Orbit Cam Virtual Trackball SceneKit

//
//  GameViewController.swift
//  StackTrackBall
//
//  Created by Dan Monaghan on 9/04/22.
//

import UIKit
import QuartzCore
import SceneKit

class GameViewController: UIViewController {

var cameraOrbit = SCNNode()
let orbitCameraNode = SCNNode()
let orbitCamera = SCNCamera()


//HANDLE PAN CAMERA
var lastWidthRatio: Float = 0
var lastHeightRatio: Float = 0.2
var fingersNeededToPan = 1
var maxWidthRatioRight: Float = 1000
var maxWidthRatioLeft: Float = 1000
var maxHeightRatioXDown: Float = 1000
var maxHeightRatioXUp: Float = 1000

//HANDLE PINCH CAMERA
var pinchAttenuation = 20.0  //1.0: very fast ---- 100.0 very slow
var lastFingersNumber = 0

override func viewDidLoad() {
    super.viewDidLoad()

    // create a new scene
    let scene = SCNScene(named: "art.scnassets/ship.scn")!

    // create and add a light to the scene
    let lightNode = SCNNode()
    lightNode.light = SCNLight()
    lightNode.light!.type = SCNLight.LightType.omni
    lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
    scene.rootNode.addChildNode(lightNode)

    // create and add an ambient light to the scene
    let ambientLightNode = SCNNode()
    ambientLightNode.light = SCNLight()
    ambientLightNode.light!.type = SCNLight.LightType.ambient
    ambientLightNode.light!.color = UIColor.darkGray
    scene.rootNode.addChildNode(ambientLightNode)

//Create a camera like Rickster said
//    let camera = SCNCamera()
//    camera.usesOrthographicProjection = true
//    camera.orthographicScale = 9
//    camera.zNear = 0
//    camera.zFar = 100
//    let cameraNode = SCNNode()
//    cameraNode.position = SCNVector3(x: 0, y: 0, z: 50)
//    cameraNode.camera = camera
//    let cameraOrbit = SCNNode()
//    cameraOrbit.addChildNode(cameraNode)
//    cubeScene.rootNode.addChildNode(cameraOrbit)
//
    orbitCamera.zNear = 1
    orbitCamera.zFar = 100
    orbitCamera.motionBlurIntensity = 0.6
    
    orbitCameraNode.position = SCNVector3(x: 0, y: 0, z: 4)
    orbitCameraNode.camera = orbitCamera
    cameraOrbit = SCNNode()
    cameraOrbit.addChildNode(orbitCameraNode)
    scene.rootNode.addChildNode(cameraOrbit)

    //initial camera setup
    self.cameraOrbit.eulerAngles.y = Float(-2 * Float.pi) * lastWidthRatio
    self.cameraOrbit.eulerAngles.x = Float(-Float.pi) * lastHeightRatio

    // retrieve the SCNView
    let scnView = self.view as! SCNView

    // set the scene to the view
    scnView.scene = scene
    scnView.showsStatistics = true
    //allows the user to manipulate the camera
    scnView.allowsCameraControl = false  //not needed

    // add a tap gesture recognizer
    let panGesture = UIPanGestureRecognizer(target: self, action:#selector(handlePan))
    scnView.addGestureRecognizer(panGesture)

    // add a pinch gesture recognizer
    let pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(handlePinch))
    scnView.addGestureRecognizer(pinchGesture)
    
    let rotateGesture = UIRotationGestureRecognizer(target: self, action: #selector(handleRotate))
    scnView.addGestureRecognizer(rotateGesture)

}

    let dollySpeed : Float = 2000
    let zRollModifier : Float = 5
    let panModifier = 100
    let pinchModifier : Float = 15
    let maxZoomIn : Float = -1000.0
    let maxZoomOut : Float = 1000.0

    @objc func handleRotate(recognizer: UIRotationGestureRecognizer) {
        let scale = recognizer.velocity
        print("scale =\(scale)")
        cameraOrbit.eulerAngles.z += Float(scale / CGFloat(zRollModifier)).radians

    }

    
@objc func handlePan(gestureRecognize: UIPanGestureRecognizer) {
    if gestureRecognize.numberOfTouches == 1 {
        let numberOfTouches = gestureRecognize.numberOfTouches
        let translation = gestureRecognize.velocity(in: gestureRecognize.view!)
        cameraOrbit.eulerAngles.y -= Float(translation.x/CGFloat(panModifier)).radians
        cameraOrbit.eulerAngles.x -= Float(translation.y/CGFloat(panModifier)).radians
    }
    if gestureRecognize.numberOfTouches == 2 {
        let scale = gestureRecognize.velocity(in: gestureRecognize.view!)
        print("scale =\(scale)")
        let translation = gestureRecognize.translation(in: gestureRecognize.view!)
        let xx = orbitCameraNode.position.x - Float(scale.x) / dollySpeed
        if xx < maxZoomOut, xx > maxZoomIn {
          orbitCameraNode.position.x = xx
        }
        
        let yy = orbitCameraNode.position.y + Float(scale.y) / dollySpeed
        if yy < maxZoomOut, yy > maxZoomIn {
          orbitCameraNode.position.y = yy
        }
    }
}

    
    @objc func handlePinch(recognizer: UIPinchGestureRecognizer) {
//        guard let camera = cameraOrbit.childNodes.first else {
//          return
//        }
        let scale = recognizer.velocity
        print("scale =\(scale)")
        let z = orbitCameraNode.position.z - Float(scale)/Float(pinchModifier)
        if z < maxZoomOut, z > maxZoomIn {
          orbitCameraNode.position.z = z
        }
      }
    
//@objc func handlePinch(gestureRecognize: UIPinchGestureRecognizer) {
//    let pinchVelocity = Double.init(gestureRecognize.velocity)
//    //print("PinchVelocity \(pinchVelocity)")
//
//    camera.orthographicScale -= (pinchVelocity/pinchAttenuation)
//
//    if camera.orthographicScale <= 0.5 {
//        camera.orthographicScale = 0.5
//    }
//
//    if camera.orthographicScale >= 10.0 {
//        camera.orthographicScale = 10.0
//    }
//
//}

//override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
//    return .Landscape
//}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Release any cached data, images, etc that aren't in use.
}
}

extension Float {
  var radians: Float {
    return self * .pi / 180
  }

  var degrees: Float {
    return self  * 180 / .pi
  }
}