Time.deltaTime Not Constant: VSync CameraFollow and Jitter

@AnsisMalinsUbisoft wants to get the most up-to-date input messages they can. How best to do this? Do all input-agnostic processing before running the PumpOSMessages logic. This would allow them to process input that the system detected while their input-agnostic logic was processing.

They simply wish to do Input-dependent logic as close to the Input "reading" as possible.

No. The link leads to a Microsoft Feedback Hub link. It requires the Feedback Hub app to open the relevant information.

 

Oh I see, it was blank page. I'm not gonna install some MS app to see it tho, thanks.

Hmm, I see. Not sure it would be much of a gain, FPS have to be pretty high for it to really matter imho. But then higher FPS implies that logic processed very fast as well so...

 

Actually, the lower the FPS the more this would matter. If you are able to hit a frametime of 3ms then by definition your response time is capped at 3ms.

If your frametime, however, is 45ms-or-more (lower framerate) then it can start to feel unresponsive.

 

Is there a way to share the information with those that are not on Windows 10?

 

Just to be clear, new input system relies on this snapshot still and doesn't do it's own polling? I ask because I was under impression that the new input system could do it's own polling outside of the main loop.

If the new input system relies on only getting new data at a specific moment in the player loop, it's totally pointless that it lets even users select where it fires in the player loop (there's a project wide setting for this on the input system).

I trigger it manually because I have custom devices that I want to poll at the exact moment I trigger the poll and that definitely works without having to wait for another main loop iteration but it also uses my own native plugin so it's not tied to Unity internals..

 

Fantastic. This is amazing.

Will you be able to contribute to the PlayerLoop documentation for the newly added system? I hope so... the current docs are extremely thin and your explanations here are like a breath of fresh air...

 

I'm now assuming Vulkan fix hasn't landed for PC?

 

You have any estimate for the multimonitor fix for 2021.1 alphas?

 

@Tautvydas-Zilys Can you post the bug link for this issue please? And do you know if this fix was backported to 2019.4 LTS?

 

Hi. Would it be possible to get an little Git Repro with some Testprojects according to this.

"Time.deltaTime stability improvements. Frame time calculations are more stable now, providing much smoother object movement when the game is running at a stable frame rate. Unity 2020.2 has time stability improvements on iOS, macOS, PS4, Switch, tvOS, UWP, Windows and Xbox One. Improvements on Android, Windows/Linux on Vulkan and XR will come later. See this forum discussion for more details."

For me it s a great improvment but it s a little intransparent what´s done, what s possible now and how to use correct.

In special in multi monitor setups and cinemachine and standard camera jittering following rigid bodys and so on.

A little Blog Post would be nice too.

And many thanks to
rz_0lento

who backfired this.

 

cool, but not for android, (VR/Oculus Quest2)

a realistic assessment of when android will be fixed?

 

O_O *nocomment*

 

it's getting better and better..... now nothing works with Unity 2020.2

> texture browser lags as hell
> preview packages checkbox for package manager doesn't work! They don't show up!

enough problems already to not start with that version as well! pfff....

Guys, UNITY is a mess and by what happened to the company last year, and all the employers who left the company (core developers!!! Whole HQ are empty (see job postings)....

....so much for the future oft game developing!

 

First off i want to say, thank you for all of your work with this project once all the bits get ironed out this will make for some great improvements across the board!

I seem to be having a problem with any kind of interaction with the 2d pixel perfect camera.

This is only a problem in 2020.2, in 2020.1 this issue is non existant!

I have a video showing the problem. when enabled it jitters very badly, and offsets the world relative to the camera

using fixedUpdate to calculate positions with a low fixedDeltaTime AND having a high framerate <- best option
(using a low fixedDeltaTime and calculating positions within fixedUpdate was how i was getting around the non consistent delta times previous to these fixes)

using fixedUpdate to calculate positions with a low fixedDeltaTime AND vsync <- close second

using deltaTime with high framerate <- third

using deltaTime with vsync at 60 (basically unplayable) <fourth

but in all scenarios when pixel perfect camera is enabled we see the characters jump forward and stutter back and fourth

Again these are only valid when using the 2d pixel perfect camera (as you can see in the video) when pixel perfect is disabled things are smooth (although not pixel perfect)

I'm not sure if here or if in the URP 2d threads is a better place to post this.

I also understand this was a huge undertaking and am extremely happy to see it implemented and only wanted to flag this as an issue so it can be known!

I will also be uploading a bug if this is an unknown issue!

 

On behalf of all Unity devs can I thank @Zullar for pushing this deep issue to a great conclusion from a standing start.

 

Glad to see the fix added to Android, but when can we expect the deltatime fix to make it to Linux as well?

 

Will the fix land on 2020.2 eventually?

 

That would be perfect! Anyhow, I am happy about the news!

release notes:
https://unity3d.com/unity/beta/2021.1.0b1

 

Any update on this?
Was just working in Android VR on Quest, after working on the windows build. It's so smooth on Windows! I thought I had broken something in my Quest build after coming back to it\.

 

I imported my 2020.x project to the 2021.1 beta and made a build. No jittering anymore! Everything runs smooth on the Oculus Quest 2. Finally! Did you made a build with 2021.1, activated phase sync as well, and set the time step to 0.01111? btw multiview/URP. and btw the quest2 is not really a strong device. I still go for render scale 1.0. Because only there you get the full fps. Also I use the Oculus Metrics Tool, to test the framerate on every corner.

appendix: ups, I see you are aware of all the things xD Now I wonder....

 

Try Time.fixedDeltaTime instead of Time.deltaTime, it worked for me.

 

It does not work, because fixedDeltaTime is the physics framerate, and not related to the display framerate.

--Eric

 

@Tautvydas-Zilys has this fix landed for all platforms?

 

I'm sorry to "reopen" the topic, but the problem persists in newer versions of unity (2021.2.8f1, 2021.3.0f1, 2022.1.0b16, I also tried the mentioned version 2021.1.0a2) in android builds, although it looks really smooth on windows builds. (new blank projects with squares, moved by transform.Translate())
Could you recheck it somehow and how can I help?

 

well, bad news: the problem seems to be not in the deltaTime values


But the picture (even this graph) "moves back and forward" for a frame like once in 0.5 - 5 sec (and this measurement was also put into empty project).

And thanks for quick response!

 

It's already on (by default)

 

Captured the symptom:
Movement of 1 object (most noticable at sec 7 to the end):

To make it more noticable (especially the second half of the video) - movement of background (same script on root bg object):

Movement code for square (almost the same for backgroud):

Code (CSharp):

1.     [SerializeField] private SpriteRenderer _renderer;
2.     [SerializeField] private Transform _startPosition;
3.  
4.     private Vector3 _movementVector;
5.  
6.     private void Start()
7.     {
8.         _movementVector = new Vector3(5, 0, 0);
9.     }
10.     private void Update()
11.     {
12.         if (!_renderer.isVisible) transform.position = _startPosition.position;
13.  
14.         transform.Translate(_movementVector * Time.deltaTime);
15.     }

 

nope, it works buttersmooth on windows
in fact it looks much better even in editor

 

shall I do something or help somehow?

 

well, I have submitted one two weeks ago but got no reaction yet, shall I post the case number here or smth else?

 

1421680

 

it looks untouched after a month, can I do something else to help?