UImportanceSamplingLibrary::MakeImportanceTexture

function Engine Blueprint Since 5.0

#include "Kismet/ImportanceSamplingLibrary.h"

Access: public Specifiers: staticUFUNCTIONBlueprintPure

Description

Builds an FImportanceTexture from a 2D texture, precomputing cumulative distribution functions per row and per pixel so ImportanceSample can later draw points proportional to the chosen weighting channel.

Caveats & Gotchas

• Only accepts RGBA8-format textures — other pixel formats will not produce valid importance data.
• Precomputation reads back and processes the full texture (capped internally to 1024x1024), so this is not something to call every frame; build the FImportanceTexture once and reuse it for repeated ImportanceSample calls.
• Requires the texture's CPU-accessible mip data to be available; textures that have had their CPU copy stripped (common in cooked builds without mip streaming settings adjusted) will fail to build correctly.

Signature

static FImportanceTexture MakeImportanceTexture(UTexture2D *Texture, TEnumAsByte<EImportanceWeight::Type> WeightingFunc)

Parameters

Name	Type	Description	Default
Texture	UTexture2D*	Source texture to build the importance data from. Must be RGBA8 format.	—
WeightingFunc	TEnumAsByte<EImportanceWeight::Type>	How to convert texture data into probability weights (Luminance, Red, Green, Blue, or Alpha).	—

Return Type

FImportanceTexture

Example

Build an importance texture from a light cookie C++

FImportanceTexture ImportanceTex = UImportanceSamplingLibrary::MakeImportanceTexture(MyTexture, EImportanceWeight::Luminance);
// Reuse ImportanceTex across many ImportanceSample calls

Version History

Introduced in: 5.0

Version	Status	Notes
5.6	stable	—

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