RotationEulerConstraintPart Class Reference

#include <RotationEulerConstraintPart.h>

Public Member Functions
void	CalculateConstraintProperties (const Body &inBody1, Mat44Arg inRotation1, const Body &inBody2, Mat44Arg inRotation2)
	Calculate properties used during the functions below. More...
void	Deactivate ()
	Deactivate this constraint. More...
bool	IsActive () const
	Check if constraint is active. More...
void	WarmStart (Body &ioBody1, Body &ioBody2, float inWarmStartImpulseRatio)
	Must be called from the WarmStartVelocityConstraint call to apply the previous frame's impulses. More...
bool	SolveVelocityConstraint (Body &ioBody1, Body &ioBody2)
	Iteratively update the velocity constraint. Makes sure d/dt C(...) = 0, where C is the constraint equation. More...
bool	SolvePositionConstraint (Body &ioBody1, Body &ioBody2, QuatArg inInvInitialOrientation, float inBaumgarte) const
	Iteratively update the position constraint. Makes sure C(...) = 0. More...
Vec3	GetTotalLambda () const
	Return lagrange multiplier. More...
void	SaveState (StateRecorder &inStream) const
	Save state of this constraint part. More...
void	RestoreState (StateRecorder &inStream)
	Restore state of this constraint part. More...

Static Public Member Functions
static Quat	sGetInvInitialOrientation (const Body &inBody1, const Body &inBody2)
	Return inverse of initial rotation from body 1 to body 2 in body 1 space. More...
static Quat	sGetInvInitialOrientationXY (Vec3Arg inAxisX1, Vec3Arg inAxisY1, Vec3Arg inAxisX2, Vec3Arg inAxisY2)
	Return inverse of initial rotation from body 1 to body 2 in body 1 space. More...
static Quat	sGetInvInitialOrientationXZ (Vec3Arg inAxisX1, Vec3Arg inAxisZ1, Vec3Arg inAxisX2, Vec3Arg inAxisZ2)
	Return inverse of initial rotation from body 1 to body 2 in body 1 space. More...

Detailed Description

Constrains rotation around all axis so that only translation is allowed

Based on: "Constraints Derivation for Rigid Body Simulation in 3D" - Daniel Chappuis, section 2.5.1

Constraint equation (eq 129):

\[C = \begin{bmatrix}\Delta\theta_x, \Delta\theta_y, \Delta\theta_z\end{bmatrix}\]

Jacobian (eq 131):

\[J = \begin{bmatrix}0 & -E & 0 & E\end{bmatrix}\]

Used terms (here and below, everything in world space):
delta_theta_* = difference in rotation between initial rotation of bodyies 1 and 2.
x1, x2 = center of mass for the bodies.
v = [v1, w1, v2, w2].
v1, v2 = linear velocity of body 1 and 2.
w1, w2 = angular velocity of body 1 and 2.
M = mass matrix, a diagonal matrix of the mass and inertia with diagonal [m1, I1, m2, I2].
\(K^{-1} = \left( J M^{-1} J^T \right)^{-1}\) = effective mass.
b = velocity bias.
\(\beta\) = baumgarte constant.
E = identity matrix.

Member Function Documentation

CalculateConstraintProperties()

void RotationEulerConstraintPart::CalculateConstraintProperties ( const Body &  inBody1, Mat44Arg  inRotation1, const Body &  inBody2, Mat44Arg  inRotation2  )

inline

Calculate properties used during the functions below.

Deactivate()

void RotationEulerConstraintPart::Deactivate ( )

inline

Deactivate this constraint.

GetTotalLambda()

Vec3 RotationEulerConstraintPart::GetTotalLambda ( ) const

inline

Return lagrange multiplier.

IsActive()

bool RotationEulerConstraintPart::IsActive ( ) const

inline

Check if constraint is active.

RestoreState()

void RotationEulerConstraintPart::RestoreState ( StateRecorder &  inStream )

inline

Restore state of this constraint part.

SaveState()

void RotationEulerConstraintPart::SaveState ( StateRecorder &  inStream ) const

inline

Save state of this constraint part.

sGetInvInitialOrientation()

static Quat RotationEulerConstraintPart::sGetInvInitialOrientation ( const Body &  inBody1, const Body &  inBody2  )

inlinestatic

Return inverse of initial rotation from body 1 to body 2 in body 1 space.

sGetInvInitialOrientationXY()

static Quat RotationEulerConstraintPart::sGetInvInitialOrientationXY ( Vec3Arg  inAxisX1, Vec3Arg  inAxisY1, Vec3Arg  inAxisX2, Vec3Arg  inAxisY2  )

inlinestatic

Return inverse of initial rotation from body 1 to body 2 in body 1 space.

Parameters

inAxisX1	Reference axis X for body 1
inAxisY1	Reference axis Y for body 1
inAxisX2	Reference axis X for body 2
inAxisY2	Reference axis Y for body 2

sGetInvInitialOrientationXZ()

static Quat RotationEulerConstraintPart::sGetInvInitialOrientationXZ ( Vec3Arg  inAxisX1, Vec3Arg  inAxisZ1, Vec3Arg  inAxisX2, Vec3Arg  inAxisZ2  )

inlinestatic

Return inverse of initial rotation from body 1 to body 2 in body 1 space.

Parameters

inAxisX1	Reference axis X for body 1
inAxisZ1	Reference axis Z for body 1
inAxisX2	Reference axis X for body 2
inAxisZ2	Reference axis Z for body 2

SolvePositionConstraint()

bool RotationEulerConstraintPart::SolvePositionConstraint ( Body &  ioBody1, Body &  ioBody2, QuatArg  inInvInitialOrientation, float  inBaumgarte  ) const

inline

Iteratively update the position constraint. Makes sure C(...) = 0.

SolveVelocityConstraint()

bool RotationEulerConstraintPart::SolveVelocityConstraint ( Body &  ioBody1, Body &  ioBody2  )

inline

Iteratively update the velocity constraint. Makes sure d/dt C(...) = 0, where C is the constraint equation.

WarmStart()

void RotationEulerConstraintPart::WarmStart ( Body &  ioBody1, Body &  ioBody2, float  inWarmStartImpulseRatio  )

inline

Must be called from the WarmStartVelocityConstraint call to apply the previous frame's impulses.

---

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

• Jolt/Physics/Constraints/ConstraintPart/RotationEulerConstraintPart.h