tearing: add fullscreen options (#1941)

Co-authored-by: Consolatis <35009135+Consolatis@users.noreply.github.com>

docs/labwc-actions.5.scd

@@ -187,7 +187,12 @@ Actions are used in menus and keyboard/mouse bindings.
 	original window. There can be multiple windows with this mode set.
 
 *<action name="ToggleTearing" />*
-	Toggles tearing for the focused window.
+	Toggles tearing for the focused window between enabled and disabled.
+	This overrides the preference (tearing hint) from the focused window.
+
+	Requires the config option 'allowTearing'. When 'allowTearing' is set
+	to 'fullscreen' or 'fullscreenForced', tearing will still only be
+	enabled if the active window is in fullscreen mode.
 
 *<action name="FocusOutput" output="HDMI-A-1" />*
 	Give focus to topmost window on given output and warp the cursor

docs/labwc-config.5.scd

@@ -185,9 +185,18 @@ this is for compatibility with Openbox.
 	*fullscreen* enables adaptive sync whenever a window is in fullscreen
 	mode.
 
-*<core><allowTearing>* [yes|no]
+*<core><allowTearing>* [yes|no|fullscreen|fullscreenForced]
-	Allow tearing, if requested by the active window, to reduce input lag.
+	Allow tearing to reduce input lag. Default is no.
-	Default is no.
+
+	*yes* allows tearing if requested by the active window.
+
+	*fullscreen* allows tearing if requested by the active window, but
+	only when the window is in fullscreen mode.
+
+	*fullscreenForced* enables tearing whenever the active window is in
+	fullscreen mode, whether or not the application has requested tearing.
+
+	Use the *ToggleTearing* action for forcefully enable tearing.
 
 	Note: Enabling this option with atomic mode setting is experimental. If
 	you experience undesirable side effects when tearing is allowed,

include/config/rcxml.h

@@ -30,6 +30,13 @@ enum adaptive_sync_mode {
 	LAB_ADAPTIVE_SYNC_FULLSCREEN,
 };
 
+enum tearing_mode {
+	LAB_TEARING_DISABLED = 0,
+	LAB_TEARING_ENABLED,
+	LAB_TEARING_FULLSCREEN,
+	LAB_TEARING_FULLSCREEN_FORCED,
+};
+
 enum tiling_events_mode {
 	LAB_TILING_EVENTS_NEVER = 0,
 	LAB_TILING_EVENTS_REGION = 1 << 0,
@@ -54,7 +61,7 @@ struct rcxml {
 	bool xdg_shell_server_side_deco;
 	int gap;
 	enum adaptive_sync_mode adaptive_sync;
-	bool allow_tearing;
+	enum tearing_mode allow_tearing;
 	bool reuse_output_mode;
 	enum view_placement_policy placement_policy;
 	bool xwayland_persistence;

include/labwc.h

@@ -535,6 +535,7 @@ struct output *output_nearest_to_cursor(struct server *server);
 bool output_is_usable(struct output *output);
 void output_update_usable_area(struct output *output);
 void output_update_all_usable_areas(struct server *server, bool layout_changed);
+bool output_get_tearing_allowance(struct output *output);
 struct wlr_box output_usable_area_in_layout_coords(struct output *output);
 struct wlr_box output_usable_area_scaled(struct output *output);
 void handle_output_power_manager_set_mode(struct wl_listener *listener,

include/view.h

@@ -30,6 +30,12 @@ enum ssd_preference {
 	LAB_SSD_PREF_SERVER,
 };
 
+enum three_state {
+	LAB_STATE_UNSPECIFIED = 0,
+	LAB_STATE_ENABLED,
+	LAB_STATE_DISABLED
+};
+
 /**
  * Directions in which a view can be maximized. "None" is used
  * internally to mean "not maximized" but is not valid in rc.xml.
@@ -187,6 +193,7 @@ struct view {
 	enum view_axis maximized;
 	bool fullscreen;
 	bool tearing_hint;
+	enum three_state force_tearing;
 	bool visible_on_all_workspaces;
 	enum view_edge tiled;
 	uint32_t edges_visible;  /* enum wlr_edges bitset */

src/action.c

@@ -1109,9 +1109,22 @@ actions_run(struct view *activator, struct server *server,
 			break;
 		case ACTION_TYPE_TOGGLE_TEARING:
 			if (view) {
-				view->tearing_hint = !view->tearing_hint;
+				switch (view->force_tearing) {
-				wlr_log(WLR_DEBUG, "tearing %sabled",
+				case LAB_STATE_UNSPECIFIED:
-					view->tearing_hint ? "en" : "dis");
+					view->force_tearing =
+						output_get_tearing_allowance(view->output)
+							? LAB_STATE_DISABLED : LAB_STATE_ENABLED;
+					break;
+				case LAB_STATE_DISABLED:
+					view->force_tearing = LAB_STATE_ENABLED;
+					break;
+				case LAB_STATE_ENABLED:
+					view->force_tearing = LAB_STATE_DISABLED;
+					break;
+				}
+				wlr_log(WLR_ERROR, "force tearing %sabled",
+					view->force_tearing == LAB_STATE_ENABLED
+						? "en" : "dis");
 			}
 			break;
 		case ACTION_TYPE_TOGGLE_SHADE:

src/config/rcxml.c

@@ -772,6 +772,20 @@ set_adaptive_sync_mode(const char *str, enum adaptive_sync_mode *variable)
 	}
 }
 
+static void
+set_tearing_mode(const char *str, enum tearing_mode *variable)
+{
+	if (!strcasecmp(str, "fullscreen")) {
+		*variable = LAB_TEARING_FULLSCREEN;
+	} else if (!strcasecmp(str, "fullscreenForced")) {
+		*variable = LAB_TEARING_FULLSCREEN_FORCED;
+	} else if (parse_bool(str, -1) == 1) {
+		*variable = LAB_TEARING_ENABLED;
+	} else {
+		*variable = LAB_TEARING_DISABLED;
+	}
+}
+
 static void
 entry(xmlNode *node, char *nodename, char *content)
 {
@@ -886,7 +900,7 @@ entry(xmlNode *node, char *nodename, char *content)
 	} else if (!strcasecmp(nodename, "adaptiveSync.core")) {
 		set_adaptive_sync_mode(content, &rc.adaptive_sync);
 	} else if (!strcasecmp(nodename, "allowTearing.core")) {
-		set_bool(content, &rc.allow_tearing);
+		set_tearing_mode(content, &rc.allow_tearing);
 	} else if (!strcasecmp(nodename, "reuseOutputMode.core")) {
 		set_bool(content, &rc.reuse_output_mode);
 	} else if (!strcmp(nodename, "policy.placement")) {

src/output.c

@@ -38,28 +38,50 @@ get_tearing_retry_count(struct output *output)
 	return refresh > 0 ? refresh / 500 : 120;
 }
 
-static bool
+bool
-get_tearing_preference(struct output *output)
+output_get_tearing_allowance(struct output *output)
 {
 	struct server *server = output->server;
 
-	/* Never allow tearing when disabled */
+	/* never allow tearing when disabled */
 	if (!rc.allow_tearing) {
 		return false;
 	}
 
-	/* Tearing is only allowed for the output with the active view */
+	struct view *view = server->active_view;
-	if (!server->active_view || server->active_view->output != output) {
+
+	/* tearing is only allowed for the output with the active view */
+	if (!view || view->output != output) {
 		return false;
 	}
 
-	/* Tearing should not have failed too many times */
+	/* tearing should not have failed too many times */
 	if (output->nr_tearing_failures >= get_tearing_retry_count(output)) {
 		return false;
 	}
 
-	/* If the active view requests tearing, or it is toggled on with action, allow it */
+	/* allow tearing for any window when requested or forced */
-	return server->active_view->tearing_hint;
+	if (rc.allow_tearing == LAB_TEARING_ENABLED) {
+		if (view->force_tearing == LAB_STATE_UNSPECIFIED) {
+			return view->tearing_hint;
+		} else {
+			return view->force_tearing == LAB_STATE_ENABLED;
+		}
+	}
+
+	/* remaining tearing options apply only to full-screen windows */
+	if (!view->fullscreen) {
+		return false;
+	}
+
+	if (view->force_tearing == LAB_STATE_UNSPECIFIED) {
+		/* honor the tearing hint or the fullscreen-force preference */
+		return view->tearing_hint ||
+			rc.allow_tearing == LAB_TEARING_FULLSCREEN_FORCED;
+	}
+
+	/* honor tearing as requested by action */
+	return view->force_tearing == LAB_STATE_ENABLED;
 }
 
 static void
@@ -128,7 +150,7 @@ output_frame_notify(struct wl_listener *listener, void *data)
 		struct wlr_scene_output *scene_output = output->scene_output;
 		struct wlr_output_state *pending = &output->pending;
 
-		pending->tearing_page_flip = get_tearing_preference(output);
+		pending->tearing_page_flip = output_get_tearing_allowance(output);
 
 		bool committed =
 			lab_wlr_scene_output_commit(scene_output, pending);

src/tearing.c

@@ -15,8 +15,15 @@ set_tearing_hint(struct wl_listener *listener, void *data)
 {
 	struct tearing_controller *controller = wl_container_of(listener, controller, set_hint);
 	struct view *view = view_from_wlr_surface(controller->tearing_control->surface);
-	if (view && controller->tearing_control->current) {
+	if (view) {
-		view->tearing_hint = true;
+		/*
+		 * tearing_control->current is actually an enum:
+		 * WP_TEARING_CONTROL_V1_PRESENTATION_HINT_VSYNC = 0
+		 * WP_TEARING_CONTROL_V1_PRESENTATION_HINT_ASYNC = 1
+		 *
+		 * Using it as a bool here allows us to not ship the XML.
+		 */
+		view->tearing_hint = controller->tearing_control->current;
 	}
 }