BLACK FRIDAY SALE: Save 50% on all my Swift books and bundles! >>

Making contact: didBegin()

Check your clock, because remarkably we’re just two methods away from finishing this game! Predictably, the two methods are critically important: one to move the player around the screen, and one to handle collisions between the player and the space debris.

Handling player movement is as simple as implementing the touchesMoved() method. We will, like always, need to use the location(in:) method to figure out where on the screen the user touched. But this time we're going to clamp the player's Y position, which in plain English means that we're going to stop them going above or below a certain point, keeping them firmly in the game area.

I'll be clamping the player's position so they can't overlap the score label, and I'll apply the same restriction on top so that the player has a symmetrical channel to fly through. This is a cinch to do, so here's the touchesMoved() method:

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touch = touches.first else { return }
    var location = touch.location(in: self)

    if location.y < 100 {
        location.y = 100
    } else if location.y > 668 {
        location.y = 668

    player.position = location

Our last task is to end the game when the player hits any piece of space debris. This is all code you know already: we're going to create a particle emitter, position it where the player is (or was!), and add the explosion to the scene while removing the player. In this game we're also going to set isGameOver to be true so that the update() method stops adding to their score. Here's all the code:

func didBegin(_ contact: SKPhysicsContact) {
    let explosion = SKEmitterNode(fileNamed: "explosion")!
    explosion.position = player.position


    isGameOver = true
Save 50% in my Black Friday sale.

SAVE 50% To celebrate Black Friday, all our books and bundles are half price, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.

Save 50% on all our books and bundles!

Sponsor Hacking with Swift and reach the world's largest Swift community!

Buy Pro Swift Buy Pro SwiftUI Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let us know!

Average rating: 4.6/5

Unknown user

You are not logged in

Log in or create account

Link copied to your pasteboard.