World Triggers

The World Trigger system pairs a TriggerSensorComponent (condition side) with a WorldTriggerComponent (response side) to create event-driven world state changes. Each component owns an array of polymorphic type objects — sensor types define what conditions to evaluate, trigger types define what happens when the condition passes. Any combination of types can be composed on a single entity without scripting.

For usage guides and setup examples, see The Basics: GS_Interaction.

 

Contents

• Architecture
• Trigger Sensors
• World Triggers
• Extension Guide
• See Also

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Architecture

Breakdown

World Triggers split conditions from responses using a polymorphic type/component pattern. The two container components sit on the entity; logic lives in the type objects they own.

Part	What It Does
TriggerSensorComponent	Owns arrays of TriggerSensorType objects (andConditions, orConditions). Evaluates all conditions and fires WorldTriggerRequestBus::Trigger on success. Automatically activates a PhysicsTriggerComponent if any sensor type requires it.
WorldTriggerComponent	Owns an array of WorldTriggerType objects (triggerTypes). On Trigger(), calls Execute() on every type. On Reset(), calls OnReset(). On Activate(), calls OnComponentActivate() for startup initialization.

No scripting is required for standard patterns. Compose sensor types and trigger types in the editor to cover the majority of interactive world objects.

E Indicates extensible classes and methods.

Patterns - Complete list of system patterns used in GS_Play.

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Trigger Sensors

The sensory side. TriggerSensorComponent holds arrays of TriggerSensorType objects that define evaluation logic — collisions, interactions, record conditions. Supports AND conditions (all must pass) and OR conditions (any must pass).

Trigger Sensors API

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World Triggers

The response side. WorldTriggerComponent holds an array of WorldTriggerType objects that execute when triggered — toggling entities, setting records, changing stages, logging messages.

World Triggers API

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Extension Guide

Use the ClassWizard templates to generate new sensor and trigger type classes — see GS_Interaction Templates:

• TriggerSensorType — generates a new TriggerSensorType subclass with EvaluateAction(), EvaluateResetAction(), and lifecycle stubs.
• WorldTriggerType — generates a new WorldTriggerType subclass with Execute(), OnReset(), and OnComponentActivate() stubs.

Custom Sensor Types

1. Create a class extending TriggerSensorType.
2. Override EvaluateAction() to define your condition logic.
3. Override EvaluateResetAction() if your type supports reset evaluation.
4. Override Activate(entityId) / Deactivate() for lifecycle setup.
5. If your type needs a physics trigger volume, return true from NeedsPhysicsTrigger().
6. For event-driven types, listen on a bus and call TriggerSensorRequestBus::DoAction() or DoResetAction() when the event fires.
7. Reflect the class manually in GS_InteractionSystemComponent::Reflect().

Custom Trigger Types

1. Create a class extending WorldTriggerType.
2. Override Execute(entityId) — implement the world state change here.
3. Override OnReset(entityId) to reverse or re-arm the effect.
4. Override OnComponentActivate(entityId) for any initial state that must be set at startup.
5. Reflect the class manually in GS_InteractionSystemComponent::Reflect().

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See Also

For component references:

• Trigger Sensors
• World Triggers

For related resources:

• Pulsors
• Targeting

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1 - Trigger Sensors

TriggerSensorComponent is the condition container of the World Trigger system. It owns arrays of TriggerSensorType objects that define evaluation logic — collisions, interactions, record checks. When conditions pass, it fires WorldTriggerRequestBus::Trigger on the same entity.

For usage guides and setup examples, see The Basics: GS_Interaction.

Container Component

TriggerSensorComponent

Owns and evaluates all sensor type objects. Not subclassed — extended by adding TriggerSensorType objects to its arrays.

Bus: TriggerSensorRequestBus (ById, Single)

On Activate, automatically activates a PhysicsTriggerComponent on the entity if any sensor type returns true from NeedsPhysicsTrigger().

Base Type Class

TriggerSensorType

Abstract base for all sensor evaluation logic. Not a component — reflected manually in GS_InteractionSystemComponent::Reflect(). Subclass this to add new condition types.

Stores m_ownerEntityId for calling back to TriggerSensorRequestBus::DoAction() or DoResetAction() from event-driven types.

Built-in Sensor Types

SensorType_Collider

Physics overlap sensor. Returns NeedsPhysicsTrigger() = true, causing the owning component to activate a PhysicsTriggerComponent.

• OnTriggerEnter stores the entering entity.
• OnTriggerExit clears the stored entity.
• EvaluateAction() returns true while a valid entity is present.
• EvaluateResetAction() returns true when no entity is present.

SensorType_Record

Fires when a named save record changes to a configured value. Extends RecordKeeperNotificationBus — connects on Activate and fires DoAction automatically when the matching record changes.

• EvaluateAction() calls GetRecord and compares against recordValue.

→ Record Sensor Type Reference

SensorType_Interact

Fires when any unit interacts with this entity via the targeting system. Extends InteractTriggerSensorRequestBus.

• On interact: stores lastCaller and calls DoAction.
• EvaluateAction() returns true while lastCaller is a valid entity.

SensorType_PlayerInteract

Player-only variant of SensorType_Interact. Extends SensorType_Interact and adds a tag check — lastCaller must have the "Player" tag for the condition to pass.

Extension Guide

To create a custom sensor type:

1. Create a class extending TriggerSensorType.
2. Override EvaluateAction() to define when your condition is satisfied.
3. Override Activate(entityId) / Deactivate() to connect and disconnect from any buses.
4. For event-driven evaluation, listen on a bus and call TriggerSensorRequestBus::DoAction(m_ownerEntityId) when the event fires — the component will run the full evaluation pipeline.
5. Return true from NeedsPhysicsTrigger() if your type needs a physics volume.
6. Reflect the class in GS_InteractionSystemComponent::Reflect() — types are not components and are not registered via CreateDescriptor().

See Also

• World Triggers
• World Trigger System

Get GS_Interaction

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1.1 - SensorType_Record

For usage guides and setup examples, see The Basics: GS_Interaction.

Overview

SensorType_Record is a TriggerSensorType that fires when a named save record is changed to a configured value. Add it to the andConditions or orConditions array on a TriggerSensorComponent.

Inherits from RecordKeeperNotificationBus — connects automatically on Activate and listens for record changes without polling. When a matching record change arrives, it calls TriggerSensorRequestBus::DoAction on the owning component, which runs the full condition evaluation pipeline.

Fields

Evaluation

EvaluateAction() calls RecordKeeperRequestBus::GetRecord(recordName) and compares the result to recordValue. Returns true if they match.

The type self-triggers on record change events — you do not need to poll or script a check manually.

Setup

1. Add a TriggerSensorComponent to your entity.
2. Add a SensorType_Record entry to the andConditions or orConditions array.
3. Set recordName to the record you want to watch.
4. Set recordValue to the value that should fire the trigger.
5. Add a WorldTriggerComponent with the desired WorldTriggerType objects to the same entity.

API

From TriggerSensorType:

//! Returns true if the watched record currently matches recordValue.
virtual bool EvaluateAction();

//! Connects to RecordKeeperNotificationBus on component activate.
virtual void Activate(AZ::EntityId entityId);

//! Disconnects from RecordKeeperNotificationBus on component deactivate.
virtual void Deactivate();

From RecordKeeperNotificationBus:

//! Called when any record changes. Fires DoAction if recordName and recordValue match.
virtual void RecordChanged(const AZStd::string& name, int value);

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2 - World Triggers

WorldTriggerComponent is the response container of the World Trigger system. It owns an array of WorldTriggerType objects that execute when triggered — toggling entities, setting records, changing stages, logging messages.

For usage guides and setup examples, see The Basics: GS_Interaction.

Container Component

WorldTriggerComponent

Owns and drives all trigger type objects. Not subclassed — extended by adding WorldTriggerType objects to triggerTypes.

Bus: WorldTriggerRequestBus (ById)

On Activate(), calls OnComponentActivate(entityId) on every type — use this for initial state seeding (e.g. entity visibility setup before any trigger fires).

Base Type Class

WorldTriggerType

Abstract base for all trigger response logic. Not a component — reflected manually in GS_InteractionSystemComponent::Reflect(). Subclass this to add new response types.

Built-in Trigger Types

Extension Guide

To create a custom trigger type:

1. Create a class extending WorldTriggerType.
2. Override Execute(entityId) — implement your world state change here.
3. Override OnReset(entityId) for reversible or re-armable effects.
4. Override OnComponentActivate(entityId) if your type needs to set up initial state at startup (e.g. TriggerType_ToggleEntities uses this to seed entity visibility).
5. Reflect the class in GS_InteractionSystemComponent::Reflect() — types are not components and are not registered via CreateDescriptor().

See Also

• Trigger Sensors
• World Trigger System

Get GS_Interaction

GS_Interaction — Explore this gem on the product page and add it to your project.