Support for old shaderpacks.

[9182736450typist]

Back when Optifine was the main shader mod, many awesome shaders with little to no performance hit such as Paolo's Lagless Shaders, Chocapic V3 and yShaders worked flawlessly. However, they fail to load on optifine 1.17+ or iris shaders. Are there any plans to support these old shaderpacks with iris?

Shader info when trying to load shaders:
Index -1 out of bounds for length 16

[Luracasmus]

Does that same error occur when loading all three shader packs? A lot more context (preferably a full log file) is going to be needed to find what the issue is preventing the shader packs from loading, which also likely isn't the same across all three packs

Given that the shader packs are so old, it's likely they were using some very outdated functionality or relying on unintentional shader loader behavior that has since been fixed

[9182736450typist]

Yes it does occur.
Chocapic V3 and Paolo's lagless fail on 1.17+ optifine while yshaders is safe. Iris breaks all three shaders.
I would suggest adding a mode that uses 1.16.5 interpretation of shaders (legacy shader mode).