Fullscreen rendering and input fixes.

* Render background when using fullscreen, because transparency.
* Check that fullscreen surface allows input.
* Don't look for surfaces in top layer if there's a fullscreen view.

sway/desktop/output.c

@@ -280,11 +280,11 @@ static void render_output(struct sway_output *output, struct timespec *when,
 
 	struct sway_container *workspace = output_get_active_workspace(output);
 
+	render_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND]);
+
 	if (workspace->sway_workspace->fullscreen) {
 		render_container(output, workspace->sway_workspace->fullscreen->swayc);
 	} else {
-		render_layer(output,
-				&output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND]);
 		render_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM]);
 
 		render_container(output, workspace);

sway/input/cursor.c

@@ -84,18 +84,21 @@ static struct sway_container *container_at_cursor(struct sway_cursor *cursor,
 				ox, oy, sx, sy))) {
 		return ws;
 	}
-	if ((*surface = layer_surface_at(output,
-				&output->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP],
-				ox, oy, sx, sy))) {
-		return ws;
-	}
-
 	if (ws->sway_workspace->fullscreen) {
+		struct wlr_surface *wlr_surface = ws->sway_workspace->fullscreen->surface;
+		if (wlr_surface_point_accepts_input(wlr_surface, ox, oy)) {
 			*sx = ox;
 			*sy = oy;
-		*surface = ws->sway_workspace->fullscreen->surface;
+			*surface = wlr_surface;
 			return ws->sway_workspace->fullscreen->swayc;
 		}
+		return NULL;
+	}
+	if ((*surface = layer_surface_at(output,
+				&output->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP],
+				ox, oy, sx, sy))) {
+		return ws;
+	}
 
 	struct sway_container *c;
 	if ((c = container_at(ws, cursor->cursor->x, cursor->cursor->y,