Trigger

A trigger is a zero-sized node that has no visual representation and triggers events when:

• It is enabled/disabled (the Enabled event is triggered).
• Its transformation is changed (the Position event is triggered).

The Node Trigger node is usually added as a child node to another node, so that the handler functions were executed on the parent node enabling/disabling or transforming.

The Node Trigger can work with procedurally created World Clutter objects.

The Node Trigger can be used, for example, to play a sound of thunder when a lightning flashes: when the lightning node is enabled, the Enabled event handler that plays a sound is executed.

See also#

To add a new Node Trigger via UnigineEditor do the following:

1. Run UnigineEditor.
2. On the Menu bar, click Create -> Logic -> Node Trigger.

   

3. Place the Node Trigger in the world.
   
4. Add the Node Trigger as a child to a node for which handlers should be executed: select the Node Trigger in the World Nodes Hierarchy window and drag it inside the required node.
   

To edit the Node Trigger, select it and go to the Node tab of the Parameters window.

Editing a trigger node includes implementing and specifying the Enabled and Position event handlers that are executed on enabling or positioning the Trigger node correspondingly.

The event handler must receive at least 1 argument of the NodeTrigger type. In addition, it can also take another 2 arguments of any type.

The event handlers are set via pointers specified when subscribing to the following events: Enabled and Position.

// subscribe to the Enabled event when the trigger is enabled
nodeTrigger->getEventEnabled().connect(enabled_event_handler);
// subscribe to the Position event when the trigger's transformation is changed
nodeTrigger->getEventPosition().connect(position_event_handler);

// subscribe to the Enabled event when the trigger is enabled
nodeTrigger.EventEnabled.Connect(enabled_event_handler);
// subscribe to the Position event when the trigger's transformation is changed
nodeTrigger.EventPosition.Connect(position_event_handler);