Create a simple 3D text object in augmented reality

ARTextViewController.swift

//  Creating a 3D text object with ARKit isn't overwhelming. It might not be immediately obvious, but these objects could
//  be quite valuable moving forward. Imagine dropping a 3D advertisement in someone's augmented reality universe...

//  We'll get started in a sec, but first 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 your object 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 ARTextViewController: 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
        
    //  Declare an SCNScene object for use later.
        let scene = SCNScene()
        
    //  Create a geometry using SCNText. The string that you pass will be the 3D text that's displayed in your AR world.
    //  The extrusion depth is how far along the z-axis the text will extend, that is how deep the text extends away from you.
    //  Use the firstMaterial.diffuse.contents property to change the color of your text.
        let textGeometry = SCNText(string: "Hello World!", extrusionDepth: 1.0)
        textGeometry.firstMaterial?.diffuse.contents = UIColor.blue
        
    //  Create an SCNNode and pass the textGeometry as a parameter.
    //  Determine your node's position using an SCNVector3. To place it at eye-level, directly in front of you, you will
    //  need to pass negative values. The text will start from left to right, with the first letter beginning at the 
    //  x-coordinate. A positive value for the z-coordinate will place your text behind you, so give it a negative value
    //  to place the text in front of you. Finally, scale down the text significantly for all coordinates, or else it will
    //  be huge. The x-coordinate assigned to the scaling vector expands or compresses the node horizontally, the y-coordinate
    //  expands or compresses the node vertically, and the z-coordinate expands or compresses the depth of the node. Values
    //  greater than one will increase the size of the object, while values less than one will make the object smaller.
        let textNode = SCNNode(geometry: textGeometry)
        textNode.position = SCNVector3(x: -1, y: -0.2, z: -1)
        textNode.scale = SCNVector3(x: 0.02, y: 0.02, z: 0.02)
        
    //  Add the node as a child node to the root node's childNodes array
        scene.rootNode.addChildNode(textNode)
        
    //  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()
    }
    
}