b2RevoluteJointDef Struct Reference

#include <b2_revolute_joint.h>

Inheritance diagram for b2RevoluteJointDef:

Public Member Functions
void	Initialize (b2Body *bodyA, b2Body *bodyB, const b2Vec2 &anchor)

Public Attributes
b2Vec2	localAnchorA
	The local anchor point relative to bodyA's origin.
b2Vec2	localAnchorB
	The local anchor point relative to bodyB's origin.
float	referenceAngle
	The bodyB angle minus bodyA angle in the reference state (radians).
bool	enableLimit
	A flag to enable joint limits.
float	lowerAngle
	The lower angle for the joint limit (radians).
float	upperAngle
	The upper angle for the joint limit (radians).
bool	enableMotor
	A flag to enable the joint motor.
float	motorSpeed
	The desired motor speed. Usually in radians per second.
float	maxMotorTorque
Public Attributes inherited from b2JointDef
b2JointType	type
	The joint type is set automatically for concrete joint types.
b2JointUserData	userData
	Use this to attach application specific data to your joints.
b2Body *	bodyA
	The first attached body.
b2Body *	bodyB
	The second attached body.
bool	collideConnected
	Set this flag to true if the attached bodies should collide.

Detailed Description

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:

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

Member Function Documentation

Initialize()

void b2RevoluteJointDef::Initialize	(	b2Body *	bodyA,
		b2Body *	bodyB,
		const b2Vec2 &	anchor
	)

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

Member Data Documentation

maxMotorTorque

float b2RevoluteJointDef::maxMotorTorque

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

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The documentation for this struct was generated from the following file:

• include/box2d/b2_revolute_joint.h