Reality Composer Pro 3 Script Graph & No-Code Game Design

import SwiftUI
import RealityKit

// MARK: - SwiftUI entry point
@main
struct SquirrelGameApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

struct ContentView: View {
    var body: some View {
        RealityView { content in
            // Load the Reality Composer Pro 3 scene bundle
            // (scene contains Squirrel + Nut entities with Script Graphs attached)
            guard let scene = try? await Entity(named: "SquirrelGame", in: realityKitContentBundle) else {
                return
            }
            content.add(scene)

            // Programmatically configure the Nut entity in case
            // components were not set in the .usda editor
            if let nut = scene.findEntity(named: "Nut") {
                NutEntityConfigurator.configure(nut)
            }
        }
    }
}

// MARK: - Component setup that mirrors the Reality Composer Pro inspector steps
enum NutEntityConfigurator {
    static func configure(_ nut: Entity) {
        // 1. Make the entity a gaze / pinch target
        nut.components.set(InputTargetComponent())

        // 2. Define the collision shape for hit-testing
        nut.components.set(
            CollisionComponent(
                shapes: [.generateBox(size: [0.05, 0.05, 0.01])]
            )
        )

        // 3. Visual hover highlight when the user looks at the nut
        nut.components.set(HoverEffectComponent())

        // 4. Physics body so the Script Graph's Add Force node works
        var physics = PhysicsBodyComponent(
            massProperties: .default,
            material: .default,
            mode: .dynamic
        )
        // Start with gravity on; the Script Graph will disable it on drag
        physics.isAffectedByGravity = true
        physics.linearDamping = 2.0
        nut.components.set(physics)

        // 5. A physics motion component is required for velocity queries
        nut.components.set(PhysicsMotionComponent())
    }
}

// MARK: - Receiving a Custom Event from the Script Graph in Swift
// In RC Pro 3 you define 'nutIsDragged' in a Custom Node Library;
// on the Swift side you can observe component changes if needed.
extension Entity {
    /// Convenience: toggle gravity the way the Script Graph's
    /// Set PhysicsBodyComponent node does it at runtime.
    func setGravityEnabled(_ enabled: Bool) {
        guard var body = components[PhysicsBodyComponent.self] else { return }
        body.isAffectedByGravity = enabled
        body.linearDamping = enabled ? 2.0 : 8.0
        components.set(body)
    }
}