Question Allocations with multiple cameras

Hi,

I'm using Unity 2022.2.8f1 and I've noticed that using multiple cameras causes huge reallocations depending on camera's resolution (around 15KB/frame in my camera setup). Additional cameras are rendering into textures.

I found similar complains, like this: https://forum.unity.com/threads/just-by-having-a-second-camera-causes-gc-kick-in-urp.930594/

But it seems I have completely different issue. Some textures like m_CameraDepthAttachment are reallocated each frame for each camera in UniversalRenderer.Setup(). Either because textures have different size (in case of cameras are sharing the same renderer) or are disposed after previous camera (in case of all cameras have their own renderer)

I tried different approaches without success. Then I checked official URP samples, like TrailEffect, and found the same issues there. So it seems I'm doing everything alight.

So I have few questions:

1. Could you please confirm that these allocations are not okay? Or maybe that's an expected behavior?
2. If first, is there a way to fix this?

[Edit] Just checked same demo in 2021.3.18f1 and allocation is 0KB per frame. So is this a bug?

Thanks

 

Hi! I saw this behavior too and it's caused by this piece of new code on the UniversalRenderPipeline.cs script:

Code (CSharp):

1. if (!isStackedRendering)
2.                 {
3.                     for (int i = 0; i < rendererCount; ++i)
4.                     {
5.                         var currRenderer = asset.GetRenderer(i);
6.                         if (baseCameraData.renderer != null && !currRenderer.hasReleasedRTs && baseCameraData.renderer != currRenderer)
7.                         {
8.                             currRenderer.ReleaseRenderTargets();
9.                         }
10.                     }
11.                 }

This code is making the RTs to be released every frame so they should be requested again (every frame, meaning GC). Also, even fixing this bug (which is pretty big), the FPS are worse in 2022.2.8 (URP 14) than in 2022.1.17 (URP 13). It would be great to have official info about these issues. Thank you!

 

Running into this issue as well, with 18kb allocations per frame as soon as a second camera is enabled. I managed to track it down to the same change mentioned by JohnHacker above and thought based on the final condition `&& baseCameraData.renderer != currRenderer` that I'd be able to avoid the allocations by giving the two cameras the same renderer asset but alas, didn't work out.

This is a pretty big issue for my game as I had up to three cameras active. I was able to refactor one camera away (yay!) but that's about as far as I can take it. The garbage generated and RTs being recreated every frame here is tanking performance.

As an aside, the second camera even seems to generate shadow textures (Inl_Setup Additional Shadows & Inl_Setup Main Shadowmap) even though it has Render Shadows = false

 

Thanks @Jonas_Sid, that's great news. Any idea of a release timeline or too soon to say?

 

Can anyone confirm if the fix has landed in a public release (2022.2.14)? I've been waiting for this before trying 2022.2 again and haven't been able to spot anything in release notes, but I might just be blind. Any updates @Jonas_Sid?

 

Are you certain this is fixed? I use 2022.3.4f1 and I added a second camera rendering into a RenderTexture for a mini map, and I get the most horrible performance drops ever witnessed.

 

Same issue here on 2022.3.4f1.
Main camera uses 1/3rd fps of my second camera, which renders to RenderTexture for water reflections...

 

I'm using 2022.3.4f1, when I add a secondary camera to render my character into renderTexture. Frame rates are getting drops from 300+ to 30 frames. Is there any solution for this ?

 

I would like to point out that this problem persists in version 2022.3.4f1. Currently, Render Texture cannot be used in any way and there is an incredible fps drop in used situations. I hope there will be an update on this topic soon.

 

Is anyone aware of when Unity is planning to release a fix in version 2022.3?

 

Hi guys, 2022.3.4f1 the same problem. FPS drops to unstable 8-12-20-40 from around 150 when I add/activate a render camera to render a particle system for my water shader. It's a game breaking bug. Unity please fix in the next update.

 

issue still persists in 2022.3.5f

 

Bumping this thread because it may be related to mine. I was seeing reasonably large allocations when a second camera is enabled, but it seems to have something to do with strings...

 

Does the situation get equally worse if you enable the 3rd camera?

 

Hey all,
Seem to be experiencing this issue on 2022.3.5f1 as well.
Game runs fine on ~150fps (in editor) until I open my UI and render a camera to texture / raw image, it then drops to 6~25 fps range.

(To clarify: If the camera is active in the scene the issue occurs, regardless of if the UI is active or not, I just disable it when the UI is not active at the moment).

16.7KB CG Alloc for PlayerLoop at the moment.


Anyone found a fix for this, or any additional info?

 

Well I upgraded to 2022.3.8f1, This particular issue is still there

However I made an attempt to build my project, and it seems to run relatively well outside of the editor. Can anyone else confirm this is an editor only issue?
I didn't run any profiling for the build itself so I can't tell whether or not this will cause me any problems in the future.

 

No fix, but new pricing lol. I'm likely switching to unreal...

 

I can agree on the first part! Unity please fix this!

https://gyazo.com/9eef34275ed5f8f7963556752c76193b

4.8 GB of render textures? I only have a camera stack in my scene and in this particular snapshot there was a sight attachment on a weapon that is using a camera rendering on a render texture. That long DBufferDepth_1024x1024 is it. And it's repeating forever in the memory profiler, allocating 8mb each time.

Also i've noticed extra render textures for the camera when switching resolutions, as someone mentioned above.

Also my game takes 2.6gb ram in total if i launch it and play it, if i open up the menu it increases to 3 (no extra camera, nothing just the camera now sees UI, the canvas is screenspace and it renders on that very same camera). If i close the menu this memory is not released.

I will probably open a new thread with more in-depth details, but let me clarify this:


https://gyazo.com/d7d10a9961ea79a020c64055d7faa054

B is if i open the game, play for hours or whatever and not open the menu. So the main camera renders the world with render textures worth of 0.7gb.

After i open the menu (see A) the game gets flooded with render textures that are never released.

Please fix this! Our game has been called a bitcoin miner for this crappy memory management. We've implemented addressables to unload memory from 25+ GB and now we have 5GB worth of render textures?

 

Having the exact same problem in 2022.3.4f1
Generating around ~10KB of garbage/frame with minimap camera & base.