Hi, would love for your help in that matter.
I try to get the position in space of two QR codes to make an alignment to their positions in space. The detection shows that the QR codes position is always 0,0,0 and I don't understand why. Here's my code:
import SwiftUI
import RealityKit
import RealityKitContent
struct AnchorView: View {
@ObservedObject var qrCoordinator: QRCoordinator
@ObservedObject var coordinator: ImmersiveCoordinator
let qrName: String
@Binding var startQRDetection: Bool
@State private var anchor: AnchorEntity? = nil
@State private var detectionTask: Task<Void, Never>? = nil
var body: some View {
RealityView { content in
// Add the QR anchor once (must exist before detection starts)
if anchor == nil {
let imageAnchor = AnchorEntity(.image(group: "QRs", name: qrName))
content.add(imageAnchor)
anchor = imageAnchor
print("📌 Created anchor for \(qrName)")
}
}
.onChange(of: startQRDetection) { enabled in
if enabled {
startDetection()
} else {
stopDetection()
}
}
.onDisappear {
stopDetection()
}
}
private func startDetection() {
guard detectionTask == nil, let anchor = anchor else { return }
detectionTask = Task {
var detected = false
while !Task.isCancelled && !detected {
print("🔎 Checking \(qrName)... isAnchored=\(anchor.isAnchored)")
if anchor.isAnchored {
// wait a short moment to let transform update
try? await Task.sleep(nanoseconds: 100_000_000)
let worldPos = anchor.position(relativeTo: nil)
if worldPos != .zero {
// relative to modelRootEntity if available
var posToSave = worldPos
if let modelEntity = coordinator.modelRootEntity {
posToSave = anchor.position(relativeTo: modelEntity)
print("converted to model position")
} else {
print("⚠️ modelRootEntity not available, using world position")
}
print("✅ \(qrName) detected at position: world=\(worldPos) saved=\(posToSave)")
if qrName == "reanchor1" {
qrCoordinator.qr1Position = posToSave
let marker = createMarker(color: [0,1,0])
marker.position = .zero // sits directly on QR
marker.position = SIMD3<Float>(0, 0.02, 0)
anchor.addChild(marker)
print("marker1 added")
} else if qrName == "reanchor2" {
qrCoordinator.qr2Position = posToSave
let marker = createMarker(color: [0,0,1])
marker.position = posToSave // sits directly on QR
marker.position = SIMD3<Float>(0, 0.02, 0)
anchor.addChild(marker)
print("marker2 added")
}
detected = true
} else {
print("⚠️ \(qrName) anchored but still at origin, retrying...")
}
}
try? await Task.sleep(nanoseconds: 500_000_000) // throttle loop
}
print("🛑 QR detection loop ended for \(qrName)")
detectionTask = nil
}
}
private func stopDetection() {
detectionTask?.cancel()
detectionTask = nil
}
private func createMarker(color: SIMD3<Float>) -> ModelEntity {
let sphere = MeshResource.generateSphere(radius: 0.05)
let material = SimpleMaterial(color: UIColor(
red: CGFloat(color.x),
green: CGFloat(color.y),
blue: CGFloat(color.z),
alpha: 1.0
), isMetallic: false)
let marker = ModelEntity(mesh: sphere, materials: [material])
marker.name = "marker"
return marker
}
}
Topic:
Spatial Computing
SubTopic:
General
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