Enemy spawner

src/ships/enemy_spawner.rs

@@ -0,0 +1,67 @@
+use std::time::Duration;
+
+use bevy::prelude::*;
+use rand::{prelude::*, rng};
+
+use crate::{
+    FIRST_CORNER_X, FIRST_CORNER_Y, GameObject, SECOND_CORNER_X, SECOND_CORNER_Y,
+    ships::{EnemySprite, enemy::spawn_enemy},
+};
+
+const MAX_ENEMIES: f32 = 20.0;
+const MIN_TIME: u64 = 2;
+const START_TIME: f32 = 10.0;
+const TIME_PENALTY: f32 = 0.1;
+const ENEMY_INCREASE: f32 = 0.25;
+
+#[derive(Component)]
+pub struct EnemySpawner {
+    spawn_timer: Timer,
+    amount: f32,
+}
+
+pub fn setup_enemy_spawner(mut commands: Commands) {
+    commands.spawn((
+        EnemySpawner {
+            spawn_timer: Timer::from_seconds(START_TIME, TimerMode::Repeating),
+            amount: 1.,
+        },
+        GameObject,
+    ));
+}
+
+pub fn tick_enemy_spawner(
+    mut commands: Commands,
+    time: Res<Time>,
+    query: Single<&mut EnemySpawner>,
+    sprite: Res<EnemySprite>,
+) {
+    let mut spawner = query.into_inner();
+
+    spawner.spawn_timer.tick(time.delta());
+
+    if spawner.spawn_timer.just_finished() == false {
+        return;
+    }
+
+    let mut random = rng();
+
+    for _ in 1..((spawner.amount).floor() as u8) {
+        let position = Vec2::new(
+            random.random_range(FIRST_CORNER_X..SECOND_CORNER_X),
+            random.random_range(FIRST_CORNER_Y..SECOND_CORNER_Y),
+        );
+
+        spawn_enemy(&mut commands, sprite.0.clone(), position);
+    }
+
+    if spawner.amount < MAX_ENEMIES {
+        spawner.amount += ENEMY_INCREASE;
+    } else if spawner.spawn_timer.duration().as_secs() >= MIN_TIME {
+        let set_time = spawner.spawn_timer.duration().as_secs_f32() - TIME_PENALTY;
+
+        spawner
+            .spawn_timer
+            .set_duration(Duration::from_secs_f32(set_time));
+    }
+}

src/ships/mod.rs

@@ -1,15 +1,18 @@
 use bevy::prelude::*;
-use rand::{prelude::*, rng};
 
 use crate::{
-    FIRST_CORNER_X, FIRST_CORNER_Y, GameState, SECOND_CORNER_X, SECOND_CORNER_Y,
-    ships::enemy::spawn_enemy,
+    GameState,
+    ships::enemy_spawner::{setup_enemy_spawner, tick_enemy_spawner},
 };
 
 pub mod enemy;
+pub mod enemy_spawner;
 pub mod gun;
 pub mod player;
 
+#[derive(Resource)]
+pub struct EnemySprite(Handle<Image>);
+
 #[derive(Component, Copy, Clone, PartialEq, Eq)]
 pub enum Factions {
     PlayerFaction,
@@ -36,7 +39,7 @@ pub struct ShipsPlugin;
 impl Plugin for ShipsPlugin {
     fn build(&self, app: &mut bevy::app::App) {
         app.insert_resource(Time::<Fixed>::from_hz(60.))
-            .add_systems(OnEnter(GameState::Game), startup)
+            .add_systems(OnEnter(GameState::Game), (startup, setup_enemy_spawner))
             .add_systems(
                 FixedUpdate,
                 (
@@ -46,6 +49,7 @@ impl Plugin for ShipsPlugin {
                     enemy::enemy_ai_system.run_if(in_state(GameState::Game)),
                 ),
             )
+            .add_systems(Update, tick_enemy_spawner)
             .add_observer(player::player_death_observer);
     }
 }
@@ -54,16 +58,7 @@ fn startup(mut commands: Commands, asset_server: Res<AssetServer>) {
     let player_sprite: Handle<Image> = asset_server.load("player.png");
     let enemy_sprite: Handle<Image> = asset_server.load("enemy.png");
 
+    commands.insert_resource(EnemySprite(enemy_sprite));
+
     player::spawn_player(&mut commands, player_sprite, Vec2::new(0., 0.));
-
-    let mut random = rng();
-
-    for _ in 0..50 {
-        let position = Vec2::new(
-            random.random_range(FIRST_CORNER_X..SECOND_CORNER_X),
-            random.random_range(FIRST_CORNER_Y..SECOND_CORNER_Y),
-        );
-
-        spawn_enemy(&mut commands, enemy_sprite.clone(), position);
-    }
 }