Add release notes for default query filters and entity disabling (#2030)

Author: alice-i-cecile

release-content/0.16/release-notes/13120_Add_DefaultQueryFilters.md

@@ -1,4 +1,25 @@
-<!-- Add DefaultQueryFilters -->
-<!-- https://github.com/bevyengine/bevy/pull/13120 -->
+How would go about marking an entity as disabled in an ECS: unseen-by-default and uninteractable?
+Simply deleting it is definitely reliable, but it's relatively expensive, throws away the data, and makes it hard to enable the entity again.
+You could move it into a shadow [`World`], but that's esoteric, expensive, and makes it challenging to fetch any data off of it and pass it back into the main [`World`].
 
-<!-- TODO -->
+What about adding a simple marker component? That seems easy enough: make a unit struct, insert it, and then use `Without<Disabled>` in all of the relevant queries!
+
+While that approach works at first, it quickly becomes frustrating. Did you forget to add the boilerplate somewhere?
+Do you vendor all of your dependencies and change their queries too? What if you're making a library? Do all of *your* users need to remember to filter out disabled entities too?
+
+Conceptually though, this seems like the right idea: simply hide the entity from queries and systems that aren't looking for it.
+To make this pattern less frustrating Bevy 0.16 introduces the idea of **default query filters**.
+
+These do what they say on the tin: every query will act as if they have a `Without<Disabled>` filter, unless they explicitly mention [`Disabled`] (generally via a `With<Disabled>` or `Option<&Disabled>` argument).
+Because this machinery was already built, Bevy allows users (and libraries) to define their own disabling components,
+which can be registered via [`App::register_disabling_component`].
+Having multiple distinct disabling components can be useful if you want each form of disabling to have its own semantics (or custom behavior!): you might use this feature for hiding networked entities, freezing entities in an off-screen chunk, creating a collection of prefab entities loaded and ready to spawn or something else entirely.
+
+To disable or enable an entity, simply remove or add the disabling component of your choice. It's that easy!
+Note that for maximum control and explicitness, only the entities that you directly add disabling components to are disabled: their children or other related entities are not automatically disabled!
+This can lead to strange bugs, so in most cases, you should either be careful to call [`Commands::insert_recursive`] and [`Commands::remove_recursive`] or add a hook or observer to get automatic hierarchy-aware disabling.
+
+[`World`]: https://dev-docs.bevyengine.org/bevy/ecs/prelude/struct.World.html
+[`Disabled`]: https://dev-docs.bevyengine.org/bevy/ecs/entity_disabling/struct.Disabled.html
+[`Commands::insert_recursive`]: https://dev-docs.bevyengine.org/bevy/prelude/struct.EntityCommands.html#method.insert_recursive
+[`Commands::remove_recursive`]: https://dev-docs.bevyengine.org/bevy/prelude/struct.EntityCommands.html#method.remove_recursive

release-content/0.16/release-notes/_release-notes.toml

@@ -29,10 +29,10 @@ prs = [16132, 16826]
 file_name = "16132_Entity_cloning.md"
 
 [[release_notes]]
-title = "Add DefaultQueryFilters"
-authors = ["@NiseVoid"]
+title = "Entity disabling via default query filters"
+authors = ["@NiseVoid", "@alice-i-cecile"]
 contributors = []
-prs = [13120]
+prs = [13120, 17514, 17768]
 file_name = "13120_Add_DefaultQueryFilters.md"
 
 [[release_notes]]