UE::Geometry::CurveUtil Namespace Reference

Functions
template<typename RealType , typename VectorType , bool bLoop>
void	GetPrevNext (const TArrayView< const VectorType > &Vertices, int32 Idx, VectorType &OutPrev, VectorType &OutNext)
template<typename RealType , typename VectorType , bool bLoop>
void	GetVectorsToPrevNext (const TArrayView< const VectorType > &Vertices, int32 VertexIndex, VectorType &OutToPrev, VectorType &OutToNext, bool bNormalize)
template<typename RealType , typename VectorType >
void	GetVectorsToPrevNext (const TArrayView< const VectorType > &Vertices, int32 VertexIndex, VectorType &OutToPrev, VectorType &OutToNext, bool bNormalize, bool bLoop)
template<typename RealType , typename VectorType , bool bLoop>
VectorType	Tangent (const TArrayView< const VectorType > &Vertices, int32 Idx)
template<typename RealType , typename VectorType >
VectorType	Tangent (const TArrayView< const VectorType > &Vertices, int32 Idx, bool bLoop=false)
template<typename RealType , typename VectorType , bool bLoop>
VectorType	GetNormal_FaceAvg2 (const TArrayView< const VectorType > &Vertices, int VertexIndex)
template<typename RealType , typename VectorType >
RealType	SignedArea2 (const TArrayView< const VectorType > &Vertices)
template<typename RealType , typename VectorType >
RealType	WindingIntegral2 (const TArrayView< const VectorType > &Vertices, const VectorType &QueryPoint)
template<typename RealType , typename VectorType >
bool	Contains2 (const TArrayView< const VectorType > &Vertices, const VectorType &QueryPoint)
template<typename RealType , typename VectorType >
int	FindNearestIndex (const TArrayView< const VectorType > &Vertices, const VectorType &V)
template<typename RealType , typename VectorType >
bool	IsConvex2 (const TArrayView< const VectorType > Vertices, RealType Tolerance=TMathUtil< RealType >::ZeroTolerance, bool bDegenerateIsConvex=true)
template<typename RealType >
bool	ProjectPointInsideConvexPolygon (const TArrayView< const TVector2< RealType > > Vertices, TVector2< RealType > &ProjPt, bool bReverseOrientation=false)
template<typename RealType , typename VectorType >
void	InPlaceSmooth (TArrayView< VectorType > Vertices, int StartIdx, int EndIdx, double Alpha, int NumIterations, bool bClosed)
template<typename RealType , typename VectorType >
void	IterativeSmooth (TArrayView< VectorType > Vertices, int StartIdx, int EndIdx, double Alpha, int NumIterations, bool bClosed)

Function Documentation

Contains2()

template<typename RealType , typename VectorType >

bool UE::Geometry::CurveUtil::Contains2	(	const TArrayView< const VectorType > &	Vertices,
		const VectorType &	QueryPoint
	)

Returns

true if the given query point is inside the closed curve (in the XY plane), based on the winding integral Note: Negative and positive windings are both considered 'inside'

FindNearestIndex()

template<typename RealType , typename VectorType >

int UE::Geometry::CurveUtil::FindNearestIndex	(	const TArrayView< const VectorType > &	Vertices,
		const VectorType &	V
	)

GetNormal_FaceAvg2()

template<typename RealType , typename VectorType , bool bLoop>

VectorType UE::Geometry::CurveUtil::GetNormal_FaceAvg2	(	const TArrayView< const VectorType > &	Vertices,
		int	VertexIndex
	)

Construct a normal at a vertex of the Polygon by averaging the adjacent face normals. This vector is independent of the lengths of the adjacent segments. Points "inward" for a Clockwise Polygon, and outward for CounterClockwise Note: Specific to 2D curves; normals computed by rotating tangents in the XY plane

GetPrevNext()

template<typename RealType , typename VectorType , bool bLoop>

void UE::Geometry::CurveUtil::GetPrevNext ( const TArrayView< const VectorType > &  Vertices, int32  Idx, VectorType &  OutPrev, VectorType &  OutNext  )

inline

Curve utility functions Get (by reference) the vertices surrounding the given vertex index If bLoop is false and the Prev or Next vertex would be out of bounds, the vertex at Idx is used instead.

GetVectorsToPrevNext() [1/2]

template<typename RealType , typename VectorType , bool bLoop>

void UE::Geometry::CurveUtil::GetVectorsToPrevNext ( const TArrayView< const VectorType > &  Vertices, int32  VertexIndex, VectorType &  OutToPrev, VectorType &  OutToNext, bool  bNormalize  )

inline

Get (by reference) vectors pointing toward the given vertex index, from its surrounding vertices If bLoop is false and the Prev or Next vertex would be out of bounds, a zero vector is used instead

GetVectorsToPrevNext() [2/2]

template<typename RealType , typename VectorType >

void UE::Geometry::CurveUtil::GetVectorsToPrevNext ( const TArrayView< const VectorType > &  Vertices, int32  VertexIndex, VectorType &  OutToPrev, VectorType &  OutToNext, bool  bNormalize, bool  bLoop  )

inline

Get (by reference) vectors pointing toward the given vertex index, from its surrounding vertices If bLoop is false and the Prev or Next vertex would be out of bounds, a zero vector is used instead

InPlaceSmooth()

template<typename RealType , typename VectorType >

void UE::Geometry::CurveUtil::InPlaceSmooth	(	TArrayView< VectorType >	Vertices,
		int	StartIdx,
		int	EndIdx,
		double	Alpha,
		int	NumIterations,
		bool	bClosed
	)

smooth vertices in-place (will not produce a symmetric result, but does not require extra buffer)

IsConvex2()

template<typename RealType , typename VectorType >

bool UE::Geometry::CurveUtil::IsConvex2	(	const TArrayView< const VectorType >	Vertices,
		RealType	Tolerance = TMathUtil<RealType>::ZeroTolerance,
		bool	bDegenerateIsConvex = true
	)

Tests closed, 2D curve for convexity, with an optional tolerance allowing for approximately-collinear points Note that tolerance is per vertex angle, so a very-finely-sampled smooth concavity could be reported as convex

Parameters

RadiansTolerance	Maximum turn in the 'wrong' direction that will still be considered convex (in radians)
bDegenerateIsConvex	What to return for degenerate input (less than 3 points or equivalent due to repeated points)

Returns

true if polygon is convex

IterativeSmooth()

template<typename RealType , typename VectorType >

void UE::Geometry::CurveUtil::IterativeSmooth	(	TArrayView< VectorType >	Vertices,
		int	StartIdx,
		int	EndIdx,
		double	Alpha,
		int	NumIterations,
		bool	bClosed
	)

smooth set of vertices using extra buffer

ProjectPointInsideConvexPolygon()

template<typename RealType >

bool UE::Geometry::CurveUtil::ProjectPointInsideConvexPolygon	(	const TArrayView< const TVector2< RealType > >	Vertices,
		TVector2< RealType > &	ProjPt,
		bool	bReverseOrientation = false
	)

Project point inside a convex polygon with known orientation

Parameters

ProjPt	Point to project
bReverseOrientation	Whether convex polygon orientation is reversed (i.e., has negative signed area)

Returns

true if the point was projected

SignedArea2()

template<typename RealType , typename VectorType >

RealType UE::Geometry::CurveUtil::SignedArea2

(

const TArrayView< const VectorType > &

Vertices

)

Compute the signed area of a closed curve, assuming vertices in the XY plane

Tangent() [1/2]

template<typename RealType , typename VectorType , bool bLoop>

VectorType UE::Geometry::CurveUtil::Tangent ( const TArrayView< const VectorType > &  Vertices, int32  Idx  )

inline

Returns

the tangent direction (normalized) of the path at Idx, using the surrounding vertices (as found by GetPrevNext())

Tangent() [2/2]

template<typename RealType , typename VectorType >

VectorType UE::Geometry::CurveUtil::Tangent ( const TArrayView< const VectorType > &  Vertices, int32  Idx, bool  bLoop = false  )

inline

Returns

the tangent direction (normalized) of the path at Idx, using the surrounding vertices (as found by GetPrevNext())

WindingIntegral2()

template<typename RealType , typename VectorType >

RealType UE::Geometry::CurveUtil::WindingIntegral2	(	const TArrayView< const VectorType > &	Vertices,
		const VectorType &	QueryPoint
	)

Compute the winding of a point relative to a closed curve, assuming vertices in the XY plane