Coaching overlay

Description

We can use a coaching overlay to prompt the user to move their device around until a goal is met (for example a horizontal plane is found in the scene).

Video

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Code

using ARKit;
using System;
using UIKit;

namespace XamarinArkitSample
{
    public partial class ViewController : UIViewController, IARCoachingOverlayViewDelegate
    {
        private readonly ARSCNView sceneView;

        ARCoachingOverlayView coachingOverlay;

        public ViewController(IntPtr handle) : base(handle)
        {
            this.sceneView = new ARSCNView();
            this.View.AddSubview(this.sceneView);
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            this.sceneView.Frame = this.View.Frame;
        }

        public override void ViewDidAppear(bool animated)
        {
            base.ViewDidAppear(animated);

            this.sceneView.Session.Run(new ARWorldTrackingConfiguration {
                PlaneDetection = ARPlaneDetection.Horizontal,
            });

            coachingOverlay = new ARCoachingOverlayView();
            coachingOverlay.Session = sceneView.Session;
            coachingOverlay.Delegate = this;
            coachingOverlay.ActivatesAutomatically = true;
            coachingOverlay.Goal = ARCoachingGoal.HorizontalPlane;
            coachingOverlay.TranslatesAutoresizingMaskIntoConstraints = false;

            sceneView.AddSubview(coachingOverlay);

            // Keeps the coaching overlay in the center of the screen
            var layoutConstraints = new NSLayoutConstraint[]
            {
                coachingOverlay.CenterXAnchor.ConstraintEqualTo(View.CenterXAnchor),
                coachingOverlay.CenterYAnchor.ConstraintEqualTo(View.CenterYAnchor),
                coachingOverlay.WidthAnchor.ConstraintEqualTo(View.WidthAnchor),
                coachingOverlay.HeightAnchor.ConstraintEqualTo(View.HeightAnchor),
            };

            NSLayoutConstraint.ActivateConstraints(layoutConstraints);
        }

        public override void ViewDidDisappear(bool animated)
        {
            base.ViewDidDisappear(animated);

            this.sceneView.Session.Pause();
        }

        public override void DidReceiveMemoryWarning()
        {
            base.DidReceiveMemoryWarning();
        }
    }
}