beginning of action system

crates/bevy_xr/src/actions.rs

@@ -0,0 +1,97 @@
+use std::marker::PhantomData;
+
+use bevy::{
+    app::{App, First, Plugin},
+    ecs::system::{ResMut, Resource},
+};
+
+pub struct ActionPlugin<A: Action>(PhantomData<A>);
+
+impl<A: Action> Default for ActionPlugin<A> {
+    fn default() -> Self {
+        Self(Default::default())
+    }
+}
+
+impl<A: Action> Plugin for ActionPlugin<A> {
+    fn build(&self, app: &mut App) {
+        app.add_systems(First, reset_action_state::<A>)
+            .init_resource::<Actions>();
+        app.world.resource_mut::<Actions>().0.push(A::INFO);
+    }
+}
+
+pub enum ActionType {
+    Bool,
+}
+
+pub trait ActionTy: Send + Sync + Default + Clone + Copy {
+    const TYPE: ActionType;
+}
+
+impl ActionTy for bool {
+    const TYPE: ActionType = ActionType::Bool;
+}
+
+pub trait Action: Send + Sync + 'static {
+    type ActionType: ActionTy;
+
+    const INFO: ActionInfo;
+}
+
+pub struct ActionInfo {
+    pub pretty_name: &'static str,
+    pub name: &'static str,
+    pub action_type: ActionType,
+}
+
+#[derive(Resource, Default)]
+pub struct Actions(pub Vec<ActionInfo>);
+
+#[derive(Resource, Default)]
+pub struct ActionState<A: Action> {
+    previous_state: A::ActionType,
+    current_state: A::ActionType,
+}
+
+impl<A: Action> ActionState<A> {
+    pub fn current_state(&self) -> A::ActionType {
+        self.current_state
+    }
+
+    pub fn previous_state(&self) -> A::ActionType {
+        self.previous_state
+    }
+}
+
+impl<A: Action<ActionType = bool>> ActionState<A> {
+    pub fn pressed(&self) -> bool {
+        self.current_state
+    }
+
+    pub fn just_pressed(&self) -> bool {
+        self.previous_state == false && self.current_state == true
+    }
+
+    pub fn just_released(&self) -> bool {
+        self.previous_state == true && self.current_state == false
+    }
+
+    pub fn press(&mut self) {
+        self.current_state = true
+    }
+}
+
+pub fn reset_action_state<A: Action>(mut action_state: ResMut<ActionState<A>>) {
+    action_state.previous_state = std::mem::take(&mut action_state.current_state);
+}
+
+pub trait ActionApp {
+    fn register_action<A: Action>(&mut self) -> &mut Self;
+}
+
+impl ActionApp for App {
+    fn register_action<A: Action>(&mut self) -> &mut Self {
+        self.add_plugins(ActionPlugin::<A>::default())
+    }
+}