Fix #23363: Layer buttons do not update when last object deleted

This happend because of incorrect order of calculating used layer mask and drawing
header. Added layer content changed notifier to recalc used layers when needed.
This also fixes header redrawing in "Move to layer" operator and when user
changes Object.layers in properties view

1 files changed, 37 insertions, 0 deletions

diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index c49f4f48e10..1e035797bea 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -513,6 +513,37 @@ static void *view3d_main_area_duplicate(void *poin)
 	return NULL;
 }
 
+static void view3d_recalc_used_layers(ARegion *ar, wmNotifier *wmn)
+{
+	wmWindow *win= wmn->wm->winactive;
+	ScrArea *sa;
+
+	if (!win) return;
+
+	sa= win->screen->areabase.first;
+
+	while(sa) {
+		if(sa->spacetype == SPACE_VIEW3D)
+			if(BLI_findindex(&sa->regionbase, ar) >= 0) {
+				View3D *v3d= sa->spacedata.first;
+				Scene *scene= wmn->reference;
+				Base *base;
+
+				v3d->lay_used= 0;
+				base= scene->base.first;
+				while(base) {
+					v3d->lay_used|= base->lay;
+
+					base= base->next;
+				}
+
+				break;
+			}
+
+		sa= sa->next;
+	}
+}
+
 static void view3d_main_area_listener(ARegion *ar, wmNotifier *wmn)
 {
 	/* context changes */
@@ -536,6 +567,10 @@ static void view3d_main_area_listener(ARegion *ar, wmNotifier *wmn)
 			break;
 		case NC_SCENE:
 			switch(wmn->data) {
+				case ND_LAYER_CONTENT:
+					view3d_recalc_used_layers(ar, wmn);
+					ED_region_tag_redraw(ar);
+					break;
 				case ND_FRAME:
 				case ND_TRANSFORM:
 				case ND_OB_ACTIVE:
@@ -677,6 +712,7 @@ static void view3d_header_area_listener(ARegion *ar, wmNotifier *wmn)
 				case ND_MODE:
 				case ND_LAYER:
 				case ND_TOOLSETTINGS:
+				case ND_LAYER_CONTENT:
 					ED_region_tag_redraw(ar);
 					break;
 			}
@@ -728,6 +764,7 @@ static void view3d_buttons_area_listener(ARegion *ar, wmNotifier *wmn)
 				case ND_OB_SELECT:
 				case ND_MODE:
 				case ND_LAYER:
+				case ND_LAYER_CONTENT:
 					ED_region_tag_redraw(ar);
 					break;
 			}