Overlay Camera Stacking problem in Unity.

[The Fusion Works]

I am a programmer writing something in Unity 2019.3 and I want to use stacked cameras to have different post processing effects but as soon as I add a second camera as an OVERLAY camera and set the main Steam VRCamera base camera to stack the secondary camera then the rendering tries to render both eyes to both left and right eyes.
Has overlay camera stacking been acocunted for with SteamVR? Am I doing something wrong with adding in an Overlay Camera

Thanks in advance,
Lindsay.

[FPGA]

I assume an overlay camera is not a camera that renders to a RenderTexture hat is used as OpenVR.Overlay Texture. But maybe it helps to know that a camera rendering to a RenderTexture is not rendering stereoscopic using this RenderTexture in the stereoscopic main camera render process might cause issues.

[The Fusion Works]

Hi @FPGA and thank you for your reply. Yes you are correct. I am not rendering to texture but trying to use the URP Camera Stacking functionality.

As the simplest of tests to see if this works at all I have done the following:

I have installed the latest unity (2019.4.0) and then started a new URP project. Then imported the SteamVR unity asset.
Then opened the scene -
\\Assets\SteamVR\InteractionSystem\Samples\Interactions_Samples.unity
So it is the base steamvr sample scene for unity.
All is good, if I run it, I can mess about in the world in my headset.

I now introduce a cube and give it a new layer (TestOverlayCamera)
I introduce a new camera and set the culling to be only "TestOverlayCamera" and set it to be an OVERLAY camera
I set the VR camera culling to be everything but TestOverlayCamera
again all is good, I cannot see the cube.

I add the overlay camera to the VRbase camera's stack

I still cant see the cube, but I can see it on the camera view on my editor window.

It seems that the headset renders ignore any overlay cameras in the base cameras stack.


Are SteamVR cameras just set up to handle URP camera stacking or has anybody managed to get this going?


Thanks again,

Lindsay.

[The Fusion Works]

It is definitely only the SteamVR headset camera that has these issues. If I unplug the headset so that it forces the demo scene to play through the game panel through the FallbackObjects Camera then it does show the cube on the overlay camera rendered over the primary camera in the stack.

So it is a fundamental difference with just the SteamVRObjects\VRCamera and the camera on NoSteamVRFallbackObjects\FallbackObjects

I think that it is pointing towards a bug then with the SteamVR. Would anybody be able to sanity check my reasoning?