IDirect3DSurface9Ex Does not Exist

[c-sorrell]

On this page https://docs.microsoft.com/en-us/dotnet/api/system.windows.interop.d3dimage.setbackbuffer?view=netframework-4.8 which appears to be https://github.com/dotnet/dotnet-api-docs/blob/master/xml/System.Windows.Interop/D3DImage.xml, it states the IDirect3DSurface9Ex must be used for multisampling. However, no documentation about IDirect3DSurface9Ex exists, and the D3DResourceType enum only contains 1 entry which is IDirect3DSurface9. Is this a mistake in the Wiki or the code base, and how would one allow multisampling on a D3DImage then?

[mairaw]

@vatsan-madhavan @SamBent can you look at this question about D3DImage.SetBackBuffer?

[SamBent]

@mairaw The doc says

Multisampling is allowed on IDirect3DSurface9Ex surfaces only

which presumably comes from the code comment "Multisampling is allowed on 9Ex only". I believe the abbreviation in the code comment actually refers to IDirect3DDevice9Ex, so the doc should say

Multisampling is allowed only on surfaces created on an IDirect3DDevice9Ex device

following the style of a remark in https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/performance-considerations-for-direct3d9-and-wpf-interoperability?view=netframework-4.8.

[c-sorrell]

So is basically as simple as using a IDirect3DDevice9Ex instead of IDirect3DDevice9? I was trying to interop a SharpDX.Direct3D11.Texture2D to a D3DImage using the methods described and some other tutorials, but when I turned MultiSampling on using a SampleDescription of (2, DeviceManager.Device.CheckMultisampleQualityLevels(Format.B8G8R8A8_UNorm, 2) - 1) or a different number like 4, swapping to D9 for the D3DImage throws an exception. The core issue could be related to SharpDX, but if there are other clarifications on the D3DImage side that would be useful.