Fix audio params variation (#4699)

Robust.Client/Audio/AudioSystem.cs

@@ -423,7 +423,7 @@ public sealed partial class AudioSystem : SharedAudioSystem
     /// <inheritdoc />
     public override (EntityUid Entity, AudioComponent Component)? PlayPredicted(SoundSpecifier? sound, EntityUid source, EntityUid? user, AudioParams? audioParams = null)
     {
-        if (Timing.IsFirstTimePredicted || sound == null)
+        if (Timing.IsFirstTimePredicted && sound != null)
             return PlayEntity(sound, Filter.Local(), source, false, audioParams);
 
         return null; // uhh Lets hope predicted audio never needs to somehow store the playing audio....
@@ -431,7 +431,7 @@ public sealed partial class AudioSystem : SharedAudioSystem
 
     public override (EntityUid Entity, AudioComponent Component)? PlayPredicted(SoundSpecifier? sound, EntityCoordinates coordinates, EntityUid? user, AudioParams? audioParams = null)
     {
-        if (Timing.IsFirstTimePredicted || sound == null)
+        if (Timing.IsFirstTimePredicted && sound != null)
             return PlayStatic(sound, Filter.Local(), coordinates, false, audioParams);
 
         return null;
@@ -618,8 +618,7 @@ public sealed partial class AudioSystem : SharedAudioSystem
         source.PlaybackPosition = offset;
 
         // For server we will rely on the adjusted one but locally we will have to adjust it ourselves.
-        ApplyAudioParams(audioP, comp);
-        comp.Params = audioP;
+        ApplyAudioParams(comp.Params, comp);
         source.StartPlaying();
         return (entity, comp);
     }

Robust.Client/Audio/Sources/BaseAudioSource.cs

@@ -157,7 +157,22 @@ internal abstract class BaseAudioSource : IAudioSource
     }
 
     /// <inheritdoc />
-    public float Pitch { get; set; }
+    public float Pitch
+    {
+        get
+        {
+            _checkDisposed();
+            AL.GetSource(SourceHandle, ALSourcef.Pitch, out var value);
+            Master._checkAlError();
+            return value;
+        }
+        set
+        {
+            _checkDisposed();
+            AL.Source(SourceHandle, ALSourcef.Pitch, value);
+            Master._checkAlError();
+        }
+    }
 
     /// <inheritdoc />
     public float Volume
@@ -189,7 +204,7 @@ internal abstract class BaseAudioSource : IAudioSource
             {
                 AL.GetSource(SourceHandle, ALSourcef.Gain, out var priorGain);
                 // Default to 0 to avoid spiking audio, just means it will be muted for a frame in this case.
-                priorOcclusion = _gain == 0 ? 0f : priorGain / _gain;
+                priorOcclusion = _gain == 0 ? 1f : priorGain / _gain;
             }
 
             _gain = value;

Robust.Shared/Audio/Systems/SharedAudioSystem.cs

@@ -141,6 +141,11 @@ public abstract partial class SharedAudioSystem : EntitySystem
             despawn.Lifetime = (float) length.TotalSeconds + 0.01f;
         }
 
+        if (comp.Params.Variation != null && comp.Params.Variation.Value != 0f)
+        {
+            comp.Params.Pitch *= (float) RandMan.NextGaussian(1, comp.Params.Variation.Value);
+        }
+
         return comp;
     }