Flowing liquid z-fights with allfaces node if you're inside the liquid

[Wuzzy2]

Minetest version

5.2.0-dev

Summary

If a flowing liquid of type A exists directly above a non-waving allfaces node and you are inside the flowing liquid and look to the allfaces node, you will see z-fighting at the allfaces surface.

Steps to reproduce

This works for MTG.

1. Turn off waving plants, liquids, and everything else before starting the test
2. Place a water source in such a way that it spawns flowing water nodes over leaves
3. Go inside the water and look downwards, to the leaves

The flowing water is z-fighting with the leaves. This is only visible if you are inside the liquid.

[Warr1024]

I also noticed this with liquid source nodes against nodebox and mesh nodes.

I put a workaround for it in NodeCore since there are gameplay elements that would encourage players to be in situations where they'd see this problem and it'd be distracting, but the workaround is ugly and I'd very much like to remove it.

[Desour]

Also happens with glasslike drawtype.
Edit: #13569

[sfan5]

Not fixed for flowing water according to #13594:

Note: does not fix flowing liquid, it was z-fighting against glasslike in 5.7.0 and needs a separate fix (enabling backface culling for each face independently).