Revolute joint definition. More...

#include <RevoluteJointConf.hpp>

Inheritance diagram for playrho::d2::RevoluteJointConf:

Collaboration diagram for playrho::d2::RevoluteJointConf:

Public Types
using	super = JointBuilder< RevoluteJointConf >
	Super type.

Public Types inherited from playrho::d2::JointBuilder< RevoluteJointConf >
using	value_type = RevoluteJointConf
	Value type.

using	reference = value_type &
	Reference type.

Public Member Functions
constexpr	RevoluteJointConf ()=default
	Default constructor.

	RevoluteJointConf (BodyID bA, BodyID bB, Length2 laA=Length2{}, Length2 laB=Length2{}, Angle ra=0_deg) noexcept
	Initialize the bodies, anchors, and reference angle using a world anchor point.

constexpr auto &	UseEnableLimit (bool v) noexcept
	Uses the given enable limit state value.

constexpr auto &	UseLowerAngle (Angle v) noexcept
	Uses the given lower angle value.

constexpr auto &	UseUpperAngle (Angle v) noexcept
	Uses the given upper angle value.

constexpr auto &	UseEnableMotor (bool v) noexcept
	Uses the given enable motor state value.

constexpr auto &	UseMotorSpeed (AngularVelocity v) noexcept
	Uses the given motor speed value.

constexpr auto &	UseMaxMotorTorque (Torque v) noexcept
	Uses the given max motor torque value.

Public Member Functions inherited from playrho::d2::JointBuilder< RevoluteJointConf >
constexpr reference	UseBodyA (BodyID b) noexcept
	Use value for body A setting.

constexpr reference	UseBodyB (BodyID b) noexcept
	Use value for body B setting.

constexpr reference	UseCollideConnected (bool v) noexcept
	Use value for collide connected setting.

Public Attributes
Length2	localAnchorA = Length2{}
	Local anchor point relative to body A's origin.

Length2	localAnchorB = Length2{}
	Local anchor point relative to body B's origin.

Vec3	impulse = Vec3{}
	Impulse. More...

AngularMomentum	angularMotorImpulse = {}
	Motor impulse. More...

Angle	referenceAngle = 0_deg
	Reference angle. More...

bool	enableLimit = false
	Flag to enable joint limits.

Angle	lowerAngle = 0_deg
	Lower angle for the joint limit.

Angle	upperAngle = 0_deg
	Upper angle for the joint limit.

bool	enableMotor = false
	Flag to enable the joint motor.

AngularVelocity	motorSpeed = 0_rpm
	Desired motor speed.

Torque	maxMotorTorque = 0
	Maximum motor torque used to achieve the desired motor speed.

Length2	rA = {}
	Rotated delta of body A's local center from local anchor A.

Length2	rB = {}
	Rotated delta of body B's local center from local anchor B.

Mat33	mass = {}
	Effective mass for point-to-point constraint.

RotInertia	angularMass = {}
	Effective mass for motor/limit angular constraint.

LimitState	limitState = LimitState::e_inactiveLimit
	Limit state.

Public Attributes inherited from playrho::d2::JointConf
BodyID	bodyA = InvalidBodyID
	1st attached body.

BodyID	bodyB = InvalidBodyID
	2nd attached body.

bool	collideConnected = false
	Collide connected. More...

Related Functions
(Note that these are not member functions.)
constexpr auto	ShiftOrigin (RevoluteJointConf &, Length2) noexcept
	Shifts the origin notion of the given configuration.

constexpr Angle	GetAngularLowerLimit (const RevoluteJointConf &conf) noexcept
	Free function for getting the angular lower limit value of the given configuration.

constexpr Angle	GetAngularUpperLimit (const RevoluteJointConf &conf) noexcept
	Free function for getting the angular upper limit value of the given configuration.

constexpr Momentum2	GetLinearReaction (const RevoluteJointConf &conf) noexcept
	Gets the current linear reaction of the given configuration.

constexpr AngularMomentum	GetAngularReaction (const RevoluteJointConf &conf) noexcept
	Gets the current angular reaction of the given configuration.

void	InitVelocity (RevoluteJointConf &object, std::vector< BodyConstraint > &bodies, const StepConf &step, const ConstraintSolverConf &conf)
	Initializes velocity constraint data based on the given solver data. More...

bool	SolveVelocity (RevoluteJointConf &object, std::vector< BodyConstraint > &bodies, const StepConf &step)
	Solves velocity constraint. More...

bool	SolvePosition (const RevoluteJointConf &object, std::vector< BodyConstraint > &bodies, const ConstraintSolverConf &conf)
	Solves the position constraint. More...

constexpr void	SetAngularLimits (RevoluteJointConf &object, Angle lower, Angle upper) noexcept
	Free function for setting the angular limits of the given configuration.

constexpr void	SetMaxMotorTorque (RevoluteJointConf &object, Torque value)
	Free function for setting the max motor torque of the given configuration.

Related Functions inherited from playrho::d2::JointConf
void	Set (JointConf &def, const Joint &joint) noexcept
	Sets the joint definition data for the given joint.

Detailed Description

Revolute joint definition.

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. 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.

Note

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.

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.

See also: https://en.wikipedia.org/wiki/Revolute_joint; Joint, World::CreateJoint

Examples: RevoluteJoint.cpp, and World.cpp.

Friends And Related Function Documentation

◆ InitVelocity()

void InitVelocity	(	RevoluteJointConf &	object,
		std::vector< BodyConstraint > &	bodies,
		const StepConf &	step,
		const ConstraintSolverConf &	conf
	)

Note: This MUST be called prior to calling SolveVelocity.

See also: SolveVelocityConstraints.

◆ SolvePosition()

bool SolvePosition	(	const RevoluteJointConf &	object,
		std::vector< BodyConstraint > &	bodies,
		const ConstraintSolverConf &	conf
	)

Returns: true if the position errors are within tolerance.

◆ SolveVelocity()

bool SolveVelocity	(	RevoluteJointConf &	object,
		std::vector< BodyConstraint > &	bodies,
		const StepConf &	step
	)

Precondition: InitVelocity has been called.

See also: InitVelocity.

Returns: true if velocity is "solved", false otherwise.

Member Data Documentation

◆ angularMotorImpulse

AngularMomentum playrho::d2::RevoluteJointConf::angularMotorImpulse = {}

Motor impulse.

Note: Modified by: InitVelocity, SolveVelocity.

◆ impulse

Vec3 playrho::d2::RevoluteJointConf::impulse = Vec3{}

Impulse.

Note: Modified by: InitVelocity, SolveVelocityConstraints.

◆ referenceAngle

Angle playrho::d2::RevoluteJointConf::referenceAngle = 0_deg

Reference angle.

This is the body-B angle minus body-A angle in the reference state (radians).

Examples: RevoluteJoint.cpp.

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

RevoluteJointConf.hpp
RevoluteJointConf.cpp

Public Types

Public Member Functions

Public Attributes

Related Functions