Enhance your spatial computing app with RealityKit

import SwiftUI
import RealityKit

struct MoonOrbit: View {
    var body: some View {
        RealityView { content, attachments in
            guard let earth = try? await Entity(named: "Earth") else {
                return
            }
            content.add(earth)

            if let earthAttachment = attachments.entity(for: "earth_label") {
                earthAttachment.position = [0, -0.15, 0]
                earth.addChild(earthAttachment)
            }
        } attachments: {
            Attachment(id: "earth_label") {
                Text("Earth")
            }
        }
    }
}

public func makeVideoEntity() -> Entity {
    let entity = Entity()

    let asset = AVURLAsset(url: Bundle.main.url(forResource: "tides_video",
                                                withExtension: "mp4")!)
    let playerItem = AVPlayerItem(asset: asset)

    let player = AVPlayer()
    entity.components[VideoPlayerComponent.self] = .init(avPlayer: player)

    entity.scale *= 0.4

    player.replaceCurrentItem(with: playerItem)
    player.play()

    return entity
}

var videoPlayerComponent = VideoPlayerComponent(avPlayer: player)
    videoPlayerComponent.isPassthroughTintingEnabled = true

    entity.components[VideoPlayerComponent.self] = videoPlayerComponent

content.subscribe(to: VideoPlayerEvents.VideoSizeDidChange.self,
                      on: entity) { event in
        // ...
    }

struct PortalView : View {
    var body: some View {
        RealityView { content in
            let world = makeWorld()
            let portal = makePortal(world: world)

            content.add(world)
            content.add(portal)
        }
    }
}

public func makeWorld() -> Entity {
    let world = Entity()
    world.components[WorldComponent.self] = .init()

    let environment = try! EnvironmentResource.load(named: "SolarSystem")
    world.components[ImageBasedLightComponent.self] = .init(source: .single(environment),
                                                            intensityExponent: 6)
    world.components[ImageBasedLightReceiverComponent.self] = .init(imageBasedLight: world)

    let earth = try! Entity.load(named: "Earth")
    let moon = try! Entity.load(named: "Moon")
    let sky = try! Entity.load(named: "OuterSpace")
    world.addChild(earth)
    world.addChild(moon)
    world.addChild(sky)

    return world
}

public func makePortal(world: Entity) -> Entity {
    let portal = Entity()

    portal.components[ModelComponent.self] = .init(mesh: .generatePlane(width: 1,
                                                                        height: 1,
                                                                        cornerRadius: 0.5),
                                                   materials: [PortalMaterial()])
    portal.components[PortalComponent.self] = .init(target: world)

    return portal
}

public class ParticleTransitionSystem: System {
    private static let query = EntityQuery(where: .has(ParticleEmitterComponent.self))

    public func update(context: SceneUpdateContext) {
        let entities = context.scene.performQuery(Self.query)
        for entity in entities {
            updateParticles(entity: entity)
        }
    }
}

public func updateParticles(entity: Entity) {
    guard var particle = entity.components[ParticleEmitterComponent.self] else {
        return
    }

    let scale = max(entity.scale(relativeTo: nil).x, 0.3)

    let vortexStrength: Float = 2.0
    let lifeSpan: Float = 1.0
    particle.mainEmitter.vortexStrength = scale * vortexStrength
    particle.mainEmitter.lifeSpan = Double(scale * lifeSpan)

    entity.components[ParticleEmitterComponent.self] = particle
}

import SwiftUI
import RealityKit

struct PortalApp: App {

    @State private var immersionStyle: ImmersionStyle = .mixed

    var body: some SwiftUI.Scene {
        ImmersiveSpace {
            RealityView { content in
                let anchor = AnchorEntity(.plane(.vertical, classification: .wall,
                                                 minimumBounds: [1, 1]))
                content.add(anchor)

                anchor.addChild(makePortal())
            }
        }
        .immersionStyle(selection: $immersionStyle, in: .mixed)
    }
}