private void OnEnable()
        {
            Undo.undoRedoPerformed   += OnUndoRedo;
            SceneView.duringSceneGui += DuringSceneGUI;
            instance     = target as GGeometryStamper;
            Tools.hidden = true;

            instance.Internal_UpdateFalloffTexture();
            GCommon.RegisterBeginRender(OnCameraRender);
            GCommon.RegisterBeginRenderSRP(OnCameraRenderSRP);
            UpdatePreview();
        }
        private void OnEnable()
        {
            Undo.undoRedoPerformed += OnUndoRedo;
            instance     = target as GGeometryStamper;
            Tools.hidden = true;

            instance.Internal_UpdateFalloffTexture();
            previewPropertyBlock = new MaterialPropertyBlock();
            GCommon.RegisterBeginRender(OnCameraRender);
#if UNITY_2019
            GCommon.RegisterBeginRenderSRP(OnCameraRenderSRP);
#endif
            UpdatePreview();
        }