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TDynamicMeshOverlay

[TDynamicMeshOverlay](API\Runtime\GeometryCore\TDynamicMeshOverlay) is an add-on to a [FDynamicMesh3](API\Runtime\GeometryCore\FDynamicMesh3) that allows for per-triangle storage of an "element" (eg like a per-triangle UV or normal).

API > API/Runtime > API/Runtime/GeometryCore

TDynamicMeshOverlay is an add-on to a FDynamicMesh3 that allows for per-triangle storage of an "element" (eg like a per-triangle UV or normal). However the elements can be shared between triangles at shared vertices because the elements are stored in a separate indexable list.

Each element has one vertex in the parent mesh as its parent, whereas each vertex may be the parent of multiple elements in cases where neighboring triangles are not sharing a single element for that vertex. This means that there may be "seam" boundary edges in the overlay topology that are not mesh boundary edges in the associated/parent mesh, but the overlay topology will not connect triangles that were not connected in the parent mesh or create any topologically degenerate triangles, since the parent vids of the elements of a triangle will have to match up to the vids of the triangle.

A "seam" edge is one where at least one of the elements of the triangles on either side of the edge is not shared between the two triangles.

The FDynamicMesh3 mesh topology operations (eg split/flip/collapse edge, poke face, etc) can be mirrored to the overlay via OnSplitEdge(), etc.

Note that although this is a template, many of the functions are defined in the .cpp file. As a result you need to explicitly instantiate and export the instance of the template that you wish to use in the block at the top of DynamicMeshOverlay.cpp

   
Name TDynamicMeshOverlay
Type class
Header File /Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/DynamicMeshOverlay.h
Include Path #include "DynamicMesh/DynamicMeshOverlay.h"

Syntax

template<typename RealType, int ElementSize>  
class TDynamicMeshOverlay

Derived Classes

Constructors

Name Remarks Include Path Unreal Specifiers
Create an empty overlay DynamicMesh/DynamicMeshOverlay.h  
Create an overlay for the given parent mesh DynamicMesh/DynamicMeshOverlay.h  

Typedefs

Name Type Remarks Include Path
element_iterator FRefCountVector::IndexEnumerable   DynamicMesh/DynamicMeshOverlay.h

Functions

Public

Name Remarks Include Path Unreal Specifiers

void Append ( const TDynamicMeshOverlay& ToAppend,
const FDynamicMesh3::FAppendInfo& AppendInfo
)

   DynamicMesh/DynamicMeshOverlay.h  

void AppendDefaulted ( const FDynamicMesh3::FAppendInfo& AppendInfo
)

   DynamicMesh/DynamicMeshOverlay.h  

int AppendElement ( const RealType* Value
)

 Allocate a new element with the given value DynamicMesh/DynamicMeshOverlay.h  

int AppendElement ( RealType ConstantValue
)

 Allocate a new element with the given constant value DynamicMesh/DynamicMeshOverlay.h  

bool AreTrianglesConnected ( int TriangleID0,
int TriangleID1
) const

   DynamicMesh/DynamicMeshOverlay.h  
Support for inserting element at specific ID. DynamicMesh/DynamicMeshOverlay.h  

bool CheckValidity ( bool bAllowNonManifoldVertices,
EValidityCheckFailMode FailMode
) const

 Checks that the overlay mesh is well-formed, ie all internal data structures are consistent DynamicMesh/DynamicMeshOverlay.h  

void ClearElements ()

 Discard all elements. DynamicMesh/DynamicMeshOverlay.h  

void ClearElements ( const EnumerableIntType& Triangles
)

 Discard elements for given triangles. DynamicMesh/DynamicMeshOverlay.h  

void CompactCopy ( const FCompactMaps& CompactMaps,
const TDynamicMeshOverlay< RealType, ElementSize >& Copy
)

 Copy the Copy overlay to a compact rep, also updating parent references based on the CompactMaps DynamicMesh/DynamicMeshOverlay.h  

void CompactInPlace ( const FCompactMaps& CompactMaps
)

 Compact overlay and update links to parent based on CompactMaps DynamicMesh/DynamicMeshOverlay.h  

void Copy ( const TDynamicMeshOverlay< RealType, ElementSize >& Copy
)

 Set this overlay to contain the same arrays as the copy overlay DynamicMesh/DynamicMeshOverlay.h  

int CountVertexElements ( int VertexID,
bool bBruteForce
) const

 Count the number of unique elements for a given parent-mesh vertex DynamicMesh/DynamicMeshOverlay.h  

void CreateFromPredicate ( TFunctionRef< bool(int ParentVertexIdx, int TriIDA, int TriIDB)> TrisCanShareVertexPredicate,
RealType InitElementValue
)

 Build overlay topology from a predicate function, e.g. to build topology for sharp normals DynamicMesh/DynamicMeshOverlay.h  

int ElementCount()

   DynamicMesh/DynamicMeshOverlay.h  

element_iterator ElementIndicesItr()

   DynamicMesh/DynamicMeshOverlay.h  

void EndUnsafeElementsInsert()

 Call after a set of unsafe InsertVertex() calls to rebuild free list DynamicMesh/DynamicMeshOverlay.h  

void FreeUnusedElements ( const TSet< int >* ElementsToCheck
)

 Goes through elements and frees any whose reference counts indicate that they are not being used. DynamicMesh/DynamicMeshOverlay.h  

SIZE_T GetByteCount()

   DynamicMesh/DynamicMeshOverlay.h  

void GetElement ( int ElementID,
AsType& Data
) const

 Get the element at a given index DynamicMesh/DynamicMeshOverlay.h  

void GetElement ( int ElementID,
RealType* Data
) const

 Accessors/Queries Get the element at a given index DynamicMesh/DynamicMeshOverlay.h  

void GetElementAtVertex ( int TriangleID,
int VertexID,
AsType& Data
) const

 Get the Element value associated with a vertex of a triangle. DynamicMesh/DynamicMeshOverlay.h  

int GetElementIDAtVertex ( int TriangleID,
int VertexID
) const

 Find the element ID at a vertex of a triangle. DynamicMesh/DynamicMeshOverlay.h  

void GetElementTriangles ( int ElementID,
TArray< int >& OutTriangles
) const

 Find the triangles connected to an element DynamicMesh/DynamicMeshOverlay.h  
  DynamicMesh/DynamicMeshOverlay.h  
  DynamicMesh/DynamicMeshOverlay.h  

int GetParentVertex ( int ElementID
) const

 Get the parent vertex id for the element at a given index DynamicMesh/DynamicMeshOverlay.h  

FIndex3i GetTriangle ( int TriangleID
) const

 Get the element index tuple for a triangle DynamicMesh/DynamicMeshOverlay.h  

bool GetTriangleIfValid ( int TriangleID,
FIndex3i& TriangleOut
) const

 If the triangle is set to valid element indices, return the indices in TriangleOut and return true, otherwise return false DynamicMesh/DynamicMeshOverlay.h  

void GetTriBaryInterpolate ( int32 TriangleID,
const AsType* BaryCoords,
AsType* DataOut
) const

 Compute interpolated parameter value inside triangle using barycentric coordinates DynamicMesh/DynamicMeshOverlay.h  

void GetVertexElements ( int VertexID,
TArray< int >& OutElements
) const

 Find the elements associated with a given parent-mesh vertex DynamicMesh/DynamicMeshOverlay.h  

bool HasInteriorSeamEdges()

   DynamicMesh/DynamicMeshOverlay.h  

void InitializeNewTriangle ( int TriangleID
)

 Set a triangle's element indices to InvalidID DynamicMesh/DynamicMeshOverlay.h  

void InitializeTriangles ( int MaxTriangleID
)

 Initialize the triangle list to the given size, and set all triangles to InvalidID DynamicMesh/DynamicMeshOverlay.h  

EMeshResult InsertElement ( int ElementID,
const RealType* Value,
bool bUnsafe
)

 Insert element at given index, assuming it is unused. DynamicMesh/DynamicMeshOverlay.h  

bool IsBowtieInOverlay ( int32 VertexID
) const

 Determines whether the base-mesh vertex has "bowtie" topology in the Overlay. DynamicMesh/DynamicMeshOverlay.h  

bool IsCompact()

   DynamicMesh/DynamicMeshOverlay.h  

bool IsElement ( int vID
) const

   DynamicMesh/DynamicMeshOverlay.h  

bool IsSameAs ( const TDynamicMeshOverlay< RealType, ElementSize >& Other,
bool bIgnoreDataLayout
) const

 Returns true if this overlay is the same as Other. DynamicMesh/DynamicMeshOverlay.h  

bool IsSeamEdge ( int EdgeID,
bool* bIsNonIntersectingOut
) const

 Returns true if the parent-mesh edge is a "Seam" in this overlay. DynamicMesh/DynamicMeshOverlay.h  

bool IsSeamEndEdge ( int EdgeID
) const

 Returns true if the parent-mesh edge is a "Seam End" in this overlay, meaning the adjacent element triangles share one element, not two DynamicMesh/DynamicMeshOverlay.h  

bool IsSeamIntersectionVertex ( int32 VertexID
) const

 Returns true if the parent-mesh vertex is at a seam 'intersection' i.e., the end of a seam, or the intersection w/ another seam. DynamicMesh/DynamicMeshOverlay.h  

bool IsSeamVertex ( int VertexID,
bool bBoundaryIsSeam
) const

 Returns true if the parent-mesh vertex is connected to any seam edges DynamicMesh/DynamicMeshOverlay.h  

bool IsSetTriangle ( int TID
) const

   DynamicMesh/DynamicMeshOverlay.h  

int MaxElementID()

   DynamicMesh/DynamicMeshOverlay.h  

bool MergeElement ( int SourceElementID,
int TargetElementID
)

 Collapse SourceElementID into TargetElementID, resulting in connecting any containing triangles and reducing the total elements in the overlay. DynamicMesh/DynamicMeshOverlay.h  

void OnCollapseEdge ( const DynamicMeshInfo::FEdgeCollapseInfo& CollapseInfo
)

 Update the overlay to reflect an edge collapse in the parent mesh DynamicMesh/DynamicMeshOverlay.h  

void OnFlipEdge ( const DynamicMeshInfo::FEdgeFlipInfo& FlipInfo
)

 Update the overlay to reflect an edge flip in the parent mesh DynamicMesh/DynamicMeshOverlay.h  

void OnMergeEdges ( const DynamicMeshInfo::FMergeEdgesInfo& MergeInfo
)

 Update the overlay to reflect an edge merge in the parent mesh DynamicMesh/DynamicMeshOverlay.h  

void OnMergeVertices ( const DynamicMeshInfo::FMergeVerticesInfo& MergeInfo
)

 Update the overlay to reflect a vertex merge in the parent mesh DynamicMesh/DynamicMeshOverlay.h  

void OnPokeTriangle ( const DynamicMeshInfo::FPokeTriangleInfo& PokeInfo
)

 Update the overlay to reflect a face poke in the parent mesh DynamicMesh/DynamicMeshOverlay.h  

void OnRemoveTriangle ( int TriangleID
)

 Remove a triangle from the overlay DynamicMesh/DynamicMeshOverlay.h  

void OnReverseTriOrientation ( int TriangleID
)

 Reverse the orientation of a triangle's elements DynamicMesh/DynamicMeshOverlay.h  

void OnSplitEdge ( const DynamicMeshInfo::FEdgeSplitInfo& SplitInfo
)

 Update the overlay to reflect an edge split in the parent mesh DynamicMesh/DynamicMeshOverlay.h  

void OnSplitVertex ( const DynamicMeshInfo::FVertexSplitInfo& SplitInfo,
const TArrayView< const int >& TrianglesToUpdate
)

 Update the overlay to reflect a vertex split in the parent mesh DynamicMesh/DynamicMeshOverlay.h  

void Serialize ( FArchive& Ar,
const FCompactMaps* CompactMaps,
bool bUseCompression
)

 Serialize to and from an archive. DynamicMesh/DynamicMeshOverlay.h  

void SetElement ( int ElementID,
const AsType& Data
)

 Set the element at a given index DynamicMesh/DynamicMeshOverlay.h  

void SetElement ( int ElementID,
const RealType* Data
)

 Set the element at a given index DynamicMesh/DynamicMeshOverlay.h  

void SetParentVertex ( int ElementIndex,
int ParentVertexIndex
)

   DynamicMesh/DynamicMeshOverlay.h  

EMeshResult SetTriangle ( int TriangleID,
const FIndex3i& TriElements,
bool bAllowElementFreeing
)

 Set the triangle to the given Element index tuple, and increment element reference counts DynamicMesh/DynamicMeshOverlay.h  

void SplitBowties()

 Refine an existing overlay topology by splitting any bow ties DynamicMesh/DynamicMeshOverlay.h  

void SplitBowtiesAtVertex ( int32 Vid,
TArray< int32 >* NewElementIDs
)

 Split any bowties at given vertex. DynamicMesh/DynamicMeshOverlay.h  

int SplitElement ( int ElementID,
const TArrayView< const int >& TrianglesToUpdate
)

 Create a new copy of ElementID, and update connected triangles in the TrianglesToUpdate array to reference the copy of ElementID where they used to reference ElementID (Note: This just calls "SplitElementWithNewParent" with the existing element's parent id.) DynamicMesh/DynamicMeshOverlay.h  

int SplitElementWithNewParent ( int ElementID,
int SplitParentVertexID,
const TArrayView< const int >& TrianglesToUpdate
)

 Create a new copy of ElementID, and update connected triangles in the TrianglesToUpdate array to reference the copy of ElementID where they used to reference ElementID. DynamicMesh/DynamicMeshOverlay.h  

void SplitVerticesWithPredicate ( TFunctionRef< bool(int ElementIdx, int TriID)> ShouldSplitOutVertex,
TFunctionRef< void(int ElementIdx, int TriID, RealType*FillVect)> GetNewElementValue
)

 Refine an existing overlay topology. DynamicMesh/DynamicMeshOverlay.h  

bool TriangleHasElement ( int TriangleID,
int ElementID
) const

   DynamicMesh/DynamicMeshOverlay.h  

void UnsetTriangle ( int TriangleID,
bool bAllowElementFreeing
)

 Set the triangle to have InvalidID element IDs, decrementing element reference counts if needed. DynamicMesh/DynamicMeshOverlay.h  

Protected

Name Remarks Include Path Unreal Specifiers

void InternalSetTriangle ( int TriangleID,
const FIndex3i& TriElements,
bool bUpdateRefCounts,
bool bAllowElementFreeing
)

 Updates the triangles array and optionally the element reference counts DynamicMesh/DynamicMeshOverlay.h  

void SetElementFromBary ( int SetElement,
int ElementA,
int ElementB,
int ElementC,
const FVector3d& BaryCoords
)

 Set the value at an Element to be a barycentric interpolation of three other Elements DynamicMesh/DynamicMeshOverlay.h  

void SetElementFromLerp ( int SetElement,
int ElementA,
int ElementB,
double Alpha
)

 Set the value at an Element to be a linear interpolation of two other Elements DynamicMesh/DynamicMeshOverlay.h  

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