Do some textures make linedefs feel "jagged" when wallrunning or is it just me?

[morrigan]

Apologies if this has been asked and answered before but I couldn't find a topic like this in this forum.

I've always been wondering why do walls textured with the "metal lattice" textures (W111_*, W112_*, M1_1) feel "jagged" or uneven when running along/against them (like these walls here in Erkatanne's MAP03). One of my guesses was that this might be a special property of these textures but that doesn't really look plausible to me.

Is it solely dependent on the angle then and was it just my own confirmation bias to only notice that effect when wallrunning against walls textured in that manner? Or is there another answer altogether?

 

Edit: see this vid for gameplay footage (prboom+ 2.5.1.7um). I'm referring to the jagged/bumpy movement when running along a W11*-textured wall.

https://i.imgur.com/QKhQhGS.mp4

Edited September 13, 2020 by gotsu

[Gez]

The textures have no gameplay impact*. Patterns in the texture may cause an optical illusion when scrolling past at certain speeds but that's all. You can edit the level to change the textures (without rebuilding the nodes) and a demo recorded before you changed the textures will not desync after.

 

 

 

* Exception: projectiles disappear without exploding in sky textures, including in sky hacks. But that's caused by ceiling textures, not wall textures.

Edited September 13, 2020 by Gez

[morrigan]

Sorry, I may have not made my point clear. Please see this vid here to see what I'm getting at:

https://i.imgur.com/QKhQhGS.mp4

It's more or less smooth movement running along other walls, save for a few bumps. But when running along the W11*-textured walls, it's bumpiness all the way.

Edit: The port is prboom+ 2.5.1.7um. I haven't noticed this in gzdoom.

Edited September 13, 2020 by gotsu

[Linguica]

The difference is not the texture, but the type of linedef. Most walls are 1S (one-sided) linedefs. The engine's collision code knows how to handle these pretty well. Some walls however are 2S (two-sided) flagged as "impassible" which stops the player from running through them. These are used for "see-through" textures like fences etc. The problem however is that the Doom engine does not actually check for 2S impassible lines in the collision code. It ends up using a fallback "stairstep" method which moves the player orthogonally along the X or Y axis. For axis-aligned lines this will coincidentally feel pretty much "normal" and instead manifests on a diagonal 2S impassible line where it feels like you are running along a jagged surface. The "canonical" place to experience it is on the chainsaw ledge on Doom 2 Map01.

[morrigan]

6 hours ago, Linguica said:

The difference is not the texture, but the type of linedef. Most walls are 1S (one-sided) linedefs. The engine's collision code knows how to handle these pretty well. Some walls however are 2S (two-sided) flagged as "impassible" which stops the player from running through them. These are used for "see-through" textures like fences etc. The problem however is that the Doom engine does not actually check for 2S impassible lines in the collision code. It ends up using a fallback "stairstep" method which moves the player orthogonally along the X or Y axis. For axis-aligned lines this will coincidentally feel pretty much "normal" and instead manifests on a diagonal 2S impassible line where it feels like you are running along a jagged surface. The "canonical" place to experience it is on the chainsaw ledge on Doom 2 Map01.

Thanks a lot for answering my dumb question! Case closed.