Frame glitch in E2M4

Vadim Z

#1 Posted 05 October 2020 - 12:42 AM

Hello!

I've noticed a not severe but disturbing glitch. See the video:

It's the first elevator on E2M4 Fusion Station. As I remember there were some other places with similar effect, but I can't say exactly where.

The glitch is there since r9202 (r9166 is ok).

Win10 Home, i3-3220 with integrated GPU.

Danukem

Duke Plus Developer

#2 Posted 05 October 2020 - 12:55 AM

Vadim Z, on 05 October 2020 - 12:42 AM, said:

The glitch is there since r9202 (r9166 is ok).

This change in that revivsion looks sus:

Quote

Duke3d: add an additional layer of camera vec3_t position smoothing across frames

This is intended to mask a slight jitter that occurs when strafing and turning at the same time as a result of turning being decoupled from movement.

I'm guessing it's interpolating the camera position from the previous player location, but since the elevator is teleporting the player to a new location, the interpolation puts the camera in a bad spot for a split second. The code should not try to interpolate if the player has teleported. Just a guess.

Vadim Z

#3 Posted 05 October 2020 - 02:04 AM

Danukem, on 05 October 2020 - 12:55 AM, said:

This change in that revivsion looks sus:

I'm guessing it's interpolating the camera position from the previous player location, but since the elevator is teleporting the player to a new location, the interpolation puts the camera in a bad spot for a split second. The code should not try to interpolate if the player has teleported. Just a guess.

In the next elevator on the same map textures on the wall are not moving smoothly. It can be related as well.

Doom64hunter

#4 Posted 05 October 2020 - 09:18 AM

Will probably be addressed soon.

Vadim Z

#5 Posted 10 October 2020 - 04:04 AM

Horizontal teleports are affected as well (can be seen at Lunatic Fringe level).

MetHy

#6 Posted 10 October 2020 - 04:18 AM

Vadim Z, on 10 October 2020 - 04:04 AM, said:

Horizontal teleports are affected as well (can be seen at Lunatic Fringe level).

Lunatic Fringe doesn't have any teleporter. You're thinking of Sector over Sector, and I have noticed as well that in recent builds sometimes when walking around SoS areas you get to to see the other SoS layer for a split second, this seems to be even more likely to happen the closer on the Z axis the other SoS layer is but I'm not sure. I'm also not sure this and the transport elevator visual hiccup are the same issue.
I got the same thing regarding SoS in voidsw btw.

This post has been edited by MetHy: 10 October 2020 - 06:43 AM

Vadim Z

#7 Posted 11 October 2020 - 12:00 AM

MetHy, on 10 October 2020 - 04:18 AM, said:

I mean that this glitch was visible while walking along the bigger 720-degree circle (don't know exactly how it's implemented).

This post has been edited by Vadim Z: 11 October 2020 - 12:03 AM

Doom64hunter

#8 Posted 16 October 2020 - 04:35 AM

Vadim Z, on 11 October 2020 - 12:00 AM, said:

I mean that this glitch was visible while walking along the bigger 720-degree circle (don't know exactly how it's implemented).

This issue is unrelated to the elevator and was introduced in a much older revision. (r7601 from what I can tell)

MetHy

#9 Posted 02 December 2020 - 01:14 AM

Doom64hunter, on 16 October 2020 - 04:35 AM, said:

This issue is unrelated to the elevator and was introduced in a much older revision. (r7601 from what I can tell)

I was just testing some Blood v1.0 in DOSBOX and noticed that this SOS visual glitch (being able to see elements from the other SOS floor for a split second) can actually happen there also, although it seems to be rarer.
It seems more likely to happen when crossing small sectors.

Point is, this looks like a DOS thing after all; although it's possible that it was fixed at some point hence why it feels new to us now.

Ninety-Six

#10 Posted 02 December 2020 - 09:16 AM

I always assumed this was a byproduct of when the eduke team fixed the SOS warping glitch. That it was the game trying to warp you and then the fix quickly throwing you back where you belong.

MetHy

#11 Posted 04 December 2020 - 02:13 AM

Ninety-Six, on 02 December 2020 - 09:16 AM, said:

I always assumed this was a byproduct of when the eduke team fixed the SOS warping glitch. That it was the game trying to warp you and then the fix quickly throwing you back where you belong.

If you record the glitch and check the video in slow-mo, it looks more like a rendering glitch; like the game thinks it needs to render the sectors on the other plane before withdrawing "Sorry, you weren't meant to see that!"