Implement MapEntities for ActionDiffEvent (#598)

* Implement MapEntities for ActionDiffEvent

* Use proper terminology in comments

Co-authored-by: Periwink <charlesbour@gmail.com>

* Add change to RELEASES.md

* Run cargo fmt --all

---------

Co-authored-by: Periwink <charlesbour@gmail.com>

RELEASES.md

@@ -12,6 +12,10 @@
 
 - Reflect `Component` and `Resource`, which enables accessing the data in the type registry
 
+#### ActionDiffEvent
+
+- Implement `MapEntities`, which lets networking crates translate owner entity IDs between ECS worlds
+
 ## Version 0.15.0
 
 ### Enhancements (0.15)

src/action_diff.rs

@@ -6,9 +6,12 @@
 //! about things like keybindings or input devices.
 
 use bevy::{
- ecs::{entity::Entity, event::Event},
+ ecs::{
+ entity::{Entity, MapEntities},
+ event::Event,
+ },
  math::Vec2,
- prelude::{EventWriter, Query, Res},
+ prelude::{EntityMapper, EventWriter, Query, Res},
  utils::{HashMap, HashSet},
 };
 use serde::{Deserialize, Serialize};
@@ -62,6 +65,16 @@ pub struct ActionDiffEvent<A: Actionlike> {
  pub action_diffs: Vec<ActionDiff<A>>,
 }
 
+/// Implements entity mapping for `ActionDiffEvent`.
+///
+/// This allows the owner entity to be remapped when transferring event diffs
+/// between different ECS worlds (e.g. client and server).
+impl<A: Actionlike> MapEntities for ActionDiffEvent<A> {
+ fn map_entities<M: EntityMapper>(&mut self, entity_mapper: &mut M) {
+ self.owner = self.owner.map(|entity| entity_mapper.map_entity(entity));
+ }
+}
+
 /// Stores the state of all actions in the current frame.
 ///
 /// Inside of the hashmap, [`Entity::PLACEHOLDER`] represents the global / resource state of the action.