NEW: Master Swift design patterns with my latest book! >>

How to add physics to an SKSpriteNode

Written by Paul Hudson    @twostraws

SpriteKit comes with a modified version of the Box2D physics framework, and it's wrapped up a lot of complicated physics mathematics into just one or two lines of code. For example, we can create a square, red sprite and give it rectangular physics like this:

let box = SKSpriteNode(color:, size: CGSize(width: 64, height: 64))
box.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: 64, height: 64))

That rectangle will wrap perfectly around the box's color, so it will bounce and rotate as it collides with other objects in your scene.

If you want to create circular physics to simulate balls, this is done using the circleOfRadius constructor:

let ball = SKSpriteNode(imageNamed: "ballRed")
ball.physicsBody = SKPhysicsBody(circleOfRadius: ball.size.width / 2.0)

Available from iOS 7.0 – see Hacking with Swift tutorial 11

Did this solution work for you? Please pass it on!

Other people are reading…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

Need to know Objective-C fast?

I wrote a book dedicated to teaching Objective-C to developers who already know Swift – it's the fastest way to get up to speed!

Click here to visit the Hacking with Swift store >>