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  3. FMarchingCubes

FMarchingCubes

API > API/Runtime > API/Runtime/GeometryCore > API/Runtime/GeometryCore/Generators

Inheritance Hierarchy

References

   
Module GeometryCore
Header /Engine/Source/Runtime/GeometryCore/Public/Generators/MarchingCubes.h
Include #include "Generators/MarchingCubes.h"

Syntax

class FMarchingCubes : public UE::Geometry::FMeshShapeGenerator

Variables

  Type Name Description
Public variable bool bEnableValueCaching If true, code will assume that Implicit() is expensive enough that it is worth it to cache evaluations when possible.
Protected variable FBlockedDenseGrid3f BlockedCornerValuesGrid Store corner values in pre-allocated grid that has FMathf::MaxReal as sentinel.
Protected variable FBlockedDenseGrid3i BlockedDoneCells  
Public variable TAxisAlignedBox3< double > Bounds Bounding-box we will mesh inside of.
Public variable bool bParallelCompute Use multi-threading? Generally a good idea unless problem is very small or you are multi-threading at a higher level (which may be more efficient)
Public variable TFunction< bool(void)> CancelF If this function returns true, we should abort calculation
Public variable FVector3i CellDimensions Cube indices range from [Origin,CellDimensions)
Public variable double CubeSize Length of edges of cubes that are marching.
Protected variable const int64 EDGE_X  
Protected variable const int64 EDGE_Y  
Protected variable const int64 EDGE_Z  
Protected variable TArray< FCriticalSection > EdgeVertexSectionLocks  
Protected variable TArray< TMap< int64, int > > EdgeVertexSections  
Protected variable FAxisAlignedBox3i GridBounds  
Public variable TFunction< double(TVector< double >)> Implicit This is the function we will evaluate
Public variable double IsoValue Mesh surface will be at this isovalue.
Protected variable FAxisAlignedBox3i LastGridBounds  
Protected variable const int64 NumEdgeVertexSections Hash table for edge vertices
Protected variable int64 NumTriangleSections  
Protected variable int64 NumVertexSections  
Protected variable bool parallel_mesh_access  
Public variable ERootfindingModes RootMode Which rootfinding method will be used to converge on surface along edges
Public variable int RootModeSteps Number of iterations of rootfinding method (ignored for SingleLerp)
Public variable int SafetyMaxDimension Max number of cells on any dimension; if exceeded, CubeSize will be automatically increased to fix
Protected variable TArray< TArray< FIndex3i > > TriangleSectionLists  
Protected variable TArray< FCriticalSection > TriangleSectionLocks  
Protected variable std::atomic< int32 > VertexCounter  
Protected variable TArray< TArray< FIndexedVertex > > VertexSectionLists  
Protected variable TArray< FCriticalSection > VertexSectionLocks  

Constructors

  Type Name Description
Public function    

Destructors

  Type Name Description
Public function Virtual    

Functions

  Type Name Description
Protected function void

append_triangle ( int A,
int B,
int C,
int64 CellHash
)

 Add triangle to mesh, with locking if we are computing in parallel
Protected function int

append_vertex ( TVector< double > V,
int64 CellHash
)

 Add vertex to mesh, with locking if we are computing in parallel
Protected function int

AppendOrFindVertexID ( int64 hash,
TVector< double > Pos
)

  
Protected function void Populate FMeshShapeGenerator data structures from accumulated vertex/triangle sets
Protected function FVector3i

cell_index ( const TVector< double >& Pos
)

  
Protected function int64

corner_hash ( int X,
int Y,
int Z
)

  
Protected function int64

corner_hash ( const FVector3i& Idx
)

 Corner and edge hash functions, these pack the coordinate integers into 16-bits, so max of 65536 in any dimension.
Protected function TVector< double >

corner_pos ( const FVector3i& IJK
)

  
Protected function void

corner_pos ( const FVector3i& IJK,
TVector< double >& Pos
)

  
Protected function double

corner_value_grid ( const FVector3i& Idx
)

  
Protected function double  
Protected function double Explicitly compute corner values as necessary
Protected function int64

edge_hash ( const FVector3i& Idx1,
const FVector3i& Idx2
)

  
Protected function int

edge_vertex_id ( const FVector3i& Idx1,
const FVector3i& Idx2,
double F1,
double F2
)

  
Protected function void

find_iso ( const TVector< double >& P1,
const TVector< double >& P2,
double ValP1,
double ValP2,
TVector< double >& PIso
)

 Root-find the intersection along edge from f(P1)=ValP1 to f(P2)=ValP2
Protected function int

FindVertexID ( int64 hash
)

  
Protected function void Fully sequential version, no threading
Protected function void

generate_continuation ( TArrayView< const FVector3d > Seeds
)

 Fully sequential version, no threading
Protected function void

generate_continuation_parallel ( TArrayView< const FVector3d > Seeds
)

 Parallel seed evaluation
Protected function void Processing z-slabs of cells in parallel
Public function FMeshShapeGenerator &

GenerateContinuation ( TArrayView< const FVector3d > Seeds
)

  
Protected function int

GetTriangleSectionIndex ( int64 hash
)

  
Protected function int

GetVertexSectionIndex ( int64 hash
)

  
Protected function void  
Protected function void

initialize_cell ( FGridCell& Cell,
const FVector3i& Idx
)

 Compute 3D corner-positions and field values for cell at index
Protected function void

initialize_cell_values_grid ( FGridCell& Cell,
bool Shift
)

  
Protected function void  
Protected function bool

polygonize_cell ( FGridCell& Cell,
int VertIndexArray
)

 Find edge crossings and generate triangles for this cell
Protected function void Reset internal mesh-assembly data structures
Protected function bool  
Protected function void  
Protected function void

shift_cell_x ( FGridCell& Cell,
int XIdx
)

 Assume we just want to slide cell at XIdx-1 to cell at XIdx, while keeping yi and ZIdx constant.
Public function bool  

Overridden from FMeshShapeGenerator

  Type Name Description
Public function Virtual FMeshShapeGenerator & Run MC algorithm and generate Output mesh

Classes

  Type Name Description
Protected struct FGridCell We pass Cells around, this makes code cleaner  
Protected struct FIndexedVertex    

Constants

Name Description
EdgeIndices Below here are standard marching-cubes tables.
EdgeTable  
TriTable  

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