#include <SweepingMeshSDF.h>

Public Types
enum	EComputeModes { FullGrid = 0 , NarrowBandOnly = 1 , NarrowBand_SpatialFloodFill = 2 }

enum	EInsideModes { CrossingCount = 0 , WindingCount = 1 }

using	CellSizeType = std::conditional_t< bScalarCellSize, float, FVector3f >

using	CellSizeTyped = std::conditional_t< bScalarCellSize, double, FVector3d >

Public Member Functions
void	SetCellSize (float InCellSize)

	TSweepingMeshSDF (const TriangleMeshType Mesh=nullptr, CellSizeType InCellSize=UnitCellSize(), TMeshAABBTree3< TriangleMeshType > Spatial=nullptr)

void	Empty ()

template<typename InterpolantRealType = double>
TTriLinearGridInterpolant< FDenseGrid3f, InterpolantRealType, bScalarCellSize >	MakeInterpolant ()

bool	Validate (const FAxisAlignedBox3d &Bounds)

bool	Compute (FAxisAlignedBox3d Bounds)

bool	Compute (FVector3f InGridOrigin, FVector3i InDimensions)

FVector3i	Dimensions () const

const FDenseGrid3i &	GetClosestTriGrid () const

const FDenseGrid3i &	GetIntersectionsGrid () const

float	At (int I, int J, int K) const

float	operator[] (const FVector3i &Idx) const

FVector3f	CellCenter (int I, int J, int K) const

float	GetValue (FVector3i Idx) const

Static Public Member Functions
static CellSizeType	UnitCellSize ()

static bool	ShouldUseSpatial (int ExactCells, double CellSize, double AvgEdgeLen)

static int	Orientation (double X1, double Y1, double X2, double Y2, double &TwiceSignedArea)

static bool	PointInTriangle2d (double X0, double Y0, double X1, double Y1, double X2, double Y2, double X3, double Y3, double &A, double &B, double &C)

static float	PointSegmentDistance (const FVector3f &x0, const FVector3f &x1, const FVector3f &x2)

static double	PointSegmentDistance (const FVector3d &x0, const FVector3d &x1, const FVector3d &x2)

static float	PointTriangleDistance (const FVector3f &x0, const FVector3f &x1, const FVector3f &x2, const FVector3f &x3)

static double	PointTriangleDistance (const FVector3d &x0, const FVector3d &x1, const FVector3d &x2, const FVector3d &x3)

static double	GetDim (CellSizeTyped CellSize, int32 Axis)

static float	GetDim (CellSizeType CellSize, int32 Axis)

static float	GetDiagLength (CellSizeType CellSize)

static bool	IsValid (CellSizeType CellSize)

Public Attributes
const TriangleMeshType *	Mesh

TMeshAABBTree3< TriangleMeshType > *	Spatial

CellSizeType	CellSize

int	ExactBandWidth = 1

FVector3d	ExpandBounds = FVector3d::Zero()

bool	bUseParallel = true

int	ApproxMaxCellsPerDimension = 4096

EComputeModes	ComputeMode = EComputeModes::NarrowBandOnly

double	NarrowBandMaxDistance = 0

bool	bComputeSigns = true

EInsideModes	InsideMode = EInsideModes::WindingCount

bool	bWantClosestTriGrid = false

bool	bWantIntersectionsGrid = false

TFunction< bool()>	CancelF

FVector3f	GridOrigin

FDenseGrid3f	Grid

Protected Attributes
FDenseGrid3i	ClosestTriGrid

FDenseGrid3i	IntersectionsGrid

Detailed Description

template<class TriangleMeshType, bool bScalarCellSize = true>
class UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >

Compute discretely-sampled (ie gridded) signed distance field for a mesh The basic approach is, first compute exact Distances in a narrow band, and then extend out to rest of Grid using fast "sweeping" (ie like a distance transform). The resulting unsigned Grid is then signed using ray-intersection counting, which is also computed on the Grid, so no BVH is necessary

If you set ComputeMode to NarrowBandOnly, result is a narrow-band signed distance field. This is quite a bit faster as the sweeping is the most computationally-intensive step.

You can optionally provide a spatial data structure to allow faster computation of narrow-band Distances; this is most beneficial if we want a wider band

Caveats:

the "narrow band" is based on triangle bounding boxes, so it is not necessarily that "narrow" if you have large triangles on a diagonal to Grid axes

TODO: a number of utility function could & should be shared between this and CachingMeshSDF!

This code is based on the implementation found at https://github.com/christopherbatty/SDFGen

Member Typedef Documentation

◆ CellSizeType

template<class TriangleMeshType , bool bScalarCellSize = true>

using UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::CellSizeType = std::conditional_t<bScalarCellSize, float, FVector3f>

◆ CellSizeTyped

template<class TriangleMeshType , bool bScalarCellSize = true>

using UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::CellSizeTyped = std::conditional_t<bScalarCellSize, double, FVector3d>

Member Enumeration Documentation

◆ EComputeModes

template<class TriangleMeshType , bool bScalarCellSize = true>

enum UE::Geometry::TSweepingMeshSDF::EComputeModes

Enumerator
FullGrid
NarrowBandOnly
NarrowBand_SpatialFloodFill

◆ EInsideModes

template<class TriangleMeshType , bool bScalarCellSize = true>

enum UE::Geometry::TSweepingMeshSDF::EInsideModes

Enumerator
CrossingCount
WindingCount

Constructor & Destructor Documentation

◆ TSweepingMeshSDF()

template<class TriangleMeshType , bool bScalarCellSize = true>

UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::TSweepingMeshSDF	(	const TriangleMeshType *	Mesh = `nullptr`,
		CellSizeType	InCellSize = `UnitCellSize()`,
		TMeshAABBTree3< TriangleMeshType > *	Spatial = `nullptr`
	)

inline

Parameters

Mesh	Triangle mesh to build an SDF around
InCellSize	Spacing between Grid points
Spatial	Optional AABB tree; note it must be provided if ComputeMode is set to NarrowBand_SpatialFloodFill

Member Function Documentation

◆ At()

template<class TriangleMeshType , bool bScalarCellSize = true>

float UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::At	(	int	I,
		int	J,
		int	K
	)		const

inline

◆ CellCenter()

template<class TriangleMeshType , bool bScalarCellSize = true>

FVector3f UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::CellCenter	(	int	I,
		int	J,
		int	K
	)		const

inline

◆ Compute() [1/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Compute ( FAxisAlignedBox3d Bounds )

inline

Compute the SDF enclosing the given bounds, with a 'safe' buffer zone

Parameters

Bounds Bounding box for the mesh data (passed as param it is usually already available, depending on TriangleMeshType and whether an AABB tree was provided)

Returns: false if cancelled or failed (e.g. due to invalid arguments); true otherwise

◆ Compute() [2/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Compute	(	FVector3f	InGridOrigin,
		FVector3i	InDimensions
	)

inline

Compute the SDF with exactly specified grid origin and dimensions

Parameters

InGridOrigin	Origin of the output grid
InDimensions	Dimensions of the output grid

Returns: false if cancelled or failed (e.g. due to invalid arguments); true otherwise

◆ Dimensions()

template<class TriangleMeshType , bool bScalarCellSize = true>

FVector3i UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Dimensions ( ) const

inline

◆ Empty()

template<class TriangleMeshType , bool bScalarCellSize = true>

void UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Empty ( )

inline

Empty out all computed result data (leaves input data alone)

◆ GetClosestTriGrid()

template<class TriangleMeshType , bool bScalarCellSize = true>

const FDenseGrid3i & UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::GetClosestTriGrid ( ) const

inline

◆ GetDiagLength()

template<class TriangleMeshType , bool bScalarCellSize = true>

static float UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::GetDiagLength ( CellSizeType CellSize )

inlinestatic

◆ GetDim() [1/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

static float UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::GetDim	(	CellSizeType	CellSize,
		int32	Axis
	)

inlinestatic

◆ GetDim() [2/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

static double UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::GetDim	(	CellSizeTyped	CellSize,
		int32	Axis
	)

inlinestatic

◆ GetIntersectionsGrid()

template<class TriangleMeshType , bool bScalarCellSize = true>

const FDenseGrid3i & UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::GetIntersectionsGrid ( ) const

inline

◆ GetValue()

template<class TriangleMeshType , bool bScalarCellSize = true>

float UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::GetValue ( FVector3i Idx ) const

inline

◆ IsValid()

template<class TriangleMeshType , bool bScalarCellSize = true>

static bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::IsValid ( CellSizeType CellSize )

inlinestatic

◆ MakeInterpolant()

template<class TriangleMeshType , bool bScalarCellSize = true>

template<typename InterpolantRealType = double>

TTriLinearGridInterpolant< FDenseGrid3f, InterpolantRealType, bScalarCellSize > UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::MakeInterpolant ( )

inline

◆ operator[]()

template<class TriangleMeshType , bool bScalarCellSize = true>

float UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::operator[] ( const FVector3i & Idx ) const

inline

◆ Orientation()

template<class TriangleMeshType , bool bScalarCellSize = true>

static int UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Orientation	(	double	X1,
		double	Y1,
		double	X2,
		double	Y2,
		double &	TwiceSignedArea
	)

inlinestatic

◆ PointInTriangle2d()

template<class TriangleMeshType , bool bScalarCellSize = true>

static bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::PointInTriangle2d	(	double	X0,
		double	Y0,
		double	X1,
		double	Y1,
		double	X2,
		double	Y2,
		double	X3,
		double	Y3,
		double &	A,
		double &	B,
		double &	C
	)

inlinestatic

◆ PointSegmentDistance() [1/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

static double UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::PointSegmentDistance	(	const FVector3d &	x0,
		const FVector3d &	x1,
		const FVector3d &	x2
	)

inlinestatic

◆ PointSegmentDistance() [2/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

static float UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::PointSegmentDistance	(	const FVector3f &	x0,
		const FVector3f &	x1,
		const FVector3f &	x2
	)

inlinestatic

◆ PointTriangleDistance() [1/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

static double UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::PointTriangleDistance	(	const FVector3d &	x0,
		const FVector3d &	x1,
		const FVector3d &	x2,
		const FVector3d &	x3
	)

inlinestatic

◆ PointTriangleDistance() [2/2]

template<class TriangleMeshType , bool bScalarCellSize = true>

static float UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::PointTriangleDistance	(	const FVector3f &	x0,
		const FVector3f &	x1,
		const FVector3f &	x2,
		const FVector3f &	x3
	)

inlinestatic

◆ SetCellSize()

template<class TriangleMeshType , bool bScalarCellSize = true>

void UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::SetCellSize ( float InCellSize )

inline

◆ ShouldUseSpatial()

template<class TriangleMeshType , bool bScalarCellSize = true>

static bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::ShouldUseSpatial	(	int	ExactCells,
		double	CellSize,
		double	AvgEdgeLen
	)

inlinestatic

Encodes heuristic for deciding whether it will be faster to use

NarrowBand_SpatialFloodFill
Or NarrowBandOnly The heuristic is to use the Spatial method unless you have relatively long edges relative to the width of the narrow band. For a 1-cell wide band, or one where few triangles interact w/ each cell in the band the spatial overhead will probably not be worthwhile. TODO: test and tune this ...

◆ UnitCellSize()

template<class TriangleMeshType , bool bScalarCellSize = true>

static CellSizeType UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::UnitCellSize ( )

inlinestatic

◆ Validate()

template<class TriangleMeshType , bool bScalarCellSize = true>

bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Validate ( const FAxisAlignedBox3d & Bounds )

inline

Member Data Documentation

◆ ApproxMaxCellsPerDimension

template<class TriangleMeshType , bool bScalarCellSize = true>

int UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::ApproxMaxCellsPerDimension = 4096

◆ bComputeSigns

template<class TriangleMeshType , bool bScalarCellSize = true>

bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::bComputeSigns = true

◆ bUseParallel

template<class TriangleMeshType , bool bScalarCellSize = true>

bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::bUseParallel = true

◆ bWantClosestTriGrid

template<class TriangleMeshType , bool bScalarCellSize = true>

bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::bWantClosestTriGrid = false

◆ bWantIntersectionsGrid

template<class TriangleMeshType , bool bScalarCellSize = true>

bool UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::bWantIntersectionsGrid = false

◆ CancelF

template<class TriangleMeshType , bool bScalarCellSize = true>

TFunction<bool()> UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::CancelF

Initial value:

= []()
    {
        return false;
    }

if this function returns true, we should abort calculation

◆ CellSize

template<class TriangleMeshType , bool bScalarCellSize = true>

CellSizeType UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::CellSize

◆ ClosestTriGrid

template<class TriangleMeshType , bool bScalarCellSize = true>

FDenseGrid3i UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::ClosestTriGrid

protected

◆ ComputeMode

template<class TriangleMeshType , bool bScalarCellSize = true>

EComputeModes UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::ComputeMode = EComputeModes::NarrowBandOnly

◆ ExactBandWidth

template<class TriangleMeshType , bool bScalarCellSize = true>

int UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::ExactBandWidth = 1

◆ ExpandBounds

template<class TriangleMeshType , bool bScalarCellSize = true>

FVector3d UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::ExpandBounds = FVector3d::Zero()

◆ Grid

template<class TriangleMeshType , bool bScalarCellSize = true>

FDenseGrid3f UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Grid

◆ GridOrigin

template<class TriangleMeshType , bool bScalarCellSize = true>

FVector3f UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::GridOrigin

◆ InsideMode

template<class TriangleMeshType , bool bScalarCellSize = true>

EInsideModes UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::InsideMode = EInsideModes::WindingCount

◆ IntersectionsGrid

template<class TriangleMeshType , bool bScalarCellSize = true>

FDenseGrid3i UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::IntersectionsGrid

protected

◆ Mesh

template<class TriangleMeshType , bool bScalarCellSize = true>

const TriangleMeshType* UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Mesh

◆ NarrowBandMaxDistance

template<class TriangleMeshType , bool bScalarCellSize = true>

double UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::NarrowBandMaxDistance = 0

◆ Spatial

template<class TriangleMeshType , bool bScalarCellSize = true>

TMeshAABBTree3<TriangleMeshType>* UE::Geometry::TSweepingMeshSDF< TriangleMeshType, bScalarCellSize >::Spatial

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

Engine/Source/Runtime/GeometryCore/Public/Implicit/SweepingMeshSDF.h

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Attributes

Detailed Description

Member Typedef Documentation

◆ CellSizeType

◆ CellSizeTyped

Member Enumeration Documentation

◆ EComputeModes

◆ EInsideModes

Constructor & Destructor Documentation

◆ TSweepingMeshSDF()

Member Function Documentation

◆ At()

◆ CellCenter()

◆ Compute() [1/2]

◆ Compute() [2/2]

◆ Dimensions()

◆ Empty()

◆ GetClosestTriGrid()

◆ GetDiagLength()

◆ GetDim() [1/2]

◆ GetDim() [2/2]

◆ GetIntersectionsGrid()

◆ GetValue()

◆ IsValid()

◆ MakeInterpolant()

◆ operator[]()

◆ Orientation()

◆ PointInTriangle2d()

◆ PointSegmentDistance() [1/2]

◆ PointSegmentDistance() [2/2]

◆ PointTriangleDistance() [1/2]

◆ PointTriangleDistance() [2/2]

◆ SetCellSize()

◆ ShouldUseSpatial()

◆ UnitCellSize()

◆ Validate()

Member Data Documentation

◆ ApproxMaxCellsPerDimension

◆ bComputeSigns

◆ bUseParallel

◆ bWantClosestTriGrid

◆ bWantIntersectionsGrid

◆ CancelF

◆ CellSize

◆ ClosestTriGrid

◆ ComputeMode

◆ ExactBandWidth

◆ ExpandBounds

◆ Grid

◆ GridOrigin

◆ InsideMode

◆ IntersectionsGrid

◆ Mesh

◆ NarrowBandMaxDistance

◆ Spatial