Voxels at edges of map affect those on the opposite side

[fkaa]

For example, you can place blocks in the air if there is a corresponding block on the opposite side of the map. It also affects AO stuff (mostly because it's done through texture lookup (?) and it wraps (?))

[rakiru]

I imagine this is largely a deliberate thing, as the map used to loop. You couldn't walk in or affect it, but it was rendered and you could place blocks off it. It does need fixed of course, but at least some of it should be easy to find as it's explicitly done.

[iamgreaser]

If you just want to prevent the wrap on the AO and it affects the compat mode which still lets the map wrap, I really don't care - as long as the compat is "pretty much there" (i.e. the map still wraps) and the only issue is an AO artifact, then if someone wants to cry about it feel free to just punch them in the face.

This DOES make me realise that the shader will need fixing, though, just so that the heightmap doesn't cast a shadow.