Does anyone know how to use UTexture2D::UpdateTextureRegions()?

Development Programming & Scripting C++
1

The function can be found here:

UTexture2D::UpdateTextureRegions | Unreal Engine Documentation

And it’s really annoying because the Wiki is just…wrong.

If you look you can see the function takes a template function as it’s final argument but when you scroll down you’ll see it lists the old final argument as a boolean.

This post shows how to use the function:

UpdateTextureRegions Pitch - Rendering - Epic Developer Community Forums

But the problem I’m having is I can’t figure out how to implement the DataCleanUpFunc in a class and I can’t seem to find any examples.

So maybe this is a more of a generic C++ question but how do I declare a Template function as a member function?

The wiki is beyond frustrating. I really wish they’d add an example on how to use things.

Any help will be greatly appreciated!

2

Looks like the interface of UpdateTextureRegions changed, but those note haven’t updated yet.

DataCleanupFunc have its own default implement, which means do nothing:


TFunction<void(uint8* SrcData, const FUpdateTextureRegion2D* Regions)> DataCleanupFunc = ](uint8*, const FUpdateTextureRegion2D*){}

DataCleanupFunc like below would be similar to bFreeData is true, any variables in DataCleanupFunc has to be thread safe:


TFunction<void(uint8*, const FUpdateTextureRegion2D*)> DataCleanupFunc = [this](uint8* InTextureData, const FUpdateTextureRegion2D* InRegions)
            {
                delete InTextureData; 
                delete InRegions; 
            };
3

I’ve spent the last 45 minutes trying to figure out how it works. Finally…

.H



static TFunction<void(uint8* SrcData, const FUpdateTextureRegion2D* Regions)> CleanMemory(uint8* srcData, const FUpdateTextureRegion2D* regions);

.CPP



TFunction<void(uint8* SrcData, const FUpdateTextureRegion2D* Regions)> UMyClass::CleanMemory(uint8* srcData, const FUpdateTextureRegion2D* regions)
{
  delete srcData;
  delete regions;
  return 0;
}

Usage



destTexture->UpdateTextureRegions(0, 1, updateTextureRegion, BufferPitch, BytesPerPixel, newTextureBuffer, &CleanMemory);
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