ViewController.swift

//
//  ViewController.swift
//  ARMotion
//
//  Created on 9/2/20.
//
// Give Credit to Sarang Borude @sarangborude

import UIKit
import SceneKit
import ARKit
import SwiftUI
import Lottie

class ViewController: UIViewController, ARSCNViewDelegate {

    @IBOutlet var sceneView: ARSCNView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Set the view's delegate
        sceneView.delegate = self
        
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

           // Create a session configuration
          let configuration = ARImageTrackingConfiguration()
            
          if let imagesToTrack = ARReferenceImage.referenceImages(inGroupNamed: "AR Resources",
                                                                  bundle: Bundle.main) {
                
              configuration.trackingImages = imagesToTrack
                  
            // this tells ARKit how many images it is supposed to track simultaneously,
            //ARKit can do upto 100
              configuration.maximumNumberOfTrackedImages = 1
            }
          
          // Run the view's session
          sceneView.session.run(configuration)
    }

    // MARK: - ARSCNViewDelegate
    

    //Override to create and configure nodes for anchors added to the view's session.
    func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode? {
        let node = SCNNode()
                
                // Cast the found anchor as image anchor
                guard let imageAnchor = anchor as? ARImageAnchor else { return nil }
                
                // get the name of the image from the anchor
                guard let imageName = imageAnchor.name else { return nil }
                
                // Check if the name of the detected image is the one you want
                if imageName == "demo" {
                    let plane = SCNPlane(width: imageAnchor.referenceImage.physicalSize.width,
                                         height: imageAnchor.referenceImage.physicalSize.height)
                    
                    
                    let planeNode = SCNNode(geometry: plane)
                    // When a plane geometry is created, by default it is oriented vertically
                    // so we have to rotate it on X-axis by -90 degrees to
                    // make it flat to the image detected
                    planeNode.eulerAngles.x = -.pi / 2
                    
                    createHostingController(for: planeNode)
                    
                    node.addChildNode(planeNode)
                    return node
                } else {
                    return nil
                }
    }
    
    func createHostingController(for node: SCNNode) {
           // create a hosting controller with SwiftUI view
           let arVC = UIHostingController(rootView: ARCView())
           
           // Do this on the main thread
           DispatchQueue.main.async {
               arVC.willMove(toParent: self)
               // make the hosting VC a child to the main view controller
               self.addChild(arVC)
               
               // set the pixel size of the Card View
               arVC.view.frame = CGRect(x: 0, y: 0, width: 500, height: 500)
               
               // add the ar card view as a subview to the main view
               self.view.addSubview(arVC.view)
               
               // render the view on the plane geometry as a material
               self.show(hostingVC: arVC, on: node)
           }
       }
       
       func show(hostingVC: UIHostingController<ARCView>, on node: SCNNode) {
           // create a new material
           let material = SCNMaterial()
           
           // this allows the card to render transparent parts the right way
           hostingVC.view.isOpaque = false
           
           // set the diffuse of the material to the view of the Hosting View Controller
           material.diffuse.contents = hostingVC.view
           
           // Set the material to the geometry of the node (plane geometry)
           node.geometry?.materials = [material]
           
           hostingVC.view.backgroundColor = UIColor.clear
       }

    
    func session(_ session: ARSession, didFailWithError error: Error) {
        // Present an error message to the user
        
    }
    
    func sessionWasInterrupted(_ session: ARSession) {
        // Inform the user that the session has been interrupted, for example, by presenting an overlay
        
    }
    
    func sessionInterruptionEnded(_ session: ARSession) {
        // Reset tracking and/or remove existing anchors if consistent tracking is required
        
    }
}