Package org.jbox2d.dynamics.joints

Class RevoluteJoint

java.lang.Object

org.jbox2d.dynamics.joints.Joint

org.jbox2d.dynamics.joints.RevoluteJoint

public class RevoluteJoint
extends Joint

A revolute joint constrains two bodies to share a common point while they are free to rotate about the point. The relative rotation about the shared point is the joint angle. You can limit the relative rotation with a joint limit that specifies a lower and upper angle. You can use a motor to drive the relative rotation about the shared point. A maximum motor torque is provided so that infinite forces are not generated.

Author:

Daniel Murphy

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp

Field Summary

Fields

Modifier and Type	Field	Description
protected final Vec2	localAnchorA	The local anchor point relative to body1's origin.
protected final Vec2	localAnchorB	The local anchor point relative to body2's origin.
protected float	referenceAngle	The body2 angle minus body1 angle in the reference state (radians).

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	RevoluteJoint(WorldPool argWorld, RevoluteJointDef def)

Method Summary

Modifier and Type	Method	Description
void	enableLimit(boolean flag)
void	enableMotor(boolean flag)
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	getJointAngle()
float	getJointSpeed()
Vec2	getLocalAnchorA()
Vec2	getLocalAnchorB()
float	getLowerLimit()
float	getMaxMotorTorque()
float	getMotorSpeed()
float	getMotorTorque(float inv_dt)
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.
float	getReferenceAngle()
float	getUpperLimit()
void	initVelocityConstraints(SolverData data)	Internal
boolean	isLimitEnabled()
boolean	isMotorEnabled()
void	setLimits(float lower, float upper)
void	setMaxMotorTorque(float torque)
void	setMotorSpeed(float speed)
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

localAnchorA

protected final Vec2 localAnchorA

The local anchor point relative to body1's origin.

localAnchorB

protected final Vec2 localAnchorB

The local anchor point relative to body2's origin.

referenceAngle

protected float referenceAngle

The body2 angle minus body1 angle in the reference state (radians).

Constructor Details

RevoluteJoint

protected RevoluteJoint(WorldPool argWorld,
 RevoluteJointDef def)

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 41 - 71

Method Details

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_revolute_joint.cpp Lines 73 - 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_revolute_joint.cpp Lines 167 - 243

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_revolute_joint.cpp Lines 245 - 321

getLocalAnchorA

public Vec2 getLocalAnchorA()

getLocalAnchorB

public Vec2 getLocalAnchorB()

getReferenceAngle

public float getReferenceAngle()

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

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 323 - 326

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

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 328 - 331

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

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 333 - 337

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

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 339 - 342

getJointAngle

public float getJointAngle()

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 344 - 349

getJointSpeed

public float getJointSpeed()

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 351 - 356

isMotorEnabled

public boolean isMotorEnabled()

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 358 - 361

enableMotor

public void enableMotor(boolean flag)

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 363 - 371

getMotorTorque

public float getMotorTorque(float inv_dt)

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 373 - 376

setMotorSpeed

public void setMotorSpeed(float speed)

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 378 - 386

setMaxMotorTorque

public void setMaxMotorTorque(float torque)

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 388 - 396

getMotorSpeed

public float getMotorSpeed()

getMaxMotorTorque

public float getMaxMotorTorque()

isLimitEnabled

public boolean isLimitEnabled()

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 398 - 401

enableLimit

public void enableLimit(boolean flag)

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 403 - 413

getLowerLimit

public float getLowerLimit()

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 415 - 418

getUpperLimit

public float getUpperLimit()

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 420 - 423

setLimits

public void setLimits(float lower,
 float upper)

Repolink:

Github: erincatto/box2d src/dynamics/b2_revolute_joint.cpp Lines 425 - 438