Waving waters are passing through slab blocks

[Athozus]

Minetest version

Minetest 5.8.0 (Linux)
Using Irrlicht 1.9.0mt13
Using LuaJIT 2.1.0-beta3
BUILD_TYPE=Release
RUN_IN_PLACE=0
USE_CURL=1
USE_GETTEXT=1
USE_SOUND=1
STATIC_SHAREDIR="/usr/share/minetest"
STATIC_LOCALEDIR="/usr/share/locale"

Irrlicht device

Wayland

Operating system and version

Trisquel 11.0 Aramo

CPU model

Intel Core i3-10110U 2.10 GHz

GPU model

Mesa Intel UHD Graphics

Active renderer

OpenGL 4.6

Summary

I've discovered a glitch with water waving while playing on LinuxForks server.

The fountain above the station (you can see on the screenshot) is using « inverted » slabs (param2 to 20), so the water is like crossing it (but floating).

It does not occur with liquid waving disabled.

Maybe it's related to the empty space between waters and blocks at Y=0 (just above see level).

Steps to reproduce

• Place *1/16 slabs oriented to the top (thx @y5nw)
• Place water above
• Go under the slabs

Lazy solution

• Join LF server (you may ask a moderator to register)
• Go to Marcuse Street station, on line 2 (you can take subway at Origin or at Spawn towards Szymon's Dam)
• Exit and look above

[y5nw]

While testing this on my own it turned out that I gave Athozus inaccurate information regarding the setup. The nodes below the fountain are 1/16 slabs from the moreblocks mod.

With flowing liquid enabled, I am able to reproduce this in 5.9.0-dev using a relatively simple setup, where a single water source node is enclosed in other nodes (I use obsidian glass here for better visualization):

[nininik0]

The re is a similar Android bug where water on a 1 block surface will just make weird waves that Clip through the block. Mostly happens with sunlight_propagates blocks