Giving yourself a physics body in AR kit? - swift

Question

In my program, I am trying to make myself collidable with other objects so that I can test collisions. Is there a way to add a physics body that moves with myself in the new AR Kit which follows you? I can make one which is at my place at the beginning of the AR but I'm sure there is a way to add it to your actual self.

Answer 1

Good day!
There is a solution to your problem.
First of all you need to create a collider. For example:
func addCollider(position: SCNVector3, name: String) {
let collider = SCNNode(geometry: SCNSphere(radius: 0.5))
collider.position = position
collider.geometry?.firstMaterial?.diffuse.contents = UIColor.clear
collider.physicsBody?.categoryBitMask = 0 // example
collider.physicsBody?.contactTestBitMask = 1 // example
collider.name = name
sceneView.scene.rootNode.addChildNode(collider)
}
Don't forget to add proper bit masks, to collide with other objects.
Next you need to implement ARSCNViewDelegate protocol and call method willRenderScene. Next you need to locate your point of view and transform it into the matrix. Than you need to extract values from third column of the matrix to get current orientation. To get current location you need to extract values of forth column from your matrix. And finally you need to combine your location and orientation to get your current position.
To combine to SCNVector3 values you need to write global function "+". Example:
func +(left: SCNVector3, right: SCNVector3) -> SCNVector3 {
return SCNVector3Make(left.x + right.x, left.y + right.y, left.z + right.z)
}
Be sure, that you wrote this method outside of class or struct.
Final accord! A function that will move a collider accordingly to your current position.
func renderer(_ renderer: SCNSceneRenderer, willRenderScene scene: SCNScene, atTime time: TimeInterval) {
guard let pontOfView = self.sceneView.pointOfView else { return }
let transform = pontOfView.transform
let orientation = SCNVector3(-transform.m31, -transform.m32, -transform.m33)
let location = SCNVector3(transform.m41, transform.m42, transform.m43)
let currentPosition = orientation + location
for node in sceneView.scene.rootNode.childNodes {
if node.name == "your collider name" {
node.position = currentPosition
}
}
}
P.S. Don't forget to add
self.sceneView.delegate = self
to your viewDidLoad.
Best of luck. I hope it helped!