ZDoom

[quote="NeuralStunner"][wiki]TEXTURES[/wiki] can do this pretty handily. Thoguh if it's something you can do by flipping the texture, setting a negative scale when mapping should work.[/quote]
This is probably a topic for a different thread/bugreport/whatnot, but as a vague mention, the latter seems to be a bit buggy; we had some issues in Square where negative scales (on the x direction in particular) were failing to actually flip the texture.

Not sure if that's a known issue/limitation/what, but there you go.

[wiki]TEXTURES[/wiki] can do this pretty handily. Thoguh if it's something you can do by flipping the texture, setting a negative scale when mapping should work.

Damn, looks like I need to get to work on texture edits then.
Thanks for the prompt response anyway :)

No, the reason being that rendering walls is done per column and it's strictly optimized to go through the texture data in a very specific manner. That makes rotation impossible unless the entire wall drawing code is redone.

We can rotate flats, but is there any chance of this being extended to sidedefs/textures? Personally I'd find this quite useful, particularly when slopes are in use.