Insert gizmo configuration

[Jondolf]

What problem does this solve or what need does it fill?

With Bevy's new support for multiple gizmo configurations (#10342), it's possible to initialize configurations using init_gizmo_group. However, there doesn't seem to be an API to initialize it with a specific value.

The only way that I found outside of scheduling a startup system (which I can't do in my case) is to do this:

// In a plugin's build method

app.init_gizmo_group::<PhysicsGizmos>();

let mut store = app.world.resource_mut::<GizmoConfigStore>();
let config = store.config_mut::<PhysicsGizmos>().0;
config.line_width = 1.5;

which is not ideal. I think it also has issues if the plugin is added before the GizmoPlugin.

My use case is that bevy_xpbd has a PhysicsDebugConfig resource and a PhysicsDebugRenderer system parameter that renders colliders, joints, contacts, and so on. With the new gizmo API, I'm combining these into a single PhysicsGizmos gizmo config group that stores the config that was previously stored in PhysicsDebugConfig and has some methods for e.g. rendering colliders.

I need to (1) configure some properties of the GizmoConfig to non-default values, and (2) give people an easy API to configure PhysicsGizmos for e.g. disabling collider rendering. This should be doable during initialization, not just in a system. I can not make a Startup system for it as it could conflict with users' systems that use GizmoConfigStore in that schedule.

What solution would you like?

Add an insert_gizmo_group method to App:

app.insert_gizmo_group(PhysicsGizmos {
    // ...
});

There must also be a way to set the GizmoConfig associated with the gizmo group. This could be an insert_gizmo_config or configure_gizmo_config method:

app.insert_gizmo_config::<PhysicsGizmos>(GizmoConfig {
    // ...
});

[pablo-lua]

I think it also has issues if the plugin is added before the GizmoPlugin.

About this, this error doesn't seen to happen after #11420, or is there another error in this fields? 🤔

[Jondolf]

Ah, I didn't actually try if it errors there, I just assumed that it wouldn't add the group if done before the GizmoPlugin. Cool if it works!

[alice-i-cecile]

I like the naming, and think this should exist.