Use a global map to track Shader ID to LRS associations #2632
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The spec indicates that any shader with associated root signatures should have a unique, global shader ID.
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MarkY-LunarG
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MarkY-LunarG
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Changes look good from a code standpoint, but I don't know if the functionality is correct, so I'll leave that for someone else to look over. It appears to do the same thing as before with the only exception being the new warning.
Maybe @bradgrantham-lunarg or @locke-lunarg
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| struct ShaderIdAssociationInfo | ||
| { | ||
| std::set<format::HandleId> state_object_ids; |
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Why are you saving this? It doesn't appear used.
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This is saved for reference, to allow developers to determine which state object(s) contained this shader. For example, useful for debugging.
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Thanks for taking a look.
The functional difference of this PR is contained in the first commit The second commit is for preserving information about which shader IDs came from which state objects. This doesn't have a functional difference on replay--it is for verification and debugging purposes. The shader ID to LRS mapping can be complicated to resolve, and the small amount of additional work to track this meta info should be useful to have around in the future. |
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Each shader identifier should be globally unique so it isn't necessary to track shader IDs per state object.
Below are supporting statements from the DXR spec:
Shader identifier
"A shader identifier is an opaque data blob of 32 bytes that uniquely identifies (within the current device / process) one of the raytracing shaders"
"An application might create the same shader multiple times. This could be the same code but with same or different export names, potentially across separate raytracing pipelines or collections of code (described later). In this case the seemingly identical shaders may or may not return the same identifier depending on the implementation. Regardless, execution behavior will be consistent with the specified shader code."
Regarding differing shader IDs on duplicate shaders:
Update v1.24 05/30/2024 - "In GetShaderIdentifier removed the sentence: "The data itself globally identifies the shader, so even if the shader appears in a different state object (with same associations like any root signatures) it will have the same identifier.". This contradicted the text in Shader identifier that allows for duplicate shaders to have the same or different identifier depending on implementation."