Feature Request Post Processing with multiple cameras is currently very problematic

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OP here, after managing to avoid this issue for half a year i'm finally stuck because of this again LOL.
And we've reached second page, woohoo! Thanks for the involvement everyone!

Also, i just realized i've never mentioned what i even need this feature for; my game is a 2D platformer with 3D graphics where most of the visuals are rendered in perspective while the level objects, enemies and characters are rendered orthographicaly (to maintain consistent perspective across the screen). The orthographic view is sandwiched between a camera rendering what's in the back and a camera rendering what's in front. I want to have one set of PP effects for the visuals and one for the level but cannot do that because of the topic at hand ;_;

 

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This is so disappointing, this possibility is what made camera stacking even remotely exciting, and it doesn't work?
We need this feature asap unity.

 

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I need my second camera to retain transparency when rendering to the texture while using post process. So it's also a big +1 from me!

 

Big +1

 

Godot engine does this for free, and is similar enough to unity that you could pick it up in a weekend.

Just saying.

 

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+1's don't help. Bug reports do. If you have an issue tracker, link those. There people can +1 to show importance.
Some of those bug reports end up already being internally known and handled, hence no issue tracker is known publically. But yeah the least you can do is report the issue with a simple reproduction project.
It might also be that the issue has already been solved in a later version of the render pipeline.

Both issues I reported are closed and supposedly fixed. I was waiting for a backport but instead I've updated to Unity 2021.1 since most of the fixes land in the newer versions of Unity first.

So take your time to report the bugs and if it ain't a bug but a missing feature, there's the roadmap

 

Since this is more of a feature (so no bug reports), and there is no way to create a item on the roadmap and share it to gain votes anymore, all we really can do is just share why we want the feature on this forum, with +1's acting as as simple voting system. Does it work? Probably not. But it's better than nothing.

 

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I too was hoping to be able to control the order in which post effects are applied and cameras in the stack are merged together. It kind of seems like a graph interface would be the best solution for this to serve the various different configurations people have described here, and still deliver the best performance.

 

I added the Feature Request today!

 

+1 on this topic. Really needed feature, there are so many things in my backlog for my game that is impossible to do before i can apply different post processing to different cameras.

 

I looked into this myself as I thought I'd had to create one Camera with a Post-Processing effect to grey-out my complete scene and than have another Camera with another Post-Processing effect that would render some of GameObjects in colour on top of the greyed-out scene. But as stated here, that just doesn't work in URP.

But I found another solution, which actually gives me more control and even only needs one Camera. Using Renderer Features gave me the ability to use a Shader to render my scene completely grey during the After Rendering Opaques event and then render my GameObjects with colour during the Before Rendering Skybox event, by putting the GameObjects in a specific Layer. It actually gave me more possibilities than I could accomplish with the Multiple Camera setup.

Renderer Features were introduced in URP 10.1.0, but is still getting more powerful (and useful)

Here's an example of my current setup:

https://i.imgur.com/FRXCb5j.jpg

Of course this doesn't mean I still don't want the multiple camera feature, I just thought I'd provide a different solution to the problem

 

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I'd really like this feature as well.

 

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+1 this is happening to me too,i am trying to make a neon effect,Unity please to something about it,it's not a bug so i cannot submit a bug report and have to suggest it here.

 

Honestly surprised this hasn't been fixed/implemented yet, I originally ran into this problem a year ago.

Really would like to be able to have post processing only apply to a specific camera in a stack.

 

yes indeed,i hope a unity staff would look into this problem and stop ignoring it.IT IS INPORTANT!!!

 

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for my sake, I want bloom on my UI to simulate a neon glow, and also be able to animate a chromatic aberration on my UI post process.
The problem (as many others have pointed out), is that this will also apply the bloom and chr.abr. to my 3D scene, which I dont want.

 

Hello, you can achieve such effect with URP but it require some work.
In the end I had to create a custom camera stack in order to do such thing, but it's properly working now :

In this view there is actually 4 cameras rendering in this order (I use culling mask to select what to render for each cam):

- Background -> PP + AA
- Dices -> PP without AA for crisp looking, and good looking texture
- Foreground (Player 2) -> PP + AA
- UICam -> No PP, No AA

As you can understand there is multiple cam with PP and AA, but still I'm able to control each one individualy without affecting the others.

For this to work properly you need to combine each cam with transparancy, so first step is to make PP compliant with transparency which is not by default, so you have to modify at least UberPost.shader and FinalPost.shader to handle transparency.

Here is how my frame debugger looks likes :

If we look camera Dices and Foreground Alpha Only, we can see this

and
Since I have modified PP shader to support Alpha that's mean that PP is also done on these intermediate renders.
This mean that we can basicaly use the alpha of each render to combine them properly.
Which is made possible by a ScriptableRenderPass, that take the output of each camera in right order and then merge them with alpha blending.
The script GenerateRenderTexture do the trick to setup properly camera, and rendering order :


Each camera in the stack will be setup by the script to output to a render texture that support alpha, and will have this priority property setup accordingly with the order in the stack.

There is some limitation to this :
- You can't use premultiply alpha for particule or effect because premultiply alpha by definition doesn't write in the alpha texture. So all your effect have to be alpha blended if you want to see them.

 

These image explain this limitation :

When I'm selecting a dice in the game view the shader as to write in the alpha so I can't use premultiply alpha on this effect otherwise, it will not be visible in the final render.


Here are all the camera config in term of PP and AA (the three first one priority and rendertexture are configured by the script GenerateRenderTexture of the fourth one which handle the stacking) :


Edit :
I can explain further and share script if needed, but you should have a basic understanding of how it can be done, and the limitation of this approach.
You can see it as compositing, where each cam render it's image with PP and AA, and later in Photoshop you combine each image with layer stacking using the alpha.

 

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camera stacking make things look wierd the turret is on the platform and not inside it but when it rendered that's what it shows in the game view when i stacked cameras it's supposed to look like this my cameras look like this

 

thank you so much for sharing this workaround! Can you go into more detail about how to modify the post processing shaders, and add the scriptable render pass? And/or share your code if that's something you're willing to do? No worries if not it just seems like this is the closest viable workaround right now.

I'm really kind of caught off guard with this issue, it's something that could be done with the built-in render pipeline and seems like a major missing feature

 

I agree,a video on how to do this may be helpful too

 

Is this problem already fixed?

 

no,not yet

 

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+1 To take attention @ali_mohebali

 

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All post processing is being applied twice. Once for each camera. This is really irritating.
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Edit 02/20/22 1:42 AM EST: I'll be investigating further, but I seem to be having trouble with Bloom seeming to deactivate after entering play mode. It might be post effects in general. Both in scene view and in game view it looks fine, but as soon as I hit play it only works for a fraction of second then disappears. If I toggle the global volume off and on again, same thing. It only works very briefly. And yes, all my settings are configured properly. Am running Unity 2021.2.7f1 on URP. Have a pipeline asset, Post effects enabled, HDR enabled, every possible setting seems to be in order. Have no idea what's going on. Only potential issue (seems) to be that I am using camera stacking for FPS view anti-clipping. Will edit post with solution if I manage to find one myself.

 

Same here. In my mobile app HoppAR, I need both the features discussed here:

1. Individual Overlay Camera PostProcessing
2. Keep Alpha while Post Processing

Cannot find this proposal on the Unity Product Board, can someone point me there in order to vote this up to Unity's team attention. Thank you!

 

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@ali_mohebali not 100% sure if you're the right dev to ping, but is this issue on the Unity Team's radar, or is it already being addressed by this Product Board Proposal?

Whatever the case, (speaking for many) it would be great if you could provide information or clarification on this topic.
Thanks!