Collision

src/collision.rs

@@ -0,0 +1,37 @@
+use bevy::prelude::*;
+
+pub struct CollisionPlugin;
+
+impl Plugin for CollisionPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(FixedUpdate, calculate_collisions);
+    }
+}
+
+#[derive(Component)]
+pub struct Collider(f32);
+
+#[derive(EntityEvent)]
+pub struct Collided {
+    entity: Entity,
+    with: Entity,
+}
+
+fn calculate_collisions(mut commands: Commands, query: Query<(Entity, &Transform, &Collider)>) {
+    for (first_entity, first_transform, first_collider) in query {
+        for (second_entity, second_transform, second_collider) in query {
+            if first_entity == second_entity {
+                continue;
+            }
+
+            if (second_transform.translation - first_transform.translation).length_squared()
+                <= (first_collider.0 + second_collider.0) * (first_collider.0 + second_collider.0)
+            {
+                commands.trigger(Collided {
+                    entity: first_entity,
+                    with: second_entity,
+                });
+            }
+        }
+    }
+}

src/main.rs

@@ -1,12 +1,15 @@
 use bevy::prelude::*;
 
+use crate::collision::CollisionPlugin;
 use crate::damagable::DamagablePlugin;
 
+mod collision;
 mod damagable;
 
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
         .add_plugins(DamagablePlugin)
+        .add_plugins(CollisionPlugin)
         .run();
 }