The per-contact velocity constraint data structure. More...

#include <VelocityConstraint.hpp>

Collaboration diagram for playrho::d2::VelocityConstraint:

Classes
struct	Conf
	Configuration data for velocity constraints. More...

struct	Point
	Velocity constraint point. More...

Public Types
using	size_type = std::remove_const< decltype(MaxManifoldPoints)>::type
	Size type.

Public Member Functions
	VelocityConstraint ()=default
	Default constructor. More...

	VelocityConstraint (const VelocityConstraint &copy)=default
	Copy constructor.

VelocityConstraint &	operator= (const VelocityConstraint &copy)=default
	Assignment operator.

	VelocityConstraint (Real friction, Real restitution, LinearVelocity tangentSpeed, const WorldManifold &worldManifold, BodyID bA, BodyID bB, const std::vector< BodyConstraint > &bodies, const Conf &conf=GetDefaultConf())
	Initializing constructor.

UnitVec	GetNormal () const noexcept
	Gets the normal of the contact in world coordinates. More...

UnitVec	GetTangent () const noexcept
	Gets the tangent.

size_type	GetPointCount () const noexcept
	Gets the count of points added to this object. More...

InvMass22	GetK () const noexcept
	Gets the "K" value. More...

Mass22	GetNormalMass () const noexcept
	Gets the normal mass. More...

Real	GetFriction () const noexcept
	Gets the combined friction of the associated contact.

Real	GetRestitution () const noexcept
	Gets the combined restitution of the associated contact.

LinearVelocity	GetTangentSpeed () const noexcept
	Gets the tangent speed of the associated contact.

BodyID	GetBodyA () const noexcept
	Gets identifier of body A.

BodyID	GetBodyB () const noexcept
	Gets identifier of body B.

Momentum	GetNormalImpulseAtPoint (size_type index) const noexcept
	Gets the normal impulse at the given point. More...

Momentum	GetTangentImpulseAtPoint (size_type index) const noexcept
	Gets the tangent impulse at the given point. More...

LinearVelocity	GetVelocityBiasAtPoint (size_type index) const noexcept
	Gets the velocity bias at the given point. More...

Mass	GetNormalMassAtPoint (size_type index) const noexcept
	Gets the normal mass at the given point. More...

Mass	GetTangentMassAtPoint (size_type index) const noexcept
	Gets the tangent mass at the given point. More...

Length2	GetPointRelPosA (size_type index) const noexcept
	Gets the point relative position of A. More...

Length2	GetPointRelPosB (size_type index) const noexcept
	Gets the point relative position of B. More...

void	SetNormalImpulseAtPoint (size_type index, Momentum value)
	Sets the normal impulse at the given point.

void	SetTangentImpulseAtPoint (size_type index, Momentum value)
	Sets the tangent impulse at the given point.

const Point &	GetPointAt (size_type index) const
	Accesses the point identified by the given index. More...

Static Public Member Functions
static constexpr Conf	GetDefaultConf () noexcept
	Gets the default configuration for a `VelocityConstraint`.

Private Member Functions
void	AddPoint (Momentum normalImpulse, Momentum tangentImpulse, Length2 relA, Length2 relB, const std::vector< BodyConstraint > &bodies, Conf conf)
	Adds the given point to this contact velocity constraint object. More...

void	RemovePoint () noexcept
	Removes the last point added.

Point	GetPoint (Momentum normalImpulse, Momentum tangentImpulse, Length2 relA, Length2 relB, const std::vector< BodyConstraint > &bodies, Conf conf) const noexcept
	Gets a point instance for the given parameters.

Point &	PointAt (size_type index)
	Accesses the point identified by the given index. More...

Private Attributes
Point	m_points [MaxManifoldPoints]
	Velocity constraint points array (at least 72-bytes).

InvMass3	m_K = InvMass3{}
	Block solver "K" info. More...

Mass3	m_normalMass = Mass3{}
	Normal mass information. More...

BodyID	m_bodyA = InvalidBodyID
	Identifier for body-A.

BodyID	m_bodyB = InvalidBodyID
	Identifier for body-B.

UnitVec	m_normal = GetInvalid<UnitVec>()
	Normal of the world manifold. 8-bytes.

Real	m_friction = GetInvalid<Real>()
	Friction coefficient (4-bytes). Usually in the range of [0,1].

Real	m_restitution = GetInvalid<Real>()
	Restitution coefficient (4-bytes).

LinearVelocity	m_tangentSpeed = GetInvalid<decltype(m_tangentSpeed)>()
	Tangent speed (4-bytes).

size_type	m_pointCount = 0
	Point count (at least 1-byte).

Detailed Description

The per-contact velocity constraint data structure.

Note: A valid contact velocity constraint must have a point count of either 1 or 2.

Invariant: The "K" value cannot be changed independent of: the total inverse mass, the normal, and the point relative positions.; The normal mass cannot be changed independent of: the "K" value.; The velocity biases cannot be changed independent of: the normal, and the point relative positions.

Constructor & Destructor Documentation

◆ VelocityConstraint()

playrho::d2::VelocityConstraint::VelocityConstraint ( )

default

Default constructor.

Initializes object with: a zero point count, an invalid K, an invalid normal mass, an invalid normal, invalid friction, invalid restitution, an invalid tangent speed.

Member Function Documentation

◆ AddPoint()

void playrho::d2::VelocityConstraint::AddPoint	(	Momentum	normalImpulse,
		Momentum	tangentImpulse,
		Length2	relA,
		Length2	relB,
		const std::vector< BodyConstraint > &	bodies,
		Conf	conf
	)

private

Adds the given point to this contact velocity constraint object.

Adds up to MaxManifoldPoints points. To find out how many points have already been added, call GetPointCount.

Warning: Behavior is undefined if an attempt is made to add more than MaxManifoldPoints points.

See also: GetPointCount().

◆ GetK()

InvMass22 playrho::d2::VelocityConstraint::GetK ( ) const

inlinenoexcept

Gets the "K" value.

Note: This value is only valid if previously set to a valid value.

Returns: "K" value previously set or the zero initialized value.

◆ GetNormal()

UnitVec playrho::d2::VelocityConstraint::GetNormal ( ) const

inlinenoexcept

Gets the normal of the contact in world coordinates.

Note: This value is set on construction.

Returns: Contact normal (in world coordinates) if previously set, an invalid value otherwise.

◆ GetNormalImpulseAtPoint()

Momentum playrho::d2::VelocityConstraint::GetNormalImpulseAtPoint ( VelocityConstraint::size_type index ) const

inlinenoexcept

Gets the normal impulse at the given point.

Note: Call the AddPoint or SetNormalImpulseAtPoint method to set this value.

Returns: Value previously set, or an invalid value.

See also: SetNormalImpulseAtPoint.

Referenced by playrho::d2::GetNormalImpulseAtPoint().

◆ GetNormalMass()

Mass22 playrho::d2::VelocityConstraint::GetNormalMass ( ) const

inlinenoexcept

Gets the normal mass.

Note: This value is only valid if previously set.

Returns: normal mass previously set or the zero initialized value.

◆ GetNormalMassAtPoint()

Mass playrho::d2::VelocityConstraint::GetNormalMassAtPoint ( VelocityConstraint::size_type index ) const

inlinenoexcept

Gets the normal mass at the given point.

Note: This value depends on the values of: the sum of the inverse-masses of the two bodies, the bodies' inverse-rotational-inertia, the point-relative A and B positions, and the normal.; The AddPoint method sets this value.

Referenced by playrho::d2::GetNormalMassAtPoint().

◆ GetPointAt()

const Point& playrho::d2::VelocityConstraint::GetPointAt ( size_type index ) const

inline

Accesses the point identified by the given index.

Warning: Behavior is undefined if given index is not less than MaxManifoldPoints.

Parameters

index Index of the point to return. This should be a value less than returned by GetPointCount.

Returns: velocity constraint point for the given index. This point's data will be invalid unless previously added and set.

See also: GetPointCount.

◆ GetPointCount()

size_type playrho::d2::VelocityConstraint::GetPointCount ( ) const

inlinenoexcept

Gets the count of points added to this object.

Returns: Value between 0 and MaxManifoldPoints.

See also: MaxManifoldPoints.; AddPoint.

Referenced by playrho::d2::GetContactImpulses().

◆ GetPointRelPosA()

Length2 playrho::d2::VelocityConstraint::GetPointRelPosA ( VelocityConstraint::size_type index ) const

inlinenoexcept

Gets the point relative position of A.

Note: The AddPoint method sets this value.

Returns: Previously set value or an invalid value.

Referenced by playrho::d2::GetPointRelPosA().

◆ GetPointRelPosB()

Length2 playrho::d2::VelocityConstraint::GetPointRelPosB ( VelocityConstraint::size_type index ) const

inlinenoexcept

Gets the point relative position of B.

Note: The AddPoint method sets this value.

Returns: Previously set value or an invalid value.

Referenced by playrho::d2::GetPointRelPosB().

◆ GetTangentImpulseAtPoint()

Momentum playrho::d2::VelocityConstraint::GetTangentImpulseAtPoint ( VelocityConstraint::size_type index ) const

inlinenoexcept

Gets the tangent impulse at the given point.

Note: Call the AddPoint or SetTangentImpulseAtPoint method to set this value.

Returns: Value previously set, or an invalid value.

See also: SetTangentImpulseAtPoint.

Referenced by playrho::d2::GetTangentImpulseAtPoint().

◆ GetTangentMassAtPoint()

Mass playrho::d2::VelocityConstraint::GetTangentMassAtPoint ( VelocityConstraint::size_type index ) const

inlinenoexcept

Gets the tangent mass at the given point.

Note: This value depends on the values of: the sum of the inverse-masses of the two bodies, the bodies' inverse-rotational-inertia, the point-relative A and B positions, and the tangent.; The AddPoint method sets this value.

Referenced by playrho::d2::GetTangentMassAtPoint().

◆ GetVelocityBiasAtPoint()

LinearVelocity playrho::d2::VelocityConstraint::GetVelocityBiasAtPoint ( size_type index ) const

inlinenoexcept

Gets the velocity bias at the given point.

Note: The AddPoint method sets this value.

Returns: Previously set value or an invalid value.

Referenced by playrho::d2::GetVelocityBiasAtPoint().

◆ PointAt()

Point& playrho::d2::VelocityConstraint::PointAt ( size_type index )

inlineprivate

Accesses the point identified by the given index.

Warning: Behavior is undefined if given index is not less than MaxManifoldPoints.

Parameters

index Index of the point to return. This should be a value less than returned by GetPointCount.

Returns: velocity constraint point for the given index. This point's data will be invalid unless previously added and set.

See also: GetPointCount.

Referenced by SetNormalImpulseAtPoint(), and SetTangentImpulseAtPoint().

Member Data Documentation

◆ m_K

InvMass3 playrho::d2::VelocityConstraint::m_K = InvMass3{}

private

Block solver "K" info.

Note: Depends on the total inverse mass, the normal, and the point relative positions.; Only used by block solver.; This field is 12-bytes (on at least one 64-bit platform).

Referenced by GetK().

◆ m_normalMass

Mass3 playrho::d2::VelocityConstraint::m_normalMass = Mass3{}

private

Normal mass information.

This is the cached inverse of the K value or the zero initialized value.

Note: Depends on the K value.; Only used by block solver.; This field is 12-bytes (on at least one 64-bit platform).

Referenced by GetNormalMass().

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

VelocityConstraint.hpp
VelocityConstraint.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ VelocityConstraint()

Member Function Documentation

◆ AddPoint()

◆ GetK()

◆ GetNormal()

◆ GetNormalImpulseAtPoint()

◆ GetNormalMass()

◆ GetNormalMassAtPoint()

◆ GetPointAt()

◆ GetPointCount()

◆ GetPointRelPosA()

◆ GetPointRelPosB()

◆ GetTangentImpulseAtPoint()

◆ GetTangentMassAtPoint()

◆ GetVelocityBiasAtPoint()

◆ PointAt()

Member Data Documentation

◆ m_K

◆ m_normalMass