Own XM/MOD replayer, audio mixer with crossfades, synthesised chip sound effects, music director

- src/xm.rs: FastTracker 2 XM and ProTracker MOD replayer (verified against libopenmpt)
- src/audio.rs: music players with crossfade + effect voices, rendered on demand
- src/sfx.rs: 29 synthesised chip sound effects
- www/dc_plugin.js: AudioContext started on first input, streams samples from WASM
- music follows the game: title, rotating build tracks, battle, gate assault, jingles
- macroquad audio removed; all tests run natively with cargo test

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/sound.rs

@@ -1,56 +1,20 @@
-// Sound playback. The game logic reports events (Sfx), they are played here.
-// Sounds will be generated later and registered via `SoundBank::set` (WAV bytes).
-// Events without a registered sound stay silent.
+// Sound effect dispatch: turns game sound events into positioned effect voices
+// (volume by distance to the camera, stereo panning along the screen's x axis).
+// The audio itself is rendered by audio.rs.
 
+use crate::audio;
 use crate::game::{Sfx, SfxEvent, SFX_ALL};
-#[cfg(feature = "audio")]
-use macroquad::audio::{load_sound_from_bytes, play_sound, PlaySoundParams, Sound};
-#[cfg(not(feature = "audio"))]
-use stub::*;
-
-// Silent stand-in when the "audio" feature is off (native tests)
-#[cfg(not(feature = "audio"))]
-mod stub {
-    #[derive(Clone)]
-    pub struct Sound;
-    pub struct PlaySoundParams {
-        pub looped: bool,
-        pub volume: f32,
-    }
-    pub async fn load_sound_from_bytes(_: &[u8]) -> Result<Sound, ()> {
-        Err(())
-    }
-    pub fn play_sound(_: &Sound, _: PlaySoundParams) {}
-}
 use macroquad::prelude::*;
 
 pub struct SoundBank {
-    sounds: Vec<Option<Sound>>,
     last: Vec<f64>,
-    pub volume: f32,
-    pub muted: bool,
 }
 
 impl SoundBank {
     pub fn new() -> SoundBank {
-        SoundBank { sounds: vec![None; SFX_ALL.len()], last: vec![-1.0; SFX_ALL.len()], volume: 0.7, muted: false }
+        SoundBank { last: vec![-1.0; SFX_ALL.len()] }
     }
 
-    // register the sound for an event (WAV or OGG bytes)
-    #[allow(dead_code)]
-    pub async fn set(&mut self, sfx: Sfx, bytes: &[u8]) -> bool {
-        match load_sound_from_bytes(bytes).await {
-            Ok(s) => {
-                self.sounds[sfx.index()] = Some(s);
-                true
-            }
-            Err(_) => false,
-        }
-    }
-
-    // procedurally generated sounds will be registered here
-    pub async fn generate_all(&mut self) {}
-
     // minimum gap between two identical sounds (avoids a wall of noise)
     fn min_gap(sfx: Sfx) -> f64 {
         match sfx {
@@ -60,51 +24,25 @@ impl SoundBank {
         }
     }
 
-    // listener: camera target on the ground; hear: audible radius in tiles
-    pub fn play(&mut self, ev: SfxEvent, listener: Vec2, hear: f32, now: f64) {
-        if self.muted || self.volume <= 0.0 {
-            return;
-        }
+    // listener: camera target on the ground; right: screen-right direction on the ground;
+    // hear: audible radius in tiles
+    pub fn play(&mut self, ev: SfxEvent, listener: Vec2, right: Vec2, hear: f32, now: f64) {
         let i = ev.sfx.index();
-        let Some(sound) = &self.sounds[i] else { return };
         if now - self.last[i] < Self::min_gap(ev.sfx) {
             return;
         }
-        // volume by distance to the listener
-        let mut vol = self.volume;
+        let mut vol = 1.0;
+        let mut pan = 0.0;
         if let Some((wx, wy)) = ev.pos {
-            let d = ((wx - listener.x).powi(2) + (wy - listener.y).powi(2)).sqrt();
-            let f = 1.0 - ((d - hear * 0.5) / hear).clamp(0.0, 1.0);
+            let d = vec2(wx, wy) - listener;
+            let f = 1.0 - ((d.length() - hear * 0.5) / hear).clamp(0.0, 1.0);
             if f <= 0.05 {
                 return;
             }
             vol *= f;
+            pan = (d.dot(right) / hear).clamp(-1.0, 1.0) * 0.7;
         }
         self.last[i] = now;
-        play_sound(sound, PlaySoundParams { looped: false, volume: vol });
+        audio::play_sfx(i, vol, pan);
     }
 }
-
-// helper for sound generation: samples (-1..1, mono) -> WAV (16 bit PCM)
-#[allow(dead_code)]
-pub fn wav_from_samples(samples: &[f32], rate: u32) -> Vec<u8> {
-    let data_len = (samples.len() * 2) as u32;
-    let mut out = Vec::with_capacity(44 + data_len as usize);
-    out.extend_from_slice(b"RIFF");
-    out.extend_from_slice(&(36 + data_len).to_le_bytes());
-    out.extend_from_slice(b"WAVEfmt ");
-    out.extend_from_slice(&16u32.to_le_bytes());
-    out.extend_from_slice(&1u16.to_le_bytes()); // PCM
-    out.extend_from_slice(&1u16.to_le_bytes()); // mono
-    out.extend_from_slice(&rate.to_le_bytes());
-    out.extend_from_slice(&(rate * 2).to_le_bytes());
-    out.extend_from_slice(&2u16.to_le_bytes());
-    out.extend_from_slice(&16u16.to_le_bytes());
-    out.extend_from_slice(b"data");
-    out.extend_from_slice(&data_len.to_le_bytes());
-    for &s in samples {
-        let v = (s.clamp(-1.0, 1.0) * 32767.0) as i16;
-        out.extend_from_slice(&v.to_le_bytes());
-    }
-    out
-}