Add a second object (a sphere) to your Augmented Reality space

ARMultipleObjectsViewController.swift

//  Adding a second object to your Augmented Reality space is not much different from adding the first, so we will change
//  things up here a bit. Here we will create a sphere in addition to a box and we will give our objects some style.

//  If you haven't already, you need to add a key-value pair to your application's Info.plist (Information Property List) file.
//  Add the key "Privacy - Camera Usage Description" with the corresponding value "This application will use your camera for
//  Augmented Reality", or some similarly descriptive note.

//  Let's get started!

//  You'll need to import SceneKit to create and edit your objects and ARKit to place it in your augmented reality space.
import UIKit
import SceneKit
import ARKit

//  Make sure you conform to the ARSCNView Delegate.
class ARMultipleObjectsViewController: UIViewController, ARSCNViewDelegate {
    
//  Declare an ARSCNView 
    var sceneView: ARSCNView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
    //  Set the view frame to match the bounds of your view controller, and add the sceneView as a subview to your view 
    //  controller's view.
        self.sceneView = ARSCNView(frame: self.view.frame)
        self.view.addSubview(self.sceneView)
        
    //  Assign the sceneView's delegate to itself, and optionally display statistics at the bottom of the view.
        sceneView.delegate = self
        
        sceneView.showsStatistics = true
        
    //  Create an SCNScene object to be used later and create an SCNBox. This box will be the 3D object that will be
    //  displayed. Note that the dimensions of the box are in meters, so choose appropriate values depending on your
    //  goals. Also, chamfer refers to an object's right-angled edge. The chamferRadius parameter is similar to editing
    //  the corner radius of two dimensional views in Swift; it determines how rounded (if at all) the edges of the box are.
        let scene = SCNScene()
        let box = SCNBox(width: 0.2, height: 0.2, length: 0.2, chamferRadius: 0.01)
        
    //  Create an SCNMaterial object for your new box. You will notice that we are assigning a UIImage named "marioSide"
    //  to the material's diffuse.contents property. Download a square image from the web, and store the image in your 
    //  Assets.xcassets folder. Give it the same name that you use here in line 44, e.g. "marioSide".
        let boxMaterial = SCNMaterial()
        boxMaterial.diffuse.contents = UIImage(named: "marioSide")
    
    //  Now create an SCNNode. Assign the box to the node's geometry property, and assign the materials to the
    //  geometry.materials property. Assign an SCNVector3 to the node's position property. Note that the parameters for the
    //  vector are in meters, so select appropriate values. Also note that a positive value for the z-coordinate will place
    //  the object behind you.
        let boxNode = SCNNode()
        boxNode.geometry = box
        boxNode.geometry?.materials = [boxMaterial]
        boxNode.position = SCNVector3(x: 0.2, y: 0.1, z: -0.5)
        
    //  Similar to the box we just created, we will create an SCNSphere and follow esssentially the same pattern. Create
    //  the objecet, assign it a material, create a node, and assign it to a position in AR space.
        let sphere = SCNSphere(radius: 0.2)
        let sphereMaterial = SCNMaterial()
        sphereMaterial.diffuse.contents = UIImage(named: "bobOmb")
        
        let sphereNode = SCNNode()
        sphereNode.geometry = sphere
        sphereNode.geometry?.materials = [sphereMaterial]
        
        sphereNode.position = SCNVector3(x: -0.2, y: -0.2, z: -1.0)
        
    //  Add the nodes as child nodes to the root node's childNodes array
        scene.rootNode.addChildNode(boxNode)
        scene.rootNode.addChildNode(sphereNode)
        
    //  Assign the scene to the scene property of the sceneView. Say that five times fast!
        sceneView.scene = scene
        
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
    //  Allow your device to track the world around a device.. This class uses the rear camera and track's a device's
    //  position and orientation and detects flat surfaces in the real world.
    //  See https://developer.apple.com/documentation/arkit/arworldtrackingconfiguration for more details.
        let configuration = ARWorldTrackingConfiguration()
        
    //  Run the sceneView's session with the configuration you just declared.
        sceneView.session.run(configuration)
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        
    //  Pause the sceneView's session when the user is not making use of the AR view. This allows the device to avoid using
    //  computationally expensive AR rendering.
        sceneView.session.pause()
    }
    
}