How to use SwiftUI with different views? - scenekit

Question

I have SCNCylinder in a SCNScene and a button in a SwiftUI frame below it. Whenever the button is pressed the cylinder is expected to rotate by 90°. I am not getting the expected result with my code.
//SwiftUI
struct ContentView: View {
var body: some View {
VStack{
Button(action: {
// What to perform
let rotationangle = 180.0
}) {
// How the button looks like
Text("90°")
.frame(width: 100, height: 100)
.position(x: 225, y: 500)
}
SceneKitView()
.frame(width: 300, height: 300)
.position(x: 0, y: 200)
}
}
}
//SceneKit
struct SceneKitView: UIViewRepresentable {
func makeUIView(context:
UIViewRepresentableContext<SceneKitView>) -> SCNView {
//Scene properties
let sceneView = SCNView()
sceneView.scene = SCNScene()
sceneView.allowsCameraControl = true
sceneView.autoenablesDefaultLighting = true
sceneView.backgroundColor = UIColor.white
sceneView.frame = CGRect(x: 0, y: 10, width: 0, height: 1)
//Cylinder properties
let cylinder = SCNCylinder(radius: 0.02, height: 2.0)
let cylindernode = SCNNode(geometry: cylinder)
cylindernode.position = SCNVector3(x: 0, y: 0, z: 0)
cylinder.firstMaterial?.diffuse.contents = UIColor.green
//Pivot and rotation of the cylinder
func degreesToRadians(_ degrees: Float) -> CGFloat {
return CGFloat(degrees * .pi / 180)
}
cylindernode.pivot = SCNMatrix4MakeTranslation(0, -1, 0)
//Line with an error: Use of unresolved identifier ‘rotationangle’
let rotation = SCNAction.rotate(by: degreesToRadians(rotationangle), around: SCNVector3 (1, 0, 0), duration: 5)
sceneView.scene?.rootNode.addChildNode(cylindernode)
cylindernode.runAction(rotation)
return sceneView
}
func updateUIView(_ uiView: SCNView, context: UIViewRepresentableContext<SceneKitView>) {
}
typealias UIViewType = SCNView
}
I am having a error saying “ Use of unresolved identifier ‘rotationangle’ “ during using ‘rotationangle‘ in SCNAction.

Answer 1

You need to declare a #State in your ContentView and set the value of the property in your Button action.
You then need to declare an angle property in your SceneKitView as a #Binding and use that value for it to work properly.
I haven't yet tested this out. Keep in mind that you don't have cone declared anywhere so I'm not sure what that is.
import SwiftUI
import SceneKit
struct ContentView: View {
#State var rotationAngle: Float = 0.0
var body: some View {
VStack {
Button(action: {
// What to perform
self.rotationAngle = 180.0
}) {
// How the button looks like
Text("90°")
.frame(width: 100, height: 100)
.position(x: 225, y: 500)
}
SceneKitView(angle: self.$rotationAngle)
.frame(width: 300, height: 300)
.position(x: 0, y: 200)
}
}
}
//SceneKit
struct SceneKitView: UIViewRepresentable {
#Binding var angle: Float
func degreesToRadians(_ degrees: Float) -> CGFloat {
print(degrees)
return CGFloat(degrees * .pi / 180)
}
func makeUIView(context: UIViewRepresentableContext<SceneKitView>) -> SCNView {
// Scene properties
let sceneView = SCNView()
sceneView.scene = SCNScene()
sceneView.allowsCameraControl = true
sceneView.autoenablesDefaultLighting = true
sceneView.backgroundColor = UIColor.white
sceneView.frame = CGRect(x: 0, y: 10, width: 0, height: 1)
return sceneView
}
func updateUIView (_ sceneView: SCNView, context: UIViewRepresentableContext<SceneKitView>) {
if self.angle > 0 {
// Cylinder properties
let cylinder = SCNCylinder(radius: 0.02, height: 2.0)
let cylindernode = SCNNode(geometry: cylinder)
cylindernode.position = SCNVector3(x: 0, y: 0, z: 0)
// cone.firstMaterial?.diffuse.contents = UIColor.green
// Pivot and rotation of the cylinder
cylindernode.pivot = SCNMatrix4MakeTranslation(0, -1, 0)
sceneView.scene?.rootNode.addChildNode(cylindernode)
//Line with an error: Use of unresolved identifier ‘rotationangle’
let rotation = SCNAction.rotate(by: self.degreesToRadians(self.angle), around: SCNVector3 (1, 0, 0), duration: 5)
cylindernode.runAction(rotation)
}
}
}