An async version of RealityKit's Entity/move that returns when the animation completes

Entity+MoveAsync.swift

//
//  Entity+MoveAsync.swift
//
//  Created by Drew Olbrich on 1/15/24.
//  Copyright © 2024 Lunar Skydiving LLC. All rights reserved.
//
//  MIT License
//  
//  Permission is hereby granted, free of charge, to any person obtaining a copy
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//  
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import Foundation
import RealityKit
import Combine

extension Entity {
    
    /// Asynchronously moves an entity over a period of time to a new location given by
    /// a transform.
    ///
    /// - Parameters:
    ///   - target: A ``Transform`` instance that indicates the new location.
    ///
    ///   - referenceEntity: The entity that defines a frame of reference. Set
    /// this to `nil` to indicate world space.
    ///
    ///   - duration: The time in seconds over which the move should occur.
    ///
    ///   - timingFunction: A timing function that controls the progress of the
    /// animation.
    @MainActor func moveAsync(to target: Transform, relativeTo referenceEntity: Entity?, duration: TimeInterval, timingFunction: AnimationTimingFunction = .default) async {
        guard let scene else {
            return
        }
        let animationPlaybackController = move(to: target, relativeTo: referenceEntity, duration: duration, timingFunction: timingFunction)
        let publisher = scene.publisher(for: AnimationEvents.PlaybackCompleted.self, on: self)
        await withCheckedContinuation { continuation in
            Task {
              for await event in publisher.values {
                  if event.playbackController == animationPlaybackController { continuation.resume() }
              }
            }
        }
    }
}

@drewolbrich For sure! Thanks a lot : )

Yeah, once you set the Swift Language version to Swift 6 you're basically opening up yourself to a week of pulling out your hairs. : P

@drewolbrich I just realise now that the comment says:
/// - Returns: An ``AnimationPlaybackController`` instance that you use to control the animation playback.

But given that this is async, the only timing we could return it would be after the animation finishes. :P So it's probably not useful at that point and I have removed that comment from the docs just now.

Thanks, I've updated the original gist based on your changes.

Good catch about the doc comment! I think that was left over from an earlier version of the function I wrote, which was not async.

I've added you to my app's credits.
: - )

I've been hesitant to update to Swift 6 because of the time suck. Also I was under the impression that even inside Apple, they're still trying to sort out what the best practices are. I figured I'd wait until Swift 7 when the fiddly edge cases have been addressed, rather than discovering them myself.