Virtual texture thumbnails appears brighter in content browser after asset is loaded

Development Pipeline & Plugins
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1

Hello, we have been noticing a regression in the content browser texture thumbnails where a virtual texture would appear brighter once its loaded.

I was able to repro the issue in 5.6 and 5.7

2

Steps to Reproduce
1-Import texture file

2-Convert texture to virtual

3-Look at the thumbnail becoming lighter

3

Hi Olivier,

Thank you for the report and repro steps, I was able to repro this behavior in my end. It looks like the thumbnail is being generated with an incorrect sRGB setting. I am looking into it and should get back to you soon.

Best regards,

Vitor

4

Hi Olivier,

After some investigation, I was not able to pinpoint the exact cause of the problem, but it looks related to CLs 30324010 and 30327472 (git b80335a and b887f69). I just filed an internal bug report so that the engine devs can take a look, here’s the tracking number: UE-357270 (the link should become accessible once the devs mark it as public).

Meanwhile, I believe the following change can be used as a quick-and-dirty workaround: on file [Texture2DPreview.cpp], function FBatchedElementTexture2DPreviewParameters::BindShaders(), look for the place where “Parameters.PackedParams” is set (line 143 on vanilla UE 5.6 from the launcher). Add the following just before that:

float UsedGamma = InGamma;
if (!bIsVirtualTexture && Texture->bSRGB && ((FTextureResource*)Texture)->GetVirtualTexture2DResource() != nullptr)
	UsedGamma = 1.0f;

Now, replace “InGamma” with “UsedGamma” on the assignment to “Parameters.PackedParams”.

Please let me know if that works for you!

Best regards,

Vitor

5

Awesome, thanks for the detailed answer!

6

I confirm, your code fixed the issue.

Thank you

PM