Why won't anything show up in my Swift Playground? - ios

Question

I have a pong game in a Swift Playground that I made by following a tutorial online but my assistant editor won't show anything! Where is my pong game!? My code is below the image, which shows that nothing is showing up.
import SpriteKit
import PlaygroundSupport
// Declare some global constants
let width = 800 as CGFloat
let height = 1200 as CGFloat
let racketHeight = 150 as CGFloat
let ballRadius = 20 as CGFloat
// Three types of collision objects possible
enum CollisionTypes: UInt32 {
case Ball = 1
case Wall = 2
case Racket = 4
}
// Racket direction
enum Direction: Int {
case None = 0
case Up = 1
case Down = 2
}
// Make a SpriteKit scene
class gameScene: SKScene, SKPhysicsContactDelegate {
let racketSpeed = 500.0
var direction = Direction.None
var score = 0
var gameRunning = false
// Screen elements
var racket: SKShapeNode?
var ball: SKShapeNode?
let scoreLabel = SKLabelNode()
// Initialize objects during first start
override func sceneDidLoad() {
super.sceneDidLoad()
scoreLabel.fontSize = 40
scoreLabel.position = CGPoint(x: width/2, y: height - 100)
self.addChild(scoreLabel)
createWalls()
createBall(position: CGPoint(x: width / 2, y: height / 2))
createRacket()
startNewGame()
self.physicsWorld.contactDelegate = self
}
// Create the ball sprite
func createBall(position: CGPoint) {
let physicsBody = SKPhysicsBody(circleOfRadius: ballRadius)
ball = SKShapeNode(circleOfRadius: ballRadius)
physicsBody.categoryBitMask = CollisionTypes.Ball.rawValue
physicsBody.collisionBitMask = CollisionTypes.Wall.rawValue | CollisionTypes.Ball.rawValue | CollisionTypes.Racket.rawValue
physicsBody.affectedByGravity = false
physicsBody.restitution = 1
physicsBody.linearDamping = 0
physicsBody.velocity = CGVector(dx: -500, dy: 500)
ball!.physicsBody = physicsBody
ball!.position = position
ball!.fillColor = SKColor.white
}
// Create the walls
func createWalls() {
createWall(rect: CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: ballRadius, height: height)))
createWall(rect: CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: width, height: ballRadius)))
createWall(rect: CGRect(origin: CGPoint(x: 0, y: height - ballRadius), size: CGSize(width: width, height: ballRadius)))
}
func createWall(rect: CGRect) {
let node = SKShapeNode(rect: rect)
node.fillColor = SKColor.white
node.physicsBody = getWallPhysicsbody(rect: rect)
self.addChild(node)
}
// Create the physics objetcs to handle wall collisions
func getWallPhysicsbody(rect: CGRect) -> SKPhysicsBody {
let physicsBody = SKPhysicsBody(rectangleOf: rect.size, center: CGPoint(x: rect.midX, y: rect.midY))
physicsBody.affectedByGravity = false
physicsBody.isDynamic = false
physicsBody.collisionBitMask = CollisionTypes.Ball.rawValue
physicsBody.categoryBitMask = CollisionTypes.Wall.rawValue
return physicsBody
}
// Create the racket sprite
func createRacket() {
racket = SKShapeNode(rect: CGRect(origin: CGPoint.zero, size: CGSize(width: ballRadius, height: racketHeight)))
self.addChild(racket!)
racket!.fillColor = SKColor.white
let physicsBody = SKPhysicsBody(rectangleOf: racket!.frame.size, center: CGPoint(x: racket!.frame.midX, y: racket!.frame.midY))
physicsBody.affectedByGravity = false
physicsBody.isDynamic = false
physicsBody.collisionBitMask = CollisionTypes.Ball.rawValue
physicsBody.categoryBitMask = CollisionTypes.Racket.rawValue
physicsBody.contactTestBitMask = CollisionTypes.Ball.rawValue
racket!.physicsBody = physicsBody
}
// Start a new game
func startNewGame() {
score = 0
scoreLabel.text = "0"
racket!.position = CGPoint(x: width - ballRadius * 2, y: height / 2)
let startLabel = SKLabelNode(text: "Game Over")
startLabel.position = CGPoint(x: width / 2, y: height / 2)
startLabel.fontSize = 160
self.addChild(startLabel)
// Animated countdown
let fadeIn = SKAction.fadeIn(withDuration: 0.5)
let fadeOut = SKAction.fadeOut(withDuration: 0.5)
startLabel.text = "3"
startLabel.run(SKAction.sequence([fadeIn, fadeOut]), completion: {
startLabel.text = "2"
startLabel.run(SKAction.sequence([fadeIn, fadeOut]), completion: {
startLabel.text = "1"
startLabel.run(SKAction.sequence([fadeIn, fadeOut]), completion: {
startLabel.text = "0"
startLabel.run(SKAction.sequence([fadeIn, fadeOut]), completion: {
startLabel.removeFromParent()
self.gameRunning = true
self.ball!.position = CGPoint(x: 30, y: height / 2)
self.addChild(self.ball!)
})
})
})
})
}
// Handle touch events to move the racket
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
let location = touch.location(in: self)
if location.y > height / 2 {
direction = Direction.Up
} else if location.y < height / 2{
direction = Direction.Down
}
}
}
// Stop racket movement
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
direction = Direction.None
}
// Game loop:
var dt = TimeInterval(0)
override func update(_ currentTime: TimeInterval) {
if gameRunning {
super.update(currentTime)
checkGameOver()
if dt > 0 {
moveRacket(dt: currentTime - dt)
}
dt = currentTime
}
}
// Move the racket up or down
func moveRacket(dt: TimeInterval) {
if direction == Direction.Up && racket!.position.y < height - racketHeight {
racket!.position.y = racket!.position.y + CGFloat(racketSpeed * dt)
} else if direction == Direction.Down && racket!.position.y > 0 {
racket!.position.y = racket!.position.y - CGFloat(racketSpeed * dt)
}
}
// Check if the ball is still on screen
// Game Over animation
func checkGameOver() {
if ball!.position.x > CGFloat(width) {
gameRunning = false
ball!.removeFromParent()
let gameOverLabel = SKLabelNode(text: "Game Over")
gameOverLabel.position = CGPoint(x: width / 2, y: height / 2)
gameOverLabel.fontSize = 80
self.addChild(gameOverLabel)
// Game Over animation
let rotateAction = SKAction.rotate(byAngle: CGFloat(M_PI), duration: 1)
let fadeInAction = SKAction.fadeIn(withDuration: 2)
gameOverLabel.run(SKAction.repeat(rotateAction, count: 2))
gameOverLabel.run(SKAction.scale(to: 0, duration: 2.5), completion: {
gameOverLabel.removeFromParent()
self.startNewGame()
})
}
}
// Detect collisions between ball and racket to increase the score
func didBegin(_ contact: SKPhysicsContact) {
if contact.bodyA.categoryBitMask == CollisionTypes.Racket.rawValue || contact.bodyB.categoryBitMask == CollisionTypes.Racket.rawValue {
score += 1
scoreLabel.text = String(score)
}
}
}
//Initialize the playground and start the scene:
let skView = SKView(frame: CGRect(origin: CGPoint.zero, size: CGSize(width: width, height: height)))
let scene = gameScene(size: skView.frame.size)
skView.presentScene(scene)
PlaygroundPage.current.liveView = skView

Answer 1

This happens to me sometimes. Playgrounds with SpriteKit just would not show anything in the Timeline view - you do have the Timeline view open, right? If you don't, tap the "Show the Assistant editor" button on the toolbar to open the Timeline view.
If you have the Timeline view open and nothing shows, try shutting down Xcode and restarting it. That generally resolves this issue for me.