[ Bug Report ] Double sided textures on floors, walls and ceilings causes double-sided rendered sectors in Geometry Mode

[Helepolis]

Tomb Editor Version

v2.0 Release Candidate 1

Game Engine

Tomb Engine

Describe the Bug

A builder's thought
I would say this is a very exotic case. No normal building workflow would normally lead into this issue. The reason I ran into this is when I was shaping the terrain for my water room (stacked room). The upper dry room originally had opacity portal and double sided textures for the water. When I started shaping later on to add walls, slanted floors etc, I started noticing this issue.

My initial reaction was confusion and worries. I thought I was messing up the boundaries of my floors/ceilings and causing geometry issues. The worries got worse when I re-applied the portals and it would persist. When Nickelony mentioned it may be rendering issue I felt relief.

To Reproduce

The uploaded video shows that if you apply double sided textures to floors, walls or ceilings it will cause those sectors Geometry Mode to show double sided view as well.

2026-07-30.10-24-27.mp4

I checked 1.11 as well, it can be reproduced there as well.

Expected Behaviour

You're not suppose to see the "back side" of floors, walls or ceilings in Geometry Mode. Otherwise the builders would get confused very fast within complex room structures.

[Nickelony]

This is not necessarily a bug, but rather a quirk of how double-sided textures are done. Not showing them would probably count more as an "enhancement" rather than a bug fix.

Also, I would not count this as a 2.0 RC1 bug, this has been in the editor since forever.