DX11 swap chain only showing first frame. Flips between it and a black image
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When I run my 3d scene, it only renders the first frame and then flips between it and a black screen, causing lots of flicker. I think it's my swap chain that's not set up correctly, but I don't really know. 

Here's my code to set it up. It's pretty much copied from an Microsoft example. 


	DXGI_SWAP_CHAIN_DESC1 sd = {0};
	sd.Width = 0;                           
	sd.Height = 0;
	sd.Format = DXGI_FORMAT_R8G8B8A8_UNORM; 
	sd.Stereo = false; 
	sd.SampleDesc.Count = 1;                
	sd.SampleDesc.Quality = 0;
	sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
	sd.BufferCount = 2;                     
	sd.Scaling = DXGI_SCALING_NONE;
	sd.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
	sd.Flags = 0;

	CoreWindow^ window =  reinterpret_cast<CoreWindow^>(mSystem->GetIWindow());
	hr = pIDXGIFactory->CreateSwapChainForCoreWindow(mD3DDevice,  reinterpret_cast<IUnknown*>(window), &sd, NULL, &mSwapChain);
	EA_ASSERT(SUCCEEDED( hr ));


And the present code:

	DXGI_PRESENT_PARAMETERS  presentParameters = {0};
	HRESULT hr = mSwapChain->Present1(0, 0, &presentParameters);

Seems to me pretty straighforward, so I don't really get why it's not working.

Also, my scene is running all the time. The update function gets run every frame.

Any ideas? Thanks!