A RoadwayTwist is used to define the actual rotating angle around the tangent at a curve to get the correct alignment to the lane. More...

#include <C:/Trend/Development/Trax3/Code/trax/RoadwayTwist.h>

Inheritance diagram for trax::RoadwayTwist:

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Public Types
enum class	TwistType : char { Unknown = -2 , None = -1 , Zero = 0 , Constant , Linear , Piecewise , PiecewiseLinear , PiecewiseCircular , PiecewiseDirectional , Directional , Positional , Combined , Parallel }

Public Member Functions
virtual const char *	TypeName () const noexcept=0
	Name for the object type that implements this interface.
virtual TwistType	GetTwistType () const noexcept=0
virtual std::unique_ptr< RoadwayTwist >	Clone () const =0
	Make a clone from this object.
virtual bool	IsValid () const noexcept=0
virtual Angle	Twist (Length s) const =0
virtual AnglePerLength	D1 (Length s) const =0
virtual bool	ZeroFlip (bool bActive) noexcept=0
virtual void	Flip () noexcept=0
	Flips the effect of the twist along the track. After calling this function, the Twist() and D1() methods will give pi - Twist(Track::GetLength() - s) and -D1(Track::GetLength() - s). Calling Flip() a second time will nullify the effect.
virtual void	Mirror () noexcept=0
	Multiplies all twist angle by -1.
virtual bool	Offset (Angle offset) noexcept=0
	Adds a global offset angle to the Twist.
virtual bool	IsDynamic () const noexcept=0
	A twist is dynamic if it relates to geometry global to the track.
virtual bool	IsDirectionalConstant () const noexcept=0
	Find wether the twist is directional only offsetted by a constant.
virtual bool	IsConstant () const noexcept=0
virtual void	Freeze (bool bFreeze=true) noexcept=0
	Freezes the twist, so that dynamic twists like DirectionalTwist don't update anymore.
virtual bool	IsFrozen () const noexcept=0
virtual bool	IsNull () const noexcept=0
virtual bool	Equals (const RoadwayTwist &toTwist, Angle epsilon_angle=epsilon__angle) const noexcept=0
	Comparison.
virtual void	OnAttach (const TrackBuilder &track) noexcept=0
	Called on attachment to a track.
virtual void	OnDetach () noexcept=0
	Called on detachment from a track.
virtual Angle	DoTwist (Length) const =0
virtual AnglePerLength	DoD1 (Length) const =0
	RoadwayTwist (RoadwayTwist &&)=delete
RoadwayTwist &	operator= (const RoadwayTwist &)=delete
RoadwayTwist &	operator= (RoadwayTwist &&)=delete

Static Public Member Functions
static dclspc std::unique_ptr< RoadwayTwist >	Make (TwistType type) noexcept
	Makes a RoadwayTwist object.
static dclspc std::unique_ptr< RoadwayTwist >	Make (TwistType type, const RoadwayTwist &fromTwist) noexcept
	Makes a RoadwayTwist object from another twist.

Protected Member Functions
	RoadwayTwist (const RoadwayTwist &)=default

Detailed Description

A RoadwayTwist is used to define the actual rotating angle around the tangent at a curve to get the correct alignment to the lane.

Member Enumeration Documentation

◆ TwistType

enum class trax::RoadwayTwist::TwistType : char

strong

Enumerator
Zero	A twist that always applies 0_rad as a twist angle.
Constant	A twist that applies a constant twist angle at every point along a track.
Linear	A twist that linearly interpolates the twist angle from front to end of a track.
Piecewise	A twist that applies different twist angles to segments long the track.
PiecewiseLinear	A twist that interpolates the angles linearly along the segments.
PiecewiseCircular	A twist that interpolates the angles in a 2pi interval and uses the shortest angular distance.
PiecewiseDirectional	A twist that interpolates directions (slerp) and uses the result as directional twist.
Directional	A twist that rotates the frame's B closest to some attractor vector.
Positional	A twist that rotates the frame's B to point closest to some point in space.
Combined	A twist that combines two twists additively.

Member Function Documentation

◆ D1()

virtual AnglePerLength trax::RoadwayTwist::D1 ( Length s ) const

pure virtual

Parameters

s	track parameter to get the derivative for [0,Track::GetLength()].

Returns: First derivative of twist.

◆ DoD1()

virtual AnglePerLength trax::RoadwayTwist::DoD1 ( Length ) const

pure virtual

Returns: The twist without ZeroFlip or addaptions for general flip.

◆ DoTwist()

virtual Angle trax::RoadwayTwist::DoTwist ( Length ) const

pure virtual

Returns: The twist without ZeroFlip or addaptions for general flip.

◆ Equals()

virtual bool trax::RoadwayTwist::Equals	(	const RoadwayTwist &	toTwist,
		Angle	epsilon_angle = epsilon__angle ) const

pure virtualnoexcept

Comparison.

Two twists of different types are considered not equal.

Returns: true if the twists are equal up to the given thresholds.

Parameters

toTwist	twist to compare with.
epsilon_angle	maximum vector rotational deviation.

◆ IsConstant()

virtual bool trax::RoadwayTwist::IsConstant ( ) const

pure virtualnoexcept

Returns: if the twist is constant in fact.

◆ IsDirectionalConstant()

virtual bool trax::RoadwayTwist::IsDirectionalConstant ( ) const

pure virtualnoexcept

Find wether the twist is directional only offsetted by a constant.

If this returns true, the relation:

/// t + dw/ds = k * AF.T/AF.B / (1 + pow<2>(AF.N/AF.B));
///

holds.

Returns: true if the twist is a directional twist or a constant twist or a combinatin of those.

◆ IsDynamic()

virtual bool trax::RoadwayTwist::IsDynamic ( ) const

pure virtualnoexcept

A twist is dynamic if it relates to geometry global to the track.

Directional or positional twists will be dynamic.

Returns: true if the twist will be updated on changing the track's pose.

◆ IsFrozen()

virtual bool trax::RoadwayTwist::IsFrozen ( ) const

pure virtualnoexcept

Returns: the freeze state of the twist. Non-dynamic twists will always return true.

◆ IsNull()

virtual bool trax::RoadwayTwist::IsNull ( ) const

pure virtualnoexcept

Returns: true if the twist is 0 at all s.

◆ IsValid()

virtual bool trax::RoadwayTwist::IsValid ( ) const

pure virtualnoexcept

Tests wether the twist was properly created.

A dynamic twist will only be valid after attaching it to a track.

Returns: true if the twist is able to deliver valid geometry.

◆ Mirror()

virtual void trax::RoadwayTwist::Mirror ( )

pure virtualnoexcept

Multiplies all twist angle by -1.

Note that some Twists like DirectionalTwist will not be able to compute such a mirror operation, due to their nature.

◆ Offset()

virtual bool trax::RoadwayTwist::Offset ( Angle offset )

pure virtualnoexcept

Adds a global offset angle to the Twist.

Note that some Twists like DirectionalTwist will not be able to compute such an offset, due to their nature.

Parameters

offset angle to offset all twist values, returned by this twist.

Returns: true, if the offset was properly added, false if that could not be done.

◆ OnAttach()

virtual void trax::RoadwayTwist::OnAttach ( const TrackBuilder & track )

pure virtualnoexcept

Called on attachment to a track.

Parameters

track Track that the Twist is attached to.

◆ Twist()

virtual Angle trax::RoadwayTwist::Twist ( Length s ) const

pure virtual

Parameters

s	track parameter to get the twist for [0,Track::GetLength()].

Returns: Twisting angle in radiants.

Implemented in trax::PiecewiseDirectionalTwist, and trax::PiecewiseTwist.

◆ ZeroFlip()

virtual bool trax::RoadwayTwist::ZeroFlip ( bool bActive )

pure virtualnoexcept

Activates a rotation of pi around the tangent vector, if the curve attached to the track would transition a point of zero curvature and is flipping its main normal vector around. This counteracts the sudden turn of tracks up direction. Several zero curvature points along the curve are handled accordingly.

Parameters

bActive if true, zero flip will be activated, which is the default if this makes sense for the twist.

Returns: The previous state of the flag.

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

C:/Trend/Development/Trax3/Code/trax/RoadwayTwist.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ TwistType

Member Function Documentation

◆ D1()

◆ DoD1()

◆ DoTwist()

◆ Equals()

◆ IsConstant()

◆ IsDirectionalConstant()

◆ IsDynamic()

◆ IsFrozen()

◆ IsNull()

◆ IsValid()

◆ Mirror()

◆ Offset()

◆ OnAttach()

◆ Twist()

◆ ZeroFlip()