Is there any way to lock the heading of the camera in a SceneView?

alionthego

I am trying to lock the heading of the camera on a SceneView to North as the user scrolls around the map.

 I can't see any option to do that other than a .onChanged modifier to the camera.  The problem with this is if you listen for changes to camera and change the heading back to North each time, you both lose the momentum scroll and also it will mess up other camera functionality like allowing the user to go to present position.  

Is there any way at all to lock the camera heading on North or any other heading as the user scrolls around the 3D sceneView other than listening to Camera changes and replacing the camera each time?

Being new to this I also have noticed that the Camera properties are get only so each time you need to assign a new Camera to the SceneView if you want to change the heading programmatically which is why the listener approach does not work well.

Ting

We don't have a specific API for this behavior. However, you can achieve this by using the interaction status modifier like below. It is a more subtle way than just replacing the camera state property, which would cause a bouncing visual effect.

import SwiftUI
import ArcGIS

struct ContentView: View {
    @State private var scene = Scene(basemapStyle: .arcGISImagery)
    
    @State private var camera: Camera? = Camera(lookingAt: Point(latitude: 34, longitude: -117), distance: 5e4, heading: 0, pitch: 30, roll: 0)
    
    var body: some View {
        SceneViewReader { proxy in
            SceneView(scene: scene, camera: $camera)
                .onInteractingChanged { isChanging in
                    if let camera, !isChanging {
                        Task {
                            await proxy.setViewpointCamera(camera.rotatedTo(heading: 0, pitch: camera.pitch, roll: camera.roll), duration: 0.3)
                        }
                    }
                }
        }
    }
}

 It will reset the viewpoint camera's heading to north once the interaction stops. You can tweak the animation duration to make it feel more natural, or use other view status changed event to reset the camera.

I'll raise this request to our 3D team so they can look further at what they can do to improve this.