Caught Up to DirectX 12 in a Single Day
The future is not certain, but Khronos Group did what they needed to.
I'm not just talking about the specification. Members of the Khronos Group have also released compatible drivers, SDKs and tools to support them, conformance tests, and a proof-of-concept patch for Croteam's The Talos Principle. To reiterate, this is not a soft launch. The API, and its entire ecosystem, is out and ready for the public on Windows (at least 7+ at launch but a surprise Vista or XP announcement is technically possible) and several distributions of Linux. Google will provide an Android SDK in the near future.
I'm going to editorialize for the next two paragraphs. There was a concern that Vulkan would be too late. The thing is, as of today, Vulkan is now just as mature as DirectX 12. Of course, that could change at a moment's notice; we still don't know how the two APIs are being adopted behind the scenes. A few DirectX 12 titles are planned to launch in a few months, but no full, non-experimental, non-early access game currently exists. Each time I say this, someone links the Wikipedia list of DirectX 12 games. If you look at each entry, though, you'll see that all of them are either: early access, awaiting an unreleased DirectX 12 patch, or using a third-party engine (like Unreal Engine 4) that only list DirectX 12 as an experimental preview. No full, released, non-experimental DirectX 12 game exists today. Besides, if the latter counts, then you'll need to accept The Talos Principle's proof-of-concept patch, too.
But again, that could change. While today's launch speaks well to the Khronos Group and the API itself, it still needs to be adopted by third party engines, middleware, and software. These partners could, like the Khronos Group before today, be privately supporting Vulkan with the intent to flood out announcements; we won't know until they do… or don't. With the support of popular engines and frameworks, dependent software really just needs to enable it. This has not happened for DirectX 12 yet, and, now, there doesn't seem to be anything keeping it from happening for Vulkan at any moment. With the Game Developers Conference just a month away, we should soon find out.
But back to the announcement.
Vulkan-compatible drivers are launching today across multiple vendors and platforms, but I do not have a complete list. On Windows, I was told to expect drivers from NVIDIA for Windows 7, 8.x, 10 on Kepler and Maxwell GPUs. The standard is compatible with Fermi GPUs, but NVIDIA does not plan on supporting the API for those users due to its low market share. That said, they are paying attention to user feedback and they are not ruling it out, which probably means that they are keeping an open mind in case some piece of software gets popular and depends upon Vulkan. I have not heard from AMD or Intel about Vulkan drivers as of this writing, one way or the other. They could even arrive day one.
On Linux, NVIDIA, Intel, and Imagination Technologies have submitted conformant drivers.
Drivers alone do not make a hard launch, though. SDKs and tools have also arrived, including the LunarG SDK for Windows and Linux. LunarG is a company co-founded by Lens Owen, who had a previous graphics software company that was purchased by VMware. LunarG is backed by Valve, who also backed Vulkan in several other ways. The LunarG SDK helps developers validate their code, inspect what the API is doing, and otherwise debug. Even better, it is also open source, which means that the community can rapidly enhance it, even though it's in a releasable state as it is. RenderDoc,
the open-source graphics debugger by Crytek, will also add Vulkan support. ((Update (Feb 16 @ 12:39pm EST): Baldur Karlsson has just emailed me to let me know that it was a personal project at Crytek, not a Crytek project in general, and their GitHub page is much more up-to-date than the linked site.))
The major downside is that Vulkan (like Mantle and DX12) isn't simple.
These APIs are verbose and very different from previous ones, which requires more effort.
Image Credit: NVIDIA
There really isn't much to say about the Vulkan launch beyond this. What graphics APIs really try to accomplish is standardizing signals that enter and leave video cards, such that the GPUs know what to do with them. For the last two decades, we've settled on an arbitrary, single, global object that you attach buffers of data to, in specific formats, and call one of a half-dozen functions to send it.
Compute APIs, like CUDA and OpenCL, decided it was more efficient to handle queues, allowing the application to write commands and send them wherever they need to go. Multiple threads can write commands, and multiple accelerators (GPUs in our case) can be targeted individually. Vulkan, like Mantle and DirectX 12, takes this metaphor and adds graphics-specific instructions to it. Moreover, GPUs can schedule memory, compute, and graphics instructions at the same time, as long as the graphics task has leftover compute and memory resources, and / or the compute task has leftover memory resources.
This is not necessarily a “better” way to do graphics programming… it's different. That said, it has the potential to be much more efficient when dealing with lots of simple tasks that are sent from multiple CPU threads, especially to multiple GPUs (which currently require the driver to figure out how to convert draw calls into separate workloads — leading to simplifications like mirrored memory and splitting workload by neighboring frames). Lots of tasks aligns well with video games, especially ones with lots of simple objects, like strategy games, shooters with lots of debris, or any game with large crowds of people. As it becomes ubiquitous, we'll see this bottleneck disappear and games will not need to be designed around these limitations. It might even be used for drawing with cross-platform 2D APIs, like Qt or even webpages, although those two examples (especially the Web) each have other, higher-priority bottlenecks. There are also other benefits to Vulkan.
The WebGL comparison is probably not as common knowledge as Khronos Group believes.
Still, Khronos Group was criticized when WebGL launched as "it was too tough for Web developers".
It didn't need to be easy. Frameworks arrived and simplified everything. It's now ubiquitous.
In fact, Adobe Animate CC (the successor to Flash Pro) is now a WebGL editor (experimentally).
Open platforms are required for this to become commonplace. Engines will probably target several APIs from their internal management APIs, but you can't target users who don't fit in any bucket. Vulkan brings this capability to basically any platform, as long as it has a compute-capable GPU and a driver developer who cares.
Thankfully, it arrived before any competitor established market share.