trax::Curve Struct Reference

Curves implement this interface that then can get attached to a track to define the tracks geometry. More...

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

Inheritance diagram for trax::Curve:

Public Types
enum class	CurveType {   none = 0 , Line , Arc , Helix ,   LineP , ArcP , HelixP , Clothoid ,   Cubic , Spline , Rotator , RotatorWithOffset ,   RotatorChain , PolygonalChain , SampledCurve , Parallel ,   EEPCurve , EEPResidual , EEPAlternative , Unknown ,   UserDefined }
	Curve type identification values. More...

Public Member Functions
virtual const char *	TypeName () const noexcept=0
virtual CurveType	GetCurveType () const noexcept=0
virtual bool	IsValid () const noexcept=0
virtual AnglePerLength	Curvature (Length s) const =0
virtual AnglePerLength	Torsion (Length s) const =0
virtual bool	IsFlat () const noexcept=0
virtual void	Transition (Length s, spat::Position< Length > &pos) const =0
	Copies the 3D Position at the specified location to pos.
virtual void	Transition (Length s, spat::Vector< One > &tan) const =0
	Copies the 3D tangential vector at the specified location to tan.
virtual void	Transition (Length s, spat::VectorBundle< Length, One > &bundle) const =0
	Copies the 3D Position and tangential vector at the specified location to bundle.
virtual void	Transition (Length s, spat::VectorBundle2< Length, One > &bundle) const =0
	Copies the 3D Position and tangential and normal vectors at the specified location to bundle.
virtual void	Transition (Length s, spat::Frame< Length, One > &frame) const =0
	Copies the 3D TBN-Frame at the specified location to frame.
virtual std::vector< Length >	ZeroSet () const =0
	Returns a list of parameters at which the normal vector flips from one side to the other.
virtual common::Interval< Length >	Range () const =0
virtual spat::Vector< One >	LocalUp () const =0
	Gives the Curve's idiosyncratic up direction. Some curves maintain some idea about where they have their upside, either because of their form (e.g Helix) or because it is extra defined (e.g. for Line). Some curves maintain no such notion (e.g. many Cubics).
virtual spat::Frame< Length, One >	GetCurveLocalTransformation () const =0
virtual std::unique_ptr< Curve >	Clone () const =0
	make an exact copy of this curve.
virtual bool	Mirror (const spat::VectorBundle< Length, One > &mirrorPlane)=0
	Make a Curve with mirrored geometry (but of course one thet returns right handed frames).
virtual bool	Equals (const Curve &toCurve, common::Interval< Length > range, Length epsilon_length=epsilon__length, Angle epsilon_angle=epsilon__angle) const =0
	Comparison.
	Curve (Curve &&)=delete
Curve &	operator= (const Curve &)=delete
Curve &	operator= (Curve &&)=delete

Protected Member Functions
	Curve (const Curve &)=default

Detailed Description

Curves implement this interface that then can get attached to a track to define the tracks geometry.

The curve has to be parametrized by its arc length to give correct results for train movement. Depending on the type of curve generally the parameter s might run from infinite negative to infinite positive value. A concrete curve has to get initialized by a create method and will not return usefull results until after calling the create method.

Member Enumeration Documentation

CurveType

enum class trax::Curve::CurveType

strong

Curve type identification values.

Enumerator
Line	A straight line.
Arc	A circle circumferrence.
Helix	A helix curve.
LineP	A straight line with owned parameters.
ArcP	A circle circumferrence with owned parameters.
HelixP	A helix curve with owned parameters.
Clothoid	An Euler spiral.
Cubic	The solution for the curve given starting and ending points and tangent vectors.
Spline	A series of cubics, generated from control points and tangents, also called 'Cubic Hermite Spline'.
Rotator	A curve with linearly rotating tangent vector.
RotatorWithOffset	A Rotator curve that starts with certain offset angles.
RotatorChain	A series of connected Rotator curves.
PolygonalChain	An ordered list of vertices with tangents.
SampledCurve	An ordered list of F,k,t,s samples coming from a real curve that are used to numerically interpolate between them.
Parallel	A Curve that is parallel to a given track.
EEPCurve	The idiosyncratic curve type used by EEP. The parametrization of the curve is like in EEP, but in general it is not the arc length. (Produces the same wrong results as in EEP).
EEPResidual	Arc length parametrized EEP curve, but only for u != 0, l!= 0 and k²+w² != 0.
EEPAlternative	Alternative curve shape, but directly parametreized by arc length. Only for u != 0, l!= 0 and k²+w² != 0. For w == 0 this curves becomes identical to EEPResidual.

Member Function Documentation

Clone()

virtual std::unique_ptr< Curve > trax::Curve::Clone ( ) const

pure virtual

make an exact copy of this curve.

Exceptions

std::bad_alloc

on memory exhaustion.

Curvature()

virtual AnglePerLength trax::Curve::Curvature ( Length s ) const

pure virtual

Parameters

s	Arc length parameter along the curve

Returns

The curvature of the curve at parameter s.

Equals()

virtual bool trax::Curve::Equals ( const Curve & toCurve, common::Interval< Length > range, Length epsilon_length = epsilon__length, Angle epsilon_angle = epsilon__angle ) const

pure virtual

Comparison.

Two curves of different types are considered not equal.

Returns

true if the geometry and absolute pose of this and the given curve are equal up to the given thresholds.

Parameters

toCurve	curve to compare with.
range	Parameter interval to compare at.
epsilon_length	maximum acceptable positional deviation.
epsilon_angle	maximum vector rotational deviation.

GetCurveLocalTransformation()

virtual spat::Frame< Length, One > trax::Curve::GetCurveLocalTransformation ( ) const

pure virtual

If there is a definition of a 'standard curve' of the given type, e.g. defined as starting (s==0) in the origin with a tangent parallel to Ex<One> and a normal pointing in Ey<One> direction, this function returns the transformation from that standard curve to the real values returned by this curve. GetCurveLocalTransformation().FromParent() transforms this curve to the standard curve. The above mentioned standard curve is just an example (Transion( 0_m) would deliver the frame), the actual standard curve might be defined deifferently, e.g. for a helix it is an angle 'slope' between Ex<One> and the tangent.

GetCurveType()

virtual CurveType trax::Curve::GetCurveType ( ) const

pure virtualnoexcept

Returns

Type that implements this interface.

IsFlat()

virtual bool trax::Curve::IsFlat ( ) const

pure virtualnoexcept

Returns

true if it is guaranteed, that Torsion() will return 0_1Im for every s.

IsValid()

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

pure virtualnoexcept

Tests wether the curve was properly created.

Returns

true if the curve is able to deliver valid geometry.

LocalUp()

virtual spat::Vector< One > trax::Curve::LocalUp ( ) const

pure virtual

Gives the Curve's idiosyncratic up direction. Some curves maintain some idea about where they have their upside, either because of their form (e.g Helix) or because it is extra defined (e.g. for Line). Some curves maintain no such notion (e.g. many Cubics).

Exceptions

std::runtime_error

if the Curve has no notion of up.

Returns

The Curve's up direction.

Mirror()

virtual bool trax::Curve::Mirror ( const spat::VectorBundle< Length, One > & mirrorPlane )

pure virtual

Make a Curve with mirrored geometry (but of course one thet returns right handed frames).

Returns

false if no mirrored curve could be created for the curve type.

Range()

virtual common::Interval< Length > trax::Curve::Range ( ) const

pure virtual

Some curves can only get evaluated at a certain parameter range. This is returned by the function, or {-infinite,infinite} if there is no intrinsic limit to the parameter value.

Exceptions

std::runtime_error

if the curve was not created yet.

Torsion()

virtual AnglePerLength trax::Curve::Torsion ( Length s ) const

pure virtual

Parameters

s	Arc length parameter along the curve

Returns

The torsion of the curve at parameter s.

Transition() [1/5]

virtual void trax::Curve::Transition ( Length s, spat::Frame< Length, One > & frame ) const

pure virtual

Copies the 3D TBN-Frame at the specified location to frame.

Parameters

s	Arc length parameter along the curve
frame	TBN-Frame on curve at parameter s

Exceptions

std::out_of_range

if s is not in the valid range of the curve.

Transition() [2/5]

virtual void trax::Curve::Transition ( Length s, spat::Position< Length > & pos ) const

pure virtual

Copies the 3D Position at the specified location to pos.

Parameters

s	Arc length parameter along the curve
pos	Position on curve at parameter s

Exceptions

std::out_of_range

if s is not in the valid range of the curve.

Transition() [3/5]

virtual void trax::Curve::Transition ( Length s, spat::Vector< One > & tan ) const

pure virtual

Copies the 3D tangential vector at the specified location to tan.

Parameters

s	Arc length parameter along the curve
tan	Tangent on curve at parameter s

Exceptions

std::out_of_range

if s is not in the valid range of the curve.

Transition() [4/5]

virtual void trax::Curve::Transition ( Length s, spat::VectorBundle2< Length, One > & bundle ) const

pure virtual

Copies the 3D Position and tangential and normal vectors at the specified location to bundle.

Parameters

s	Arc length parameter along the curve
bundle	VectorBundle on curve at parameter s

Exceptions

std::out_of_range

if s is not in the valid range of the curve.

Transition() [5/5]

virtual void trax::Curve::Transition ( Length s, spat::VectorBundle< Length, One > & bundle ) const

pure virtual

Copies the 3D Position and tangential vector at the specified location to bundle.

Parameters

s	Arc length parameter along the curve
bundle	VectorBundle on curve at parameter s

Exceptions

std::out_of_range

if s is not in the valid range of the curve.

TypeName()

virtual const char * trax::Curve::TypeName ( ) const

pure virtualnoexcept

Returns

Name for the type that implements this interface.

ZeroSet()

virtual std::vector< Length > trax::Curve::ZeroSet ( ) const

pure virtual

Returns a list of parameters at which the normal vector flips from one side to the other.

In general for a curve the curvature might become zero. If this results in a rotation of the normal by pi, the parameter ist listed in the returned vector. No parameter is returned if the curvature gets zero without flipping the normal (e.g. for a straight line) The values are sorted by size.

Exceptions

std::runtime_error

if the curve was not created yet.

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

• C:/Trend/Development/Trax3/Code/trax/Curve.h