http://blogs.windows.com/windows/b/appbuilder/archive/2013/10/14/raising-the-bar-with-direct3d.aspx
Oct 14 2013
Developers creating content for the Xbox One are able to use the same programing constructs across Windows and Xbox, and benefit from all the improvements that have been introduced on Windows.
With Xbox One we have also made significant enhancements to the implementation of Direct3D 11, especially in the area of runtime overhead. The result is a very streamlined, “close to metal” level of runtime performance. In conjunction with the third generation PIX performance tool for Xbox One, developers can use Direct3D 11 to unlock the full performance potential of the console.
...........We’re also working with our ISV and IHV partners on future efforts, including bringing the lightweight runtime and tooling capabilities of the Xbox One Direct3D implementation to Windows, and identifying the next generation of advanced 3D graphics technologies.
http://majornelson.com/cast/2013/08/02/mnr-486-marc-whitten-updates-us-on-the-progress-of-xbox-one/
(23:23)
Whitten:
"You know this is the time and this is the thing as we go into GamesCom and people really get their 1st look at new things since E3, but this is the time when developers have final devkits in their hands, their really working closely with us on how things have come together. There are some things that have really have started to come together quite well. "
Neslon:
"Yeah tell me about that"
Whitten:
"Since E3 we've dropped in what we've internally called the Mono Driver."
Nelson:
"What is that?"
Whitten:
"It's our graphics driver that really is 100 percent optimised for the Xbox One hardware. You start with the base [DirectX] driver, and then you take out all parts that don't look like Xbox One and you add in everything that really optimises that experience. Almost all of our content partners have really picked it up now, and
I think it's made a really nice improvement."
Major Nelson:
"And this is how game developers can really, like we say, write to the metal?"
Whitten:
"That's right, exactly"
AMD -“
What Mantle creates for the PC is a development environment that’s *similar* to the consoles, which already offer low-level APIs, close-to-metal programming, easier development and more (vs. the complicated PC environment). By creating a more console-like developer environment, Mantle: improves time to market; reduces development costs; and allows for considerably more efficient rendering, improving performance for gamers. The console connection is made because next-gen uses Radeon, so much of the programming they’re doing for the consoles are already well-suited to a modern Radeon architecture on the desktop; that continuum is what allows Mantle to exist.”
If the api was in such a poor state I think we'd hear more about its "apparent" poor state.
Xbox 360
http://download.microsoft.com/downl...neration_graphics_programming_on_xbox_360.ppt
Direct3D 9+ on Xbox 360
Similar API to PC Direct3D 9.0
Optimized for Xbox 360 hardware
No abstraction layers or drivers—it’s direct to the metal
Exposes all Xbox 360 custom hardware features
New state enums
New APIs for finer-grained control and completely new features
Lazy state
Direct3D batches up state in blocks that are optimized for submission to the GPU
Uses special CPU instructions for very low CPU overhead
Communicates with GPU via a command buffer
Ring buffer in system memory
Conclusion
Direct Command Buffer Playback support
Direct3D customized and optimized for the hardware
New APIs to take advantage of custom features
Direct to the metal, no drivers or HAL
