Audio: per-SoundEffect occlusion via Steam Audio + 3D flag refactor

- New occlusion opt-in on SoundEffect: spatialized instances get a
  SteamAudioSource with raycast occlusion + frequency-dependent
  transmission (walls muffle instead of hard-mute)
- Replace SoundEffectDistanceRange asset indirection with an explicit
  _3d bool (user refactor); rolloff/distance now left to defaults
- Hey.asset: occlusion enabled

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/Scripts/Audio/SoundEffect.cs

@@ -7,7 +7,6 @@ namespace Prototype
     [CreateAssetMenu(menuName = "Prototype/Sound Effect")]
     public class SoundEffect : ScriptableObject
     {
-        [SerializeField] SoundEffectDistanceRange distanceRange;
         [SerializeField] Vector2 volumeMultiplier = new(1, 1);
         [SerializeField] Vector2 pitch = new(.95f, 1.05f);
 
@@ -15,7 +14,10 @@ namespace Prototype
         public AudioMixerGroup audioMixerGroup;
         public float volumeMultiplierFactor = 1;
         [SerializeField] bool loop;
+        [SerializeField] bool _3d;
         [SerializeField] bool spatialize;
+        [Tooltip("Occlude/muffle the sound behind walls via Steam Audio. Requires spatialize and exported scene geometry.")]
+        [SerializeField] bool occlusion;
 
         [Header("Additional Settings")]
         [SerializeField, Range(0, 1)] float defaultVolume = .8f;
@@ -35,8 +37,9 @@ namespace Prototype
             volumeMultiplier = Random.Range(volumeMultiplier.x, volumeMultiplier.y) * volumeMultiplierFactor,
             pitch = Random.Range(pitch.x, pitch.y),
             loop = loop,
+            _3d = _3d,
             spatialize = spatialize,
-            distanceRange = distanceRange ? distanceRange.range : null
+            occlusion = occlusion
         };
 
 #if UNITY_EDITOR

Assets/Scripts/Audio/SoundEffectDistanceRange.cs

@@ -1,10 +0,0 @@
-using UnityEngine;
-
-namespace Prototype
-{
-    [CreateAssetMenu(menuName = "Prototype/Sound Effect Distance Range")]
-    public class SoundEffectDistanceRange : UnityEngine.ScriptableObject
-    {
-        public Vector2 range = new SoundEffectOptions().GetDistanceRange();
-    }
-}

Assets/Scripts/Audio/SoundEffectDistanceRange.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: 523ce7d83fde21c419a5d637cbe7bf04
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Assets/Scripts/Audio/SoundEffectInstance.cs

@@ -23,16 +23,19 @@ namespace Prototype
                 audioSource.volume = options.GetVolume();
                 audioSource.pitch = options.GetPitch();
 
-                var range = options.GetDistanceRange();
-
-                audioSource.spatialBlend = range.x == 0 && range.y == 0 ? 0 : 1;
+                audioSource.spatialBlend = options.Get3D() ? 1 : 0;
                 audioSource.spatialize = options.GetSpatialize() && audioSource.spatialBlend > 0;
-                audioSource.rolloffMode = AudioRolloffMode.Linear;
-                audioSource.minDistance = range.x;
-                audioSource.maxDistance = range.y;
                 audioSource.loop = options.GetLoop();
             }
 
+            if (audioSource.spatialize && options.GetOcclusion())
+            {
+                var steamAudioSource = gameObject.AddComponent<SteamAudio.SteamAudioSource>();
+                steamAudioSource.occlusion = true;
+                steamAudioSource.transmission = true;
+                steamAudioSource.transmissionType = SteamAudio.TransmissionType.FrequencyDependent;
+            }
+
             if (!options.ShouldDestroyOnLoad())
             {
                 DontDestroyOnLoad(this);

Assets/Scripts/Audio/SoundEffectOptions.cs

@@ -1,4 +1,3 @@
-using UnityEngine;
 using UnityEngine.Audio;
 
 namespace Prototype
@@ -17,8 +16,8 @@ namespace Prototype
         public bool? loop;
         public bool GetLoop() => loop ?? false;
 
-        public Vector2? distanceRange;
-        public Vector2 GetDistanceRange() => distanceRange ?? new(30, 200);
+        public bool? _3d;
+        public bool Get3D() => _3d ?? false;
 
         public bool? destroyOnLoad;
         public bool ShouldDestroyOnLoad() => destroyOnLoad ?? true;
@@ -28,5 +27,8 @@ namespace Prototype
 
         public bool? spatialize;
         public bool GetSpatialize() => spatialize ?? false;
+
+        public bool? occlusion;
+        public bool GetOcclusion() => occlusion ?? false;
     }
 }