Canvatorium Visio Lab 5020

struct Lab5020: View {

    var dragGesture: some Gesture {

        DragGesture()
            // 1. targetedToAnyEntity will convert the gesture to one compatble with RealityKit
            .targetedToAnyEntity()
            .onChanged { value in

                // 2. Get the location 3D from the gesture and convert it to 3D space for the entity
                value.entity.position = value.convert(value.location3D, from: .global, to: value.entity.parent!)

                // 3. Toggle our particle emitters to show fullSpeed while dragging
                if let fullSpeed = value.entity.findEntity(named: "FullSpeed"), let cruisingSpeed = value.entity.findEntity(named: "CruisingSpeed") {
                    if(!fullSpeed.isEnabled) {
                        fullSpeed.isEnabled = true
                    }
                    if(cruisingSpeed.isEnabled) {
                        cruisingSpeed.isEnabled = false
                    }
                }


            }
            .onEnded { value in
                print(value.entity)
                // 4. Toggle our particle emitters to the default state on end
                if let fullSpeed = value.entity.findEntity(named: "FullSpeed"), let cruisingSpeed = value.entity.findEntity(named: "CruisingSpeed") {
                    fullSpeed.isEnabled = false
                    cruisingSpeed.isEnabled = true
                }

            }
    }

    var body: some View {
        RealityView { content in

            if let root = try? await Entity(named: "5019ScaleVolume", in: realityKitContentBundle) {

                // Set up the tiny skybox
                guard let resource = try? await TextureResource(named: "Starfield") else {
                    fatalError("Unable to load starfield texture.")
                }
                var material = UnlitMaterial()
                material.color = .init(texture: .init(resource))
                let skybox = Entity()
                skybox.components.set(ModelComponent(
                    mesh: .generateSphere(radius: 5),
                    materials: [material]
                ))
                skybox.scale *= .init(x: -1, y: 1, z: 1)
                root.addChild(skybox, preservingWorldTransform: true)

                // 5. Set the initial state
                // Deactivating an entity in RCP seems to be different than isEnabled
                if let fullSpeed = root.findEntity(named: "FullSpeed"), let cruisingSpeed = root.findEntity(named: "CruisingSpeed") {
                    fullSpeed.isEnabled = false
                    cruisingSpeed.isEnabled = true
                }

                root.scale = [0.2, 0.2, 0.2]
                root.position = [0, -1, 0]

                content.add(root)
            }

        }
        .scaleEffect(x: 0.2, y: 0.2, z: 0.2)
        // 6. Use the gesture
        .gesture(dragGesture)

    }
}