How to get texture pixels using UTextureRenderTarget2D class?

Development Asset Creation
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15

For reading from a render target on the render thread:

UTextureRenderTarget2D* RT;
TArray<FColor>* OutPixels;

// If you're on the game thread (or any non-render thread) you need this to schedule work for the render thread
ENQUEUE_RENDER_COMMAND(ReadRTCmd)(
	[RT, OutPixels](FRHICommandListImmediate& RHICmdList)
{
	// If you're already on the render thread, you just need this
	FTextureRenderTarget2DResource* RTResource =
		static_cast<FTextureRenderTarget2DResource*>(RT->GetRenderTargetResource());
	RHICmdList.ReadSurfaceData(
		RTResource->GetTextureRHI(),
		FIntRect(0, 0, RT->SizeX, RT->SizeY),
		*OutPixels,
		FReadSurfaceDataFlags());
});

// Call this if you need to wait for the read to finish before continuing work on the game thread.
// It's potentially slow though and if you need it, you're probably fine using the UKismetRendererLibrary functions.
FlushRenderingCommands();
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