[Unity 6] APV

[Cyanilux]

Unity 6 has a new light probe system
https://docs.unity3d.com/6000.0/Documentation/Manual/urp/probevolumes-concept.html

ShaderLibrary code here suggests that the Baked GI node that URP provides should support APV, provided the graph defines the appropriate keywords. Lit Graphs should already include them (but for custom lighting you'd typically use an Unlit Graph)

For an Unlit Graph, should be able to use an Enum Keyword in the blackboard :

• Reference : PROBE_VOLUMES and Entries : OFF, L1 & L2
• Set to Global/IsOverridable and untick Exposed/GenerateMaterialProperty

Alternatively, could use a Custom Function with :

• #pragma multi_compile _ PROBE_VOLUMES_L1 PROBE_VOLUMES_L2
  or
• #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/ProbeVolumeVariants.hlsl"

Those may also avoid shadergraph keyword limits.

[Cyanilux]

Hello, what exactly should we combine the APV information with in the graph, and how should we use it?

Kinda up to the shader. But I think typically the Baked GI (which should include APV if keywords are used as mentioned above) would be tinted by the albedo texture and added with the rest of the shading/lighting model
e.g. (bakedGI * albedo) + (diffuse * albedo) + specular

[EMGrossman]

(Unity 6.1)
I've implemented your suggestion (Enum keyword) but have found that APV do not seem to write in an unlit graph. Have you experienced this? Implementing a custom function has been a rabbit hole producing many errors, which are equally hard to troubleshoot.

[Cyanilux]

(Unity 6.1) I've implemented your suggestion (Enum keyword) but have found that APV do not seem to write in an unlit graph. Have you experienced this? Implementing a custom function has been a rabbit hole producing many errors, which are equally hard to troubleshoot.

Afaik it's a shadergraph limitation. You can sample baked GI but unlit graphs don't seem to affect it.
I know you can change the Lightmap Flags under the Debug version of the inspector (or assign a Custom ShaderGUI that exposes it), which I think in the past has helped for contributing to baked GI but couldn't get that working in 6.1.
The Unlit Graph doesn't generate the Meta pass which is what handles baking GI & probes so is likely the issue