add enemy spawners

src/enemy.rs

@@ -0,0 +1,94 @@
+use bevy::prelude::*;
+use bevy_rand::{prelude::WyRand, resource::GlobalEntropy};
+use rand::Rng;
+
+use crate::METER;
+
+#[derive(Debug, Event)]
+pub struct SpawnEvent {
+    pos: (f32, f32),
+    spawner: Entity,
+}
+
+#[derive(Component)]
+pub struct Spawner {
+    pos: (f32, f32),
+    size: (f32, f32),
+    spawn_cooldown: Timer,
+    cur_enemies: u8,
+    max_enemies: u8,
+    amount_range: std::ops::Range<u8>,
+}
+
+pub fn enemies_plugin(app: &mut App) {
+    app.add_event::<SpawnEvent>()
+        .add_systems(Startup, setup_spawners)
+        .add_systems(Update, (spawn_enemies, do_spawn));
+}
+
+pub fn setup_spawners(mut commands: Commands) {
+    commands.spawn(Spawner {
+        pos: (-6.5 * METER, 5.5 * METER),
+        size: (14. * METER, 1.5 * METER),
+        spawn_cooldown: Timer::from_seconds(5., TimerMode::Repeating),
+        cur_enemies: 0,
+        max_enemies: 10,
+        amount_range: 2..4,
+    });
+}
+
+#[derive(Component)]
+pub struct Enemy;
+
+// TODO: waves n stuff
+// and gamestate lolz
+pub fn spawn_enemies(
+    mut ev_spawn: EventWriter<SpawnEvent>,
+    mut rng: ResMut<GlobalEntropy<WyRand>>,
+    mut query: Query<(Entity, &mut Spawner)>,
+    time: Res<Time>,
+) {
+    for (entity, mut spawner) in query.iter_mut() {
+        if spawner.spawn_cooldown.tick(time.delta()).finished()
+            && spawner.cur_enemies <= spawner.max_enemies
+        {
+            // TODO: randomness
+            (0..rng.gen_range(spawner.amount_range.clone())).for_each(|_| {
+                if spawner.cur_enemies < spawner.max_enemies {
+                    spawner.cur_enemies += 1;
+                    ev_spawn.send(SpawnEvent {
+                        pos: (
+                            rng.gen_range(
+                                (spawner.pos.0 + 0.5 * METER)
+                                    ..((spawner.pos.0) + (spawner.size.0 - 0.5 * METER)),
+                            ),
+                            rng.gen_range(
+                                (spawner.pos.1 + 0.5 * METER)
+                                    ..((spawner.pos.1) + (spawner.size.1 - 0.5 * METER)),
+                            ),
+                        ),
+                        spawner: entity,
+                    });
+                }
+            })
+        }
+    }
+}
+
+pub fn do_spawn(
+    mut ev_spawn: EventReader<SpawnEvent>,
+    mut commands: Commands,
+    asset_server: Res<AssetServer>,
+) {
+    for ev in ev_spawn.read() {
+        println!("spawn!: {} {}", ev.pos.0 / METER, ev.pos.1 / METER);
+        commands.spawn((
+            Enemy,
+            SpriteBundle {
+                texture: asset_server.load("sprites/enemy.png"),
+                transform: Transform::from_xyz(ev.pos.0, ev.pos.1, 1.),
+                ..default()
+            },
+        ));
+    }
+}

src/main.rs

@@ -1,19 +1,27 @@
 use bevy::prelude::*;
+use bevy_rand::{plugin::EntropyPlugin, prelude::WyRand};
 use bevy_rapier2d::prelude::*;
+use enemy::enemies_plugin;
 use player::{add_player, move_player};
+use rand::SeedableRng;
 use some_bevy_tools::{camera_2d::Camera2DPlugin, controller_2d::SimpleTopDownControllerPlugin};
+const METER: f32 = 64.;
 
+mod enemy;
 mod player;
 mod scene;
 
 fn main() {
+    let r = rand::rngs::SmallRng::from_seed(*b"Meow UwU nyaaa~ mrrrp~ meew miau");
     App::new()
         .insert_resource(RapierConfiguration {
             gravity: Vec2::new(0.0, 0.0),
             ..Default::default()
         })
+        .add_plugins(EntropyPlugin::<WyRand>::default())
+        .add_plugins(enemies_plugin)
         .add_plugins(DefaultPlugins)
-        .add_plugins(RapierPhysicsPlugin::<NoUserData>::pixels_per_meter(64.0))
+        .add_plugins(RapierPhysicsPlugin::<NoUserData>::pixels_per_meter(METER))
         .add_plugins(RapierDebugRenderPlugin::default())
         .add_plugins(Camera2DPlugin)
         .add_plugins(SimpleTopDownControllerPlugin)

src/scene.rs

@@ -3,7 +3,11 @@ use bevy::{
     sprite::{MaterialMesh2dBundle, Mesh2dHandle},
 };
 use bevy_rapier2d::prelude::*;
-const METER: f32 = 64.;
+
+use crate::METER;
+
+#[derive(Component)]
+pub struct Wall;
 
 pub fn setup_scene(
     mut commands: Commands,
@@ -24,7 +28,8 @@ pub fn setup_scene(
     for (shape_, pos) in scene_objs {
         let shape = Mesh2dHandle(meshes.add(shape_));
         commands
-            .spawn(MaterialMesh2dBundle {
+            .spawn(Wall)
+            .insert(MaterialMesh2dBundle {
                 mesh: shape,
                 material: materials.add(Color::rgb(1., 0., 0.)),
                 transform: Transform::from_xyz(pos.0, pos.1, 1.),