As of 1.21.11’s snapshots, many cross-shaped blocks now use this mipmapping method. However, it is not perfect: artifacts will still appear if blocks are viewed from the correct angle. This also appears to affect items (MC-303439).
A suggested fix: any pixel that strays outside of the not-mipmapped area should be truncated to fit the geometry of the not-mipmapped texture in-game. This effect can be recreated with block models - an example resource pack that does this for brown mushrooms is attached to this ticket. However, it’d be better to somehow perform this cutout-ing in a different way, rather than having to provide custom models for every cross block, while still yielding identical visual results.
Thank you for your report!
After consideration, the issue is being closed as Won't Fix.
Please note that this is not the same as Working as Intended, as this bug report correctly describes behavior in the game that might not be the intended or desirable behavior, but it will not be fixed right now. Sometimes, this is because the issue reported is minor and/or impossible to change without large architectural changes to the code base.
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