Create TbtSettings to reference BrushManifest

Prep for future work.
Also allows the toolkit to work in play mode in the editor
googlevr#35

Change-Id: Id000b01589c82fbb9bb6fd2e23d193c2936ba94b

UnitySDK/Assets/TiltBrush/Assets/Brushes/AllBrushes.asset

@@ -11,7 +11,6 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 8a4e1c4479d3ef54a83ac7187217ec6a, type: 3}
   m_Name: AllBrushes
   m_EditorClassIdentifier: 
-  m_DefaultManifest: {fileID: 0}
   m_Brushes:
   - {fileID: 11400000, guid: cadc04d18daae874aa63168911a19ba6, type: 2}
   - {fileID: 11400000, guid: 94e865ca3b92ee5568334254825adac1, type: 2}

UnitySDK/Assets/TiltBrush/Resources/TiltBrushToolkitSettings.asset

@@ -0,0 +1,14 @@
+%YAML 1.1
+%TAG !u! tag:unity3d.com,2011:
+--- !u!114 &11400000
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_PrefabParentObject: {fileID: 0}
+  m_PrefabInternal: {fileID: 0}
+  m_GameObject: {fileID: 0}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: bd66b8f767459f44e84273c6abbfc402, type: 3}
+  m_Name: TiltBrushToolkitSettings
+  m_EditorClassIdentifier: 
+  m_BrushManifest: {fileID: 11400000, guid: 2b3e59298bb8cfc47bddd1e1ea01be06, type: 2}

UnitySDK/Assets/TiltBrush/Scripts/BrushManifest.cs

@@ -20,32 +20,6 @@
 namespace TiltBrushToolkit {
 
 public class BrushManifest : ScriptableObject {
-  // static API
-
-  private static BrushManifest sm_Instance;
-  public static BrushManifest Instance {
-    get {
-      // How can we get a reference to the singleton AllBrushes.asset?
-      // LoadAssetAtPath<>() is fragile, because it bakes in a file path.
-      // Instead, (ab)use the ability for scripts to have default values
-      // (which are stored in the .meta)
-      if (sm_Instance == null) {
-        var dummy = CreateInstance<BrushManifest>();
-        sm_Instance = dummy.m_DefaultManifest;
-        DestroyImmediate(dummy);
-      }
-      Debug.Assert(sm_Instance != null, "Misconfigured singleton");
-      return sm_Instance;
-    }
-  }
-
-  // instance API
-
-  // See Instance.get for an explanation of this
-  [HideInInspector]
-  [SerializeField]
-  private BrushManifest m_DefaultManifest;
-
   [SerializeField] private BrushDescriptor[] m_Brushes;
   private Dictionary<Guid, BrushDescriptor> m_ByGuid;
   private ILookup<string, BrushDescriptor> m_ByName;
@@ -76,7 +50,7 @@ public ILookup<string, BrushDescriptor> BrushesByName {
 #if UNITY_EDITOR
   [UnityEditor.MenuItem("Tilt Brush/Update Manifest")]
   public static void MenuItem_UpdateManifest() {
-    BrushManifest manifest = Instance;
+    BrushManifest manifest = TbtSettings.BrushManifest;
     manifest.m_Brushes = UnityEditor.AssetDatabase.FindAssets("t:BrushDescriptor")
         .Select(g => UnityEditor.AssetDatabase.GUIDToAssetPath(g))
         .Select(p => UnityEditor.AssetDatabase.LoadAssetAtPath<BrushDescriptor>(p))

UnitySDK/Assets/TiltBrush/Scripts/Editor/ModelImportSettings.cs

@@ -321,7 +321,7 @@ void PerformTexcoordCoordinateConversion(BrushDescriptor desc, Mesh mesh, int uv
   void OnPostprocessModel(GameObject g) {
     // For backwards compatibility, if people have projects that use the old naming
     if (sm_forceOldMeshNamingConvention) {
-      Dictionary<Material, BrushDescriptor> lookup = BrushManifest.Instance.AllBrushes
+      Dictionary<Material, BrushDescriptor> lookup = TbtSettings.BrushManifest.AllBrushes
           .ToDictionary(desc => desc.m_Material);
       ChangeNamesRecursive(lookup, d => d.m_DurableName + "_geo", g.transform);
     }
@@ -375,7 +375,7 @@ BrushDescriptor GetDescriptorForStroke(string oldMaterialName) {
     if (match.Success) {
       Guid brushGuid = new Guid(match.Groups[1].Value);
       try {
-        return BrushManifest.Instance.BrushesByGuid[brushGuid];
+        return TbtSettings.BrushManifest.BrushesByGuid[brushGuid];
       } catch (KeyNotFoundException) {
         LogWarningWithContext(string.Format(
             "Unexpected: Couldn't find Tilt Brush material for guid {0}.",
@@ -386,7 +386,7 @@ BrushDescriptor GetDescriptorForStroke(string oldMaterialName) {
 
     // Older versions use material.name == brush.m_DurableName
     {
-      var descs = BrushManifest.Instance.BrushesByName[oldMaterialName].ToArray();
+      var descs = TbtSettings.BrushManifest.BrushesByName[oldMaterialName].ToArray();
       if (descs.Length == 1) {
         return descs[0];
       } else if (descs.Length > 1) {

UnitySDK/Assets/TiltBrush/Scripts/TbtSettings.cs

@@ -0,0 +1,44 @@
+// Copyright 2019 Google LLC
+//
+// 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
+//
+//     https://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 System;
+using UnityEngine;
+
+namespace TiltBrushToolkit {
+
+public class TbtSettings : ScriptableObject {
+  const string kAssetName = "TiltBrushToolkitSettings";
+
+  private static TbtSettings sm_Instance;
+
+  public static TbtSettings Instance {
+    get {
+      if (sm_Instance == null) {
+        sm_Instance = Resources.Load<TbtSettings>(kAssetName);
+        if (sm_Instance == null) {
+          throw new InvalidOperationException("Cannot find " + kAssetName + ".asset");
+        }
+      }
+      return sm_Instance;
+    }
+  }
+
+  public static BrushManifest BrushManifest {
+    get { return Instance.m_BrushManifest; }
+  }
+
+  [SerializeField] private BrushManifest m_BrushManifest;
+}
+
+}