Microsoft Announces DirectX 12: Low Level Graphics Programming Comes To DirectX
by Ryan Smith on March 24, 2014 8:00 AM ESTThe Changing State of Game Development
The entry of Microsoft and Direct3D into this world stands to significantly change the status quo, due to the fact that Direct3D is by far the most widely used PC graphics API. As the maintainer of Direct3D Microsoft gets to set the pace in the PC graphics industry in several ways, so while Direct3D 12 won’t be the first modern low level graphics API, there’s little question after this announcement that it’s going to have the widest impact on game developers.
Perhaps the biggest reason for this is because of the fact that like every version of Direct3D before it, Direct3D 12 is going to be a cross-vendor standard that works on multiple GPUs. Though I don’t think it’s wise to treat Mantle and Direct3D as competitors at this point, the fact that this is a cross-vendor standard and not an AMD standard means that using it targets every video card and not just AMD video cards. So for all of the impact Mantle has had over the past 6 months, and will continue to have over the coming years, the fact that we’re to a point where there’s a cross-vendor standard will be a significant milestone.
That said, whenever we talk about low level programming it’s good to also recall who this model is and isn’t for. The purpose of abstraction is not only to provide wider hardware compatibility, but to outright hide certain types of execution ugliness from programmers. The reduction in abstraction will bring with it a reduction in the amount of this ugliness that gets hidden, and as a result the amount of knowledge needed to efficiently program at a low level goes up. Low level programing should not require a code wizard, but it’s unquestionably harder than straightforward (no optimization tricks) Direct3D 11.
Which is why the launch of Direct3D 12 is poised to increase the number of options available to graphics programmers, but not replace the high level programming model entirely. The development teams best suited for taking advantage of Direct3D 12 will be the well-funded AAA game studios, particularly those doing multi-platform titles across PCs and consoles. If you’re already doing low level programming for Xbox One and Playstation 4 – and more importantly have the staff and institutional knowledge for such an endeavor – then Direct3D 12 is but a small step, mostly one of learning the syntax of the new API. But for smaller game developers that aren’t able to put together large, experienced game development teams, then a need for a high level programming API will remain. Microsoft has not talked about high level programming within the context of Direct3D 12 thus far, but one way or another – be it Direct3D 11 or a high level friendly Direct3D 12 – high level programming will be here to stay.
Though when it comes to development, the role of middleware cannot be ignored. AMD and NVIDIA already target middleware developers for integration of their proprietary technologies, and the same concept applies on a larger scale when we’re talking about making low level programming accessible to more developers. Furthermore with the massive change in middleware licensing terms we’re seeing with this generation – Unreal Engine 4 for example is just 5% of gross revenues for smaller developers that can’t negotiate otherwise – powerful middleware is increasingly accessible to all categories of developers. So even if smaller developers can’t internally develop their own Direct3D 12 code, they will have the ability to target it by inheriting the capabilities through the middleware they use.
Consoles & Mobile Devices Too
The introduction of Direct3D 12 stands to not only change the nature of graphics development for Windows, but on other Microsoft platforms too. With Microsoft’s consumer arm having their hand in everything from phones to consoles, Microsoft is seeking to extend Direct3D 12 and its benefits to these platforms too.
Specifically, Microsoft is already committing to bringing Direct3D 12 to the Xbox One, their current-generation console. Powered by an AMD SoC whose GPU in turn is based on GCN 1.1, the Xbox One is functionally an x86 PC with a modern AMD GPU, so the fact that this is even technically possible is not a surprise. But what does come as a surprise is that the Direct3D12 API is different enough that this is even necessary.
The Xbox One, as you may recall, uses Microsoft’s Direct3D 11.X API. This details of this API are scarce as they’re only open to registered Xbox One developers, but fundamentally it’s said to be a variant of Direct3D 11 with a number of Xbox One additions, including low level API features that would be suitable for programming a console. Having the Xbox One be in alignment with Direct3D 12 is going to be a good thing regardless – it will make porting between the platforms easier – but the fact that Direct3D 12 will bring any kind of meaningful improvement to the Xbox One is unexpected. Without more details on the Xbox One API it’s impossible to say with any certainty what exact functionality isn’t currently available in Direct3D 11.X or what kind of performance benefit this would bring the Xbox One, but it stands to reason that unless most Xbox One programmers have been doing high level programming, the gains won’t be as great as for the PC.
Moving on, we have the fact that Microsoft will also be bringing Direct3D 12 to handheld devices. We’re presumably talking about Windows RT tablets and Windows Phone phones, extending Direct3D 12 to the bottom as well as it goes to the top on the PC. Handheld devices stand to gain just as much from this as PCs and consoles do, due to the fact that handheld devices are even more CPU-bottlenecked than PC laptops and desktops, so a low level API is as much a natural development for these platforms as it is the PC.
The question on our end is what kind of impact this will have on the Direct3D 12 standard with respect to abstraction. SoC-class GPUs are typically years behind PC GPUs in functionality (never mind performance), and at least among current GPUs wildly differ from each other in ways the PC GPU market hasn’t seen in years. So while extending Direct3D 12 to cover multiple PC GPUs should be relatively easy, having to support SoC GPUs certainly muddles the picture. This may mean Microsoft is looking at the long view here, when SoCs such as the Tegra K1 come along with feature sets that match recent PC architectures, coupled with the fact that Windows RT/Phone has not traditionally supported a large number of SoC GPU architectures. In which case only having to cover a handful of SoC GPU architectures instead of all 7 would certainly be an easier task.
Facebook
Twitter
RSS
105 Comments
View All Comments
ninjaquick - Tuesday, March 25, 2014 - link
It is not BS at all. Developers have been asking, even crying out, for low level access to GPU hardware on PC for ages. The Xbox One was the last straw though, currently it is no more programmable than a PC. This caused Crytek a massive headache as they budgeted rendering based on 'to the metal' efficiency, and were instead met with massive draw overheads forcing them to severely reduce the quality of their work in 'Ryse'. Other developers have complained on the very same thing.. The Xbox 360 is more programmable. The benefit D3D12 has this time around is that the X1 is based on a hybrid WindowsRT/8x64, meaning d3d12 can be pushed to all win8 gen devices.rootheday3 - Monday, March 24, 2014 - link
I am pretty sure that at least one of the demos (3D MARK?) was actually run on Haswell iGpu - meaning Intel is well along on driver development. Some if the announced features (support for order independent transparency) also sound like Intrl extensions on dx11 (pixel sync)rootheday3 - Monday, March 24, 2014 - link
Also- reducing driver cost and single threaded perf should also help ensure that mobile gaming on laptops and tablets is less likely to be cpu bound due to frequency constraints. Should also allow more of the thermal budget to go to gpu for better rendering/ less throttling.Zak - Tuesday, March 25, 2014 - link
"Powered by a GeForce GTX Titan Black, Microsoft tells us the demo is capable of sustaining 60fps."Titan Black? No kidding. At what resolution?
Scali - Tuesday, March 25, 2014 - link
"To use consoles as an example once again, this is why they are capable of so much with such a (relatively) weak CPU, as they’re better able to utilize their multiple CPU cores than a high level programmed PC can."This is patently false.
Namely, the PS3 with its Cell has only a single regular CPU core. The SPEs are very limited and not suitable for batching up draw calls.
The XBox 360 is a more 'regular' CPU, but it has 'only' 3 cores, and the rendering is mostly done on a single core. (PS4 and XBox One are too new to draw any conclusions yet, so 'console efficiency' is what we know of consoles that are not all about multithreading).
You are confusing low-level with multithreading. Low-level is about programming the GPU with a very direct path, little abstraction. That is why it is efficient on consoles. There is a much thinner layer between OS, GPU, driver, API and application than on a regular PC.
Multithreading is another way of speeding up graphics, but this does not necessarily require programming the GPU directly. Which is also not what DX12 is going to do. It will still abstract the hardware to a point where vendor and implementation are not relevant. But it will allow better control of batching up calls on threads other than the master rendering thread (D3D11 already has support for multithreading, but it has some limitations).
It seems that AMD has done a great job on confusing the general public, with its Mantle propaganda.
Death666Angel - Tuesday, March 25, 2014 - link
All these articles make me think of John Carmack's QuakeCon 2013 (I think) keynote where he talked about having the same access to the GPU as he does to the CPU and basically programming in machine code. Hope this is coming. :) I need the performance for 120fps/4k Oculus Rift games! :DScali - Tuesday, March 25, 2014 - link
The ironly is that the original D3D had low-level access to the GPU, with its execute buffer system. This would easily allow multiple threads to batch up commands for the GPU in parallel efficiently.But Carmack complained that the API was too hard to use.
It looks like we're going back in time somewhat, getting closer to the original D3D.
Ramon Zarat - Tuesday, March 25, 2014 - link
The only thing I really want to know is this:Does the current gen GPU hardware, mainly Kepler/Maxwell and Tahiti/Hawaii, *technically* ABLE to support DX12? With strong emphasis on ABLE, as even if they are able, I seriously doubt AMD or Nvidia will be "charitable" enough to actually do it and instead, force us all to upgrade again, thanks to the wonder of artificial market segmentation.
Will we see modded driver enabling (at least partially) DX12 featues on current hardware? That would be interesting... For example, I'm currently running a modded Intel OROM BIOS on my Z68 board so it can use TRIM under RAID0 with SSD. With the Z77 and Z87, no TRIM problem out of the box and they are 99.9% identical to the Z68 SATA controller. I had ZERO problem in 2 1/2 years, so yeah, TRIM work in RAID0 SSD on the Z68, thanks a lot, Intel...for nothing.
inighthawki - Wednesday, March 26, 2014 - link
Considering nvidia made it a huge point that Fermi and above will be supported and represent >50% of the existing market, yeah probably. Why would they announce that then not write drivers for it?TheJian - Wednesday, March 26, 2014 - link
"For low level PC graphics APIs Mantle will be the only game in town for the next 18-20 months; but after that, then what?"Ignorance or Dumbest comment I've seen this year ;) Either ignorant of just trying to pretend OpenGL can't do this already for years. You forgot the OpenGL speeches showing 5-30x better draw calls and it is ALREADY here, not 2yrs away like DX12.
http://blogs.nvidia.com/blog/2014/03/20/opengl-gdc...
Still showing bias here I guess...Fee free to watch the 52min video in that link on DRAW CALLS and how pointless Mantle is as OpenGL has had this stuff for years. He even shows some code.
"How to get a crap-ton more draw calls" (a new technical term he said in the video…LOL), which clearly is telling you in the first minute, there is no need for mantle as it is about 10x draw calls right? Mantle=dead. If not by DX12 (but this isn’t out for a while-Win9?), then OpenGL/SteamOS/Android pushing OpenGL.
NV’s speech wasn't a SMALL speech or there wouldn't be a 130 slide doc (at least you guys mentioned it, that's not enough) explaining what they covered right (on top of the 52min dev day video covering Draw Calls +many others)? Considering it is ALREADY working in opengl (same crap as mantle, even carmack said you can do the same thing already and get as close to metal as you'd like in OpenGL with extensions a YEAR ago), I'm sure the OpenGL speeches had more concrete info than the DX speech at GDC (valve didn’t say a word about anything BUT OpenGL recently and how to port DX9 to it). How can you not detail the info on OpenGL and call yourself a hardware site? I know you guys hate cuda (or you'd test it vs. opencl/AMD repeatedly to death), but why the hate for OpenGL which NV has no control over?
Mantle's main competitor for 2yrs while we wait for DX12 is ...wait for it...OPENGL, which already does the same crap mantle does... ;) I expected nothing less from Ryan Smith. Where is the big OpenGL speeches coverage? Devs skipped the VR speech to hear about the draw call speech (it was going on right next door and John Mcdonald even says at the end of the vid he'd be in there if he wasn't giving the speech...LOL) and NV was a bit surprised those devs skipped VR. They expected 5 people, got a crowd wanting OpenGL draw call info ;)
But believe Ryan, Mantle's only competition is DX even though OpenGL (ES) is the only thing really used in games on mobile which will further Valves desktop opengl push too. Steam Dev Days was all about leaving DX and going OpenGL, much of GDC was the same or on ES3.1 mobile info. DX12 won't get far unless you believe MS will take out Android/SteamOS/iOS. They are already stuck in cement being so far ahead with pure unit sales off the charts, game devs' mind share already on ios/android, etc, they can easily push OpenGL together and all 3 want DX/Wintel dead.
Wintel lost 21% of ALL notebook share last year. This year we have 64bit cpus coming from all ARM soc players and they'll will use those to go further up the chain from crapbooks (chromebooks to me...LOL) to REAL notebooks, and low-end desktops (+some servers) and move up again with the next revs into everything high-end that x86 owns today.
NV’s speech wasn't a SMALL speech or there wouldn't be a 130 slide doc explaining what they covered right (on top of the 52min video from steam dev days+many others)? Considering it is ALREADY working in opengl (same stuff as mantle, even carmack said you can do the same thing already and get as close to metal as you'd like in OpenGL with extensions a YEAR ago on stage), I'm sure the OpenGL speeches had more concrete info than the DX speech at GDC (valve didn’t say a word about anything BUT OpenGL). How can you not detail the info on OpenGL and call yourself a hardware site? I know you guys hate cuda (or you'd test it vs. opencl/AMD repeatedly to death), but why the hate for OpenGL which NV has no control over? It hurts mantle, is DONE now, AMD pays you for a portal etc, so it's off limits?