Generate a material as a subasset for ShaderGraphs

[adrien-de-tocqueville]

Purpose of this PR

This PR adds an automatically generated material subasset on ShaderGraphs:

I bumped the shadergraph importer version, so for existing projects every graph will be reimported and the material willl be generated.

Benefits:

• It avoids having to manually create a material each time a shadergraph is created
• When the shadergraph is saved, the material is regenerated, so the default values for properties are updated on the material
• When changing the default values in the blackboard, the material is updated and therefore changes can be seen instantly in the scene view.

Supported properties:

• float/vector2/vector3/vector4
• color
• boolean
• texture 2D/3D/Array/Cube
• keyword Enum/Boolean

That's essentially all properties that can be exposed, I don't think I am missing one

This is part of this JIRA task https://unity3d.atlassian.net/browse/UR-1450

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Testing status

See the gif above.
Tested undo/redo of shadergraph properties.
Tested closing shadergraph window with saving or discarding changes.
Tested that the generated material works on a mesh renderer in a standalone build.

The feature has also been tested by several artists in the context of material variants
I will add a graphic test.

[github-actions]

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Shader Graph
/.yamato%252Fall-shadergraph.yml%2523PR_ShaderGraph_trunk
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[sebastienlagarde]

For existing projects, the material will not be generated until the SG is saved. It can be done by bumping the importer version but I don't think it's necessary

yes we should bump the importer version.

Should the user be able to disable this feature in the graph settings ?
no

[sebastienlagarde]

What is happening if a users setup this on the fly material to an object and build. does it works in player? (i.e is the build step considering it is a true material and store it correctly in build data? Because shader graph don't exist at runtime.

[adrien-de-tocqueville]

What is happening if a users setup this on the fly material to an object and build. does it works in player? (i.e is the build step considering it is a true material and store it correctly in build data? Because shader graph don't exist at runtime.

It works fine, actually it's the same process as for the shader itself, which is an artifact generated by the shadergraph importer that is available at runtime

[cdxntchou]

Looks good!

As we discussed, there might be an edge case if some script comes along and forces AssetDatabase to save the dynamic changes to the default material artifact. Not sure if that is even possible, but that should be an issue with the script if so.

[adrien-de-tocqueville]

@ellioman tagging you here although this will not directly impact URP, but for awareness

[alindmanUnity]

UX approval

[GrantLamb-Unity]

Ran some manual tests with the following exposed properties:

• float
• Texture 2D
• Color

Also ran tests to ensure naming conflicts don't cause issues with this auto generated material. No issues were encountered during these tests.

[sebastienlagarde]

do we have any what's new for shader graph?