This doesn't happen when using just MTS, so I suspect it's a mod which draws near the crosshairs?

I don't currently have a screenshot of the bug, it's on another computer. I'll put that up ASAP, I just wanted to get this up here.

Here's an approximate paint . net render of what it looks like, an area around the crosshairs gets inverted: Not really a huge annoyance, it just looks wacky

The area was ~1 square inch on the computer I usually play on (24" monitor)

Tested with these mods, saw no issue:
mods.txt

Here's the list of mods I usually play with (NOTE: The mods prefixed "SM" may not be released yet, those are ones that I've made)
mods.txt

You know, I think I may know what's going on. I think I might be messing with the alpha settings and leaving them disabled so MC doesn't make the whole crosshair texture bits transparent. Can you tell me if this works for you? It's an experimental version, so make sure to backup your world before using.
Immersive Vehicles-1.12.2-18.3.0.zip

Yep, that fixed the issue!

Nice! I had a few odd issues with the HUD when re-doing the instruments and found some "dirty" OpenAL states, so good to see that's taken care of them. Will mark this as closed when I drop the release, but feel free to hang on to that one as mostly everything in there is final. Only exception is the plane physics, so if you aren't about to go flying that should be fine.

ok, thanks!

Fixed in V18.3.0.

OK, took a little while longer than expected, but here's the actual screenshot

The mods used in this one are the second "mods.txt"

Question: if you go into the P-key config menu, and turn off the HUD so nothing renders, does the issue go away? Does this also happen in third-person?

What if both are set? If you don't render the HUD and make it transparent?

I haven't tested that yet, I'll test and report tomorrow

Yeah, but in 3rd person, the crosshairs aren't visible, so there's no glitched area. I assume it's something interfering with the crosshair drawing methods, either in MTS of some other mod

Fair enough. Did you try turning off the HUD? Also, have you tried without any instruments in the HUD? Need to isolate what part of MTS's rendering causes this issue.

I don't think I've tried turning off the HUD, here's the options that I've tried (individually). This happens with instruments and without instruments.

Okay? So what are the results of those options being set or un-set?

They still gave the same glitchy area. Should've mentioned that, sorry

Interesting. So not rendering the HUD makes the issue go away. If you go into a vehicle, and set renderHud to true, but transp to true, what happens?

Both set to not display/transparent HUD:

Also, this only occurs when you are in command of/ driving a vehicle:

Starting with HUD off/ transp. off, outside a vehicle, entering it, then setting them to true still causes the glitch. Turning transparency off doesn't fix it; however, not rendering the HUD doesn't cause the glitch.

Okay, now you're confusing me. Can you tell me what happens in these cases:

1. HUD rendering off, transparency off.
2. HUD rendering on, transparency off.
3. HUD rendering off, transparency on.
4. HUD rendering on, transparency on.
5. HUD rendering on, transparency on, and with instruments in the HUD.
6. HUD rendering on, transparency on, and with out instruments in the HUD.

I don't care about you being in a seat that doesn't bring up the HUD, as I know it's something in the HUD that's causing this. But I need all permutations of the configs tested. I need to know which condition causes this to happen to try to make a fix.

HUD rendering off, transparency off. > > > > > > > > > > > > > > > > > > > No glitch
HUD rendering on, transparency off. > > > > > > > > > > > > > > > > > > > glitch
HUD rendering off, transparency on. > > > > > > > > > > > > > > > > > > > No glitch
HUD rendering on, transparency on. > > > > > > > > > > > > > > > > > > > > glitch
HUD rendering on, transparency on, and with instruments in the HUD. > > > glitch
HUD rendering on, transparency on, and with out instruments in the HUD. > glitch

Where "glitch" is the inverted (64*64 pixel) area centered on the crosshairs

Now this, this I should be able to fix. I'm not sure why having the HUD render with transparency causes the glitch, as that prevents all rendering entirely if you don't have instruments. It must be something I set to render the HUD background itself that's causing this error. One last question set:

HUD rendering off, transparency on, and with instruments in the HUD.
HUD rendering off, transparency on, and with out instruments in the HUD.

HUD rendering off, transparency on, and with instruments in the HUD. ======= No glitch
HUD rendering off, transparency on, and with out instruments in the HUD. === No glitch

Okay, was not expecting this, as I do texture rendering for instruments. I must set something when rendering the HUD that I don't un-set later...