feat: Add striking sound with random pitch shift

Closes #1

CREDITS.md

@@ -54,6 +54,12 @@ https://grappe.itch.io/medal
 
 ### Sounds
 
+#### Swing
+
+- https://freesound.org/people/Eponn/sounds/547040/
+- https://freesound.org/people/spycrah/sounds/471097/
+- https://freesound.org/people/Artninja/sounds/700220/
+
 ### Music
 
 https://shononoki.itch.io/bullet-hell-music-pack

src/assets.rs

@@ -116,6 +116,10 @@ pub struct GameAssets {
     #[asset(path = "music/bgm.ogg")]
     pub bgm: Handle<AudioSource>,
 
+    // --- SOUND ---
+    #[asset(path = "sounds/strike_sound.ogg")]
+    pub strike_sound: Handle<AudioSource>,
+
     // --- FONT ---
     #[asset(path = "fonts/PressStart2P.ttf")]
     pub font: Handle<Font>,

src/audio/mod.rs

@@ -1,7 +1,6 @@
 mod bgm;
 mod sound;
 
-#[allow(unused_imports)]
 pub use sound::PlaySound;
 
 use bevy::prelude::*;

src/player/strike.rs

@@ -1,10 +1,13 @@
 use std::time::Duration;
 
+use rand::{thread_rng, Rng};
+
 use bevy::prelude::*;
 use bevy_rapier2d::prelude::*;
 use bevy_trickfilm::prelude::*;
 
 use crate::{
+    audio::PlaySound,
     utils::{quat_from_vec2, FixedRotation},
     world::camera::YSort,
     GameAssets, GameState,
@@ -19,6 +22,7 @@ const OFFSET: Vec3 = Vec3::new(0.0, -10.0, 0.0);
 const CHAIN_COOLDOWN: f32 = 0.35;
 const STRIKE_COOLDOWN: f32 = 0.4;
 const STRIKE_CHAIN_COUNT: usize = 3;
+const SOUND_PITCH_CHANGE: f64 = 0.1;
 
 #[derive(Resource, Default)]
 struct StrikeCooldown {
@@ -120,6 +124,21 @@ fn despawn_strikes(
     }
 }
 
+fn play_strike_sound(
+    assets: Res<GameAssets>,
+    mut ev_spawn_strike: EventReader<SpawnStrike>,
+    mut ev_play_sound: EventWriter<PlaySound>,
+) {
+    let mut rng = thread_rng();
+    for _ in ev_spawn_strike.read() {
+        ev_play_sound.send(PlaySound {
+            clip: assets.strike_sound.clone(),
+            playback_rate: 1.0 + rng.gen_range(-1.0..1.0) * SOUND_PITCH_CHANGE,
+            ..default()
+        });
+    }
+}
+
 fn trigger_strike(
     player_input: Res<PlayerInput>,
     mouse_coords: Res<MouseWorldCoords>,
@@ -197,6 +216,7 @@ impl Plugin for PlayerStrikePlugin {
             (
                 spawn_strikes,
                 despawn_strikes,
+                play_strike_sound,
                 trigger_strike,
                 reset_chain,
                 tick_strike_cooldown,