstraints(TimeStep step, Settings settings)`	Solves the position constraints.
`void`	`solveVelocityConstraints(TimeStep step, Settings settings)`	Solves the velocity constraints.
`String`	`toString()`

Methods inherited from class Joint
getBody1, getBody2, getOtherBody, getOwner, getUserData, isActive, isCollisionAllowed, isEnabled, isOnIsland, setCollisionAllowed, setOnIsland, setOwner, setUserData

Methods inherited from class Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface DataContainer
getUserData, setUserData

- Constructor Detail
  - RevoluteJoint
```
public RevoluteJoint(T body1,
                     T body2,
                     Vector2 anchor)
```
    Minimal constructor.
    
    Parameters:
    
    body1 - the first PhysicsBody
    
    body2 - the second PhysicsBody
    
    anchor - the anchor point in world coordinates
    
    Throws:
    
    NullPointerException - if body1, body2 or anchor is null
    
    IllegalArgumentException - if body1 == body2
- Method Detail
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Joint<T extends PhysicsBody>
  - initializeConstraints
```
public void initializeConstraints(TimeStep step,
                                  Settings settings)
```
    Description copied from class: Joint
    
    Performs any initialization of the velocity and position constraints.
    
    Specified by:
    
    initializeConstraints in class Joint<T extends PhysicsBody>
    
    Parameters:
    
    step - the time step information
    
    settings - the current world settings
  - solveVelocityConstraints
```
public void solveVelocityConstraints(TimeStep step,
                                     Settings settings)
```
    Description copied from class: Joint
    
    Solves the velocity constraints.
    
    Specified by:
    
    solveVelocityConstraints in class Joint<T extends PhysicsBody>
    
    Parameters:
    
    step - the time step information
    
    settings - the current world settings
  - solvePositionConstraints
```
public boolean solvePositionConstraints(TimeStep step,
                                        Settings settings)
```
    Description copied from class: Joint
    
    Solves the position constraints.
    
    Specified by:
    
    solvePositionConstraints in class Joint<T extends PhysicsBody>
    
    Parameters:
    
    step - the time step information
    
    settings - the current world settings
    
    Returns:
    
    boolean true if the position constraints were solved
  - getAnchor1
```
public Vector2 getAnchor1()
```
    Description copied from class: Joint
    
    Returns the anchor point on the first PhysicsBody in world coordinates.
    
    Specified by:
    
    getAnchor1 in class Joint<T extends PhysicsBody>
    
    Returns:
    
    Vector2
  - getAnchor2
```
public Vector2 getAnchor2()
```
    Description copied from class: Joint
    
    Returns the anchor point on the second PhysicsBody in world coordinates.
    
    Specified by:
    
    getAnchor2 in class Joint<T extends PhysicsBody>
    
    Returns:
    
    Vector2
  - getReactionForce
```
public Vector2 getReactionForce(double invdt)
```
    Description copied from class: Joint
    
    Returns the force applied to the PhysicsBodys in order to satisfy the constraint in newtons.
    
    Specified by:
    
    getReactionForce in class Joint<T extends PhysicsBody>
    
    Parameters:
    
    invdt - the inverse delta time
    
    Returns:
    
    Vector2
  - getReactionTorque
```
public double getReactionTorque(double invdt)
```
    Description copied from class: Joint
    
    Returns the torque applied to the PhysicsBodys in order to satisfy the constraint in newton-meters.
    
    Specified by:
    
    getReactionTorque in class Joint<T extends PhysicsBody>
    
    Parameters:
    
    invdt - the inverse delta time
    
    Returns:
    
    double
  - shift
```
public void shift(Vector2 shift)
```
    Description copied from interface: Shiftable
    
    Translates the object to match the given coordinate shift.
    
    Specified by:
    
    shift in interface Shiftable
    
    Parameters:
    
    shift - the amount to shift along the x and y axes
  - getJointSpeed
```
public double getJointSpeed()
```
    Returns the relative speed at which the PhysicsBodys are rotating in radians/second.
    
    Returns:
    
    double
  - getJointAngle
```
public double getJointAngle()
```
    Returns the relative angle between the two PhysicsBodys in radians in the range [-π, π].
    
    Returns:
    
    double
  - isMotorEnabled
```
public boolean isMotorEnabled()
```
    Returns true if this motor is enabled.
    
    Returns:
    
    boolean
  - setMotorEnabled
```
public void setMotorEnabled(boolean flag)
```
    Sets whether the motor for this joint is enabled or not.
    
    Parameters:
    
    flag - true if the motor should be enabled
  - getMaximumMotorTorque
```
public double getMaximumMotorTorque()
```
    Returns the maximum torque this motor will apply in newton-meters.
    
    Returns:
    
    double
  - setMaximumMotorTorque
```
public void setMaximumMotorTorque(double maximumMotorTorque)
```
    Sets the maximum torque this motor will apply in newton-meters.
    
    Parameters:
    
    maximumMotorTorque - the maximum motor torque in newton-meters; must be greater than or equal to zero
    
    Throws:
    
    IllegalArgumentException - if maxMotorTorque is less than zero
    
    See Also:
    
    setMotorSpeed(double)
  - getMotorSpeed
```
public double getMotorSpeed()
```
    Returns the desired motor speed in radians/second.
    
    Returns:
    
    double
  - setMotorSpeed
```
public void setMotorSpeed(double motorSpeed)
```
    Sets the target motor speed in radians/second.
    
    Parameters:
    
    motorSpeed - the motor speed desired in radians/second
    
    See Also:
    
    setMaximumMotorTorque(double)
  - getMotorTorque
```
public double getMotorTorque()
```
    Returns the motor torque in newton-meters.
    
    Returns:
    
    double
  - isLimitEnabled
```
public boolean isLimitEnabled()
```
    Returns true if the rotational limit is enabled.
    
    Returns:
    
    boolean
  - setLimitEnabled
```
public void setLimitEnabled(boolean flag)
```
    Enables or disables the rotational limit.
    
    Parameters:
    
    flag - true if the limit should be enabled
  - getUpperLimit
```
public double getUpperLimit()
```
    Returns the upper rotational limit in radians.
    
    Returns:
    
    double
  - setUpperLimit
```
public void setUpperLimit(double upperLimit)
```
    Sets the upper rotational limit.
    Must be greater than or equal to the lower rotational limit.
    See the class documentation for more details on the limit ranges.
    
    Parameters:
    
    upperLimit - the upper rotational limit in radians
    
    Throws:
    
    IllegalArgumentException - if upperLimit is less than the current lower limit
  - getLowerLimit
```
public double getLowerLimit()
```
    Returns the lower rotational limit in radians.
    
    Returns:
    
    double
  - setLowerLimit
```
public void setLowerLimit(double lowerLimit)
```
    Sets the lower rotational limit.
    Must be less than or equal to the upper rotational limit.
    See the class documentation for more details on the limit ranges.
    
    Parameters:
    
    lowerLimit - the lower rotational limit in radians
    
    Throws:
    
    IllegalArgumentException - if lowerLimit is greater than the current upper limit
  - setLimits
```
public void setLimits(double lowerLimit,
                      double upperLimit)
```
    Sets the upper and lower rotational limits.
    The lower limit must be less than or equal to the upper limit.
    See the class documentation for more details on the limit ranges.
    
    Parameters:
    
    lowerLimit - the lower limit in radians
    
    upperLimit - the upper limit in radians
    
    Throws:
    
    IllegalArgumentException - if the lowerLimit is greater than upperLimit
  - getReferenceAngle
```
public double getReferenceAngle()
```
    Returns the reference angle.
    The reference angle is the angle calculated when the joint was created from the two joined bodies. The reference angle is the angular difference between the bodies.
    
    Returns:
    
    double
    
    Since:
    
    3.0.1
  - setReferenceAngle
```
public void setReferenceAngle(double angle)
```
    Sets the reference angle.
    This method can be used to set the reference angle to override the computed reference angle from the constructor. This is useful in recreating the joint from a current state.
    
    Parameters:
    
    angle - the reference angle in radians
    
    Since:
    
    3.0.1
    
    See Also:
    
    getReferenceAngle()
  - getLimitState
```
@Deprecated
public LimitState getLimitState()
```
    Deprecated.
    Deprecated in 4.0.0.
    
    Returns the current state of the limit.
    
    Returns:
    
    LimitState
    
    Since:
    
    3.2.0

Class RevoluteJoint<T extends PhysicsBody>

Constructor Summary

Method Summary

Methods inherited from class Joint

Methods inherited from class Object

Methods inherited from interface DataContainer

Constructor Detail

RevoluteJoint

Method Detail

toString

initializeConstraints

solveVelocityConstraints

solvePositionConstraints

getAnchor1

getAnchor2

getReactionForce

getReactionTorque

shift

getJointSpeed

getJointAngle

isMotorEnabled

setMotorEnabled

getMaximumMotorTorque

setMaximumMotorTorque

getMotorSpeed

setMotorSpeed

getMotorTorque

isLimitEnabled

setLimitEnabled

getUpperLimit

setUpperLimit

getLowerLimit

setLowerLimit

setLimits

getReferenceAngle

setReferenceAngle

getLimitState