SpotLight + Camera on the same entity causes incorrect culling

[NickTheFox99]

Bevy version

v0.16.1
(Cargo.toml stated >=0.16, noticeable in both 0.16.0 and 0.16.1)

Relevant system information

Adapter Info:

`AdapterInfo { name: "NVIDIA GeForce RTX 4060 Laptop GPU", vendor: 4318, device: 10464, device_type: DiscreteGpu, driver: "NVIDIA", driver_info: "561.09", backend: Vulkan }`

What you did

I attempted to try to add a SpotLight component (with shadows_enabled: true) to an entity that had a Camera3d component after the Camera was initially spawned. I added the component to the same entity as the camera, not to a child.

What went wrong

I was expecting everything (but the spot light) to remain the same after adding the component.

What actually happened was the objects would disappear when camera rotated correctly, the amount of error where objects would disappear changing when closer or further.

Additional information

Code: https://github.com/NickTheFox99/bill-boards-bevy/tree/985506e56053e864438870a3440341d8ce8aca96
Relevant Files (in src/): lighting.rs, player.rs, cube.rs

Correct / Expected behaviour

Unexpected / Observed behaviour

I'm thinking that somehow the SpotLight may be triggering the Camera culling more actively when placed on the Camera, but I don't know how much of the components work under the hood and I may be wrong.

To work around this, I've added a child entity to the Camera and added the SpotLight to that. I've also noticed that setting the shadows_enabled field on the SpotLight to false fixes the issue.

I've looked, and do not think there are any similar issues noticed.

[alice-i-cecile]

Thanks for the issue, and especially the investigation and reproduction!

[NickTheFox99]

After taking a quick look, I noticed both the SpotLight and the Camera components require the Frustum component.
These components may have conflicting uses, causing the Frustum Culling on the camera to break.
What's strange is that setting shadows_enabled: true on the SpotLight fixed the issue.

[alice-i-cecile]

Oh I see: you're trying to add a spotlight directly to your camera entity? That would cause the problem...

You want to make the spotlight a child instead. I think this is probably a docs issue: I don't think this is a reasonable thing to try and support due to the conflicting requirements.

[alice-i-cecile]

We could instead move the Frustrum into the camera and/or spotlight components: it's not clear to me that we should split it out into its own component.