Getting Started with Direct3D - Direct3D Rendering - page 30

Within the Direct3D Initialization region and after the window is created, we have
changed the declaration of the device and swapChain variables to be of type Device1
and SwapChain1 . We then create Device with the same parameters as before except
using a constructor rather than the previous Device.CreateWithSwapChain method.
This is done within a using statement so that the reference to the first device is automatically
disposed. Within the using block we query the device for a reference to the Device1 class.
If the implementation of Device1 was unavailable in the Direct3D API, the return value from
device11.QueryInterfaceOrNull<Device1> would be null while using the regular
QueryInterface<T> method would result in a SharpDX.SharpDXException being thrown.
All SharpDX classes that wrap a native COM object support a
number of variations of the QueryInterface method to query
the underlying IUnknown interface.
To create the swap chain, we need to first get a reference to a SharpDX.DXGI.Factory2
instance. Rather than creating a new factory, we will use the one that was initialized internally
to create our device. All device instances also implement the interface for SharpDX.DXGI.
Device , which gives us access to the Adapter property. As this is provided by the DXGI API
we can work our way back from the device to a SharpDX.DXGI.Factory2 instance via the
GetParent method.
The equivalent unmanaged example of this section would look something like:
// pd3dDevice creation omitted
IDXGIDevice2* pDXGIDevice;
hr = pd3dDevice->QueryInterface(__uuidof(IDXGIDevice2),
&pDXGIDevice);
IDXGIAdapter* pDXGIAdapter;
hr = pDXGIDevice->GetParent(__uuidof(IDXGIAdapter),
&pDXGIAdapter);
IDXGIFactory2* pDXGIFactory;
pDXGIAdapter->GetParent(__uuidof(IDXGIFactory2), &pDXGIFactory);
Describing the swap chain for Direct3D 11.1 is slightly different as it separates the
description into two structures. The first structure, SwapChainDescription1 , describes
the buffer size, format, size, usage, and so on like the original but introduces a Stereo
and Scaling option and excludes the fullscreen properties. The second structure,
SwapChainFullScreenDescription , describes the fullscreen behavior of the swap
chain also with a Scaling option.