ARKit Calculate distance from a wall to the camera - arkit

Question

I’m developing a project with ARKit. I want to calculate the measure from a wall to the camera and it updates when I move away or I move closer.
Now, i have activated that it detects horizontal and vertical surfaces. When I get a surface, I calculate the distance from the camera position and the center of the surface. After I apply the calculus that it gets the distance between 2 points in a 3D space (Euclidean).
https://math.stackexchange.com/questions/42640/calculate-distance-in-3d-space
Is it correct? Can you help me?
class ViewController: UIViewController, ARSCNViewDelegate, ARSessionDelegate {
let configuration = ARWorldTrackingConfiguration()
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
configuration.planeDetection = [.horizontal, .vertical]
sceneView.session.run(configuration)
......
}
func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
guard let planeAnchor = anchor as? ARPlaneAnchor else { return }
let plane = SCNPlane(width: CGFloat(planeAnchor.extent.x), height:
CGFloat(planeAnchor.extent.z))
let planeNode = SCNNode(geometry: plane)
planeNode.simdPosition = float3(planeAnchor.center.x, 0,
planeAnchor.center.z)
planeNode.eulerAngles.x = -.pi / 2
node.addChildNode(planeNode)
let distance = distanceFromCamera(x: planeAnchor.center.x, y: 0, z: planeAnchor.center.z)
let formatted = String(format: "Distance: %.2f", distance)
print(formatted) q
}
private func distanceFromCamera(x: Float, y:Float, z:Float) -> Float {
let cameraPosition = self.sceneView.session.currentFrame!.camera.transform.columns.3
print("Camera: \(cameraPosition)")
let vector = SCNVector3Make(cameraPosition.x - x, cameraPosition.y - y, cameraPosition.z - z)
// Scene units map to meters in ARKit.
return sqrtf(vector.x * vector.x + vector.y * vector.y + vector.z * vector.z)
}
}

Answer 1

Add Following method
func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
guard let currentBall = self.currentBall else {return}
DispatchQueue.main.async {
if let centerPosition = self.hitTestCenterVector() {
let startPositionOfBall = currentBall.position
let distance = self.getDistanceBetween(vector1: centerPosition, vector2: startPositionOfBall)
self.lblDistance.text = String(format: "%.1f", distance) //meter
}
}
}
Just replace self.currentBall in guard statement with your SCNNode it is from where you want to cal. distance
Now This is method to for calculations
func hitTestCenterVector () -> SCNVector3? {
let results = self.sceneView.hitTest(self.sceneView.center, types: .existingPlane)
if let firstObject = results.first {
return SCNVector3(firstObject.worldTransform.columns.3.x, firstObject.worldTransform.columns.3.y, firstObject.worldTransform.columns.3.z)
}
return nil
}
func getDistanceBetween(vector1:SCNVector3, vector2:SCNVector3) -> CGFloat {
return CGFloat(sqrt((vector1.x - vector2.x) * (vector1.x - vector2.x)
+ (vector1.y - vector2.y) * (vector1.y - vector2.y)
+ (vector1.z - vector2.z) * (vector1.z - vector2.z)))
}
Hope it is helpful