Iterate through all cameras - possible?

Hey everyone, I'm curious about executing code for each camera in the scene, including the scene camera.

For objects that only need to execute code for the camera I use OnWillRenderObject(), but that will only consider cameras that will render the object in question. Is there a way to iterate through EVERY camera, whether they're rendering an object or not? Is that even possible?

 

I have never tried this, but I would begin something like this:
https://docs.unity3d.com/ScriptReference/Resources.FindObjectsOfTypeAll.html search for all camera. Probably the scene camera isn't among those.
You can gain access to the SceneView camera through this: https://docs.unity3d.com/ScriptReference/SceneView-camera.html

Just add this to the list. But keep in mind that you can't change the camera settings directly through this reference.

 

SRP also allow you to do this

 

I'm confused, are you trying to run something from the camera, or iterate over the cameras from somewhere else? You could just add a component to each camera, that way every active camera will call Update on your object.

If you want to do some iteration from another class, you could just store references to each camera in a static list. I have a number of places where I do that. In a camera object's constructor, push it onto a list, when it's destroyed, pop it off. Then from any place in the code, you can just iterate through the list without any performance hits trying to search.

 

Creating an array of cameras was an idea too, however I don't think, that's the issue. The issue is that that alone won't help me execute code for every camera individually before they render. If I do it in Update() everything will be done before the first camera even starts rendering - I need to do stuff between each camera rendering. OnWillRenderObject() seems to be the only event that will allow me to do that, but it's selective - pity. :S

 

Have you tried this?
https://docs.unity3d.com/ScriptReference/MonoBehaviour.OnPreRender.html

I don't think it is suitable for the SceneCamera though.

 

Take this as an example: I have a cube. And I want to move that cube to the middle of the screen of every camera. I can't use multiple cubes, it must be that one. OnWillRenderObject() allows me to do that, but it only works as long as each camera is rendering the cube anyway, I need every camera to render it at the exact predefined position regardless of whether it sees it or not. I can't do that anywhere in update, can I?

P.S.: My script would be on the cube, not on every camera.

 

That works only for one camera, the camera that is attached to your gameobject.

 

Yes, you need to attach it to every camera you have.

I think more detailed handling is only available in SRPs. Where you can inject anything you like to the render process.

 

FindObjectsOfType<Camera>() will work.

Its not super fast, so I would suggest caching the results if you want to use it frequently.

Also note that at editor time this will find scene cameras as well. You may want to use Camera.cameraType to distinguish between different cameras.

 

Unfortunately it is not what he's looking for. Later he stated that he needs the cameras one by one right before they render and not in a big list at some point in the update loop. He wants to move one object in the front of the camera right before rendering. The same one for every camera.

 

Subscribe the SceneView events, then you have the scene camera in the correct context to draw.
https://docs.unity3d.com/ScriptReference/SceneView.html

SceneView also contains properties to iterate over all open scene Windows and get their camera in case this is useful.

For game cameras you can use Camera.allCameras:
https://docs.unity3d.com/ScriptReference/Camera-allCameras.html