How to add a target to SCNCamera?

Question

Swift

How to add a target to SCNCamera? In any position, the camera must always be aimed at the point of zero coordinates.
So far my code is this:

// create and add a camera to the scene
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        cameraNode.position = SCNVector3(x: 0, y: 0, z: 20)
        scene.rootNode.addChildNode(cameraNode)

Answer 1

I solved the issue in the following way:

// create and add a camera to the scene
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        //let cameraRoot = SCNNode()
        cameraNode.position = SCNVector3(x: 0, y: 10, z: 20)
        //cameraRoot.addChildNode(cameraNode)
        scene.rootNode.addChildNode(cameraNode)
        
        // setup a target object
        let sphere = SCNSphere(radius: 0)
        let sphereNode = SCNNode(geometry: sphere)
        scene.rootNode.addChildNode(sphereNode)
        
        // put a constraint on the camera
        let targetNode = SCNLookAtConstraint(target: sphereNode)
        targetNode.isGimbalLockEnabled = true
        cameraNode.constraints = [targetNode]