fs2open.github.com Main hall ANI rendering artifact

When using FSO and the original, retail GTD Bastion main hall, a black, squiggly line can be seen jumping around the crane in the upper-left corner. (As seen below.)

gtd-bastion-hall-black-line

This is not present in the retail executable. (As seen below.)

gtd-bastion-hall-black-line-retail

Jul 17 '22 22:07 daftmugi

I've noticed a few more lines that shouldn't be there, and there may be more. (Below is a screenshot with the lines highlighted.)

gtd-baston-hall-highlighted-lines

Jul 23 '22 04:07 daftmugi

Would you please toss us a debug log so we can see what mods (if any) are loaded as well as the commandline flags passed to FSO?

Jul 23 '22 16:07 z64555

I removed all command-line options, and I tried with only the fsport mod -- no mediavps. Same results.

Passed cmdline options:
   -mod fsport

Jul 23 '22 23:07 daftmugi

Are you able to try at 640x480 and 1024x768? The original original resolution is 640x480, so it should not display any scaling artifacts there. It's probably also worth trying one or two other 4:3 resolutions.

Jul 25 '22 03:07 Goober5000

640x480 and 1024x768 do not show any artifacts. That's hopeful! 800x600 and 1280x960 have the same artifacts as reported.

It does seem to be an issue with the scaling.

Are you all able to reproduce this on your end or is it just me?

Jul 25 '22 06:07 daftmugi

I wonder if each image/animation of the scene is scaled and then compositing is done, which exposes a one pixel gap in some places. Instead, if the compositing is done first and then the result is scaled, it would be fine, possibly? (Just a hunch of mine.)

Jul 25 '22 19:07 daftmugi

Are you all able to reproduce this on your end or is it just me?

I can reproduce it on my end, yeah.

Jul 26 '22 13:07 Kiloku

I've seen it too.

I know very little about the graphics code, so I couldn't say how the scaling could be modified to fix this.

Jul 26 '22 16:07 Goober5000