Add Steam Audio 4.8.1 spatializer plugin

Official Unity package under Assets/Plugins/SteamAudio; enabled as
Spatializer + Ambisonic Decoder in the audio settings (HRTF: sounds
behind the listener are filtered/muffled directionally). Download
staging Tools/SteamAudio/ gitignored.

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

Assets/Plugins/SteamAudio/Scripts/Editor/SteamAudioProbeBatchInspector.cs

@@ -0,0 +1,160 @@
+//
+// Copyright 2017-2023 Valve Corporation.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+using UnityEngine;
+using UnityEngine.SceneManagement;
+using UnityEditor;
+using UnityEditor.SceneManagement;
+
+namespace SteamAudio
+{
+    [CustomEditor(typeof(SteamAudioProbeBatch))]
+    public class SteamAudioProbeBatchInspector : Editor
+    {
+#if STEAMAUDIO_ENABLED
+        SerializedProperty mPlacementStrategy;
+        SerializedProperty mHorizontalSpacing;
+        SerializedProperty mHeightAboveFloor;
+        SerializedProperty mAsset;
+
+        static bool mShouldShowProgressBar = false;
+
+        private void OnEnable()
+        {
+            mPlacementStrategy = serializedObject.FindProperty("placementStrategy");
+            mHorizontalSpacing = serializedObject.FindProperty("horizontalSpacing");
+            mHeightAboveFloor = serializedObject.FindProperty("heightAboveFloor");
+            mAsset = serializedObject.FindProperty("asset");
+        }
+
+        public override void OnInspectorGUI()
+        {
+            serializedObject.Update();
+
+            var oldGUIEnabled = GUI.enabled;
+            GUI.enabled = !Baker.IsBakeActive() && !EditorApplication.isPlayingOrWillChangePlaymode;
+
+            var tgt = target as SteamAudioProbeBatch;
+
+            EditorGUILayout.PropertyField(mAsset);
+
+            EditorGUILayout.PropertyField(mPlacementStrategy);
+            if ((ProbeGenerationType) mPlacementStrategy.enumValueIndex == ProbeGenerationType.UniformFloor)
+            {
+                EditorGUILayout.PropertyField(mHorizontalSpacing);
+                EditorGUILayout.PropertyField(mHeightAboveFloor);
+            }
+
+            EditorGUILayout.Space();
+            if (GUILayout.Button("Generate Probes"))
+            {
+                tgt.GenerateProbes();
+                EditorSceneManager.MarkSceneDirty(SceneManager.GetActiveScene());
+            }
+
+            if (tgt.GetNumProbes() > 0)
+            {
+                EditorGUILayout.Space();
+                EditorGUILayout.LabelField("Baked Pathing Settings", EditorStyles.boldLabel);
+                if (GUILayout.Button("Bake"))
+                {
+                    tgt.BeginBake();
+                    mShouldShowProgressBar = true;
+                }
+            }
+
+            GUI.enabled = oldGUIEnabled;
+
+            if (mShouldShowProgressBar && !Baker.IsBakeActive())
+            {
+                mShouldShowProgressBar = false;
+            }
+
+            if (mShouldShowProgressBar)
+            {
+                Baker.DrawProgressBar();
+            }
+
+            Repaint();
+
+            if (tgt.GetNumProbes() > 0)
+            {
+                EditorGUILayout.Space();
+                EditorGUILayout.LabelField("Probe Statistics", EditorStyles.boldLabel);
+                EditorGUILayout.LabelField("Probes", tgt.GetNumProbes().ToString());
+                EditorGUILayout.LabelField("Data Size", Common.HumanReadableDataSize(tgt.probeDataSize));
+
+                if (tgt.GetNumLayers() > 0)
+                {
+                    EditorGUILayout.Space();
+                    EditorGUILayout.LabelField("Detailed Statistics", EditorStyles.boldLabel);
+                    for (var i = 0; i < tgt.GetNumLayers(); ++i)
+                    {
+                        var layerInfo = tgt.GetInfoForLayer(i);
+
+                        var name = "";
+                        if (layerInfo.identifier.type == BakedDataType.Pathing)
+                        {
+                            name = "Pathing";
+                        }
+                        else if (layerInfo.identifier.variation == BakedDataVariation.Reverb)
+                        {
+                            name = "Reverb";
+                        }
+                        else
+                        {
+                            name = layerInfo.gameObject.name;
+                        }
+
+                        EditorGUILayout.BeginHorizontal();
+                        EditorGUILayout.LabelField(name, Common.HumanReadableDataSize(layerInfo.dataSize));
+                        if (GUILayout.Button("Clear"))
+                        {
+                            tgt.DeleteBakedDataForIdentifier(layerInfo.identifier);
+                            EditorSceneManager.MarkSceneDirty(SceneManager.GetActiveScene());
+                        }
+                        EditorGUILayout.EndHorizontal();
+                    }
+                }
+            }
+
+            serializedObject.ApplyModifiedProperties();
+        }
+
+        [MenuItem("Steam Audio/Steam Audio Probe Batch/Bake All Pathing In Current Scene", false, 63)]
+        public static void BakeAllPathingInScene()
+        {
+            var probeBatches = FindObjectsByType<SteamAudioProbeBatch>(FindObjectsSortMode.None);
+            if (probeBatches.Length == 0)
+            {
+                EditorUtility.DisplayDialog(
+                    "No Steam Audio Probe Batches Found",
+                    "No Steam Audio Probe Batch components were found in the currently-open scene.",
+                    "OK");
+                return;
+            }
+
+            SteamAudioProbeBatch.BeginBake(probeBatches);
+            mShouldShowProgressBar = true;
+        }
+#else
+        public override void OnInspectorGUI()
+        {
+            EditorGUILayout.HelpBox("Steam Audio is not supported for the target platform or STEAMAUDIO_ENABLED define symbol is missing.", MessageType.Warning);
+        }
+#endif
+    }
+}