Reality Composer Pro 3 Script Graph (No-Code Visual Scripting)

import SwiftUI
import RealityKit

// MARK: - Model
// The Script Graph lives inside SquirrelGame.reality (built in Reality Composer Pro 3).
// The Nut entity has a ScriptingComponent whose public variable
// "dragSpeed" (Float) controls drag responsiveness.

@MainActor
final class SquirrelGameModel: ObservableObject {
    var rootEntity: Entity?

    func loadScene() async throws {
        // Load the .reality bundle produced by Reality Composer Pro 3
        let scene = try await Entity(named: "SquirrelGame", in: Bundle.main)
        rootEntity = scene
        // Override the public Script Graph variable on the Nut entity
        applyDragSpeed(1.15, entityNamed: "Nut")
    }

    /// Write a value into a Script Graph public variable via ScriptingComponent.
    func applyDragSpeed(_ speed: Float, entityNamed name: String) {
        guard let nut = rootEntity?.findEntity(named: name) else { return }
        // ScriptingComponent stores overrides for Script Graph public variables.
        if var scripting = nut.components[ScriptingComponent.self] {
            scripting.variables["dragSpeed"] = .float(speed)
            nut.components[ScriptingComponent.self] = scripting
        }
    }
}

// MARK: - View
struct SquirrelGameView: View {
    @StateObject private var model = SquirrelGameModel()
    @State private var dragSpeed: Float = 1.15

    var body: some View {
        VStack {
            RealityView { content in
                do {
                    try await model.loadScene()
                    if let root = model.rootEntity {
                        content.add(root)
                    }
                } catch {
                    print("Failed to load SquirrelGame scene: \(error)")
                }
            } update: { _ in
                // Push the current slider value into the Script Graph variable
                model.applyDragSpeed(dragSpeed, entityNamed: "Nut")
            }
            .frame(width: 600, height: 400)

            // Runtime control of a Script Graph public variable from Swift UI
            VStack(alignment: .leading) {
                Text("Drag Speed: \(dragSpeed, specifier: "%.2f")").bold()
                Slider(value: $dragSpeed, in: 0.5...2.5, step: 0.05)
                    .padding(.horizontal)
            }
            .padding()
        }
    }
}

#Preview {
    SquirrelGameView()
}