create a dedicated layer for fullscreen clients

Bug: https://github.com/djpohly/dwl/issues/327

dwl.c

@@ -73,7 +73,7 @@
 /* enums */
 enum { CurNormal, CurPressed, CurMove, CurResize }; /* cursor */
 enum { XDGShell, LayerShell, X11Managed, X11Unmanaged }; /* client types */
-enum { LyrBg, LyrBottom, LyrTop, LyrOverlay, LyrTile, LyrFloat, LyrDragIcon, NUM_LAYERS }; /* scene layers */
+enum { LyrBg, LyrBottom, LyrTop, LyrOverlay, LyrTile, LyrFloat, LyrFS, LyrDragIcon, NUM_LAYERS }; /* scene layers */
 #ifdef XWAYLAND
 enum { NetWMWindowTypeDialog, NetWMWindowTypeSplash, NetWMWindowTypeToolbar,
 	NetWMWindowTypeUtility, NetLast }; /* EWMH atoms */
@@ -102,7 +102,6 @@ typedef struct {
 	struct wlr_scene_tree *scene;
 	struct wlr_scene_rect *border[4]; /* top, bottom, left, right */
 	struct wlr_scene_tree *scene_surface;
-	struct wlr_scene_rect *fullscreen_bg; /* See setfullscreen() for info */
 	struct wl_list link;
 	struct wl_list flink;
 	union {
@@ -171,6 +170,7 @@ struct Monitor {
 	struct wl_list link;
 	struct wlr_output *wlr_output;
 	struct wlr_scene_output *scene_output;
+	struct wlr_scene_rect *fullscreen_bg; /* See createmon() for info */
 	struct wl_listener frame;
 	struct wl_listener destroy;
 	struct wlr_box m;      /* monitor area, layout-relative */
@@ -445,6 +445,9 @@ arrange(Monitor *m)
 		if (c->mon == m)
 			wlr_scene_node_set_enabled(&c->scene->node, VISIBLEON(c, m));
 
+	wlr_scene_node_set_enabled(&m->fullscreen_bg->node,
+			(c = focustop(m)) && c->isfullscreen);
+
 	if (m && m->lt[m->sellt]->arrange)
 		m->lt[m->sellt]->arrange(m);
 	motionnotify(0);
@@ -655,6 +658,7 @@ cleanupmon(struct wl_listener *listener, void *data)
 	m->wlr_output->data = NULL;
 	wlr_output_layout_remove(output_layout, m->wlr_output);
 	wlr_scene_output_destroy(m->scene_output);
+	wlr_scene_node_destroy(&m->fullscreen_bg->node);
 
 	closemon(m);
 	free(m);
@@ -874,6 +878,18 @@ createmon(struct wl_listener *listener, void *data)
 	wl_list_insert(&mons, &m->link);
 	printstatus();
 
+	/* The xdg-protocol specifies:
+	 *
+	 * If the fullscreened surface is not opaque, the compositor must make
+	 * sure that other screen content not part of the same surface tree (made
+	 * up of subsurfaces, popups or similarly coupled surfaces) are not
+	 * visible below the fullscreened surface.
+	 *
+	 */
+	/* updatemons() will resize and set correct position */
+	m->fullscreen_bg = wlr_scene_rect_create(layers[LyrFS], 0, 0, fullscreen_bg);
+	wlr_scene_node_set_enabled(&m->fullscreen_bg->node, 0);
+
 	/* Adds this to the output layout in the order it was configured in.
 	 *
 	 * The output layout utility automatically adds a wl_output global to the
@@ -1724,8 +1740,6 @@ resize(Client *c, struct wlr_box geo, int interact)
 	wlr_scene_node_set_position(&c->border[1]->node, 0, c->geom.height - c->bw);
 	wlr_scene_node_set_position(&c->border[2]->node, 0, c->bw);
 	wlr_scene_node_set_position(&c->border[3]->node, c->geom.width - c->bw, c->bw);
-	if (c->fullscreen_bg)
-		wlr_scene_rect_set_size(c->fullscreen_bg, c->geom.width, c->geom.height);
 
 	/* wlroots makes this a no-op if size hasn't changed */
 	c->resize = client_set_size(c, c->geom.width - 2 * c->bw,
@@ -1833,32 +1847,16 @@ setfullscreen(Client *c, int fullscreen)
 		return;
 	c->bw = fullscreen ? 0 : borderpx;
 	client_set_fullscreen(c, fullscreen);
+	wlr_scene_node_reparent(&c->scene->node, layers[fullscreen
+			? LyrFS : c->isfloating ? LyrFloat : LyrTile]);
 
 	if (fullscreen) {
 		c->prev = c->geom;
 		resize(c, c->mon->m, 0);
-		/* The xdg-protocol specifies:
-		 *
-		 * If the fullscreened surface is not opaque, the compositor must make
-		 * sure that other screen content not part of the same surface tree (made
-		 * up of subsurfaces, popups or similarly coupled surfaces) are not
-		 * visible below the fullscreened surface.
-		 *
-		 * For brevity we set a black background for all clients
-		 */
-		if (!c->fullscreen_bg) {
-			c->fullscreen_bg = wlr_scene_rect_create(c->scene,
-				c->geom.width, c->geom.height, fullscreen_bg);
-			wlr_scene_node_lower_to_bottom(&c->fullscreen_bg->node);
-		}
 	} else {
 		/* restore previous size instead of arrange for floating windows since
 		 * client positions are set by the user and cannot be recalculated */
 		resize(c, c->prev, 0);
-		if (c->fullscreen_bg) {
-			wlr_scene_node_destroy(&c->fullscreen_bg->node);
-			c->fullscreen_bg = NULL;
-		}
 	}
 	arrange(c->mon);
 	printstatus();
@@ -1976,6 +1974,7 @@ setup(void)
 	layers[LyrBottom] = wlr_scene_tree_create(&scene->tree);
 	layers[LyrTile] = wlr_scene_tree_create(&scene->tree);
 	layers[LyrFloat] = wlr_scene_tree_create(&scene->tree);
+	layers[LyrFS] = wlr_scene_tree_create(&scene->tree);
 	layers[LyrTop] = wlr_scene_tree_create(&scene->tree);
 	layers[LyrOverlay] = wlr_scene_tree_create(&scene->tree);
 	layers[LyrDragIcon] = wlr_scene_tree_create(&scene->tree);
@@ -2342,6 +2341,9 @@ updatemons(struct wl_listener *listener, void *data)
 		/* Don't move clients to the left output when plugging monitors */
 		arrange(m);
 
+		wlr_scene_node_set_position(&m->fullscreen_bg->node, m->m.x, m->m.y);
+		wlr_scene_rect_set_size(m->fullscreen_bg, m->m.width, m->m.height);
+
 		config_head->state.enabled = 1;
 		config_head->state.mode = m->wlr_output->current_mode;
 		config_head->state.x = m->m.x;
@@ -2411,7 +2413,7 @@ xytonode(double x, double y, struct wlr_surface **psurface,
 	Client *c = NULL;
 	LayerSurface *l = NULL;
 	const int *layer;
-	int focus_order[] = { LyrOverlay, LyrTop, LyrFloat, LyrTile, LyrBottom, LyrBg };
+	int focus_order[] = { LyrOverlay, LyrTop, LyrFS, LyrFloat, LyrTile, LyrBottom, LyrBg };
 
 	for (layer = focus_order; layer < END(focus_order); layer++) {
 		if ((node = wlr_scene_node_at(&layers[*layer]->node, x, y, nx, ny))) {