D3D12: Get rid of DXIL.dll!

[RandomShaper]

This finally allows Godot editor and games to ship with Direct3D 12 without any separate library.

This is thanks to https://devblogs.microsoft.com/directx/open-sourcing-dxil-validator-hash/.

• Partners with Remove patch to the no longer needed validation feature godot-nir-static#15.
• UPDATE: Partners with Remove references to the no longer needed DXC godot-docs#9593.

UPDATE: Testing procedure: clearing the shader cache of a project, disabling dev mode on Windows, patching code to generate wrong hashes and verify D3D12 complains, taking code back to normal, clearing shader cache again and verifying the game works with shaders and all.

[bruvzg]

There are multiple mentions of DXIL and DXC in the https://github.com/godotengine/godot-docs/blob/master/contributing/development/compiling/compiling_for_windows.rst that should be removed as well.

[RandomShaper]

Added link to the docs PR.

[akien-mga]

Didn't test, but code looks good to me.

[Calinou]

Is #91475 still relevant for Agility SDK? As I understand it, our D3D12 renderer only works out of the box on Windows 11, not Windows 10. This means running the setup script would still be required for users on Windows 10.

[RandomShaper]

It works on W10 as well. The Agility SDK is a way of having features backported to W10, as long as the GPU driver supports them. As a recap, at the moment, the only two features Agility brings to W10 that Godot can use are these:

• Relaxed format casting, used in certain advanced render features. Disabled at the moment since it was making certain GPU drivers crash.
• Enhanced barriers. This one is very interesting for performance.

So, Agility is beneficial, but not a must.

I don't know if this answers your question.

[akien-mga]

Thanks! Glad to finally have this solved properly 🎉

[DarioSamo]

* Relaxed format casting, used in certain advanced render features. Disabled at the moment since it was making certain GPU drivers crash.

I forgot to report back this is actually no longer the case at least for me, but that doesn't mean people won't run into it sadly if the driver isn't up to date.

* Enhanced barriers. This one is very interesting for performance.

So, Agility is beneficial, but not a must.

Yeah, the performance benefit is pretty much the exact improvement the ARG added, so I think we ought to document somewhere that it is actually pretty significant nowadays to use the Agility SDK for any serious project. Plus it enhances compatibility with older systems as well.