Added GenerateMask to AssetsHelpers;

Editor/AssetsHelpers/Implementation/Material/CreateTerrainLayer/CreateTerrainLayerMenu.cs

@@ -0,0 +1,34 @@
+using UnityEditor;
+using UnityEngine;
+
+namespace Misaki.ArtToolEditor
+{
+    public class CreateTerrainLayerMenu
+    {
+        private const string Terrain_Layer_Extension = ".terrainlayer";
+
+        [MenuItem("Assets/Art Tools/Material Helpers/Create Terrain Layer", true)]
+        public static bool CreateTerrainLayerValidator()
+        {
+            foreach (var selectedObject in Selection.objects)
+            {
+                if (selectedObject is not Material)
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        [MenuItem("Assets/Art Tools/Material Helpers/Create Terrain Layer")]
+        public static void CreateTerrainLayer()
+        {
+            var window = EditorWindow.GetWindow<OutputOptionsWindow>(true, "Extract Materials Output Options");
+            window.WithItemSource(Selection.objects);
+            window.RegisterProcessor<CreateTerrainLayerProcessor>();
+
+            window.InitializeAndShow();
+        }
+    }
+}