Allow FMOD system to be re-created during hot code compile & reload, and added some debug UI to inspect what FMOD is doing

Assets/Scripts/AudioManager.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Text;
 using UnityEngine;
 
 public class AudioManager : MonoBehaviour
@@ -31,6 +32,33 @@ public class AudioManager : MonoBehaviour
     
     void Awake()
     {
+        // Ensure FMOD is initialized the moment Instance is accessed
+        InitFmod();
+    }
+
+    void OnEnable()
+    {
+        // Ensure FMOD gets re-initialized after hot reload
+        InitFmod();
+    }
+
+    void OnDisable()
+    {
+        // Ensure FMOD gets closed before hot reload
+        CloseFmod();
+    }
+
+    void OnDestroy()
+    {
+        CloseFmod();
+        instance = null;
+    }
+    
+    private void InitFmod()
+    {
+        if (fmodSystem.hasHandle())
+            return;
+        
         FMOD.RESULT result = FMOD.Factory.System_Create(out fmodSystem);
         CheckFmodResult(result, "FMOD.Factory.System_Create");
 
@@ -54,11 +82,6 @@ public class AudioManager : MonoBehaviour
         result = fmodSystem.init(MaxChannels, FMOD.INITFLAGS.NORMAL, IntPtr.Zero);
         CheckFmodResult(result, "FMOD.System.init");
     }
-    
-    void OnDestroy()
-    {
-        CloseFmod();
-    }
 
     private void CheckFmodResult(FMOD.RESULT result, string cause)
     {
@@ -73,9 +96,25 @@ public class AudioManager : MonoBehaviour
     {
         if (fmodSystem.hasHandle())
         {
+            Debug.Log("[FMOD] Closing FMOD System");
             fmodSystem.close();
             fmodSystem.release();
             fmodSystem.clearHandle();
         }
     }
+    
+#if UNITY_EDITOR || DEVELOPMENT_BUILD
+    void OnGUI()
+    {
+        var debug = new StringBuilder("FMOD System\n");
+        
+        FMOD.Memory.GetStats(out int currentAlloc, out int maxAlloc);
+        debug.AppendFormat("MEMORY: cur = {0}MB, max = {1}MB\n", currentAlloc >> 20, maxAlloc >> 20);
+
+        fmodSystem.getChannelsPlaying(out int channels, out int realChannels);
+        debug.AppendFormat("CHANNELS: real = {0}, total = {1}\n", realChannels, channels);
+        
+        GUI.Box(new Rect(0, 300, 250, 60), debug.ToString());
+    }
+#endif
 }