Integrating Direct3D with XAML and Windows 8.1 - Direct3D Rendering

Graphics Reference

In-Depth Information

Although the panel allows any number of immediate child controls as would a regular grid,

the Microsoft guidelines indicate that no more than eight immediate child controls should be

used. Another best practice is to avoid placing a control over the entire swap chain panel in

order to prevent overdraws. Each child control of the swap chain panel can then contain any

number of subsequent child controls depending on the element type; for example, the UI in

the top right of each of the previous screenshots is contained within a StackPanel instance

that is an immediate child of our SwapChainPanel implementation.

By retrieving the ISwapChainPanelNative interface from the SwapChainPanel

instance, we have connected our new swap chain to the panel through the

ISwapChainPanelNative.SwapChain property (natively this is done through the

ISwapChainPanelNative.SetSwapChain method). The panel then takes care of

associating the swap chain with the appropriate area on the screen.

The Windows.UI.Xaml.Media.CompositionTarget class is a static class that

represents the display surface on which our application is being drawn. The Rendering

event is fired for each frame, allowing us to integrate our Direct3D rendering with the XAML

scene. For applications that require more control over the frame rate, a separate rendering

loop thread can be implemented, provided there is appropriate synchronization in place to

prevent threading issues when resizing/rescaling during the render loop.

As with the previous recipe, we must set the Output Merger render targets in each frame of

our D3DApp class's Render method.

There's more…

When changing the size of a composition swap chain, it is possible to set the SwapChain2.

SourceSize property provided, the new size is less than or equal to the original swap chain

size. This identifies a portion of the swap chain to be used when presenting its contents to the

display and is more efficient than using the SwapChain.ResizeBuffers function which

forces the swap chain buffers to be physically resized.

There are a couple of other approaches to rendering Direct3D surfaces to XAML controls using

brushes. We can use the Windows.UI.Xaml.Media.Imaging.SurfaceImageSource

and Windows.UI.Xaml.Media.Imaging.VirtualSurfaceImageSource classes and

their corresponding DXGI interfaces, SharpDX.DXGI.ISurfaceImageSourceNative and

SharpDX.DXGI.IVirtualSurfaceImageSourceNative respectively. However, these

are not suitable for real-time rendering—instead they can be useful for effects or rendering

content that requires less frequent updates.