Integrate bevy_picking support

[spectria-limina]

bevy_mod_picking, which previously implemented egui support in the bevy_picking_egui crate, now has been integrated into Bevy 0.15.

As a result, bevy_mod_picking and its associated crates are deprecated, and support can now exist in egui proper anyway.

Please important the picking library for egui so that it can continue to be used in 0.15.

[vladbat00]

Hi! Thank you for the issue, this is planned. Though if anyone wants to port the functionality and create a PR themselves, it's welcome as well (as I have quite limited free time myself).

[jnhyatt]

I'm happy to try and tackle at least the most basic version of this if nobody else has gotten to it yet. I figure the easiest thing is just to move the old mod_picking egui backend into bevy_egui. I don't know if there are plans to integrate it more tightly, but my game relied on the old functionality, so getting it back to where it was is important to me

[jnhyatt]

I take it back, it looks like the backend has already been added! Any chance we could get a new release? Are there outstanding issues on main?

[vladbat00]

I want to add a few more fixes and features to the release, but if that delays me for too long, I'll make the release without them. Anyway, expect a new version next week (or next year 😄). Btw, if that works in your case, you can also patch bevy_egui with its git version:

[patch.crates-io]
bevy_egui = { git = "https://github.com/vladbat00/bevy_egui.git", rev = "45b79aba77f1fd8aed056bbd1be3272a5a8b4c1b" }

(just append this to your Cargo.toml)

[vladbat00]

I'll leave this issue open, since #338 doesn't add a proper bevy_picking support (as in support interacting with world-space UIs), it only helps to prevent clicking "through" Egui windows and accidentally picking entities.

The new release will bring this support much closer, but there are still some blockers on the Bevy end before we are able to implement it.