[v10] Add Frustum to rootState #3648
Description
Related to #3647
The Renderer in its core has a frustum that it does all it checks against. Of course it doesn't expose this and that seems intentional.
If we make one ourselves or at a minimum make a utility to make this not a nightmare it is incredibly useful.
The main issue is if you do postprocessing or any other camera type the internal frustum is totally different. So I think it would make sense to bind it to the default camera. If someone wants a special camera and frustum a util like:
frustumFromCamera(camera, existingFrustum); //update
const myFrust = frustumFromCamera(camera); // creates new