org.jbox2d.dynamics.joints

Class RevoluteJointDef

java.lang.Object

org.jbox2d.dynamics.joints.JointDef

org.jbox2d.dynamics.joints.RevoluteJointDef

public class RevoluteJointDef
extends JointDef

Revolute joint definition. This requires defining an anchor point where the bodies are joined. The definition uses local anchor points so that the initial configuration can violate the constraint slightly. You also need to specify the initial relative angle for joint limits. This helps when saving and loading a game. The local anchor points are measured from the body's origin rather than the center of mass because:

• you might not know where the center of mass will be.
• if you add/remove shapes from a body and recompute the mass, the joints will be broken.

Field Summary

Fields

Modifier and Type	Field and Description
boolean	enableLimit A flag to enable joint limits.
boolean	enableMotor A flag to enable the joint motor.
Vec2	localAnchorA The local anchor point relative to body1's origin.
Vec2	localAnchorB The local anchor point relative to body2's origin.
float	lowerAngle The lower angle for the joint limit (radians).
float	maxMotorTorque The maximum motor torque used to achieve the desired motor speed.
float	motorSpeed The desired motor speed.
float	referenceAngle The body2 angle minus body1 angle in the reference state (radians).
float	upperAngle The upper angle for the joint limit (radians).

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

bodyA, bodyB, collideConnected, type, userData

Constructor Summary

Constructors

Constructor and Description
RevoluteJointDef()

Method Summary

Modifier and Type	Method and Description
void	initialize(Body b1, Body b2, Vec2 anchor) Initialize the bodies, anchors, and reference angle using the world anchor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

localAnchorA

public Vec2 localAnchorA

The local anchor point relative to body1's origin.

localAnchorB

public Vec2 localAnchorB

The local anchor point relative to body2's origin.

referenceAngle

public float referenceAngle

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

enableLimit

public boolean enableLimit

A flag to enable joint limits.

lowerAngle

public float lowerAngle

The lower angle for the joint limit (radians).

upperAngle

public float upperAngle

The upper angle for the joint limit (radians).

enableMotor

public boolean enableMotor

A flag to enable the joint motor.

motorSpeed

public float motorSpeed

The desired motor speed. Usually in radians per second.

maxMotorTorque

public float maxMotorTorque

The maximum motor torque used to achieve the desired motor speed. Usually in N-m.

Constructor Detail

RevoluteJointDef

public RevoluteJointDef()

Method Detail

initialize

public void initialize(Body b1,
                       Body b2,
                       Vec2 anchor)

Initialize the bodies, anchors, and reference angle using the world anchor.

Parameters:

b1 -

b2 -

anchor -