Jumping lines

[termrork]

Since I could not find this issue I guess I simply did not know how it is called.

 

Namely the effect which has been occurring in a lot of source ports (it seems a lot of them fixed it by now):

when you are close to a line and you are looking at the texture of the line it jumps.

as an example: in map01, when you cross the lines of the steps the textures jump just before you cross that line.

it seems the effect can be seen better when the lines are longer.

 

if I could not describe it enough I will make screenshots to explain it more.

my question: how is this called? what causes the engine to do this?

 

I am thankful for any information!

 

[Linguica]

https://doomwiki.org/wiki/Wall_wiggle_bug

 

[termrork]

ahh wiggle... of course. thank you a lot linguica!

[Blastfrog]

IIRC, didn't you help kb1 with the wiggle fix, @Linguica?

Edited December 20, 2017 by Blastfrog

[kb1]

I had published a half-ass fix a long time ago that did a static evaluation of the level at level load time, and adjusted the renderer once per level. Later, entryway and I published a new version that dynamically corrects wiggle during rendering: Wall wiggle fix

Linguica then proceeded to create a nice long wall fix that attacks a similar issue. Virtually all weird renderer "wiggle" problems can be traced back to the decision to use fixed-point variables. Fixed-point was used everywhere in the renderer, for performance. This was typically ok in 320x200 resolution in most situations, but with modern resolutions, the problem gets a lot worse, much more often.

[termrork]

thank you guys, I am going to try out your wiggle fix and see what it can do for my purposes :)!

[kb1]

2 hours ago, termrork said:

thank you guys, I am going to try out your wiggle fix and see what it can do for my purposes :)!

I'd love to hear about any successes, and let me know if you have any problems too. It's very vanilla+Boom-specific, so if your port is along those lines, it should go pretty smoothly.

[termrork]

I used your method for mochadoom, a java port. it worked perfectly. though for the exact purpose I need it for it seems to make no change.

namely:

lines still seems to wiggle when they are long and very far away. for some reason I thought this might be the same reason for the map01 stairs texture wiggle.

you mentioned that Linguica made a long wall fix. maybe this is the effect I have to fix. sadly I cannot find it, how is it called exactly?

[boris]

Maybe it's this? https://doomwiki.org/wiki/Long_wall_error

[kb1]

On 12/23/2017 at 4:27 AM, termrork said:

I used your method for mochadoom, a java port. it worked perfectly. though for the exact purpose I need it for it seems to make no change.

namely:

lines still seems to wiggle when they are long and very far away. for some reason I thought this might be the same reason for the map01 stairs texture wiggle.

you mentioned that Linguica made a long wall fix. maybe this is the effect I have to fix. sadly I cannot find it, how is it called exactly?

It is here.

[termrork]

thank you a lot kbl! I could not find it anywhere... I will let you know whether it worked.