Polished slab decals

This behavior was presented by zozozrob on X (Twitter), all the credit goes directly to him.

With the addition of the calcite set, a new discrepancy has been detected regarding the polished calcite slabs: they feature a line down the middle, similar to smooth stone slabs, yet they contradict all other slab types when placed within the same block.

Edit: Upon closer inspection following publication, I noticed that smooth stone slab blocks utilize the same texture as a full block, simply adding overlays along the edges to distinguish them. However, this does not appear to be the case for polished calcite in the bottom half of the block, even though it still features the side overlay. I am updating this ticket to refine the text.

What is the proposal?

Polished block slabs should not blend their textures when placed within the same block space; instead, they should use edge overlays, similar to smooth stone or polished calcite slabs to create a new, combined texture with a line in the center when two slabs are placed together in the same block space.

Observed behavior

Only smooth stone slabs and the new polished calcite slabs show a visible line between them when placed side by side; for all other types of polished slabs, the game ignores the block's edge and includes only the side portion of the block that would normally be used. As shown in the "sliced" and "side" attachments, the texture is applied to these slabs in a non-standardized way, with decals appearing on all polished slabs—a detail that becomes even more apparent in the other attachments.

Expected result

All polished slabs should use a decal texture at the corners so that new textures are created when they are placed within the same block, resulting in an appearance distinct from that of full blocks. This approach is similar to the one used for smooth stone and polished calcite; it reuses an existing texture rather than producing the odd, anomalous patterns seen when polished calcite slabs are placed side by side.

Affected blocks

All polished blocks that have corresponding slab variants are affected by this, with the exception of smooth stone and the new polished calcite. Below is a list of all the blocks where the decal texture is expected:

- Polished granite slab
- Polished diorite slab
- Polished andesite slab
- Polished deepslate slab
- Polished tuff slab
- Polished cinnabar slab
- Polished sulfur slab
- Polished blackstone slab

I’ve listed these main ones because they are the only ones with "polished" versions, but it would be interesting if this also applied to these others:
- Quartz slab
- Prismarine brick slab