Module org.dyn4j

Package org.dyn4j.dynamics.joint

Class RopeJoint<T extends PhysicsBody>

Object

Joint<T>

RopeJoint<T>

Type Parameters:

T - the PhysicsBody type

All Implemented Interfaces:

DataContainer, Shiftable, Ownable

public class RopeJoint<T extends PhysicsBody>
extends Joint<T>
implements Shiftable, DataContainer

Implementation a maximum and/or minimum length distance joint.

A rope joint contains the distance between two bodies. The bodies can rotate freely about the anchor points. The system as a whole can rotate and translate freely as well.

This joint is like the DistanceJoint, but includes an upper and lower limit and does not include a spring-damper system.

By default the lower and upper limits are set to the current distance between the given anchor points and will function identically like a DistanceJoint. The upper and lower limits can be enabled separately.

The lower limit constraint requires that the bodies are initially separated for it to be enforced. The lower limit will be enforced as soon as the bodies separate, but it's recommended that they start separated instead. If the lower limit is not being used, then the initial state doesn't matter.

Since:

2.2.1

Version:

4.0.1

Author:

William Bittle

See Also:

Documentation, Distance Constraint, Max Distance Constraint

Constructor Summary

Constructors

Constructor	Description
RopeJoint(T body1, T body2, Vector2 anchor1, Vector2 anchor2)	Minimal constructor.

Method Summary

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.
LimitState	getLimitState()	Deprecated. Deprecated in 4.0.0.
double	getLowerLimit()	Returns the lower limit in meters.
Vector2	getReactionForce(double invdt)	Returns the force applied to the PhysicsBodys in order to satisfy the constraint in newtons.
double	getReactionTorque(double invdt)	Returns the torque applied to the PhysicsBodys in order to satisfy the constraint in newton-meters.
double	getUpperLimit()	Returns the upper limit in meters.
void	initializeConstraints(TimeStep step, Settings settings)	Performs any initialization of the velocity and position constraints.
boolean	isLowerLimitEnabled()	Returns true if the lower limit is enabled.
boolean	isUpperLimitEnabled()	Returns true if the upper limit is enabled.
void	setLimits(double limit)	Sets both the lower and upper limits to the given limit.
void	setLimits(double lowerLimit, double upperLimit)	Sets both the lower and upper limits.
void	setLimitsEnabled(boolean flag)	Enables or disables both the lower and upper limits.
void	setLimitsEnabled(double limit)	Sets both the lower and upper limits to the given limit and enables both.
void	setLimitsEnabled(double lowerLimit, double upperLimit)	Sets both the lower and upper limits and enables both.
void	setLowerLimit(double lowerLimit)	Sets the lower limit in meters.
void	setLowerLimitEnabled(boolean flag)	Sets whether the lower limit is enabled.
void	setUpperLimit(double upperLimit)	Sets the upper limit in meters.
void	setUpperLimitEnabled(boolean flag)	Sets whether the upper limit is enabled.
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

RopeJoint

public RopeJoint(T body1,
                 T body2,
                 Vector2 anchor1,
                 Vector2 anchor2)

Minimal constructor.

Creates a rope joint between the two bodies that acts like a distance joint.

Parameters:

body1 - the first PhysicsBody

body2 - the second PhysicsBody

anchor1 - in world coordinates

anchor2 - in world coordinates

Throws:

NullPointerException - if body1, body2, anchor1, or anchor2 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)

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

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

getUpperLimit

public double getUpperLimit()

Returns the upper limit in meters.

Returns:

double

setUpperLimit

public void setUpperLimit(double upperLimit)

Sets the upper limit in meters.

Parameters:

upperLimit - the upper limit in meters; must be greater than or equal to zero

Throws:

IllegalArgumentException - if upperLimit is less than zero or less than the current lower limit

setUpperLimitEnabled

public void setUpperLimitEnabled(boolean flag)

Sets whether the upper limit is enabled.

Parameters:

flag - true if the upper limit should be enabled

isUpperLimitEnabled

public boolean isUpperLimitEnabled()

Returns true if the upper limit is enabled.

Returns:

boolean true if the upper limit is enabled

getLowerLimit

public double getLowerLimit()

Returns the lower limit in meters.

Returns:

double

setLowerLimit

public void setLowerLimit(double lowerLimit)

Sets the lower limit in meters.

Parameters:

lowerLimit - the lower limit in meters; must be greater than or equal to zero

Throws:

IllegalArgumentException - if lowerLimit is less than zero or greater than the current upper limit

setLowerLimitEnabled

public void setLowerLimitEnabled(boolean flag)

Sets whether the lower limit is enabled.

Parameters:

flag - true if the lower limit should be enabled

isLowerLimitEnabled

public boolean isLowerLimitEnabled()

Returns true if the lower limit is enabled.

Returns:

boolean true if the lower limit is enabled

setLimits

public void setLimits(double lowerLimit,
                      double upperLimit)

Sets both the lower and upper limits.

Parameters:

lowerLimit - the lower limit in meters; must be greater than or equal to zero

upperLimit - the upper limit in meters; must be greater than or equal to zero

Throws:

IllegalArgumentException - if lowerLimit is less than zero, upperLimit is less than zero, or lowerLimit is greater than upperLimit

setLimitsEnabled

public void setLimitsEnabled(double lowerLimit,
                             double upperLimit)

Sets both the lower and upper limits and enables both.

Parameters:

lowerLimit - the lower limit in meters; must be greater than or equal to zero

upperLimit - the upper limit in meters; must be greater than or equal to zero

Throws:

IllegalArgumentException - if lowerLimit is less than zero, upperLimit is less than zero, or lowerLimit is greater than upperLimit

setLimitsEnabled

public void setLimitsEnabled(boolean flag)

Enables or disables both the lower and upper limits.

Parameters:

flag - true if both limits should be enabled

Since:

2.2.2

setLimits

public void setLimits(double limit)

Sets both the lower and upper limits to the given limit.

This makes the joint a fixed length joint.

Parameters:

limit - the desired limit

Throws:

IllegalArgumentException - if limit is less than zero

Since:

2.2.2

setLimitsEnabled

public void setLimitsEnabled(double limit)

Sets both the lower and upper limits to the given limit and enables both.

This makes the joint a fixed length joint.

Parameters:

limit - the desired limit

Throws:

IllegalArgumentException - if limit is less than zero

Since:

2.2.2

getLimitState

@Deprecated
public LimitState getLimitState()

Deprecated.

Deprecated in 4.0.0.

Returns the current state of the limit.

Returns:

LimitState

Since:

3.2.0