How can i have multiple select options for a single image? - ios

Question

I am using SceneKit to import a 3d image model of a human body. When i select a particular location point in the image, i want the app to recognize the body part and perform a different function for each part. How do i go about implementing this? What is the best way to do this?
P.s. when the image is rotated it shows a different view. I need the app to be able to recognize the body part even when it is rotated by the user. Any guidance as to how to proceed would be appreciated..

Answer 1

Here's a simple SceneKit picking example.
The scene is setup in the viewDidLoad, for your use case I'd expect a scene would be loaded from file (best done in another method). This file will hopefully have the different components you wish to pick as separate components in a tree-like hierarchy. The author of this 3D body model will have hopefully labelled these components appropriately so that your code can identify what to do when your left-femur is selected (and not comp2345).
For a complex model expect several 'hits' for any xy coordinate as you will be returned all nodes intersected by the hit ray. You may wish to only use the first hit.
import UIKit
import SceneKit
class ViewController: UIViewController {
#IBOutlet var scenekitView: SCNView!
override func viewDidLoad() {
super.viewDidLoad()
let scene = SCNScene()
let boxNode = SCNNode(geometry: SCNBox(width: 1, height: 1, length: 1, chamferRadius: 0))
boxNode.name = "box"
scene.rootNode.addChildNode(boxNode)
let sphereNode = SCNNode(geometry: SCNSphere(radius: 1))
sphereNode.name = "sphere"
sphereNode.position = SCNVector3Make(2, 0, 0)
boxNode.addChildNode(sphereNode)
let torusNode = SCNNode(geometry: SCNTorus(ringRadius: 1, pipeRadius: 0.3))
torusNode.name = "torus"
torusNode.position = SCNVector3Make(2, 0, 0)
sphereNode.addChildNode(torusNode)
scenekitView.scene = scene
scenekitView.autoenablesDefaultLighting = true
scenekitView.allowsCameraControl = true
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
//get the first touch location in screen coordinates
guard let touch = touches.first else {
return
}
//convert the screen coordinates to view coordinates as the SCNView make not take
//up the entire screen.
let pt = touch.locationInView(self.scenekitView)
//pass a ray from the points 2d coordinates into the scene, returning a list
//of objects it hits
let hits = self.scenekitView.hitTest(pt, options: nil)
for hit in hits {
//do something with each hit
print("touched ", hit.node.name!)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}