Support for vk graphics pipeline library extension

[warriormaster12]

This is a first draft of graphics pipeline library extension support in Godot. This extension allows splitting graphics pipeline creation into 4 different stages vertex input, vertex shader (It includes geometry and tesselation), fragment shader and fragment output which in turn allows re-usage of different stages when for example creating a new pipeline with similar permutations. In addition, extension allows PSOs to be compiled in creation time.

There are still things that need to be resolved before merging the PR.

• pipeline layouts should be split in a way that they are used in a correct stage. As far as I know, if we have a descriptor set x that is being used both with vertex and fragment shader, we can bind the vertex bit without waiting for a fragment bit being ready.
• VkShaderModules are being deprecated, we don't have to go through the process of creating them.
• VRS is at the moment broken.
• Celebrate my first PR.

More info about the extension

[clayjohn]

For future readers. This is a very new Vulkan extension (less than 1 year old) and is only supported by a few devices (GPUinfo reports 5.46% coverage so far. While that number is biased as most samples were reported before the extension was made it highlights that this is quite new).

That being said, its a very exciting change to the Vulkan spec that hopefully will help further reduce pipeline compilation stalls.

[Riteo]

@clayjohn

This is a very new Vulkan extension (less than 1 year old) and is only supported by a few devices

Do you know if this is an hardware limitation or if there will also be some driver (e.g. Mesa) implementations, if they're even possible?

[warriormaster12]

Mesa team is working on a RADV GPL implementation. I believe it works but doesn't have shader cache mechanism implemented yet.

[warriormaster12]

TPS-Demo with GPL enabled

Getting hashing to work was a bit tedious and painful. Might be due to my inexperience of making custom hash-able classes but I finally got pipeline stages caching to work🥳 (I at least hope so). The journey hasn't ended yet but I think that this is a good opportunity to ask for some battle testing to make sure that everything works like before. If anyone can find bugs that might be related to graphics pipeline library caching, let me know.

Best way to know if it is related to pipeline caching is comparing renderdoc captures between each other with graphics pipeline library enabled and without it.

Example:

Incorrect offset in uv_attrib with GPL enabled

Correct offset in uv_attrib without it

[warriormaster12]

Quickly made an update that reduced amount of cached elements.