Add option to disable gizmo rendering for specific cameras

[tim-blackbird]

Added GizmoConfig::render_layers, which will ensure Gizmos are only rendered on cameras that can see those RenderLayers.

[nicopap]

Bevy usually has additive components (ie: component that enables gizmo) rather than subtractive components.

But here is the catch:

• I'm not sure how a RenderGizmos component would work. Surely, it would be added to the CameraBundle, but then how do you remove the RenderGizmos component?
• gizmos exist for debugging, so API ergonomics trump all.

[mockersf]

couldn't render layers be used?

[tim-blackbird]

couldn't render layers be used?

This was originally my plan but render layers are not extracted to the render world so using that would require additional bookkeeping.

[mockersf]

render layers are not extracted to the render world so using that would require additional bookkeeping.

Would this similar to what is done in #8332 for UI?

[tim-blackbird]

Would this similar to what is done in #8332 for UI?

Yeah, would you prefer I grab the RenderLayers extraction code from that PR and go with that?

[mockersf]

Yeah, would you prefer I grab the RenderLayers extraction code from that PR and go with that?

Yes. @james7132 seemed to not be a fan to add those to the render app, but if ECS/renderer experts are OK with that it would have my preference

[alice-i-cecile]

My preference is also for reusing the RenderLayers mechanism here. No strong opinions on exactly how that should be done though.

[tim-blackbird]

@james7132 probably didn't like paying the cost of extracting RenderLayers for every ui node, but we only need them per camera/view here.

[mockersf]

I would prefer to be able to set the render layer per gizmo to decide which goes to which camera, but that seems already useful as is

[tim-blackbird]

We definitely want more granular settings. I'll open some issues for future improvements to bevy_gizmos soon.

[alice-i-cecile]

@devil-ira can you update the PR description to reflect the new changes?

[cart]

I updated the description and reverted the split_screen "renderlayer gizmo" changes. split_screen exists to show a minimal split screen setup. Adding gizmo config to it adds unnecessary noise. We should create a new example if we want that.

[tim-blackbird]

Oops, didn't mean to commit the split_screen changes.