Arrange SCNNodes in Circle - swift

Question

I'm creating multiple nodes automatically and I want to arrange them around me, because at the moment I'm just increasing of 0.1 the current X location.
capsuleNode.geometry?.firstMaterial?.diffuse.contents = imageView
capsuleNode.position = SCNVector3(self.counterX, self.counterY, self.counterZ)
capsuleNode.name = topic.name
self.sceneLocationView.scene.rootNode.addChildNode(capsuleNode)
self.counterX += 0.1
So the question is, how can I have all of them around me instead of just in one line?
Did someone of you have some math function for this? Thank you!

Answer 1

Use this code (macOS version) to test it:
import SceneKit
class GameViewController: NSViewController {
override func viewDidLoad() {
super.viewDidLoad()
let scene = SCNScene()
let scnView = self.view as! SCNView
scnView.scene = scene
scnView.allowsCameraControl = true
scnView.backgroundColor = NSColor.black
for i in 1...12 { // HERE ARE 12 SPHERES
let sphereNode = SCNNode(geometry: SCNSphere(radius: 1))
sphereNode.position = SCNVector3(0, 0, 0)
// ROTATE ABOUT THIS OFFSET PIVOT POINT
sphereNode.simdPivot.columns.3.x = 5
sphereNode.geometry?.firstMaterial?.diffuse.contents = NSColor(calibratedHue: CGFloat(i)/12,
saturation: 1,
brightness: 1,
alpha: 1)
// ROTATE ABOUT Y AXIS (STEP is 30 DEGREES EXPRESSED IN RADIANS)
sphereNode.rotation = SCNVector4(0, 1, 0, (-CGFloat.pi * CGFloat(i))/6)
scene.rootNode.addChildNode(sphereNode)
}
}
}
P.S. Here's a code for creating 90 spheres:
for i in 1...90 {
let sphereNode = SCNNode(geometry: SCNSphere(radius: 0.1))
sphereNode.position = SCNVector3(0, 0, 0)
sphereNode.simdPivot.columns.3.x = 5
sphereNode.geometry?.firstMaterial?.diffuse.contents = NSColor(calibratedHue: CGFloat(i)/90, saturation: 1, brightness: 1, alpha: 1)
sphereNode.rotation = SCNVector4(0, 1, 0, (-CGFloat.pi * (CGFloat(i))/6)/7.5)
scene.rootNode.addChildNode(sphereNode)
}

Answer 2

You need some math here
How I prepare the circle nodes
var nodes = [SCNNode]()
for i in 1...20 {
let node = createSphereNode(withRadius: 0.05, color: .yellow)
nodes.append(node)
node.position = SCNVector3(0,0,-1 * 1 / i)
scene.rootNode.addChildNode(node)
}
DispatchQueue.main.asyncAfter(deadline: .now() + 5) {
self.arrangeNode(nodes: nodes)
}
func createSphereNode(withRadius radius: CGFloat, color: UIColor) -> SCNNode {
let geometry = SCNSphere(radius: radius)
geometry.firstMaterial?.diffuse.contents = color
let sphereNode = SCNNode(geometry: geometry)
return sphereNode
}
Math behind arrange the view into circle
func arrangeNode(nodes:[SCNNode]) {
let radius:CGFloat = 1;
let angleStep = 2.0 * CGFloat.pi / CGFloat(nodes.count)
var count:Int = 0
for node in nodes {
let xPos:CGFloat = CGFloat(self.sceneView.pointOfView?.position.x ?? 0) + CGFloat(cosf(Float(angleStep) * Float(count))) * (radius - 0)
let zPos:CGFloat = CGFloat(self.sceneView.pointOfView?.position.z ?? 0) + CGFloat(sinf(Float(angleStep) * Float(count))) * (radius - 0)
node.position = SCNVector3(xPos, 0, zPos)
count = count + 1
}
}
Note: In third image I have set.
let xPos:CGFloat = -1 + CGFloat(cosf(Float(angleStep) * Float(count))) * (radius - 0)
let zPos:CGFloat = -1 + CGFloat(sinf(Float(angleStep) * Float(count))) * (radius - 0)
That means if you need view around the camera then
use CGFloat(self.sceneView.pointOfView?.position.x ?? 0) or at the random place then provide the value
Output