Don't create VFXGraph during import callbacks (#148)

* do not Create VFXGraph in import callbacks

* error when graph missing. Better test code for asset creation

Author: iTris666

com.unity.visualeffectgraph/Editor/Models/VFXGraph.cs

@@ -28,8 +28,11 @@ void OnPreprocessAsset()
                 VisualEffectResource resource = VisualEffectResource.GetResourceAtPath(assetPath);
                 if (resource == null)
                     return;
-
-                resource.GetOrCreateGraph().SanitizeForImport();
+                VFXGraph graph = resource.graph as VFXGraph;
+                if (graph != null)
+                    graph.SanitizeForImport();
+                else
+                    Debug.LogError("VisualEffectGraphResource without graph");
             }
         }
 
@@ -38,9 +41,11 @@ static string[] OnAddResourceDependencies(string assetPath)
             VisualEffectResource resource = VisualEffectResource.GetResourceAtPath(assetPath);
             if (resource != null)
             {
-                VFXGraph graph = resource.GetOrCreateGraph();
+                VFXGraph graph = resource.graph as VFXGraph;
                 if (graph != null)
-                    return graph.GetImportDependencies();
+                    return resource.GetOrCreateGraph().GetImportDependencies();
+                else
+                    Debug.LogError("VisualEffectGraphResource without graph");
             }
             return null;
         }
@@ -49,11 +54,11 @@ static void OnCompileResource(VisualEffectResource resource)
         {
             if (resource != null)
             {
-                VFXGraph graph = resource.GetOrCreateGraph();
+                VFXGraph graph = resource.graph as VFXGraph;
                 if (graph != null)
-                {
-                    graph.CompileForImport();
-                }
+                    resource.GetOrCreateGraph().CompileForImport();
+                else
+                    Debug.LogError("VisualEffectGraphResource without graph");
             }
         }
 

com.unity.visualeffectgraph/Editor/VFXAssetEditorUtility.cs

@@ -84,7 +84,16 @@ public static VisualEffectAsset CreateNewAsset(string path)
 
         public static T CreateNew<T>(string path) where T : UnityObject
         {
-            string emptyAsset = "%YAML 1.1\n%TAG !u! tag:unity3d.com,2011:\n--- !u!2058629511 &1\nVisualEffectResource:\n";
+            string emptyAsset =
+@"%YAML 1.1
+%TAG !u! tag:unity3d.com,2011:
+--- !u!114 &114350483966674976
+MonoBehaviour:
+  m_Script: {fileID: 11500000, guid: 7d4c867f6b72b714dbb5fd1780afe208, type: 3}
+--- !u!2058629511 &1
+VisualEffectResource:
+  m_Graph: {fileID: 114350483966674976}
+";
 
             File.WriteAllText(path, emptyAsset);