started work on combat subsystem and triggers

src/gameplay/navi.rs

@@ -5,6 +5,7 @@ use rand::Rng;
 
 use crate::{
     GameState, PauseState,
+    gameplay::combat::StartCombat,
     utils::input::{GameInputPlugin, InputButton, InputPressStatus},
 };
 
@@ -20,6 +21,8 @@ impl Plugin for NaviGameplayPlugin {
                 (
                     move_player
                         .run_if(in_state(GameState::Navi).and(in_state(PauseState::Running))),
+                    detect_colision
+                        .run_if(in_state(GameState::Navi).and(in_state(PauseState::Running))),
                     follow_player,
                 ),
             );
@@ -68,14 +71,18 @@ pub fn spawn_bus(mut commands: Commands, asset_server: Res<AssetServer>) {
     ));
 }
 
+#[derive(Component)]
+pub struct MapEncounter(i32);
+
 pub fn spawn_enemy(
     mut commands: Commands,
     mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<ColorMaterial>>,
 ) {
     let mut rng = rand::rng();
-    for _ in 0..10 {
+    for i in 0..10 {
         commands.spawn((
+            MapEncounter(i),
             Mesh2d(meshes.add(Circle::new(10.))),
             MeshMaterial2d(materials.add(Color::srgb(1.1, 0.2, 0.3))),
             Transform::from_xyz(
@@ -121,6 +128,21 @@ pub fn move_player(
     }
 }
 
+fn detect_colision(
+    player: Single<&Transform, With<PlayerVWBus>>,
+    enemies: Query<(&Transform, &MapEncounter), (With<MapEncounter>, Without<MainCamera>)>,
+    mut start_combat_writer: MessageWriter<StartCombat>,
+    mut next_state: ResMut<NextState<GameState>>, // May or may not need
+) {
+    for (en_trans, enc) in enemies {
+        if (en_trans.translation - player.translation).length() < 30. {
+            info!("colide {}", enc.0);
+            start_combat_writer.write(StartCombat(enc.0));
+            next_state.set(GameState::Combat);
+        }
+    }
+}
+
 fn follow_player(
     mut camera: Single<&mut Transform, (With<MainCamera>, Without<PlayerVWBus>)>,
     player: Single<&Transform, (With<PlayerVWBus>, Without<MainCamera>)>,