Gets a shared texture handle from an Unreal texture.

SharedTexture.cpp

#include "SharedTexture.h"

FSharedTexture FSharedTexture::FromRenderTarget(const UTextureRenderTarget2D& RenderTarget)
{
	const FTextureRHIRef TextureRHI = RenderTarget.Resource->TextureRHI;

	if (TextureRHI == nullptr)
	{
		return {};
	}

	void* NativeResource = TextureRHI->GetNativeResource();

	// GetNativeResource returns a different type depending on the platform. 
	// For Windows, a DirectX 11 texture should be a safe bet.
	ID3D11Texture2D* D3D11Texture2D = static_cast<ID3D11Texture2D*>(NativeResource);
	const unsigned long Handle = GetHandle(*D3D11Texture2D);

	if (Handle == 0)
	{
		return {};
	}

	FSharedTexture SharedTexture;
	SharedTexture.Handle = Handle;
	SharedTexture.Format = GetFormat(*D3D11Texture2D);
	SharedTexture.Width = RenderTarget.SizeX;
	SharedTexture.Height = RenderTarget.SizeY;
	return SharedTexture;
}

unsigned long FSharedTexture::GetHandle(ID3D11Texture2D& D3D11Texture2D)
{
	IDXGIResource* DXGIResource;

	const HRESULT DXGIResourceResult = D3D11Texture2D.QueryInterface(
		__uuidof(IDXGIResource),
		reinterpret_cast<void**>(&DXGIResource)
	);

	if (FAILED(DXGIResourceResult))
	{
		return 0;
	}

	HANDLE SharedHandle;
	const HRESULT SharedHandleResult = DXGIResource->GetSharedHandle(&SharedHandle);
	DXGIResource->Release();

	if (FAILED(SharedHandleResult))
	{
		return 0;
	}

	return HandleToULong(SharedHandle);
}

int FSharedTexture::GetFormat(ID3D11Texture2D& D3D11Texture2D)
{
	D3D11_TEXTURE2D_DESC TextureDescription;
	D3D11Texture2D.GetDesc(&TextureDescription);
	return static_cast<int>(TextureDescription.Format);
}

SharedTexture.h

#pragma once

#include "Engine/TextureRenderTarget2D.h"

#include "Windows/AllowWindowsPlatformTypes.h"
#include <d3d11.h>
#include "Windows/HideWindowsPlatformTypes.h"

struct FSharedTexture
{
	unsigned long Handle = 0;
	int Format = 0;
	int Width = 0;
	int Height = 0;

	static FSharedTexture FromRenderTarget(const UTextureRenderTarget2D& RenderTarget);

private:
	static unsigned long GetHandle(ID3D11Texture2D& D3D11Texture2D);
	static int GetFormat(ID3D11Texture2D& D3D11Texture2D);
};