In the DirectX SDK (June 2010) release, there was this release note:
The new D3DX_DXGIFormatConvert.inl inline header includes light-weight conversion functions for use in Compute Shaders or Pixel Shaders on D3D11 Hardware that can be useful when applications need to simultaneously read and write to textures, such as in-place editing scenarios.
A number of developers found it useful, including Tom Forsyth. Unfortunately, the header more or less disappeared after that. This Microsoft Docs Programming Guide page mentions the header, and there are detailed Reference Guide pages, but they all failed to mention where to find it…
In order to support potential contributions or bug-reports for this header, I set up a little GitHub project to host this header and some related test code. You can obtain it from there as well.
This file can be built in both C++ and HLSL. For C++, the original June 2010 version relied on XNAMath which was part of the legacy DirectX SDK. The 9.29.952.3 and 9.29.952.7 versions of the NuGet package includes this original version.
I’ve recently updated both the header and the NuGet package to make use of DirectXMath instead when building with C++, which is part of the Windows 8.x SDK and Windows 10 SDK. This is included in
Microsoft.DXSDK.D3DX version 9.29.952.8 or later. You can also obtain DirectXMath from GitHub.