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NaniteUtilities

API > API/Developer

   
Name NaniteUtilities
Type Developer
Location /Engine/Source/Developer/NaniteUtilities/
Module Build Rules NaniteUtilities.Build.cs

Classes

Name Remarks
DisplacementPolicyFunctor Same as above but use function references as original nanite code
FAdaptiveTessellator  
FDisplacementMap  
FEdgeHash Find edge with opposite direction that shares these 2 verts.
FMinimalMesh Mesh topology implementation for UE::Geometry::FAdaptiveTesselation.
FSettingsLayout  

Structs

Name Remarks
FAdjacency  
FLerpVert Lerpable version of FStaticMeshBuildVertex.
FRange  
FTriangle Fixed point rasterization.
FTriangle3f Floating point rasterization.
TAffine [ Thonat et al. 2021, "Tessellation-Free Displacement Mapping for Ray Tracing" ] [ de Figueiredo and Stolf 2004, "Affine Arithmetic: Concepts and Applications" ] [ Rump and Kashiwagi 2015, "Implementation and improvements of affine arithmetic" ]
TSGGX Linearly filtering SGGX, which is the same as using the covariance matrix, directly is a decent fit.

Typedefs

Name Type Remarks Include Path
FBoundsFunc TFunctionRef< FVector2f( const FVector3f[3], const FLerpVert &, const FLerpVert &, const FLerpVert &, const FVector3f &, const FVector3f &, const FVector3f &, int32) >   AdaptiveTessellator.h
FDispFunc TFunctionRef< FVector3f( const FVector3f &, const FLerpVert &, const FLerpVert &, const FLerpVert &, int32) >   AdaptiveTessellator.h
FNumFunc TFunctionRef< int32( const FVector3f[3], const FLerpVert &, const FLerpVert &, const FLerpVert &, int32) >   AdaptiveTessellator.h

Variables

Public

Name Type Remarks Include Path Unreal Specifiers
SubpixelBits int32   Rasterizer.h  
SubpixelSamples int32   Rasterizer.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

float BrentRootFind ( float y,
float Tolerance,
float xA,
float yA,
float xB,
float yB,
float xGuess,
bool bInitialGuess,
int32 MaxIter,
FuncType&& Func
)

 Brent's method. Optimize.h  

TAffine< T, Num > Clamp ( const TAffine< T, Num >& x,
T Min,
T Max
)

   Affine.h  

float DownhillSimplex ( FVector2f& x,
float xDelta,
float Tolerance,
int32 MaxIter,
FuncType&& Func
)

 Nelder-Mead optimization TODO This is only 2D, make any dimensions. Optimize.h  

uint32 EvolveSobolSeed ( uint32& Seed
)

 All Sobol code adapted from PathTracingRandomSequence.ush. MonteCarlo.h  

uint32 FastOwenScrambling ( uint32 Index,
uint32 Seed
)

   MonteCarlo.h  

FVector2f GaussianSampleDisk ( FVector2f E,
float Sigma,
float Window
)

 Exp( -0.5 * x^2 / Sigma^2 ) MonteCarlo.h  

float InverseLerp ( float y,
float x0,
float y0,
float x1,
float y1
)

   Optimize.h  

float InverseLerp ( float y,
float x0,
float y0,
float x1,
float y1,
float x2,
float y2
)

   Optimize.h  

TAffine< T, Num > InvSqrt ( const TAffine< T, Num >& x
)

   Affine.h  

void JacobiSVD::EigenSolver3 ( T*__restrict A,
T*__restrict S,
T*__restrict V,
const T tol
)

 Diagonalize matrix A = V S V^T MatrixUtil.h  

void JacobiSVD::EigenSolver4 ( T*__restrict A,
T*__restrict S,
T*__restrict V,
const T tol
)

 Diagonalize matrix A = V S V^T MatrixUtil.h  

T JacobiSVD::MaxOffDiagSymm ( T*__restrict A,
uint32 Size
)

   MatrixUtil.h  

bool JacobiSVD::Rotation3 ( T*__restrict A,
T*__restrict V,
T*__restrict Z,
const T tol,
int j,
int k,
int L
)

   MatrixUtil.h  

bool JacobiSVD::Rotation4 ( T*__restrict A,
T*__restrict V,
T*__restrict Z,
const T tol,
int j,
int k,
int L1,
int L2
)

   MatrixUtil.h  

void JacobiSVD::Update ( T*__restrict A,
T s,
T tau,
uint32 d1,
uint32 d2
)

 Copyright (c) 2002-2012, Industrial Light & Magic, a division of Lucas Digital Ltd. MatrixUtil.h  

FVector4f LatticeSampler ( uint32 SampleIndex,
uint32& Seed
)

   MonteCarlo.h  

bool LUPFactorize ( T*__restrict A,
uint32*__restrict Pivot,
uint32 Size,
T Epsilon
)

 LUP factorization using Doolittle's method with partial pivoting. MatrixUtil.h  

void LUPSolve ( const T*__restrict LU,
const uint32*__restrict Pivot,
uint32 Size,
const T*__restrict b,
T*__restrict x
)

 Solve system of equations A*x = b. MatrixUtil.h  

bool LUPSolveIterate ( const T*__restrict A,
const T*__restrict LU,
const uint32*__restrict Pivot,
uint32 Size,
const T*__restrict b,
T*__restrict x
)

 Newton's method iterative refinement. MatrixUtil.h  

float Nanite::Barycentric::Cotangent ( const FVector3f& Barycentrics0,
const FVector3f& Barycentrics1,
const FVector3f& Barycentrics2,
const FVector3f& EdgeLengthsSqr,
float TriangleArea
)

 Angle at corner 0. TriangleUtil.h  

float Nanite::Barycentric::DistanceToEdge ( float Barycentric,
float EdgeLength,
float TriangleArea
)

 https://math.stackexchange.com/questions/3748903/closest-point-to-triangle-edge-with-barycentric-coordinates TriangleUtil.h  

float Nanite::Barycentric::LengthSquared ( const FVector3f& Barycentrics0,
const FVector3f& Barycentrics1,
const FVector3f& EdgeLengthsSqr
)

 [ Schindler and Chen 2012, "Barycentric Coordinates in Olympiad Geometry" https://web.evanchen.cc/handouts/bary/bary-full.pdf ] TriangleUtil.h  

float Nanite::Barycentric::SubtriangleArea ( const FVector3f& Barycentrics0,
const FVector3f& Barycentrics1,
const FVector3f& Barycentrics2,
float TriangleArea
)

   TriangleUtil.h  

TAffine< T, Num > Normalize ( const TAffine< T, Num >& x
)

   Affine.h  

TAffine< T, Num > operator* ( const TAffine< T, Num >& A,
const TAffine< U, Num >& B
)

   Affine.h  

TSGGX< T > operator* ( T Scalar,
const TSGGX< T >& SGGX
)

   SGGX.h  

TAffine< float, Num > operator| ( const TAffine< T, Num >& A,
const TAffine< T, Num >& B
)

   Affine.h  

void PseudoInverse ( T*__restrict S,
uint32 Size,
T Tolerance
)

 Moore-Penrose pseudo inverse. MatrixUtil.h  

void PseudoSolve ( const T*__restrict V,
const T*__restrict S,
uint32 Size,
const T*__restrict b,
T*__restrict x
)

   MatrixUtil.h  

bool PseudoSolveIterate ( const T*__restrict A,
const T*__restrict V,
const T*__restrict S,
uint32 Size,
const T*__restrict b,
T*__restrict x
)

 Newton's method iterative refinement. MatrixUtil.h  

int32 Rasterizer::EdgeC ( const FIntVector2& Edge,
const FIntVector2& Vert,
int32 SubpixelDilate
)

   Rasterizer.h  

bool Rasterizer::IsCovered ( const FVector2f& Edge,
const FVector2f& Vert,
const FVector2f& Center,
const FVector2f& Extent
)

   Rasterizer.h  

void RasterizeTri ( const FVector3f Verts,
const FIntRect& ScissorRect,
uint32 SubpixelDilate,
bool bBackFaceCull,
FWritePixel&& WritePixel
)

   Rasterizer.h  

FVector2f SobolSampler ( uint32 SampleIndex,
uint32& Seed
)

   MonteCarlo.h  

float SurfaceAreaEllipsoid ( float a,
float b,
float c
)

 Approx surface area of ellipsoid. SGGX.h  

T UE::Math::Scalar::Abs ( const T A
)

   VectorUtil.h  

int32 UE::Math::Scalar::CeilToInt ( const T A
)

   VectorUtil.h  

int32 UE::Math::Scalar::FloorToInt ( const T A
)

   VectorUtil.h  

T UE::Math::Scalar::Max ( const T A,
const T B
)

   VectorUtil.h  

T UE::Math::Scalar::Max3 ( const T A,
const T B,
const T C
)

   VectorUtil.h  

T UE::Math::Scalar::Min ( const T A,
const T B
)

   VectorUtil.h  

T UE::Math::Scalar::Min3 ( const T A,
const T B,
const T C
)

   VectorUtil.h  

int32 UE::Math::Scalar::RoundToInt ( const T A
)

   VectorUtil.h  

FVector2f UniformSampleDisk ( FVector2f E
)

   MonteCarlo.h  

FVector3f UniformSampleSphere ( FVector2f E
)

   MonteCarlo.h  

void VoxelizeTri26 ( const Rasterizer::FTriangle3f& Tri,
FWriteVoxel&& WriteVoxel
)

 26-separating voxelization, conservative Rasterizer.h  

void VoxelizeTri6 ( const Rasterizer::FTriangle3f& Tri,
FWriteVoxel&& WriteVoxel
)

 6-separating voxelization Rasterizer.h  

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