Async/Await with PhotogrammetrySession

Question

Adamgoodapp OP

Created Jun ’21

Replies 2

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Participants 3

I'm trying out the PhotogrammetrySession api following the wwdc2021-10076 tutorial here

However I get this error when trying the async/await for looping the session.output

For-in loop requires 'AnyPublisher<PhotogrammetrySession.Output, Error>' to conform to 'AsyncSequence'

Code:

async {

    for try await output in session.output {

        switch output {

        case .requestProgress(let request, let fraction):

            print("Request progressL \(fraction)")

        }

    }

}

Using Xcode 13.0 beta and macOS 12.0 Beta. MacBook Pro (15-inch, 2019) Thanks.

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Answer 1

Ethan_ OP

Jun ’21

I have the same question! The sample code shows an outputs property on session but only output exists in Xcode, which is for the Combine publisher.

0

Answer 2

Engineer OP

Apple

Jun ’21

The API described in the session video is slightly different than the one that shipped with the beta. The beta API uses a Combine Publisher named output to produce the message stream. The Output messages are the same, but for this version you will need to use a Combine pipeline to dispatch messages rather than the AsyncStream approach referred to in the video. For an example of how to do this, please see the command-line app sample code HelloPhotogrammetry which uses a Combine sink to dispatch messages.

1