Object
- Joint<T>
- - PinJoint<T>

Type Parameters:

T - the PhysicsBody type

All Implemented Interfaces:

DataContainer, Shiftable, Ownable
```
public class PinJoint<T extends PhysicsBody>
extends Joint<T>
implements Shiftable, DataContainer
```
Implementation of a pin joint.
A pin joint is a joint that pins a body to a specified world space point using a spring-damper system. 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.
The pin joint requires the spring-damper system to function properly and as such the frequency value must be greater than zero. Use a RevoluteJoint instead if a spring-damper system is not desired. A good starting point is a frequency of 8.0 and damping ratio of 0.3 then adjust as necessary.
The getAnchor1() method returns the target and the getAnchor2() method returns the world space anchor point.
Both the Joint.getBody1() and Joint.getBody2() methods return the same body.
Renamed from MouseJoint in 3.2.0.

Since:

1.0.0

Version:

4.0.0

Author:

William Bittle

See Also:

Documentation

Constructor Summary

Constructors
Constructor Description

PinJoint(T body, Vector2 anchor, double frequency, double dampingRatio, double maximumForce)
Full constructor.

Method Summary

All Methods Instance Methods Concrete 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`	`getDampingRatio()`	Returns the damping ratio.
`double`	`getFrequency()`	Returns the spring frequency.
`double`	`getMaximumForce()`	Returns the maximum force this constraint will apply in newtons.
`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.
`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.
`void`	`setDampingRatio(double dampingRatio)`	Sets the damping ratio.
`void`	`setFrequency(double frequency)`	Sets the spring frequency.
`void`	`setMaximumForce(double maximumForce)`	Sets the maximum force this constraint will apply in newtons.
`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()`

Methods inherited from class Joint
getBody1, getBody2, getOtherBody, getOwner, getUserData, isActive, 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
  - PinJoint
```
public PinJoint(T body,
                Vector2 anchor,
                double frequency,
                double dampingRatio,
                double maximumForce)
```
    Full constructor.
    
    Parameters:
    
    body - the body to attach the joint to
    
    anchor - the anchor point on the body
    
    frequency - the oscillation frequency in hz
    
    dampingRatio - the damping ratio
    
    maximumForce - the maximum force this constraint can apply in newtons
    
    Throws:
    
    NullPointerException - if body or anchor is null
    
    IllegalArgumentException - if frequency is less than or equal to zero, or if dampingRatio is less than zero or greater than one, or if maxForce is less than zero
- 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()
```
    Returns the anchor point on the first PhysicsBody in world coordinates.
    Returns the target point in world space.
    
    Specified by:
    
    getAnchor1 in class Joint<T extends PhysicsBody>
    
    Returns:
    
    Vector2
  - getAnchor2
```
public Vector2 getAnchor2()
```
    Returns the anchor point on the second PhysicsBody in world coordinates.
    Returns the anchor point on the body in world space.
    
    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)
```
    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 class Joint<T extends PhysicsBody>
    
    Parameters:
    
    invdt - the inverse delta time
    
    Returns:
    
    double
  - isCollisionAllowed
```
public boolean isCollisionAllowed()
```
    Description copied from class: Joint
    
    Returns true if collision between the joined PhysicsBodys is allowed.
    
    Overrides:
    
    isCollisionAllowed in class Joint<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
  - 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
  - getMaximumForce
```
public double getMaximumForce()
```
    Returns the maximum force this constraint will apply in newtons.
    
    Returns:
    
    double
  - setMaximumForce
```
public void setMaximumForce(double maximumForce)
```
    Sets the maximum force this constraint will apply in newtons.
    
    Parameters:
    
    maximumForce - the maximum force in newtons; in the range [0, ∞]
    
    Throws:
    
    IllegalArgumentException - if maxForce less than zero
  - getDampingRatio
```
public double getDampingRatio()
```
    Returns the damping ratio.
    
    Returns:
    
    double
  - setDampingRatio
```
public void setDampingRatio(double dampingRatio)
```
    Sets the damping ratio.
    
    Parameters:
    
    dampingRatio - the damping ratio; in the range [0, 1]
    
    Throws:
    
    IllegalArgumentException - if dampingRation is less than zero or greater than one
  - getFrequency
```
public double getFrequency()
```
    Returns the spring frequency.
    
    Returns:
    
    double
  - setFrequency
```
public void setFrequency(double frequency)
```
    Sets the spring frequency.
    
    Parameters:
    
    frequency - the spring frequency in hz; must be greater than zero
    
    Throws:
    
    IllegalArgumentException - if frequency is less than or equal to zero

Class PinJoint<T extends PhysicsBody>

Constructor Summary

Method Summary

Methods inherited from class Joint

Methods inherited from class Object

Methods inherited from interface DataContainer

Constructor Detail

PinJoint

Method Detail

toString

initializeConstraints

solveVelocityConstraints

solvePositionConstraints

getAnchor1

getAnchor2

getReactionForce

getReactionTorque

isCollisionAllowed

shift

setTarget

getTarget

getMaximumForce

setMaximumForce

getDampingRatio

setDampingRatio

getFrequency

setFrequency