Overview#

omni.activity.core provides a centralized mechanism for processing activity and progress events within the Omniverse Kit SDK. It offers a standardized interface to send and track activity state changes—from when an activity begins, to updates in its progress, and finally to its conclusion. This extension underpins the activity monitoring system by efficiently dispatching events and managing callbacks on a per-frame basis.

Concepts#

EventType
Defines the types of activity events handled by the system. The core members are BEGAN, UPDATED, and ENDED, which signal the start, change, or finish of an activity.
IActivity
Acts as the central processor for activities and their progress updates. It provides methods to subscribe to event notifications, push events into the system, and ensure that event callbacks are processed each frame.
IEvent
Represents individual events containing custom data—such as progress or other state changes. This interface standardizes how additional event information is accessed.
INode
Organizes events and can contain other nodes, enabling a hierarchical structure for tracking complex activities with multiple nested events.

Functionality#

Event Dispatching and Processing
The extension exposes functions to signal the beginning, progress, update, and ending of activities. Through the public APIs like began, progress, updated, and ended, developers can broadcast activity events without having to manage low-level details. Callbacks can be subscribed via IActivity, and the pump method ensures these events are processed each frame.
Global Activity Management
Using the get_instance API, developers can retrieve a singleton instance of the activity processor, allowing for a consistent and centralized way to manage activity events across the application. The extension also includes utility functions to enable or disable event dispatching when needed.

Considerations#

Per-Frame Processing
To ensure that events are dispatched to subscribers reliably, it is important to call the pump method each frame. This design enforces synchronization across activity updates.
Callback Subscription
Subscribers can register their callbacks using the provided API. These callbacks receive nodes representing activity events, which makes it easier to integrate with custom UI or logging systems.

Relationships#

Integration with Other Components
omni.activity.core is a core building block within the activity monitoring system of the Omniverse Kit SDK. It relies on proper integration with other modules—such as UI and logging extensions—that visualize or further process the dispatched activity events.
Dependencies
The extension is defined with native plugins and integrates with the underlying core object system of Omniverse Kit SDK (via omni.core._core). This ensures that activity tracking works seamlessly across different layers of the application.

This concise overview highlights the essential aspects of omni.activity.core and its role in managing activity events, making it straightforward for developers to integrate progress and event tracking in their applications.