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));
+    }
+}