simple hitpoint mechanic

src/aim.rs

@@ -5,11 +5,12 @@ use crate::{
 };
 use bevy::prelude::*;
 use bevy_sprite3d::{Sprite3dBuilder, Sprite3dParams};
+use ops::sin;
 use std::f32::consts::PI;
 
 #[derive(Resource, Reflect)]
 #[reflect(Resource)]
-struct AimState {
+pub struct AimState {
     pub target: Option<Entity>,
     pub range: f32,
     pub angle: f32,
@@ -37,7 +38,7 @@ enum MarkerEvent {
 
 pub fn plugin(app: &mut App) {
     app.init_resource::<AimState>();
-    app.add_systems(Update, update);
+    app.add_systems(Update, (update, move_marker));
     app.add_observer(marker_event);
 }
 
@@ -63,7 +64,7 @@ fn marker_event(
             Name::new("aim-marker"),
             Billboard,
             Marker,
-            Transform::from_translation(Vec3::new(0., 3., 0.)),
+            Transform::default(),
             Sprite3dBuilder {
                 image: selector,
                 pixels_per_metre: 30.,
@@ -129,3 +130,9 @@ fn update(
         state.target = new_target;
     }
 }
+
+fn move_marker(mut query: Query<&mut Transform, With<Marker>>, time: Res<Time>) {
+    for mut transform in query.iter_mut() {
+        transform.translation = Vec3::new(0., 3. + (sin(time.elapsed_secs() * 6.) * 0.2), 0.);
+    }
+}