When the Loading Screen Is Shown

The Loading Screen Manager is a Game Instance Subsystem. Every frame it asks a list of questions, in order. The first one that says "show" wins, and its answer becomes the reason for the loading screen.

The checks, in order

1. Force Loading Screen Visible (or CommonLoadingScreen.AlwaysShow) is on.
2. There is no world yet, or the Game State has not replicated.
3. A map is being loaded, unless the map is in Blocked Map Names.
4. There is a pending travel, unless the target map is in Blocked Map Names.
5. The game is connecting to a server.
6. The world has not begun play.
7. The game is in seamless travel.
8. The Game State or one of its components returns true from Should Show Loading Screen.
9. A registered loading process returns true, for example a task from Create Loading Screen Process Task.
10. A local Player Controller or one of its components returns true from Should Show Loading Screen.
11. A Watcher returns true from Should Show Loading Screen.
12. No local Player Controller exists yet. In split screen, every local player must have one.

If nothing asks for the loading screen, the reason becomes (nothing wants to show it anymore).

During seamless travel to a map in Blocked Map Names, only the first check is made. The loading screen stays hidden until the travel has finished.

The checks are also made while the game is paused.

Holding the loading screen up

When nothing needs the loading screen anymore, it stays up for Show Loading Screen Additional Secs more, so texture streaming can catch up. The world is rendered behind the loading screen during this time. The On Show Loading Screen Additional Secs Triggered event fires with true when the hold starts, and with false when the loading screen is hidden.

The hold time does not apply:

• In the editor, unless Show Loading Screen Additional Secs Even in Editor is on.
• On maps in Blocked Map Names.

While the loading screen is shown

• The widget is added to the game viewport with Loading Screen ZOrder.
• All keyboard, mouse and gamepad input is blocked. Input is not blocked in the editor. In builds other than Shipping, the console keys and typing in an open console still work, so you can run commands. The console may be drawn behind the loading screen widget.
• The shader pipeline cache compiles in fast mode, and the hitch detector is paused.
• On Loading Screen Visibility Changed Delegate fires with true when it is shown and false when it is hidden.
• A garbage collection runs just before the loading screen is hidden.

Keeping the widget animated while a map loads

Loading a map with Open Level blocks the game thread, so the widget stops animating until the map has loaded. Turn on Use Movie Player During Load Map to show the widget with Unreal's Movie Player during the load instead. The Movie Player draws it on its own thread, so animations keep playing.

• A second instance of Loading Screen Widget is created for the Movie Player.
• The widget is drawn outside the game thread. Animations and bindings work, but don't rely on Blueprint Tick or other game logic in it.
• It is only used in a packaged or standalone game, never in the editor.
• It is not used for maps in Blocked Map Names or during seamless travel, which doesn't block the game thread.

Map events

The Loading Screen Manager also forwards these events, which you can bind in Blueprint:

Event	When
On Pre Load Map Triggered	A map starts loading. Gives the map name.
On Post Load Map Triggered	The map has finished loading.
On Seamless Travel Start	Seamless travel to a map starts. Gives the map name.

Turning it off for testing

Start the game with -NoLoadingScreen on the command line to never show the loading screen. This works in all builds except Shipping.