fix(light despawn / pcss example): add extracted lights and shadow related components to SyncComponent for lights

[kfc35]

Objective

• Fixes Pcss example is broken #23769 !

Solution

I git bisect’d the issue to bbcc1e6 which has to do with SyncComponents. The problem was that not all the relevant components were being despawned when toggling an entity between different Light components within the example. Expanding SyncComponents for each light ensures that the lights clean up properly between toggling.

I also had to review #23713 and I connected the dots that de-spawning the light should also despawn the light view entity. Duh!

Testing

• cargo run --example pcss --features=“experimental_pbr_pcss”: toggling works!

[JMS55]

I think this overlaps with the observers, e.g. extracted_light_removed. We should probably remove the observers in favor of this?

[kfc35]

I think this overlaps with the observers, e.g. extracted_light_removed. We should probably remove the observers in favor of this?

I removed that specific observer extracted_light_removed and added DirectionalLightViewEntities to the SyncComponent Target for DirectionalLight. However, I kept the remove_light_view_entities observer around since that one despawns the individual entities within the DirectionalLightViewEntities component (which SyncComponent does not cover)

I also removed some (I think?) redundant code in extract_lights that kept the main and render world sync’d with respect to Lights and their Extracted equivalents since SyncComponents should do that job now, and it actually improved the example — it removed the one frame blip of darkness between toggles of point and spot (although the shadows are still broken toggling between the two)! Hopefully the code is truly redundant, it seemed well documented for a specific reason...

[kfc35]

I figured it out after reading #23713 a little more deeply!!! I’m confident this is a full fix now, and it fixes the pcss example completely 😄

[Zeophlite]

Great work