Persistence

Persistence is a system for saving World Anchor states across multiple runs of the same application. This can be thought of as a “save game” functionality for physical locations in the real world. An example of this is remembering where a game board is placed in the world when the application re-launches.

The WorldAnchorStore provides basic functionality for saving and loading World Anchors. Retrieve a WorldAnchorStore by calling WorldAnchorStore.GetAsync and providing it with a callback. Your callback saves the WorldAnchorStore returned so that it can be used for future operations.

To save an existing World Anchor, give it a name and call the Save function on the WorldAnchorStore. See an example below:

private void SaveAnchor()
{
    if (!this.savedAnchor) // only save this once
    {
        this.savedAnchor = this.MyWorldAnchorStore.Save("MyAnchor", MyWorldAnchor);
        if (!this.savedAnchor)
        {
            // Anchor failed to save to the store.
            // Handle errors here.
        }
    }
}

Loading is essentially a reflection of the above:

private void LoadAnchor()
{
    this.savedAnchor = this.Load("MyAnchor", MyWorldAnchor);
    if (!this.savedAnchor)
    {
        // An anchor with that name wasn't saved to the store.  
        // Handle errors here.
    }
}

To remove an anchor from the store, call the Delete method on the WorldAnchorStore. To remove all anchors from the store, call the Clear method.