UKismetMathLibrary::LinearColor_GetLuminance

function Engine Blueprint Since 4.0

#include "Kismet/KismetMathLibrary.h"

Access: public Specifiers: staticUFUNCTIONBlueprintPure

Description

Returns the perceptual luminance of a linear color using standard human-eye channel weights (green contributes most, blue least). Use this when you need a single brightness value that matches how bright the color looks on screen.

Caveats & Gotchas

• Uses the Rec. 709 luminance coefficients (R*0.2126, G*0.7152, B*0.0722) — appropriate for linear (gamma-decoded) colors. Applying it to a gamma-encoded sRGB color will give inaccurate results.
• The alpha channel is ignored in the luminance calculation.

Signature

static UE_INL_API float LinearColor_GetLuminance(FLinearColor InColor);

Parameters

Name	Type	Description	Default
InColor	FLinearColor	Color to compute luminance for.	—

Return Type

float

Example

Branch on perceived brightness C++

FLinearColor SurfaceColor = /* sample from material */;
float Lum = UKismetMathLibrary::LinearColor_GetLuminance(SurfaceColor);
bool bIsBright = Lum > 0.5f;

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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