Copy render frame (DirectX12) to opencv

Development Programming & Scripting C++
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1

Hello,
I would like to copy the render frame to en openCV GpuMat.
GpuMat use cuda so I’ve decided first to copy the render frame to cuda.

  • I retrieve the render frame using OnBackBufferReadyToPresent delegate
  • In the delegate I get the native resource of the texture:

struct DX12Texture
{
	void* handle;
	ID3D12Resource* resource;
	unsigned long long memSize;
};

void MyActor::OnGetRendering(SWindow& Window, const FTexture2DRHIRef& Texture) const
{
static HANDLE SharedHandle = nullptr;
	if (GDynamicRHI)
	{
		ID3D12Resource* NativeResource
			= reinterpret_cast<ID3D12Resource*>(Texture->GetNativeResource());
		
		if (NativeResource)
		{
			ID3D12Device* Device
				= reinterpret_cast<ID3D12Device*>(GDynamicRHI->RHIGetNativeDevice());

			//Device->GetAdapterLuid();
			if (SharedHandle == nullptr)
			{
				WindowsSecurityAttributes windowsSecurityAttributes;
				LPCWSTR name = nullptr;

				HRESULT Result = Device->CreateSharedHandle(
					NativeResource,
					&windowsSecurityAttributes,
					GENERIC_ALL,
					name,
					&SharedHandle);
			}

			D3D12_RESOURCE_DESC Desc = NativeResource->GetDesc();
			D3D12_RESOURCE_ALLOCATION_INFO allocInfo = Device->GetResourceAllocationInfo(0, 1, &Desc);
			DX12Texture Texture{ SharedHandle, NativeResource, allocInfo.SizeInBytes };

                         // copy to cuda
			CaptureDX12(Texture);
			DebugUI->bTakeScreenshot = false;
		}
	
}

CaptureDX12( DX12Texture& d3d12Texture)
{
         cv::cuda::GpuMat mat;
	getExternalMemory(d3d12Texture);
	mapMemory(mat, d3d12Texture);
}

void OptroD3D12Interop::mapMemory(cv::cuda::GpuMat& mat, DX12Texture& d3d12Texture)
{
	void* pData = nullptr;
	cudaExternalMemoryBufferDesc buffDesc{};
	memset(&buffDesc, 0, sizeof(buffDesc));

	buffDesc.offset = 0;
	buffDesc.size = d3d12Texture.memSize;

	cudaExternalMemoryGetMappedBuffer(&pData, m_externalMemory, &buffDesc);

	mat = cv::cuda::GpuMat(static_cast<int>(d3d12Texture.resource->GetDesc().Height),
		static_cast<int>(d3d12Texture.resource->GetDesc().Width), 
		cv::directx::getTypeFromDXGI_FORMAT(d3d12Texture.resource->GetDesc().Format), pData);
}
void getExternalMemory(DX12Texture& d3d12Texture)
{
	cudaExternalMemoryHandleDesc memDesc{};
	memset(&memDesc, 0, sizeof(memDesc));

	memDesc.type = cudaExternalMemoryHandleTypeD3D12Resource;
	memDesc.handle.win32.handle = d3d12Texture.handle;
	memDesc.size = d3d12Texture.memSize;
	memDesc.flags = cudaExternalMemoryDedicated;

	cudaImportExternalMemory(&m_externalMemory, &memDesc);
	
}

My problem is cudaImportExternalMemory wich block the application.
I know it’s a cuda mistake but am I in the good way for my purpose ?
Thanks,
Sorry for my terrible english.