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  3. FImportanceTexture

FImportanceTexture

Texture processed for importance sampling Holds marginal PDF of the rows, as well as the PDF of each row

Unreal Engine C++ API Reference > Runtime > Engine > Kismet

References

   
Module Engine
Header /Engine/Source/Runtime/Engine/Classes/Kismet/ImportanceSamplingLibrary.h
Include #include "Kismet/ImportanceSamplingLibrary.h"

Syntax

struct FImportanceTexture

Remarks

Texture processed for importance sampling Holds marginal PDF of the rows, as well as the PDF of each row

Variables

  Type Name Description
Public variable TArray< float > ConditionalCDF Unnormalized cumulative probability of each pixel in a row (Size.Y row CDFs of Size.X+1) First entry of each row is zero, final entry in each row is the CDF normalization factor for that row
Public variable TArray< float > MarginalCDF Unnormalized cumulative density of the image by rows (Size.Y+1) First entry is zero, final entry is the CDF normalization factor
Public variable int NumMips Active number of MIP levels
Public variable FIntPoint Size Active texture dimensions, capped to 1024 x 1024
Public variable TWeakObjectPtr< UTexture2D > Texture Original texture object for Break function.
Public variable TArray< FColor > TextureData Packed copy of MIP level data for filtered sampling (capped to 1024x1024) local copy seems better than allocating and copying the same data temporarily for each sample
Public variable TEnumAsByte< EImportanceWeight::Type > Weighting Original importance weight for Break function.

Constructors

  Type Name Description
Public function   Default constructor, must Initialize before use
Public function  

FImportanceTexture ( UTexture2D* SourceTexture,
TEnumAsByte< EImportanceWeight::Type > WeightingFunc
)

 Constructor with initialization

Functions

  Type Name Description
Public function Const FLinearColor

GetColorBilinear ( FVector2D Position,
int32 Mip
)

 Return color of texel at given MIP level, clamped to available Mip levels
Public function Const FLinearColor

GetColorTrilinear ( FVector2D Position,
float Mip
)

 Return color interpolated between MIP levels
Public function Const void

ImportanceSample ( const FVector2D& Rand,
int Samples,
float Intensity,
FVector2D& SamplePosition,
FLinearColor& SampleColor,
float& SampleIntensity,
float& SampleSize
)

 Distribute sample points proportional to Texture2D luminance.
Public function Const float Importance probability weight for given texel
Public function void

Initialize ( UTexture2D* SourceTexture,
TEnumAsByte< EImportanceWeight::Type > WeightingFunc
)

 Allocate and compute PDF arrays for a texture

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