Add a bounding box gizmo

[tim-blackbird]

Objective

Add a bounding box gizmo

Changes

• Added the AabbGizmo component that will draw the Aabb component on that entity.
• Added an option to draw all bounding boxes in a scene on the GizmoConfig resource.
• Added TransformPoint trait to generalize over the point transformation methods on various transform types (e.g Transform and GlobalTransform).
• Changed the Gizmos::cuboid method to accept an impl TransformPoint instead of separate translation, rotation, and scale.

[IceSentry]

Adding it to the scene_viewer is a great idea, but I think it would be nice as a standalone example too. Or maybe just use it in the gizmo example?

[nicopap]

Yes please, this is very welcome. A future improvement could be to do the same with the Node struct.

[mockersf]

the difference between a bounding box and a cuboid is not clear enough, why do we need both?

[tim-blackbird]

I've removed bounding_box and modified cuboid instead, and TransformPoint was moved to bevy_transform.

[nicopap]

Widely useful, if this existed earlier it would have saved me a few headaches.

[nicopap]

I love the following function so much, I've definitively needed something similar in personal projects. Maybe it could be implemented as a From<Entity> for Color impl in a different PR.

bevy/crates/bevy_gizmos/src/lib.rs

Lines 201 to 204 in 9e41e7a

	fn color_from_entity(entity: Entity) -> Color {
	let hue = entity.to_bits() as f32 * 100_000. % 360.;
	Color::hsl(hue, 1., 0.5)
	}