Clean up the observation architecture and content construction flags.

ExampleVisionOS/EuclidMesh.swift

@@ -22,7 +22,8 @@ let euclidMesh: Mesh = {
     print("Triangles:", mesh.triangulate().polygons.count)
     print("Watertight:", mesh.isWatertight)
 
-    sleep(5) // simulate long-running task
+    // Sleep here to simulate a long-running mesh construction.
+    sleep(5)
 
     return mesh
 }()

ExampleVisionOS/MeshViewModel.swift

@@ -10,28 +10,33 @@ import CoreGraphics
 import Euclid
 import RealityKit
 
+/// Holds an Entity built from a Euclid Mesh, plus state for the VolumetricView.
 @Observable
 class MeshViewModel: ObservableObject {
+    /// The Euclid mesh's Entity lands here.
     public var entity: Entity? = nil
-    public var status = false
+    /// Euclid has finished preparing the content.
+    public var contentReady = false
+    /// The RealityView instance has added the content.
+    public var contentAdded = false
 
-    func prepareContent()  {
+    func prepareContent() {
         Task.init {
             do {
-                let demoBoxEntity = try await ModelEntity(euclidMesh.scaled(by: 0.5))// {
-                
+                let demoBoxEntity = try await ModelEntity(euclidMesh.scaled(by: 0.5))
+
                 // for more realism, add a shadow
                 await demoBoxEntity.components.set(GroundingShadowComponent(castsShadow: true))
-                
+
                 // needed for tap detection/response
                 await demoBoxEntity.generateCollisionShapes(recursive: true)
-                
+
                 // for gesture targeting
                 await demoBoxEntity.components.set(InputTargetComponent())
-                
+
                 print(#function, "complete")
                 entity = demoBoxEntity
-                status = true
+                contentReady = true
             } catch {
                 print("nope")
             }

ExampleVisionOS/VolumetricView.swift

@@ -14,23 +14,27 @@ struct VolumetricView: View {
     @State private var spinY = 0.0
 
     private var viewModel = MeshViewModel()
-    @State private var contentAdded = false
-
+
     var body: some View {
         let _ = Self._printChanges()
 
         RealityView { content in
+            // In this demo we'll skip adding content at init time. But if you have other content
+            // that you want visible while the EuclidMesh is being built, add it in this closure.
+            // A simulated expensive, long-running Mesh generation happens on its own Task.
+            debugPrint(content)
         } update: { content in
-            if !contentAdded,
-               let box = viewModel.entity {
+            if viewModel.contentReady,
+               !viewModel.contentAdded,
+               let box = viewModel.entity
+            {
                 content.add(box)
-                contentAdded = true
+                viewModel.contentAdded = true
             }
-            print(content.entities)
             guard let entity = content.entities.first else {
                 return
             }
-            
+
             let pitch = Transform(pitch: Float(spinX * -1)).matrix
             let yaw = Transform(yaw: Float(spinY)).matrix
             entity.transform.matrix = pitch * yaw
@@ -49,9 +53,9 @@ struct VolumetricView: View {
         .task {
             viewModel.prepareContent()
             print("content preparation launched...")
-            }
         }
     }
+}
 
 #Preview {
     VolumetricView()