#include <VehicleConstraint.h>

Inheritance diagram for VehicleConstraint:

Public Member Functions
	VehicleConstraint (Body &inVehicleBody, const VehicleConstraintSettings &inSettings)
	Constructor / destructor. More...

virtual	~VehicleConstraint () override

virtual EConstraintSubType	GetSubType () const override
	Get the type of a constraint. More...

void	SetMaxPitchRollAngle (float inMaxPitchRollAngle)
	Defines the maximum pitch/roll angle (rad), can be used to avoid the car from getting upside down. The vehicle up direction will stay within a cone centered around the up axis with half top angle mMaxPitchRollAngle, set to pi to turn off. More...

void	SetVehicleCollisionTester (const VehicleCollisionTester *inTester)
	Set the interface that tests collision between wheel and ground. More...

Vec3	GetLocalForward () const
	Get the local space forward vector of the vehicle. More...

Vec3	GetLocalUp () const
	Get the local space up vector of the vehicle. More...

Body *	GetVehicleBody () const
	Access to the vehicle body. More...

const VehicleController *	GetController () const
	Access to the vehicle controller interface (determines acceleration / decelleration) More...

VehicleController *	GetController ()
	Access to the vehicle controller interface (determines acceleration / decelleration) More...

const Wheels &	GetWheels () const
	Get the state of the wheels. More...

Wheels &	GetWheels ()
	Get the state of a wheels (writable interface, allows you to make changes to the configuration which will take effect the next time step) More...

Wheel *	GetWheel (uint inIdx)
	Get the state of a wheel. More...

const Wheel *	GetWheel (uint inIdx) const

void	GetWheelLocalBasis (const Wheel *inWheel, Vec3 &outForward, Vec3 &outUp, Vec3 &outRight) const

Mat44	GetWheelLocalTransform (uint inWheelIndex, Vec3Arg inWheelRight, Vec3Arg inWheelUp) const

RMat44	GetWheelWorldTransform (uint inWheelIndex, Vec3Arg inWheelRight, Vec3Arg inWheelUp) const

virtual bool	IsActive () const override

virtual void	NotifyShapeChanged (const BodyID &inBodyID, Vec3Arg inDeltaCOM) override

virtual void	SetupVelocityConstraint (float inDeltaTime) override

virtual void	WarmStartVelocityConstraint (float inWarmStartImpulseRatio) override

virtual bool	SolveVelocityConstraint (float inDeltaTime) override

virtual bool	SolvePositionConstraint (float inDeltaTime, float inBaumgarte) override

virtual void	BuildIslands (uint32 inConstraintIndex, IslandBuilder &ioBuilder, BodyManager &inBodyManager) override
	Link bodies that are connected by this constraint in the island builder. More...

virtual uint	BuildIslandSplits (LargeIslandSplitter &ioSplitter) const override
	Link bodies that are connected by this constraint in the same split. Returns the split index. More...

virtual void	DrawConstraint (DebugRenderer *inRenderer) const override

virtual void	DrawConstraintLimits (DebugRenderer *inRenderer) const override

virtual void	SaveState (StateRecorder &inStream) const override
	Saving state for replay. More...

virtual void	RestoreState (StateRecorder &inStream) override
	Restoring state for replay. More...

virtual Ref< ConstraintSettings >	GetConstraintSettings () const override
	Debug function to convert a constraint to its settings, note that this will not save to which bodies the constraint is connected to. More...

Public Member Functions inherited from Constraint
JPH_OVERRIDE_NEW_DELETE	Constraint (const ConstraintSettings &inSettings)
	Constructor. More...

virtual	~Constraint ()=default
	Virtual destructor. More...

virtual EConstraintType	GetType () const
	Get the type of a constraint. More...

virtual EConstraintSubType	GetSubType () const =0
	Get the sub type of a constraint. More...

void	SetNumVelocityStepsOverride (int inN)
	Override for the number of solver velocity iterations to run, the total amount of iterations is the max of PhysicsSettings::mNumVelocitySteps and this for all constraints in the island. More...

int	GetNumVelocityStepsOverride () const

void	SetNumPositionStepsOverride (int inN)
	Override for the number of position velocity iterations to run, the total amount of iterations is the max of PhysicsSettings::mNumPositionSteps and this for all constraints in the island. More...

int	GetNumPositionStepsOverride () const

void	SetEnabled (bool inEnabled)

bool	GetEnabled () const
	Test if a constraint is enabled. More...

uint64	GetUserData () const
	Access to the user data, can be used for anything by the application. More...

void	SetUserData (uint64 inUserData)

virtual void	NotifyShapeChanged (const BodyID &inBodyID, Vec3Arg inDeltaCOM)=0

virtual void	BuildIslands (uint32 inConstraintIndex, IslandBuilder &ioBuilder, BodyManager &inBodyManager)=0
	Link bodies that are connected by this constraint in the island builder. More...

virtual uint	BuildIslandSplits (LargeIslandSplitter &ioSplitter) const =0
	Link bodies that are connected by this constraint in the same split. Returns the split index. More...

virtual void	DrawConstraint (DebugRenderer *inRenderer) const =0

virtual void	DrawConstraintLimits (DebugRenderer *inRenderer) const

virtual void	DrawConstraintReferenceFrame (DebugRenderer *inRenderer) const

float	GetDrawConstraintSize () const
	Size of constraint when drawing it through the debug renderer. More...

void	SetDrawConstraintSize (float inSize)

virtual void	SaveState (StateRecorder &inStream) const
	Saving state for replay. More...

virtual void	RestoreState (StateRecorder &inStream)
	Restoring state for replay. More...

virtual Ref< ConstraintSettings >	GetConstraintSettings () const =0
	Debug function to convert a constraint to its settings, note that this will not save to which bodies the constraint is connected to. More...

Public Member Functions inherited from RefTarget< Constraint >
	RefTarget ()=default
	Constructor. More...

	RefTarget (const RefTarget &)

	~RefTarget ()
	assert no one is referencing us More...

void	SetEmbedded () const

RefTarget &	operator= (const RefTarget &)
	Assignment operator. More...

uint32	GetRefCount () const
	Get current refcount of this object. More...

void	AddRef () const
	Add or release a reference to this object. More...

void	Release () const

Public Member Functions inherited from NonCopyable
	NonCopyable ()=default

	NonCopyable (const NonCopyable &)=delete

void	operator= (const NonCopyable &)=delete

Public Member Functions inherited from PhysicsStepListener
virtual	~PhysicsStepListener ()=default
	Ensure virtual destructor. More...

virtual void	OnStep (float inDeltaTime, PhysicsSystem &inPhysicsSystem)=0

Additional Inherited Members
Static Public Member Functions inherited from RefTarget< Constraint >
static int	sInternalGetRefCountOffset ()
	INTERNAL HELPER FUNCTION USED BY SERIALIZATION. More...

Protected Member Functions inherited from Constraint
void	ToConstraintSettings (ConstraintSettings &outSettings) const
	Helper function to copy settings back to constraint settings for this base class. More...

Protected Attributes inherited from Constraint
float	mDrawConstraintSize
	Size of constraint when drawing it through the debug renderer. More...

Protected Attributes inherited from RefTarget< Constraint >
atomic< uint32 >	mRefCount
	Current reference count. More...

Static Protected Attributes inherited from RefTarget< Constraint >
static constexpr uint32	cEmbedded
	A large value that gets added to the refcount to mark the object as embedded. More...

Detailed Description

Constraint that simulates a vehicle Note: Don't forget to register the constraint as a StepListener with the PhysicsSystem!

When the vehicle drives over very light objects (rubble) you may see the car body dip down. This is a known issue and is an artifact of the iterative solver that Jolt is using. Basically if a light object is sandwiched between two heavy objects (the static floor and the car body), the light object is not able to transfer enough force from the ground to the car body to keep the car body up. You can see this effect in the HeavyOnLightTest sample, the boxes on the right have a lot of penetration because they're on top of light objects.

There are a couple of ways to improve this:

You can increase the number of velocity steps (global settings PhysicsSettings::mNumVelocitySteps or if you only want to increase it on the vehicle you can use VehicleConstraintSettings::mNumVelocityStepsOverride). E.g. going from 10 to 30 steps in the HeavyOnLightTest sample makes the penetration a lot less. The number of position steps can also be increased (the first prevents the body from going down, the second corrects it if the problem did occur which inevitably happens due to numerical drift). This solution costs CPU cycles.
You can reduce the mass difference between the vehicle body and the rubble on the floor (by making the rubble heavier or the car lighter).
You could filter out collisions between the vehicle collision test and the rubble completely. This would make the wheels ignore the rubble but would cause the vehicle to drive through it as if nothing happened. You could create fake wheels (keyframed bodies) that move along with the vehicle and that only collide with rubble (and not the vehicle or the ground). This would cause the vehicle to push away the rubble without the rubble being able to affect the vehicle (unless it hits the main body of course).

Note that when driving over rubble, you may see the wheel jump up and down quite quickly because one frame a collision is found and the next frame not. To alleviate this, it may be needed to smooth the motion of the visual mesh for the wheel.

Constructor & Destructor Documentation

◆ VehicleConstraint()

VehicleConstraint::VehicleConstraint	(	Body &	inVehicleBody,
		const VehicleConstraintSettings &	inSettings
	)

Constructor / destructor.

◆ ~VehicleConstraint()

VehicleConstraint::~VehicleConstraint ( )

overridevirtual

Member Function Documentation

◆ BuildIslands()

void VehicleConstraint::BuildIslands	(	uint32	inConstraintIndex,
		IslandBuilder &	ioBuilder,
		BodyManager &	inBodyManager
	)

overridevirtual

Link bodies that are connected by this constraint in the island builder.

Implements Constraint.

◆ BuildIslandSplits()

uint VehicleConstraint::BuildIslandSplits ( LargeIslandSplitter & ioSplitter ) const

overridevirtual

Link bodies that are connected by this constraint in the same split. Returns the split index.

Implements Constraint.

◆ DrawConstraint()

void VehicleConstraint::DrawConstraint ( DebugRenderer * inRenderer ) const

overridevirtual

Implements Constraint.

◆ DrawConstraintLimits()

void VehicleConstraint::DrawConstraintLimits ( DebugRenderer * inRenderer ) const

overridevirtual

Reimplemented from Constraint.

◆ GetConstraintSettings()

Ref< ConstraintSettings > VehicleConstraint::GetConstraintSettings ( ) const

overridevirtual

Debug function to convert a constraint to its settings, note that this will not save to which bodies the constraint is connected to.

Implements Constraint.

◆ GetController() [1/2]

VehicleController * VehicleConstraint::GetController ( )

inline

Access to the vehicle controller interface (determines acceleration / decelleration)

◆ GetController() [2/2]

const VehicleController * VehicleConstraint::GetController ( ) const

inline

Access to the vehicle controller interface (determines acceleration / decelleration)

◆ GetLocalForward()

Vec3 VehicleConstraint::GetLocalForward ( ) const

inline

Get the local space forward vector of the vehicle.

◆ GetLocalUp()

Vec3 VehicleConstraint::GetLocalUp ( ) const

inline

Get the local space up vector of the vehicle.

◆ GetSubType()

virtual EConstraintSubType VehicleConstraint::GetSubType ( ) const

inlineoverridevirtual

Get the type of a constraint.

Implements Constraint.

◆ GetVehicleBody()

Body * VehicleConstraint::GetVehicleBody ( ) const

inline

Access to the vehicle body.

◆ GetWheel() [1/2]

Wheel * VehicleConstraint::GetWheel ( uint inIdx )

inline

Get the state of a wheel.

◆ GetWheel() [2/2]

const Wheel * VehicleConstraint::GetWheel ( uint inIdx ) const

inline

◆ GetWheelLocalBasis()

void VehicleConstraint::GetWheelLocalBasis	(	const Wheel *	inWheel,
		Vec3 &	outForward,
		Vec3 &	outUp,
		Vec3 &	outRight
	)		const

Get the basis vectors for the wheel in local space to the vehicle body (note: basis does not rotate when the wheel rotates arounds its axis)

Parameters

inWheel	Wheel to fetch basis for
outForward	Forward vector for the wheel
outUp	Up vector for the wheel
outRight	Right vector for the wheel

◆ GetWheelLocalTransform()

Mat44 VehicleConstraint::GetWheelLocalTransform	(	uint	inWheelIndex,
		Vec3Arg	inWheelRight,
		Vec3Arg	inWheelUp
	)		const

Get the transform of a wheel in local space to the vehicle body, returns a matrix that transforms a cylinder aligned with the Y axis in body space (not COM space)

Parameters

inWheelIndex	Index of the wheel to fetch
inWheelRight	Unit vector that indicates right in model space of the wheel (so if you only have 1 wheel model, you probably want to specify the opposite direction for the left and right wheels)
inWheelUp	Unit vector that indicates up in model space of the wheel

◆ GetWheels() [1/2]

Wheels & VehicleConstraint::GetWheels ( )

inline

Get the state of a wheels (writable interface, allows you to make changes to the configuration which will take effect the next time step)

◆ GetWheels() [2/2]

const Wheels & VehicleConstraint::GetWheels ( ) const

inline

Get the state of the wheels.

◆ GetWheelWorldTransform()

RMat44 VehicleConstraint::GetWheelWorldTransform	(	uint	inWheelIndex,
		Vec3Arg	inWheelRight,
		Vec3Arg	inWheelUp
	)		const

Get the transform of a wheel in world space, returns a matrix that transforms a cylinder aligned with the Y axis in world space

Parameters

inWheelIndex	Index of the wheel to fetch
inWheelRight	Unit vector that indicates right in model space of the wheel (so if you only have 1 wheel model, you probably want to specify the opposite direction for the left and right wheels)
inWheelUp	Unit vector that indicates up in model space of the wheel

◆ IsActive()

virtual bool VehicleConstraint::IsActive ( ) const

inlineoverridevirtual

Reimplemented from Constraint.

◆ NotifyShapeChanged()

virtual void VehicleConstraint::NotifyShapeChanged	(	const BodyID &	inBodyID,
		Vec3Arg	inDeltaCOM
	)

inlineoverridevirtual

Notify the constraint that the shape of a body has changed and that its center of mass has moved by inDeltaCOM. Bodies don't know which constraints are connected to them so the user is responsible for notifying the relevant constraints when a body changes.

Parameters

inBodyID	ID of the body that has changed
inDeltaCOM	The delta of the center of mass of the body (shape->GetCenterOfMass() - shape_before_change->GetCenterOfMass())

Implements Constraint.

◆ RestoreState()

void VehicleConstraint::RestoreState ( StateRecorder & inStream )

overridevirtual

Restoring state for replay.

Reimplemented from Constraint.

◆ SaveState()

void VehicleConstraint::SaveState ( StateRecorder & inStream ) const

overridevirtual

Saving state for replay.

Reimplemented from Constraint.

◆ SetMaxPitchRollAngle()

void VehicleConstraint::SetMaxPitchRollAngle ( float inMaxPitchRollAngle )

inline

Defines the maximum pitch/roll angle (rad), can be used to avoid the car from getting upside down. The vehicle up direction will stay within a cone centered around the up axis with half top angle mMaxPitchRollAngle, set to pi to turn off.

◆ SetupVelocityConstraint()

void VehicleConstraint::SetupVelocityConstraint ( float inDeltaTime )

overridevirtual

Implements Constraint.

◆ SetVehicleCollisionTester()

void VehicleConstraint::SetVehicleCollisionTester ( const VehicleCollisionTester * inTester )

inline

Set the interface that tests collision between wheel and ground.

◆ SolvePositionConstraint()

bool VehicleConstraint::SolvePositionConstraint	(	float	inDeltaTime,
		float	inBaumgarte
	)

overridevirtual

Implements Constraint.

◆ SolveVelocityConstraint()

bool VehicleConstraint::SolveVelocityConstraint ( float inDeltaTime )

overridevirtual

Implements Constraint.

◆ WarmStartVelocityConstraint()

void VehicleConstraint::WarmStartVelocityConstraint ( float inWarmStartImpulseRatio )

overridevirtual

Implements Constraint.

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

Jolt/Physics/Vehicle/VehicleConstraint.h
Jolt/Physics/Vehicle/VehicleConstraint.cpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ VehicleConstraint()

◆ ~VehicleConstraint()

Member Function Documentation

◆ BuildIslands()

◆ BuildIslandSplits()

◆ DrawConstraint()

◆ DrawConstraintLimits()

◆ GetConstraintSettings()

◆ GetController() [1/2]

◆ GetController() [2/2]

◆ GetLocalForward()

◆ GetLocalUp()

◆ GetSubType()

◆ GetVehicleBody()

◆ GetWheel() [1/2]

◆ GetWheel() [2/2]

◆ GetWheelLocalBasis()

◆ GetWheelLocalTransform()

◆ GetWheels() [1/2]

◆ GetWheels() [2/2]

◆ GetWheelWorldTransform()

◆ IsActive()

◆ NotifyShapeChanged()

◆ RestoreState()

◆ SaveState()

◆ SetMaxPitchRollAngle()

◆ SetupVelocityConstraint()

◆ SetVehicleCollisionTester()

◆ SolvePositionConstraint()

◆ SolveVelocityConstraint()

◆ WarmStartVelocityConstraint()