Package org.jbox2d.dynamics.joints

Class PulleyJoint

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 anchor points with static shapes to prevent one side from going to zero length.

Author:

Daniel Murphy

Repolink:

Github: erincatto/box2d src/dynamics/b2_pulley_joint.cpp

Field Summary

Fields

Modifier and Type	Field	Description
static final float	MIN_PULLEY_LENGTH

Fields inherited from class org.jbox2d.dynamics.joints.Joint

bodyA, bodyB, edgeA, edgeB, islandFlag, next, pool, prev, userData

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PulleyJoint(WorldPool argWorldPool, PulleyJointDef def)

Method Summary

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 invDt, Vec2 argOut)	Get the reaction force on body2 at the joint anchor in Newtons.
float	getReactionTorque(float invDt)	Get the reaction torque on body2 in N*m.
void	initVelocityConstraints(SolverData data)	Internal
boolean	solvePositionConstraints(SolverData data)	This returns true if the position errors are within tolerance.
void	solveVelocityConstraints(SolverData data)	Internal

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 Details

MIN_PULLEY_LENGTH

public static final float MIN_PULLEY_LENGTH

See Also:

• Constant Field Values

Constructor Details

PulleyJoint

protected PulleyJoint(WorldPool argWorldPool,
 PulleyJointDef def)

Repolink:

Github: erincatto/box2d src/dynamics/b2_pulley_joint.cpp Lines 39 - 56

Method Details

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 invDt,
 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 invDt)

Description copied from class: Joint

Get the reaction torque on body2 in N*m.

Specified by:

getReactionTorque in class Joint

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)

Description copied from class: Joint

Internal

Specified by:

initVelocityConstraints in class Joint

Repolink:

Github: erincatto/box2d src/dynamics/b2_pulley_joint.cpp Lines 77 - 165

solveVelocityConstraints

public void solveVelocityConstraints(SolverData data)

Description copied from class: Joint

Internal

Specified by:

solveVelocityConstraints in class Joint

Repolink:

Github: erincatto/box2d src/dynamics/b2_pulley_joint.cpp Lines 167 - 192

solvePositionConstraints

public boolean solvePositionConstraints(SolverData data)

Description copied from class: Joint

This returns true if the position errors are within tolerance. Internal.

Specified by:

solvePositionConstraints in class Joint

Repolink:

Github: erincatto/box2d src/dynamics/b2_pulley_joint.cpp Lines 194 - 264