Actions System
The Actions system provides a universal pattern for attaching discrete, reusable behaviors to entities and triggering them from any source — ScriptCanvas, World Triggers, UI buttons, or C++ code. Actions are data-driven components that fire on named channels, enabling composition without custom scripting.
For architecture details, component properties, and creating custom actions in C++, see the Framework API reference.
Contents
How Actions Work
An Action is a component you attach to an entity. Each Action has a channel name. When something calls DoAction(channelName) on that entity’s bus, every Action component whose channel matches the name will execute.
This decoupling is the core value — the system that fires DoAction does not need to know what kind of action is attached. You can change, add, or remove action components on an entity without modifying any calling code.
| Concept | What It Means |
|---|---|
| Channel | A named string. Actions on the same channel fire together. |
| Composition | Multiple actions on the same channel execute in parallel — stack components to compose behaviors. |
| Chaining | An action can fire a different channel on completion, enabling lightweight sequences. |
Triggering Actions
ScriptCanvas
[ActionRequestBus → DoAction(channelName)]
└─► All Action components on this entity with matching channel execute
To know when an action completes:
[ActionNotificationBus → OnActionComplete]
└─► Action has finished executing
Built-In Actions
GS_Core ships with these ready-to-use actions:
| Action | What It Does |
|---|---|
| PrintLog | Logs a configurable message to the console. Useful for debugging trigger chains. |
| ToggleMouseCursor | Shows or hides the system mouse cursor. |
Additional actions are available in other gems (e.g., World Trigger actions in GS_Interaction, dialogue effects in GS_Cinematics).
Common Patterns
World Trigger → Action
A World Trigger detects a collision or interaction event and fires DoAction on its entity. Action components on the same entity respond — one might play a sound, another might set a record, another might toggle an entity.
UI Button → Action
A UI button press fires DoAction with a channel name. Actions handle the response — navigate to a different UI page, start a new game, or toggle the pause menu.
Chaining Actions
Set an action’s “Chain Channel” property to fire a different channel when it completes:
Channel "OpenDoor" → [ToggleEntity action] → chains to "PlayDoorSound" → [AudioEvent action]
Quick Reference
| Need | Bus | Method / Event |
|---|---|---|
| Fire an action | ActionRequestBus | DoAction(channelName) |
| Know when an action completes | ActionNotificationBus | OnActionComplete |
Glossary
| Term | Meaning |
|---|---|
| Action | A component that executes a discrete behavior when triggered on a named channel |
| Channel | A named string identifier that groups actions — all actions on the same channel fire together |
| Chaining | Configuring an action to fire a different channel on completion, creating lightweight sequences |
For full definitions, see the Glossary.
See Also
For the full API, component properties, and C++ extension guide:
For related systems:
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