fix(lod-generator-helper): mark scene as dirty

When generating or destroying lods in the editor, the
scene that the object is in will now be marked as dirty.
This fixes issues where Unity doesn't properly detect
the changes made, for example when editing prefabs.

Author: Whinarn

Editor/LODGeneratorHelperEditor.cs

@@ -28,6 +28,7 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 using System.Linq;
 using UnityEngine;
 using UnityEditor;
+using UnityEditor.SceneManagement;
 
 namespace UnityMeshSimplifier.Editor
 {
@@ -522,6 +523,7 @@ private void GenerateLODs()
             }
             finally
             {
+                MarkSceneAsDirty();
                 EditorUtility.ClearProgressBar();
             }
         }
@@ -548,6 +550,7 @@ private void DestroyLODs()
             }
             finally
             {
+                MarkSceneAsDirty();
                 EditorUtility.ClearProgressBar();
             }
         }
@@ -671,6 +674,11 @@ where go.transform.IsChildOf(ourTransform)
             return rendererList.ToArray();
         }
 
+        private void MarkSceneAsDirty()
+        {
+            EditorSceneManager.MarkSceneDirty(lodGeneratorHelper.gameObject.scene);
+        }
+
         private static void DisplayError(string title, string message, string ok, Object context)
         {
             EditorUtility.DisplayDialog(title, message, ok);