Object
- AbstractJoint<T>
- - AbstractSingleBodyJoint<T>
  - - PinJoint<T>

Type Parameters:

T - the PhysicsBody type

All Implemented Interfaces:

DataContainer, Joint<T>, LinearSpringJoint, SingleBodyJoint<T>, Shiftable, Ownable
```
public class PinJoint<T extends PhysicsBody>
extends AbstractSingleBodyJoint<T>
implements LinearSpringJoint, SingleBodyJoint<T>, Joint<T>, Shiftable, DataContainer, Ownable
```
Implementation of a pin joint.
A pin joint is a joint that pins a body to a specified world space point. This joint will attempt to place the given anchor point at the target position.
NOTE: The anchor point does not have to be within the bounds of the body.
By default the target position will be the given world space anchor. Use the setTarget(Vector2) method to set a different target.
By default the pin joint is setup with a linear spring-damper with a maximum force. The defaults are a frequency of 8.0, damping ratio of 0.3 and a maximum force of 1000.0.
You can disable the spring-damper using the setSpringEnabled(boolean) method. This turns the joint into an unary MotorJoint. You can use the setCorrectionFactor(double) method to set how quickly the constraint violation should be resolved and you can set the maximum force the correction should apply using the setMaximumCorrectionForce(double). Both of these settings are only relevant when the spring-damper is disabled.
The getAnchor() method returns the anchor point on body in world space. The getTarget() returns the target point in world space.
Renamed from MouseJoint in 3.2.0. Can function without a spring-damper as of 5.0.0.

Since:

1.0.0

Version:

5.0.0

Author:

William Bittle

See Also:

Documentation

Field Summary

Fields
Modifier and Type	Field	Description
`protected double`	`correctionFactor`	The correction factor in the range [0, 1]
`protected double`	`correctionMaximumForce`	The maximum force the constraint can apply
`protected Vector2`	`localAnchor`	The local anchor point for the body
`protected boolean`	`springDamperEnabled`	True if the spring's damper is enabled
`protected double`	`springDampingRatio`	The damping ratio
`protected boolean`	`springEnabled`	True if the spring is enabled
`protected double`	`springFrequency`	The oscillation frequency in hz
`protected double`	`springMaximumForce`	The maximum force the spring can apply
`protected boolean`	`springMaximumForceEnabled`	True if the spring maximum force is enabled
`protected int`	`springMode`	The current spring mode
`protected double`	`springStiffness`	The stiffness (k) of the spring
`protected Vector2`	`target`	The world space target point

Fields inherited from class AbstractSingleBodyJoint
body

Fields inherited from class AbstractJoint
bodies, collisionAllowed, owner, userData

Fields inherited from interface Joint
SPRING_MODE_FREQUENCY, SPRING_MODE_STIFFNESS

Constructor Summary

Constructors
Constructor Description

PinJoint(T body, Vector2 anchor)
Full constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Vector2`	`getAnchor()`	Returns the anchor point on the body in world space.
`double`	`getCorrectionFactor()`	Returns the correction factor.
`double`	`getCorrectionForce(double invdt)`	Returns the correction force from the last step.
`double`	`getMaximumCorrectionForce()`	Returns the maximum correction force this constraint will apply in newtons.
`double`	`getMaximumSpringForce()`	Returns the maximum spring force that will be applied.
`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`	`getSpringDampingRatio()`	Returns the damping ratio for the spring's damper.
`double`	`getSpringForce(double invdt)`	Returns the force in netwons applied by the spring in the last timestep.
`double`	`getSpringFrequency()`	Returns the spring frequency.
`int`	`getSpringMode()`	Returns the current spring mode.
`double`	`getSpringStiffness()`	Returns the spring stiffness.
`Vector2`	`getTarget()`	Returns the target point in world coordinates
`void`	`initializeConstraints(TimeStep step, Settings settings)`	Performs any initialization of the velocity and position constraints.
`boolean`	`isCollisionAllowed()`	Returns true if collision between the joined `PhysicsBody`s is allowed.
`boolean`	`isMaximumSpringForceEnabled()`	Returns true if the spring force is limited to the maximum.
`boolean`	`isSpringDamperEnabled()`	Returns true if the damper is enabled for the spring.
`boolean`	`isSpringEnabled()`	Returns true if the spring is enabled.
`void`	`setCorrectionFactor(double correctionFactor)`	Sets the correction factor.
`void`	`setMaximumCorrectionForce(double maximumForce)`	Sets the maximum correction force this constraint will apply in newtons.
`void`	`setMaximumSpringForce(double maximum)`	Sets the maximum force the spring can apply.
`void`	`setMaximumSpringForceEnabled(boolean enabled)`	Sets whether the spring force is limited to the maximum.
`void`	`setSpringDamperEnabled(boolean enabled)`	Sets whether the spring's damper is enabled or not.
`void`	`setSpringDampingRatio(double dampingRatio)`	Sets the damping ratio.
`void`	`setSpringEnabled(boolean enabled)`	Sets whether the spring is enabled or not.
`void`	`setSpringFrequency(double frequency)`	Sets the spring frequency.
`void`	`setSpringStiffness(double stiffness)`	Sets the spring stiffness.
`void`	`setTarget(Vector2 target)`	Returns the target point in world coordinates.
`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()`
`protected void`	`updateSpringCoefficients()`	Computes the spring coefficients from the current state of the joint.

Methods inherited from class AbstractSingleBodyJoint
getBody, getBody, getBodyCount, isEnabled, isMember

Methods inherited from class AbstractJoint
getBodies, getBodyIterator, getConstraintImpulseMixing, getErrorReductionParameter, getFrequency, getNaturalFrequency, getNaturalFrequency, getOwner, getSpringDampingCoefficient, getSpringStiffness, getUserData, setCollisionAllowed, setOwner, setUserData

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

Methods inherited from interface DataContainer
getUserData, setUserData

Methods inherited from interface Joint
getBodies, getBody, getBodyCount, getBodyIterator, isEnabled, isMember, setCollisionAllowed

Methods inherited from interface Ownable
getOwner, setOwner

Methods inherited from interface SingleBodyJoint
getBody

- Field Detail
  - target
```
protected final Vector2 target
```
    The world space target point
  - localAnchor
```
protected final Vector2 localAnchor
```
    The local anchor point for the body
  - springEnabled
```
protected boolean springEnabled
```
    True if the spring is enabled
  - springMode
```
protected int springMode
```
    The current spring mode
  - springFrequency
```
protected double springFrequency
```
    The oscillation frequency in hz
  - springStiffness
```
protected double springStiffness
```
    The stiffness (k) of the spring
  - springDamperEnabled
```
protected boolean springDamperEnabled
```
    True if the spring's damper is enabled
  - springDampingRatio
```
protected double springDampingRatio
```
    The damping ratio
  - springMaximumForceEnabled
```
protected boolean springMaximumForceEnabled
```
    True if the spring maximum force is enabled
  - springMaximumForce
```
protected double springMaximumForce
```
    The maximum force the spring can apply
  - correctionFactor
```
protected double correctionFactor
```
    The correction factor in the range [0, 1]
  - correctionMaximumForce
```
protected double correctionMaximumForce
```
    The maximum force the constraint can apply
- Constructor Detail
  - PinJoint
```
public PinJoint(T body,
                Vector2 anchor)
```
    Full constructor.
    
    Parameters:
    
    body - the body to attach the joint to
    
    anchor - the anchor point on the body
    
    Throws:
    
    NullPointerException - if body or anchor is null
- Method Detail
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class AbstractJoint<T extends PhysicsBody>
  - initializeConstraints
```
public void initializeConstraints(TimeStep step,
                                  Settings settings)
```
    Description copied from interface: Joint
    
    Performs any initialization of the velocity and position constraints.
    
    Specified by:
    
    initializeConstraints in interface 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 interface: Joint
    
    Solves the velocity constraints.
    
    Specified by:
    
    solveVelocityConstraints in interface 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 interface: Joint
    
    Solves the position constraints.
    
    Specified by:
    
    solvePositionConstraints in interface Joint<T extends PhysicsBody>
    
    Parameters:
    
    step - the time step information
    
    settings - the current world settings
    
    Returns:
    
    boolean true if the position constraints were solved
  - updateSpringCoefficients
```
protected void updateSpringCoefficients()
```
    Computes the spring coefficients from the current state of the joint.
    This method is intended to set the springStiffness OR springFrequency and damping for use during constraint solving.
  - getAnchor
```
public Vector2 getAnchor()
```
    Returns the anchor point on the body in world space.
    
    Returns:
    
    Vector2
  - setTarget
```
public void setTarget(Vector2 target)
```
    Returns the target point in world coordinates.
    
    Parameters:
    
    target - the target point
    
    Throws:
    
    NullPointerException - if target is null
  - getTarget
```
public Vector2 getTarget()
```
    Returns the target point in world coordinates
    
    Returns:
    
    Vector2
  - getReactionForce
```
public Vector2 getReactionForce(double invdt)
```
    Description copied from interface: Joint
    
    Returns the force applied to the PhysicsBodys in order to satisfy the constraint in newtons.
    
    Specified by:
    
    getReactionForce in interface Joint<T extends PhysicsBody>
    
    Parameters:
    
    invdt - the inverse delta time
    
    Returns:
    
    Vector2
  - getReactionTorque
```
public double getReactionTorque(double invdt)
```
    Returns the torque applied to the PhysicsBodys in order to satisfy the constraint in newton-meters.
    Not applicable to this joint. Always returns zero.
    
    Specified by:
    
    getReactionTorque in interface Joint<T extends PhysicsBody>
    
    Parameters:
    
    invdt - the inverse delta time
    
    Returns:
    
    double
  - isCollisionAllowed
```
public boolean isCollisionAllowed()
```
    Description copied from interface: Joint
    
    Returns true if collision between the joined PhysicsBodys is allowed.
    
    Specified by:
    
    isCollisionAllowed in interface Joint<T extends PhysicsBody>
    
    Overrides:
    
    isCollisionAllowed in class AbstractJoint<T extends PhysicsBody>
    
    Returns:
    
    boolean
  - 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
  - getSpringDampingRatio
```
public double getSpringDampingRatio()
```
    Description copied from interface: LinearSpringJoint
    
    Returns the damping ratio for the spring's damper.
    
    Specified by:
    
    getSpringDampingRatio in interface LinearSpringJoint
    
    Returns:
    
    double
  - getSpringMode
```
public int getSpringMode()
```
    Description copied from interface: LinearSpringJoint
    
    Returns the current spring mode.
    NOTE: The spring mode is set automatically when you call either LinearSpringJoint.setSpringFrequency(double) or LinearSpringJoint.setSpringStiffness(double). Use this method to store the spring mode when saving the simulation state and use the value to call either LinearSpringJoint.setSpringFrequency(double) or LinearSpringJoint.setSpringStiffness(double).
    
    Specified by:
    
    getSpringMode in interface LinearSpringJoint
    
    Returns:
    
    int
    
    See Also:
    
    Joint.SPRING_MODE_FREQUENCY, Joint.SPRING_MODE_STIFFNESS
  - getCorrectionFactor
```
public double getCorrectionFactor()
```
    Returns the correction factor.
    
    Returns:
    
    double
    
    Since:
    
    5.0.0
  - setCorrectionFactor
```
public void setCorrectionFactor(double correctionFactor)
```
    Sets the correction factor.
    The correction factor controls the rate at which the bodies perform the desired actions. The default is 0.3.
    A value of zero means that the bodies do not perform any action.
    
    Parameters:
    
    correctionFactor - the correction factor in the range [0, 1]
    
    Since:
    
    5.0.0
  - getMaximumCorrectionForce
```
public double getMaximumCorrectionForce()
```
    Returns the maximum correction force this constraint will apply in newtons.
    
    Returns:
    
    double
    
    Since:
    
    5.0.0
  - setMaximumCorrectionForce
```
public void setMaximumCorrectionForce(double maximumForce)
```
    Sets the maximum correction force this constraint will apply in newtons.
    
    Parameters:
    
    maximumForce - the maximum force in newtons; in the range [0, ∞]
    
    Throws:
    
    IllegalArgumentException - if maxForce is less than zero
    
    Since:
    
    5.0.0
  - getCorrectionForce
```
public double getCorrectionForce(double invdt)
```
    Returns the correction force from the last step.
    
    Parameters:
    
    invdt - the inverse delta time
    
    Returns:
    
    double
  - setSpringDampingRatio
```
public void setSpringDampingRatio(double dampingRatio)
```
    Description copied from interface: LinearSpringJoint
    
    Sets the damping ratio.
    Larger values reduce the oscillation of the spring.
    
    Specified by:
    
    setSpringDampingRatio in interface LinearSpringJoint
    
    Parameters:
    
    dampingRatio - the damping ratio; in the range (0, 1]
  - getSpringFrequency
```
public double getSpringFrequency()
```
    Description copied from interface: LinearSpringJoint
    
    Returns the spring frequency.
    
    Specified by:
    
    getSpringFrequency in interface LinearSpringJoint
    
    Returns:
    
    double
  - getSpringStiffness
```
public double getSpringStiffness()
```
    Description copied from interface: LinearSpringJoint
    
    Returns the spring stiffness.
    
    Specified by:
    
    getSpringStiffness in interface LinearSpringJoint
    
    Returns:
    
    double
  - setSpringFrequency
```
public void setSpringFrequency(double frequency)
```
    Description copied from interface: LinearSpringJoint
    
    Sets the spring frequency.
    Larger values increase the stiffness of the spring.
    Calling this method puts the spring into fixed frequency mode. In this mode, the spring stiffness is computed based on the frequency.
    
    Specified by:
    
    setSpringFrequency in interface LinearSpringJoint
    
    Parameters:
    
    frequency - the spring frequency in hz; must be greater than zero
  - setSpringStiffness
```
public void setSpringStiffness(double stiffness)
```
    Description copied from interface: LinearSpringJoint
    
    Sets the spring stiffness.
    Larger values increase the stiffness of the spring.
    Calling this method puts the spring into fixed stiffness mode. In this mode, the spring frequency is computed based on the stiffness.
    
    Specified by:
    
    setSpringStiffness in interface LinearSpringJoint
    
    Parameters:
    
    stiffness - the spring stiffness (k); must be greater than zero
  - getMaximumSpringForce
```
public double getMaximumSpringForce()
```
    Description copied from interface: LinearSpringJoint
    
    Returns the maximum spring force that will be applied.
    
    Specified by:
    
    getMaximumSpringForce in interface LinearSpringJoint
    
    Returns:
    
    double
  - setMaximumSpringForce
```
public void setMaximumSpringForce(double maximum)
```
    Description copied from interface: LinearSpringJoint
    
    Sets the maximum force the spring can apply.
    
    Specified by:
    
    setMaximumSpringForce in interface LinearSpringJoint
    
    Parameters:
    
    maximum - the maximum force
  - isMaximumSpringForceEnabled
```
public boolean isMaximumSpringForceEnabled()
```
    Description copied from interface: LinearSpringJoint
    
    Returns true if the spring force is limited to the maximum.
    
    Specified by:
    
    isMaximumSpringForceEnabled in interface LinearSpringJoint
    
    Returns:
    
    boolean
  - setMaximumSpringForceEnabled
```
public void setMaximumSpringForceEnabled(boolean enabled)
```
    Description copied from interface: LinearSpringJoint
    
    Sets whether the spring force is limited to the maximum.
    
    Specified by:
    
    setMaximumSpringForceEnabled in interface LinearSpringJoint
    
    Parameters:
    
    enabled - true if the spring force should be limited
  - isSpringEnabled
```
public boolean isSpringEnabled()
```
    Description copied from interface: LinearSpringJoint
    
    Returns true if the spring is enabled.
    
    Specified by:
    
    isSpringEnabled in interface LinearSpringJoint
    
    Returns:
    
    boolean
  - setSpringEnabled
```
public void setSpringEnabled(boolean enabled)
```
    Description copied from interface: LinearSpringJoint
    
    Sets whether the spring is enabled or not.
    
    Specified by:
    
    setSpringEnabled in interface LinearSpringJoint
    
    Parameters:
    
    enabled - true if the spring should be enabled
  - isSpringDamperEnabled
```
public boolean isSpringDamperEnabled()
```
    Description copied from interface: LinearSpringJoint
    
    Returns true if the damper is enabled for the spring.
    NOTE: for the damper to have any effect, the spring must be enabled.
    
    Specified by:
    
    isSpringDamperEnabled in interface LinearSpringJoint
    
    Returns:
    
    boolean
    
    See Also:
    
    LinearSpringJoint.isSpringEnabled()
  - setSpringDamperEnabled
```
public void setSpringDamperEnabled(boolean enabled)
```
    Description copied from interface: LinearSpringJoint
    
    Sets whether the spring's damper is enabled or not.
    NOTE: for the damper to have any effect, the spring must be enabled.
    
    Specified by:
    
    setSpringDamperEnabled in interface LinearSpringJoint
    
    Parameters:
    
    enabled - true if the damper should be enabled
    
    See Also:
    
    LinearSpringJoint.setSpringEnabled(boolean)
  - getSpringForce
```
public double getSpringForce(double invdt)
```
    Description copied from interface: LinearSpringJoint
    
    Returns the force in netwons applied by the spring in the last timestep.
    
    Specified by:
    
    getSpringForce in interface LinearSpringJoint
    
    Parameters:
    
    invdt - the inverse delta time
    
    Returns:
    
    double

Class PinJoint<T extends PhysicsBody>

Field Summary

Fields inherited from class AbstractSingleBodyJoint

Fields inherited from class AbstractJoint

Fields inherited from interface Joint

Constructor Summary

Method Summary

Methods inherited from class AbstractSingleBodyJoint

Methods inherited from class AbstractJoint

Methods inherited from class Object

Methods inherited from interface DataContainer

Methods inherited from interface Joint

Methods inherited from interface Ownable

Methods inherited from interface SingleBodyJoint

Field Detail

target

localAnchor

springEnabled

springMode

springFrequency

springStiffness

springDamperEnabled

springDampingRatio

springMaximumForceEnabled

springMaximumForce

correctionFactor

correctionMaximumForce

Constructor Detail

PinJoint

Method Detail

toString

initializeConstraints

solveVelocityConstraints

solvePositionConstraints

updateSpringCoefficients

getAnchor

setTarget

getTarget

getReactionForce

getReactionTorque

isCollisionAllowed

shift

getSpringDampingRatio

getSpringMode

getCorrectionFactor

setCorrectionFactor

getMaximumCorrectionForce

setMaximumCorrectionForce

getCorrectionForce

setSpringDampingRatio

getSpringFrequency

getSpringStiffness

setSpringFrequency

setSpringStiffness

getMaximumSpringForce

setMaximumSpringForce

isMaximumSpringForceEnabled

setMaximumSpringForceEnabled

isSpringEnabled

setSpringEnabled

isSpringDamperEnabled

setSpringDamperEnabled

getSpringForce