Emulate AudioSource Playback State For Effect Sounds

Util/Audio/OfflineAudioMixer.cs

@@ -50,7 +50,7 @@ internal sealed class OfflineAudioMixer : IDisposable
     private readonly int _latencySamples;
 
     // Main thread.
-    private ConditionalWeakTable<AudioSource, Voice> _sourceVoices = new();
+    private ConditionalWeakTable<AudioSource, SourceState> _sourceStates = new();
     private readonly List<Voice> _effectVoices = new();
     private int _effectVoicePruneAt = EffectVoicePruneCount;
     private AudioClipSource? _bgmSource;
@@ -191,9 +191,9 @@ internal sealed class OfflineAudioMixer : IDisposable
 
     /// <summary>
     /// Starts an effect sound at <paramref name="startTime"/>. An <paramref name="endTime"/> of 0 or more makes it loop until then.
-    /// <paramref name="source"/> (when given) is mapped to the voice for later changes through the AudioSource.
+    /// <paramref name="source"/> (when given) is mapped to the returned state, which reports and applies later changes through the AudioSource.
     /// </summary>
-    public Voice RegisterSoundEvent(AudioSource? source, string clipName, double startTime, double endTime, float volume, float pitch, double now)
+    public SourceState RegisterSoundEvent(AudioSource? source, string clipName, double startTime, double endTime, float volume, float pitch, double now)
     {
         var clipSource = GetOrAddSource(clipName);
         var loop = endTime >= 0;
@@ -207,26 +207,30 @@ internal sealed class OfflineAudioMixer : IDisposable
         }
         _effectVoices.Add(voice);
 
-        if (source) MapSource(source!, voice);
-        return voice;
+        var state = new SourceState(voice, Math.Max(startTime, now), pitch, loop, loop ? endTime : double.PositiveInfinity,
+            clipSource?.Duration ?? 0.0, _sampleRate);
+        if (source) MapSource(source!, state);
+        return state;
     }
 
-    /// <summary>Maps <paramref name="source"/> to <paramref name="voice"/> for later changes through the AudioSource (replaces an earlier mapping).</summary>
-    public void MapSource(AudioSource source, Voice voice)
+    /// <summary>
+    /// Maps <paramref name="source"/> to <paramref name="state"/> (replaces an earlier mapping) and takes the clip length and
+    /// sample rate from the clip of the source.
+    /// </summary>
+    public void MapSource(AudioSource source, SourceState state)
     {
-        _sourceVoices.Remove(source);
-        _sourceVoices.Add(source, voice);
+        state.BindClip(source.clip);
+        _sourceStates.Remove(source);
+        _sourceStates.Add(source, state);
     }
 
-    /// <summary>Voice started for <paramref name="source"/> by <see cref="RegisterSoundEvent"/>.</summary>
-    public bool TryGetVoice(AudioSource? source, out Voice voice)
+    /// <summary>State of the effect sound last started for <paramref name="source"/>. The mapping stays after the sound ends or stops.</summary>
+    public bool TryGetSourceState(AudioSource? source, out SourceState state)
     {
-        voice = null!;
-        return source != null && _sourceVoices.TryGetValue(source, out voice);
+        state = null!;
+        return source != null && _sourceStates.TryGetValue(source, out state);
     }
 
-    public bool RemoveSourceMapping(AudioSource source) => _sourceVoices.Remove(source);
-
     /// <summary>
     /// Stops every effect sound at <paramref name="now"/>, including ones scheduled to start later
     /// (AudioManager.StopAllSounds destroys every AudioSource in liveSources, which holds the sources of
@@ -237,7 +241,7 @@ internal sealed class OfflineAudioMixer : IDisposable
         foreach (var voice in _effectVoices)
             voice.Stop(now);
         _effectVoices.Clear();
-        _sourceVoices = new ConditionalWeakTable<AudioSource, Voice>();
+        _sourceStates = new ConditionalWeakTable<AudioSource, SourceState>();
     }
 
     /// <summary>
@@ -348,7 +352,7 @@ internal sealed class OfflineAudioMixer : IDisposable
             foreach (var filter in _filters)
                 filter.Reset();
         }
-        _sourceVoices = new ConditionalWeakTable<AudioSource, Voice>();
+        _sourceStates = new ConditionalWeakTable<AudioSource, SourceState>();
         _effectVoices.Clear();
     }
 }