I think this was pretty much a given already, but it's nice to have confirmation. In a post on the official DirectX Developer Blog, Microsoft's Bryan Langley has revealed that Windows 10 will ship with DirectX 12.
"As a part of the Windows team, we're super excited about the Windows 10 Technical Preview that was just released!" Langley writes. "The final version of Windows 10 will ship with DirectX 12, and we think it's going to be awesome."
Microsoft's current schedule calls for Windows 10 to be released in mid-2015. When it announced DirectX 12 at GDC in March, the company said it expected the first games based on the new API to be out late next year.
We still don't know which, if any, previous Windows releases will support DX12. Microsoft has ruled out Windows XP, but there's no word yet on Windows 7 and 8. AMD keeps saying Microsoft may leave Windows 7 users in the cold, although that suggestion always comes in the context of a sales pitch for Mantle, its own graphics API.
In related news, Langley's post says Microsoft has worked with Epic Games to add a DirectX 12 branch of the Unreal Engine 4 source code to the official UE4 GitHub repository. The branch is based on the latest UE4 release, version 4.4, and it should be accessible to UE4 subscribers who also belong to Microsoft's DirectX Early Access program. (Thanks to TR reader SH SOTN for the link.)