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Sub-events

Published 17 Aug, 2017
392 words
~2-3 mins

Sub-events appear indented beneath other events. They carry on picking instances from where the "parent" event left off. They run after the parent event's actions have finished. An example is below.

Example of sub-events in Construct

This event runs like so:

  1. Test if any Monster instances are overlapping Player. If so, the instances involved are remembered.
  2. The top event's actions would run next, but it doesn't have any.
  3. The second event (note it is indented) then tests if the Player's ShieldEnabled instance variable is set. If so, it subtracts 1 from the health of the Monster overlapping the player.
  4. The third event (also indented) tests if the Player's ShieldEnabled instance variable is not set (see inverting conditions). If so, it subtracts 1 from the health of the Player.

In other words, monsters hurt the player when they touch, unless the player's ShieldEnabled instance variable is set, in which case the monsters are hurt instead.

This works because the objects picked by the top event are remembered and also used for sub-events. If the second and third events were not sub-events (not appearing indented) the second event would subtract 1 from the health of all Monsters, because it was not referenced in the event. (See Unreferenced objects in How events work for more on this.)

Sub-events can have other sub-events too, which makes sub-events very powerful and flexible for setting up advanced game logic.

Note sub-events run after the actions only if the actions run - in the above example, if no monsters are overlapping the player, neither the actions of that event nor its sub-events run at all.

Triggers in sub-events

If a trigger is in a sub-event, all of its parent event's conditions must be true at the time the trigger fires, otherwise the event will not run.

There can also only be one trigger in a single branch of sub-events. In other words, one of the events above a trigger cannot also contain a trigger.

Adding and removing sub-events

To add a sub-event, right-click the event margin and choose AddAdd sub-event. Alternatively choose the Add sub-event option from the Add... link on the right, or press the S keyboard shortcut.

Adding and editing conditions to sub-events works identically to ordinary events. You can also create more deeply nested sub-events by adding a sub-event to a sub-event.