Overlay DirectX Content on XAML control

Question

I want to overlay DirectX Content (WinRT Component) over a XAML control in Win 8 metro style app so that XAMl  control and its contents will be visible beneath the DirectX content.

Approach I) I explored the 3 ways of using Xaml and Direct3D interop.

(1)  SurfaceImageSource, (2) VirtualSurfaceImageSource (3) SwapChainBackgroundPanel.

*but in all three of these cases mentioned above, Xaml either comes above the DirectX content(SwapChainBackgroundPanel) or can share part of the screen with directX content (SurfaceImageSource).*

Approach II) If i use blending it only handles the color blending  and transparency of the objects being rendered on the renderTarget. For example we can render a semi transparent cube on a opaque background.  If i clear the renderTarget with a color where the alpha channel is set to 0.0f. Setting the alpha channel to 0.0f doesn't change the transparency with the code given below.

const float clearColor[4] = { 0.0f, 0.0f, 0.0f, 0.0f };  
m_d3dContext->ClearRenderTargetView(m_renderTargetView.Get(), clearColor);

I know it is possible to overlay xaml over DirectX but is it possible to do it the other way (overlaying DirectX on Xaml)?

Answer 1

Hi mukhe,

Welcome to MSDN forum!

Please refer this article which maybe is helpful.

http://blogs.msdn.com/b/windowsappdev/archive/2012/03/15/combining-xaml-and-directx.aspx

Regards!

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Answer 2

Thanks for reply.

I found the solution. It is a 2 step process

Step 1:

While creating an object of SurfaceImageSource class, it takes 3 arguments, the 3rd argument is for

opacity on setting it to false will allow support for transparency.

public SurfaceImageSource(int pixelWidth, int pixelHeight, bool isOpaque);

Step 2: 

After this if we clear the 3D rendertarget with transparent color as given below, it will work.

const float clearColor[4] = { 0.0f, 0.0f, 0.0f, 0.0f };  
m_d3dContext->ClearRenderTargetView(m_renderTargetView.Get(), clearColor);

Regards,

mukhe