AWS Documentation » Amazon Lumberyard » User Guide » Working with Component Entities » Component Reference » Trigger Area

Trigger Area

Component entity system is in preview release and is subject to change.

The Trigger Area component provides generic triggering services by using Shape components as its bounds.

To add a trigger component

1. Create a new entity, or add the Trigger Area component to an existing entity.

2. In the Entity Inspector, click Add Component, then select Trigger Area.

   Entity Inspector displays a message, "This component is missing a required component service and has been disabled.

3. Click Add Required Component, then click one of the shape components that appears.

   The shape component you select defines the boundaries for the trigger.

4. If you want to change the boundaries of your shape component, simply remove the existing shape component, and then add a different shape component.

Trigger Area Component Properties

The Trigger Area component has the following properties:

Network Bindable

Network bindable components are synchronized over the network.

Bind To Network

When selected, synchronizes component across the network.

Activation

Trigger once

If selected, the trigger deactivates after the first trigger event.

Activated by

Select whether trigger is activated by All entities, which allows any entity to trigger the area, or by Specific Entities, which allows you to select specific entities.

Tag filters

RequiredTags

A list of tags that are required for an entity to trigger this area.

ExcludedTags

A list of tags that exclude an entity from triggering this area.

EBus Request Bus Interface

Use the following request functions with the EBus interface to communicate with other components of your game.

For more information about using the Event Bus (EBus) interface, see Working with the Event Bus (EBus) System.

AddRequiredTag

Adds a required tag to the activation filtering criteria of this component. Results in a reevaluation of the trigger. Entities inside that no longer satisfy tag criteria are ejected.

Parameters

const Tag&

requiredTag – Tag to be added

Return

None

Scriptable

Yes

RemoveRequiredTag

Removes a required tag from the activation filtering criteria of this component. Results in a reevaluation of the trigger. Entities inside that no longer satisfy tag criteria are ejected.

Parameters

const Tag&

requiredTag – Tag to be removed

Return

None

Scriptable

Yes

AddExcludedTag

Adds an excluded tag to the activation filtering criteria of this component. Results in a reevaluation of the trigger. Entities inside that no longer satisfy tag criteria are ejected.

Parameters

const Tag&

excludedTag – Tag to be added

Return

None

Scriptable

Yes

RemoveExcludedTag

Removes an excluded tag from the activation filtering criteria of this component. Results in a reevaluation of the trigger. Entities inside that no longer satisfy tag criteria are ejected.

Parameters

const Tag& excludedTag – Tag to be removed

Return

None

Scriptable

Yes

EBus Notification Bus Interface

Use the following request functions with the EBus interface to communicate with other components of your game.

For more information about using the Event Bus (EBus) interface, see Working with the Event Bus (EBus) System.

The Trigger component sends notifications to:

• Entities listening on the TriggerAreaNotificationBus for the entity with the trigger on it.

• Entities listening on the TriggerAreaEntityNotificationBus for the entity that enters or exits the trigger.

TriggerAreaNotificationBus

This bus allows the game to listen for events associated with a particular trigger. Notifies of all the entities that enter and exit this trigger.

OnTriggerAreaEntered

Notifies listeners when enteringEntityId enters this trigger.

Parameters

enteringEntityId – ID of entity that has entered this trigger

Return

None

Scriptable

Yes

OnTriggerAreaExited

Notifies listeners when enteringEntityId exits this trigger.

Parameters

enteringEntityId – ID of entity that has exited this trigger

Return

None

Scriptable

Yes

TriggerAreaEntityNotificationBus

This bus allows the game to listen for trigger-related events associated with a particular entity. Notifies every time the player enters or exits any trigger.

OnEntityEnteredTriggerArea

Sent when the entity enters triggerID.

Parameters

triggerId – ID of entity that the trigger is on

Return

None

Scriptable

Yes

OnEntityExitedTriggerArea

Sent when the entity exits triggerID.

Parameters

triggerId – ID of entity that the trigger is on

Return

None

Scriptable

Yes

The following is an example of script using the EBus interface.

local triggerexample =
{
    Properties =
    {
    }
}
 
function triggerexample:OnActivate()
    self.triggerHandler = TriggerAreaEntityNotificationBus.Connect(self, self.entityId)
end
 
function triggerexample:OnDeactivate()
    self.triggerHandler:Disconnect()
end
 
function triggerexample:OnEntityEnteredTriggerArea(entityId)
    Debug.Log("------- TRIGGERED.")
end
 
return triggerexample