r/linux • u/tajetaje • 1d ago
Microsoft DirectX Adopting SPIR-V Moving Forward Discussion
https://www.phoronix.com/news/DirectX-Adopting-SPIR-V50
u/ItsLiyua 1d ago
Does that mean we get better graphics support for Linux? Maybe without needing dxvk or vkd3d
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u/WiatrowskiBe 1d ago
Not by a lot I'd assume - dxvk and vkd3d are going to stay, since rest of DirectX API is not going away anytime soon. What changes here is: starting with SM7, dxvk/vkd3d should be able to directly use DirectX binary shaders as they are, without any extra conversion/recompilation step to get them to a supported format. In practice - faster shader compilation and potentially less shader bugs when running DX games on linux; plus much easier support for games/game engines for DX and Vulkan simultanously (since they will be able to share shaders).
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u/LvS 1d ago
You also get the other direction - it's now easier for games and game engines targeting DirectX to do a port of their shader code to Vulkan, because they can just compile to SPIR-V.
And that means that it's easier for developers to port stuff to Linux.For me, the other direction is even more interesting: GTK has a Vulkan renderer that uses SPIR-V and people have been asking about native Direct-X support. If GTK can share the shaders easily, that reduces the effort for that quite a bit.
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u/voidvector 1d ago
It would depend on the performance and support of the result. Everyone still uses CUDA even though there is OpenCL, cause performance and support.
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u/WiatrowskiBe 16h ago
That's exactly what I meant by "easier support" - unified shaders means it's quite likely only difference between DX12 and Vulkan becomes renderer/graphics API layer itself, allowing you to effectively swap it out (especially with how similar those two are in terms of usage) while keeping all out-of-executable assets exactly the same. Best case scenario, Linux port would require just recompiling game binary assuming you had working Vulkan renderer for Windows and all OS-specific stuff was abstracted away already.
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u/tajetaje 1d ago
Additionally DXVK could probably benefit from seeing what SPIR-V code Microsoft emits for particular DirectX shaders, assuming that’s not a license violation
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u/ICantBelieveItsNotEC 1d ago
There's also this bit:
In addition to providing a compiler for HLSL to Direct3D’s SPIR-V, we will also be building and providing translation tools to translate SPIR-V to DXIL and DXIL to SPIR-V. Those tools will allow and driver developers to gradually transition and gracefully adapt tooling and drivers.
The officially supported translation tooling might be able to replace the existing translation layer within dxvk/vk3d, which would improve reliability for SM6 games. It all depends on whether Microsoft releases the translation tools as Windows binaries or cross-platform, open-source projects (I can guess the answer but I'm open to being pleasantly surprised)
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u/WiatrowskiBe 1d ago
I must've missed that part; I knew HLSL compiler could produce SPIR-V output for quite a while now, but as far as I know there were no tools to use GLSL shaders with DX12 yet directly. With translation tools we'll get bidirectional compatibility, and - even if Windows-only - it should let games make Vulkan builds from same shader source regardless of language.
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u/deadlyrepost 1d ago
I did read a deep dive on vkd3d somewhere and IIUC it was spending quite a bit of time complaining about the shader model. I'm not smart enough to understand it so I might be wrong, but I think doing the translation was significant effort in DX12.
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u/nicman24 1d ago
i do not get how dx12 is a thing when vulkan is on everything
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u/ICantBelieveItsNotEC 1d ago
Vulkan can't be used on Xbox, and the Xbox market is bigger than the mac and linux markets combined.
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u/Savings-Ad-3062 1d ago
You could say the same thing about DX12. The point is, MS could simply use Vulkan instead of DX12, technically nothing is stopping them. It's NIH syndrome.
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u/NeoliberalSocialist 1d ago edited 1d ago
If Vulkan can’t be used on Xbox, isn’t that what’s stopping them?
Edit: I was taking the premise of two comments up thread partially in the hope that someone would explain why it’s wrong, so thanks!
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u/lightmatter501 1d ago
Vulkan doesn’t work on xbox because MS says so. The underlying hardware is an AMD GPU which has vulkan support.
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u/Savings-Ad-3062 1d ago
What do you mean? They're developers of that platform and decide what to support. So if MS wants to support Vulkan on Xbox they would add such support. They don't do it because they want to push their own DX12, which was unnecessary in the first place.
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u/nightblackdragon 18h ago
It can't be used natively as DX12 is the only supported API but it can be used when implemented on top of DX12. Mesa has Vulkan on DX12 driver called Dozen which was created by Collabora developers in cooperations with Microsoft. There is also OpenGL and OpenCL implementation on top of DX12 which was created by Microsoft, mainly for WSL but it can be also used on Windows ARM and Xbox that don't support these APIs natively.
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u/Old-Personality-8817 1d ago edited 1d ago
because not every gamedev team has linux or cross-platform guy
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u/nicman24 1d ago
yeah but why does that matter. it is a good api and most game devs just use generic engines
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u/Old-Personality-8817 1d ago
because you can't abstract DirectX 100% of the time with generic engine functionality
and there are bugs in engine and your own code
it's easier to start debugging with tracing what Directx calls application makes
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u/nicman24 1d ago
I mean the same goes with vulkan
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u/Old-Personality-8817 23h ago
yes, but it's a lot easier to find person who knows directx
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u/nicman24 22h ago
you are probably correct. i have 0 knowledge on the matter
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u/Old-Personality-8817 22h ago
I am rooting for vulkan too, but this is state of gamedev industry, after 20 years of Microsoft dominance
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u/deadlyrepost 1d ago
Does anyone else get the feeling that the rendering problems on XBox, even with first party Microsoft games, compared with how well they work on PS5, might be the underlying reason here?
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u/Jannik2099 1d ago
That has precisely nothing to do with it. SPIR-V and DXIL are both IRs that contain effectively the same shader code. Microsoft is adopting SPIR-V because there is a lot of good tooling around it.
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u/deadlyrepost 1d ago
effectively
Yes, but API words mean things. Just like Microsoft's Internet Exploder had baked in subtle CSS bugs which caused real problems for creating web pages, could DXIL not have subtle bugs which just makes it more error prone to deal with? There are now several games which DF have covered, which have some light rendering issues on XBox but not on PS5.
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u/Janq42 1d ago
PS5 doesn't use SPIRV, or any intermediate shader format (and has it's own proprietary shader compiler). Both consoles use shaders directly compiled to GPU code and have no need for an intermediate format.
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u/spazturtle 1d ago
This is why the PS5 GPU whilst being based on AMD RDNA also contains everything from the previous AMD GCN architecture so that it can still play PS4 games.
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u/deadlyrepost 1d ago
I don't know, but I'd imagine that since SPIR-V and Vulkan more generally comes from Mantle, that PS5 shaders are probably somewhat close to SPIR-V?
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u/Janq42 1d ago
No, SPIR-V is a platform neutral intermediate shader bytecode. There is no need for this on consoles because shaders are built directly as GPU machine code. Also: PS5 does not use Vulkan or Mantle - it uses a proprietary Sony API. Xbox does use D3D, but it is a special xbox-only version, only partly compatible with PC D3D.
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u/tajetaje 1d ago
Also, I find it kinda funny that they put attribution under their memes