Microsoft Comments on State of Direct3D, Mantle Support, & Names XB1 API “Direct3D 11.x”
by Ryan Smith on October 15, 2013 9:00 AM EST
In a somewhat unusual technical/promotional blog entry called “Raising the Bar with Direct3D”, Microsoft has released some additional details on the version of Direct3D for Xbox One, along with providing a general summary of the state of Direct3D 11.2.
First and foremost, for the Xbox One we finally have an official name for the consoles version of Direct3D along with some confirmation of some general details about the API. The Xbox One’s version of the API is being called Direct3D 11.x – X as in Xbox, not an algebraic X – and as expected it’s a superset of Direct3D 11.2. Microsoft doesn’t go into further detail on what else that superset contains, but traditionally we’d expect to see further API calls that are specifically designed to take advantage of the underlying APU, including of course the low-level programming constructs to do close to metal programming and fully exploit quirks such as the console’s 32MB of eSRAM.
Furthermore it’s interesting to note that Microsoft also took the time to specifically mention API overhead in a high-level context, and that they’ve been doing a lot of work to chip away at said overhead for the Xbox One. This is fairly similar to how Microsoft is said to have approached Direct3D for the 360, being able to exploit the fixed platform to remove some of the overhead from abstraction while maintaining the functionality of the high level API functions.
Moving on to Direct3D 11.2 in general, the next section of the blog is primarily a summarization of the Direct3D 11.2 feature set, with Microsoft primarily reiterating support for tiled resources (the headline feature for 11.2) along with briefly mentioning other features such as pre-compiled headers and CPU/GPU memory sharing improvements. Unlike Direct3D 11.1 and Windows 8, 11.2 is coming with a Windows point update, so it’s a similarly smaller addition to Direct3D.
However it’s the final section of Microsoft’s blog that may be the most interesting, although it’s also the least detailed. In discussing the future of Direct3D, Microsoft specifically mentions their general commitments to improving Direct3D alongside “bringing the lightweight runtime and tooling capabilities of the Xbox One Direct3D implementation to Windows,” though providing no details on how they intend to accomplish the latter. Assuming Microsoft intends to keep up a yearly(ish) development cadence for Windows, this may be something we see as soon as next year. There’s certainly quite a bit of interest in cutting down on the CPU overhead in graphics APIs, due in part to declining improvements in single-threaded CPU performance gains, so this is something that’s going to be worth keeping an eye on.
Finally, in an unexpected move, Microsoft also used the blog to quickly address the subject of AMD’s Mantle API, specifically saying that the Xbox One doesn’t support it nor OpenGL. The fact that Mantle isn’t supported comes as no surprise – Xbox One already has its own low level constructs versus the still in development Mantle – but we weren’t expecting Microsoft to comment on the matter since they aren’t involved in the development of Mantle. Though this unfortunately doesn’t shed any further light on the big question of just what Mantle adopts from the low-level programming constructs in Direct3D 11.x.
Source: Microsoft Windows Blog
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Wolfpup - Wednesday, October 16, 2013 - link
Yeah, if Mantle isn't (more or less) running on one or both consoles, it's dead. More important to focus on getting Direct3D/DirectX and OpenGL as good as possible.StealthGhost - Tuesday, October 15, 2013 - link
"Let’s be very clear here: AMD will not discuss the matter let alone confirm it, so this is speculation on our part. But it’s speculation that we believe is well grounded. Based on what we know thus far, we believe Mantle is the Xbox One’s low level API brought to the PC."But now...
"The fact that Mantle isn’t supported comes as no surprise"
Well it is to me! I read your stuff!
Ryan Smith - Tuesday, October 15, 2013 - link
Which is why that's a one-way arrow in our API diagram. It's our belief that Mantle is the Xbox One's low level API brought to the PC; but it's not a low level PC API brought to the Xbox One. The symmetric property wouldn't apply here.MADDER1 - Tuesday, October 15, 2013 - link
Ironically that seems like a DirectX is waste if they can get 9x Draw calls with Mantle. That means Direct 11.x is that much better?nathanddrews - Tuesday, October 15, 2013 - link
"Mantle is the Xbox One’s low level API brought to the PC"Overall, I've been confused by AT's obsession with the Xbone API, considering the Xbone and PS4 are near identical on paper. Anyway, try re-reading that above statement a couple times. The key words are "brought to the PC". I don't believe this was ever literally, specifically the Xbone API, but AMD's PC equivalent. At least, I never interpreted it that way. If that's what AT meant, then it's definitely wrong, but figuratively it is spot on.
Mantle isn't an API for Xbone, but is a means for games to achieve low-level calls using GCN GPUs on Windows/Mac/Linux. AMD plans to use Mantle the same way Microsoft uses their own low-level calls. Compatible? Likely not. Effectively similar? Yes.
I'm looking forward to more information. So far I can't say I'm a fan of the way AMD has handled this launch. I've nearly lost interest in Hawaii. At this point it would have to dominate Titan and be priced significantly lower in order to live up to AMD's hype.
Hrel - Tuesday, October 15, 2013 - link
I love calling it "xbone".tuxRoller - Tuesday, October 15, 2013 - link
The reason why I don't understand the insistence that the Mantle api is so similar to low level dx is that the point was made, several times, that Mantle is intended to be x-platform. With that in mind, is dx's low level constructs the best possible to represent GCN? If AT thinks so I'd love to know why.HisDivineOrder - Tuesday, October 15, 2013 - link
Agreed. I don't get this, either. I mean, it was very specific. It was all about Xbone specifically, not PS4. Nothing about OpenGL. It was specifically Xbone, specifically the Xbone API, and I'm not sure where they were getting that from EXCEPT FROM AMD on the side.AMD Center perchance?
BMNify - Tuesday, October 15, 2013 - link
Mantle is Dead Before Arrival, All your assumptions were crushed with that Direct3D 11.x blogpost, Just accept your assumptions were wrong or don't accept it but please don't further push that theory on a reputed site like Anandtech.kyuu - Tuesday, October 15, 2013 - link
The blogpost does not disprove the theory that AMD's Mantle is largely identical to the Xbone's API. Don't further push your foolishness on a reputed site like Anandtech.