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FDelaunay2

API > API/Runtime > API/Runtime/GeometryCore

   
Name FDelaunay2
Type class
Header File /Engine/Source/Runtime/GeometryCore/Public/CompGeom/Delaunay2.h
Include Path #include "CompGeom/Delaunay2.h"

Syntax

class FDelaunay2

Enums

Public

Name Remarks
EFillMode Options for selecting what triangles to include in the output, for constrained Delaunay triangulation of polygons.
EResult Indicates result of triangulation.

Variables

Public

Name Type Remarks Include Path Unreal Specifiers
bAutomaticallyFixEdgesToDuplicateVertices bool Option to automatically track duplicate vertices and treat edges that reference them as if they referenced the instance that was actually used in the triangulation Note: Cannot change this to 'true' after triangulation and then call ConstrainEdges; duplicate vertices will only be detected on their initial insertion CompGeom/Delaunay2.h  
bKeepFastEdgeAdjacencyData bool Option to keep extra vertex->edge adjacency data; useful if you will call ConstrainEdges many times on the same triangulation. CompGeom/Delaunay2.h  
bValidateEdges bool Option to validate that edges remain in the triangulation after multiple constraint edges passed in Only validates for the edges in the current call; if separate calls constrain additional edges, set this to 'false' and call HasEdges() on the full edge set TODO: Consider having the internal mesh remember what edges have been constrained, so we can set an error flag when constrained edges cross previous constrained edges CompGeom/Delaunay2.h  
RandomStream FRandomStream Source for random permutations, used internally in the triangulation algorithm. CompGeom/Delaunay2.h  

Protected

Name Type Remarks Include Path Unreal Specifiers
Result EResult   CompGeom/Delaunay2.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

bool CanComputeVoronoiCells()

   CompGeom/Delaunay2.h  

bool ConstrainEdges ( TArrayView< const TVector2< float > > Vertices,
TArrayView< const FIndex2i > Edges
)

   CompGeom/Delaunay2.h  

bool ConstrainEdges ( TArrayView< const TVector2< double > > Vertices,
TArrayView< const FIndex2i > Edges
)

 Update an already-computed triangulation so the given edges are in the triangulation. CompGeom/Delaunay2.h  

void FixDuplicatesOnEdge ( FIndex2i& Edge
)

 Remap any references to duplicate vertices to only reference the vertices used in the triangulation. CompGeom/Delaunay2.h  
Return the triangles that are inside the given edges, removing the outer boundary triangles If a Winding-Number-based fill mode is used, assumes edges are oriented and tracks the winding number across edges CompGeom/Delaunay2.h  

bool GetFilledTriangles ( TArray< FIndex3i >& TrianglesOut,
TArrayView< const FIndex2i > BoundaryEdges,
TArrayView< const FIndex2i > HoleEdges
) const

 Get (by reference) the triangles that are inside the given edges, removing the outside-boundary triangles and the inside-hole triangles CompGeom/Delaunay2.h  

bool GetFilledTriangles ( TArray< FIndex3i >& TrianglesOut,
TArrayView< const FIndex2i > Edges,
EFillMode FillMode
) const

 Get (by reference) the triangles that are inside the given edges, removing the outer boundary triangles If a Winding-Number-based fill mode is used, assumes edges are oriented and tracks the winding number across edges CompGeom/Delaunay2.h  

bool GetFilledTrianglesGeneralizedWinding ( TArray< FIndex3i >& TrianglesOut,
TArrayView< const TVector2< float > > Vertices,
TArrayView< const FIndex2i > Edges,
EFillMode FillMode
) const

   CompGeom/Delaunay2.h  

bool GetFilledTrianglesGeneralizedWinding ( TArray< FIndex3i >& TrianglesOut,
TArrayView< const TVector2< double > > Vertices,
TArrayView< const FIndex2i > Edges,
EFillMode FillMode
) const

 Get (by reference) the triangles that are inside the given edges, using a generalized winding number method to determine which triangles are inside Not valid for EFillMode::Solid, will fall back to the above GetFilledTriangles method in that case. CompGeom/Delaunay2.h  

EResult GetResult()

   CompGeom/Delaunay2.h  

TArray< FIndex3i > GetTriangles()

 TODO: Support incremental vertex insertion Update the triangulation incrementally, assuming Vertices are unchanged before FirstNewIndex, and nothing after FirstNewIndex has been inserted yet Note that updating with new vertices after constraining edges may remove previously-constrained edges, unless we also add a way to tag constrained edges bool Update(TArrayView> Vertices, int32 FirstNewIdx); Get the triangulation as an array of triangles Note: This creates a new array each call, because the internal data structure does not have a triangle array CompGeom/Delaunay2.h  

void GetTrianglesAndAdjacency ( TArray< FIndex3i >& Triangles,
TArray< FIndex3i >& Adjacency
) const

 Get the triangulation as an array with a corresponding adjacency array, indicating the adjacent triangle on each triangle edge (-1 if no adjacent triangle) CompGeom/Delaunay2.h  

TArray< TArray< FVector2d > > GetVoronoiCells ( TArrayView< const FVector2d > Vertices,
bool bIncludeBoundary,
FAxisAlignedBox2d ClipBounds,
double ExpandBounds
) const

 Get Voronoi diagram cells as dual of the Delaunay triangulation. CompGeom/Delaunay2.h  

TArray< TArray< FVector2f > > GetVoronoiCells ( TArrayView< const FVector2f > Vertices,
bool bIncludeBoundary,
FAxisAlignedBox2f ClipBounds,
float ExpandBounds
) const

   CompGeom/Delaunay2.h  

bool HasDuplicates()

   CompGeom/Delaunay2.h  

bool HasEdge ( const FIndex2i& Edge,
bool bRemapDuplicates
)

   CompGeom/Delaunay2.h  

bool HasEdges ( TArrayView< const FIndex2i > Edges
) const

   CompGeom/Delaunay2.h  

bool IsConstrained()

   CompGeom/Delaunay2.h  

bool IsDelaunay ( TArrayView< const FVector2f > Vertices,
TArrayView< const FIndex2i > SkipEdges
) const

   CompGeom/Delaunay2.h  

bool IsDelaunay ( TArrayView< const FVector2d > Vertices,
TArrayView< const FIndex2i > SkipEdges
) const

   CompGeom/Delaunay2.h  

int32 RemapIfDuplicate ( int32 Index
) const

   CompGeom/Delaunay2.h  

bool Triangulate ( const TPolygon2< RealType >& Polygon,
TArray< FIndex3i >* TrianglesOut
)

 Triangulate a polygon, and optionally pass back the resulting triangles Uses the 'solid' fill mode, and fills the polygon regardless of the edge orientation Note: TrianglesOut may be empty or incomplete if the input is self-intersecting. CompGeom/Delaunay2.h  

bool Triangulate ( TArrayView< const TVector2< double > > Vertices,
TArrayView< const FIndex2i > Edges
)

 TODO: it would often be useful to pass in sparse vertex data / Optional function to allow Triangulate to skip vertices. CompGeom/Delaunay2.h  

bool Triangulate ( TArrayView< const TVector2< float > > Vertices,
TArrayView< const FIndex2i > Edges
)

   CompGeom/Delaunay2.h  

bool Triangulate ( const TGeneralPolygon2< RealType >& GeneralPolygon,
TArray< FIndex3i >* TrianglesOut,
TArray< TVector2< RealType > >* VerticesOut,
bool bFallbackToGeneralizedWinding
)

 Triangulate a polygon, and optionally pass back the resulting triangles Uses a winding-number-based fill mode, and relies on the general polygon having correct orientations (Uses TGeneralPolygon2's OuterIsClockwise() to automatically choose between positive or negative winding) Note: TrianglesOut may be empty or incomplete if the input is self-intersecting. CompGeom/Delaunay2.h  

Protected

Name Remarks Include Path Unreal Specifiers

bool ValidateResult ( TArrayView< const FIndex2i > Edges
) const

 Helper to perform standard validation on results after Triangulate or ConstrainEdges calls CompGeom/Delaunay2.h  

Static

Name Remarks Include Path Unreal Specifiers

static TArray< TArray< TVector2< RealType > > > ComputeVoronoiCells ( TArrayView< const TVector2< RealType > > Sites,
bool bIncludeBoundary,
TAxisAlignedBox2< RealType > ClipBounds,
RealType ExpandBounds
)

 Compute Voronoi diagram cells CompGeom/Delaunay2.h  

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