public static void ShowWindow()
{
SceneView.onSceneGUIDelegate -= OnSceneGUI;
SceneView.onSceneGUIDelegate += OnSceneGUI;
//BSPTree tree = new BSPTree(Selection.activeGameObject, Selection.activeGameObject.GetComponent<MeshFilter>().sharedMesh);
btree = ScriptableObject.CreateInstance(typeof(BSPTree)) as BSPTree;
btree.Init(Selection.activeGameObject, Selection.activeGameObject.GetComponent<MeshFilter>().sharedMesh);
hasfinished = true;
}