Lag when activating GameObjects

Question

I'm doing a simple script of a character running through a dynamically generated track, defined in segments. I have multiple instances of the segments instantiated in Start() with active=false, and have 4 segments active at any point of time.

Everytime the character crosses the end of 1 segment, I will deactivate the segment be$$anonymous$$nd and activate a new segment at the end of the track. When t$$anonymous$$s action takes place, there is a significant lag (1-2s). T$$anonymous$$s lag is reduced to almost not$$anonymous$$ng when all the segments have been set active=true at least once.

T$$anonymous$$nking that all segments must be rendered at least once, I set Update() to have everyt$$anonymous$$ng active=true when first called, and then as normal from the second time Update() is called. There is a much longer lag at the start (expected) but the lag still remains.

What else can I do to eliminate t$$anonymous$$s lag?

Thanks in advance.

Answer 1

Answer by loboclerk · Oct 21, 2013 at 03:05 AM

Thanks for everyone's inputs.

After several rounds of tests and alternatives, I'll list my conclusions here. Eventual result was smooth gameplay with additional user input initially.

Enabling and disabling the renderer had the best performance, compared to SetActive() and Instantiate/Destroy.
Lag on the first render of each GameObject instance could not be resolved, so everyt$$anonymous$$ng had to be rendered first and "covered", w$$anonymous$$le waiting for user to click on a button to start.

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tubelightboy · Oct 28, 2020 at 05:58 PM 0

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I did not have this problem for some time and somehow when I was cleaning up my scripts, it crept in. I've tried all performance tweaks but none of em worked for this. The first lag for an object which renders initially... is it inevitable?

Answer 2

Answer by $$anonymous$$ · Oct 17, 2013 at 01:33 PM

I would take a look at the way you're initializing your track segments. You may have some initialization code inside the Start method for each track segment that's causing the delay. If that's the case, then the delay makes sense since Start only runs if the script instance is enabled.

https://docs.unity3d.com/Documentation/ScriptReference/MonoBehaviour.Start.html

Does the lag go away once you go through all 4 segments at least once?

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$$anonymous$$ · Oct 17, 2013 at 03:56 PM 0

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Just re-read original question - it looks like the lag indeed goes away, so I would look at your Start() initialization code for each track.

loboclerk · Oct 17, 2013 at 05:07 PM 0

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Thanks for your comments. The lag happens when I deactivate 1 segment (and attached children) behind, and activate 1 segment in front. I will also activate some gameobjects (also from a pool), set position/rotation and attach them as child to the main segment.

The code that is being run is exactly the same each time, just that for each instance, the first time takes longer.

$$anonymous$$ · Oct 17, 2013 at 05:16 PM 0

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Could you post your object activation code from the Update() function? Maybe you're loading the same track multiple times?

loboclerk · Oct 18, 2013 at 12:58 AM 0

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Posted above! Ran Debug.Log() to make sure it wasn't run multiple times. If it did lag due to multiple calls, the lag wouldn't disappear after the first call for each instance?

Answer 3

Answer by meat5000 · Oct 17, 2013 at 01:47 PM

Pre-instantiate and cycle

Enabling and disabling gameobjects is far cheaper than instantiate/destroy. Consider employing an object pool to take advantage of t$$anonymous$$s.

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loboclerk · Oct 17, 2013 at 05:09 PM 0

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Hi, sorry I did not make it clear above. I am coding my own object pool, that's why I am only activating/deactivating game objects instead of instantiating/destroying them. Unless I'm missing something here? (new to this)

meat5000 ♦ · Oct 17, 2013 at 06:43 PM 0

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Sounds right. Maaaaybe time to post some code?

Answer 4

Answer by Chaosgod_Esper · Oct 17, 2013 at 01:59 PM

A 3rd approach is - add your model to a scene and save it from there as a prefab. I recognized that Prefabs are loaded much faster than a direct model (tested in my Dungeon keeper System)

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loboclerk · Oct 17, 2013 at 05:10 PM 0

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Thanks, will give it a shot and update!

loboclerk · Oct 18, 2013 at 03:54 AM 0

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I realize that by calling this, it is working effectively like a prefab. When the script is running, the generated gameobjects are all already indicated as (Clone). The performance difference then would only affect whatever's run in Start() and not in Update().

 Instantiate(Resources.Load(resourceRef));

In any case, I tried cloning prefabs explicitly and it was the same.

Answer 5

Answer by whydoidoit · Oct 17, 2013 at 05:15 PM

I'd be guessing you have colliders in there. If the colliders don't have rigidbodies attached then they take a long time to make active at a new location. Attach kinematic rigidbodies to the colliders an it may help.

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loboclerk · Oct 18, 2013 at 01:01 AM 0

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Actual instances were created inside Start() using

 Instantiate(Resources.Load(resourceRef));

Inside Unity Editor, Generate Colliders is unchecked for the imported model. I suppose with this, all physics for these objects would be off already, or am I missing something?

whydoidoit · Oct 18, 2013 at 01:12 AM 0

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So these sections have to colliders when you look at them in the editor?

loboclerk · Oct 18, 2013 at 01:20 AM 0

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I looked at the inspector when the code was running and clicked on the objects in the scene. None of them had any colliders or anything physics related. hmmm..

whydoidoit · Oct 18, 2013 at 01:27 AM 0

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You are setting and checking .active -> that should now be SetActive and activeInHierarchy presuming you are using Unity 4

loboclerk · Oct 18, 2013 at 01:50 AM 0

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Thanks for pointing that out. Changed all to SetActive and activeInHierarchy/activeSelf already. No change to performance unfortunately.

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Lag when activating GameObjects

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