box2d::RevoluteJointDef Struct Reference

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: More...

#include <RevoluteJoint.hpp>

Inheritance diagram for box2d::RevoluteJointDef:

Public Member Functions
constexpr	RevoluteJointDef () noexcept
	RevoluteJointDef (Body *bodyA, Body *bodyB, const Length2D anchor, bool cc=false)
	Initialize the bodies, anchors, and reference angle using a world anchor point. More...
Public Member Functions inherited from box2d::JointDef
	JointDef ()=delete
	Deleted default constructor for abstract base class. More...
constexpr	JointDef (JointType t) noexcept
constexpr	JointDef (JointType t, Body *bA, Body *bB, bool cc=false, void *u=nullptr) noexcept

Public Attributes
Length2D	localAnchorA = Vec2_zero * Meter
	The local anchor point relative to bodyA's origin. More...
Length2D	localAnchorB = Vec2_zero * Meter
	The local anchor point relative to bodyB's origin. More...
Angle	referenceAngle = Angle{0}
	The bodyB angle minus bodyA angle in the reference state (radians). More...
bool	enableLimit = false
	A flag to enable joint limits. More...
Angle	lowerAngle = Angle{0}
	The lower angle for the joint limit (radians). More...
Angle	upperAngle = Angle{0}
	The upper angle for the joint limit (radians). More...
bool	enableMotor = false
	A flag to enable the joint motor. More...
AngularVelocity	motorSpeed = AngularVelocity{0}
	The desired motor speed. More...
Torque	maxMotorTorque = 0
	The maximum motor torque used to achieve the desired motor speed. Usually in N-m. More...
Public Attributes inherited from box2d::JointDef
const JointType	type
	The joint type is set automatically for concrete joint types. More...
Body *	bodyA = nullptr
	The first attached body. More...
Body *	bodyB = nullptr
	The second attached body. More...
bool	collideConnected = false
	Set this flag to true if the attached bodies should collide. More...
void *	userData = nullptr
	Use this to attach application specific data to your joints. More...

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.

Constructor & Destructor Documentation

RevoluteJointDef() [1/2]

constexpr box2d::RevoluteJointDef::RevoluteJointDef ( )

inlinenoexcept

RevoluteJointDef() [2/2]

RevoluteJointDef::RevoluteJointDef	(	Body *	bodyA,
		Body *	bodyB,
		const Length2D	anchor,
		bool	cc = false
	)

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

Member Data Documentation

enableLimit

bool box2d::RevoluteJointDef::enableLimit = false

A flag to enable joint limits.

enableMotor

bool box2d::RevoluteJointDef::enableMotor = false

A flag to enable the joint motor.

localAnchorA

Length2D box2d::RevoluteJointDef::localAnchorA = Vec2_zero * Meter

The local anchor point relative to bodyA's origin.

localAnchorB

Length2D box2d::RevoluteJointDef::localAnchorB = Vec2_zero * Meter

The local anchor point relative to bodyB's origin.

lowerAngle

Angle box2d::RevoluteJointDef::lowerAngle = Angle{0}

The lower angle for the joint limit (radians).

maxMotorTorque

Torque box2d::RevoluteJointDef::maxMotorTorque = 0

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

motorSpeed

AngularVelocity box2d::RevoluteJointDef::motorSpeed = AngularVelocity{0}

The desired motor speed.

referenceAngle

Angle box2d::RevoluteJointDef::referenceAngle = Angle{0}

The bodyB angle minus bodyA angle in the reference state (radians).

upperAngle

Angle box2d::RevoluteJointDef::upperAngle = Angle{0}

The upper angle for the joint limit (radians).

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

• RevoluteJoint.hpp
• RevoluteJoint.cpp