Relates to MC-164001 and MC-163153.
The bug
Cauldrons, water cauldrons, lava cauldrons and powder snow cauldrons render as solid blocks, rather than rendering as "cutout" blocks. This is a problem for two reasons:
cauldrons did render as "cutout" upon their first implementation
hoppers, a visually and structurally very similar block, do use cutout rendering
As a result, any transparent pixels which are in a texture that a cauldron block uses will be rendered completely opaque.
How to reproduce
A resource pack is attached to this ticket which replaces the "blockstates" files for cauldrons (including water_cauldron, lava_cauldron and powder_snow_cauldron) and hoppers with the potted fern. Place one of each cauldron type (including empty) and a hopper in close proximity, and apply the resource pack.
Expected results
All of the ferns would appear fern-shaped.
Actual results
The ferns which represent the cauldrons have a solid white rectangle behind them. The hopper correctly does not have this background.
How to fix
All cauldrons should be changed to use the "cutout" render type (with the exception of water cauldrons, which should use the "translucent" render type instead to fix MC-13187).
Related issues
Attachments
Comments


Almost all blocks supported cutout rendering until the x-ray patch implementation. That cauldrons don't anymore is because nothing does except blocks that have transparency in vanilla.
I'd rather say the fact hoppers use cutout is the bug, not that cauldrons don't.

Going to have to disagree. MC-13187 is triaged, and the fix for that would result in water cauldrons using the translucent render type, which by extension would allow for it to support "cutout" textures. If the other cauldrons aren't updated to at least use the cutout renderer, that would make water cauldrons inconsistent and models that use cutout textures that work fine with water cauldrons would mysteriously look ugly if applied to any other cauldron. It'd end up being pretty much the same problem as MC-171683, but inconsistent between cauldron contents rather than door types.