Using SceneKit in Swift Playground

Question

I've looked everywhere for this but I'm coming up blank. How do you replicate what Chris Lattner was demonstrating with Playgrounds and SceneKit at WWDC? I want to have a SceneKit scene, animating, in Playgrounds.

I tried cutting and pasting the setup code from the SceneKit project template, thinking it would magically start rendering, but it does not.

I tried watching the keynote and pausing and zooming on on Lattner's screen looking for hints at the source code, but he appeared to be importing all his code from elsewhere in his project, so it gave me no clues. There does not seem to be anything in the documentation, or I'm missing it.

Answer 1

Since Swift doesn't have source compatibility between versions, the code in this answer might not work in either future or previous versions of Swift. Currently is has been updated to work in Xcode 7.0 Playgrounds with Swift 2.0.

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The XCPlayground framework is what you need, and it is documented here.

Here is a very simple scene to get you started with Scene Kit in Swift:

import SceneKit
import QuartzCore   // for the basic animation
import XCPlayground // for the live preview
import PlaygroundSupport

// create a scene view with an empty scene
var sceneView = SCNView(frame: CGRect(x: 0, y: 0, width: 300, height: 300))
var scene = SCNScene()
sceneView.scene = scene

// start a live preview of that view
PlaygroundPage.current.liveView = sceneView

// default lighting
sceneView.autoenablesDefaultLighting = true

// a camera
var cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(x: 0, y: 0, z: 3)
scene.rootNode.addChildNode(cameraNode)

// a geometry object
var torus = SCNTorus(ringRadius: 1, pipeRadius: 0.35)
var torusNode = SCNNode(geometry: torus)
scene.rootNode.addChildNode(torusNode)

// configure the geometry object
torus.firstMaterial?.diffuse.contents  = NSColor.red   // (or UIColor on iOS)
torus.firstMaterial?.specular.contents = NSColor.white // (or UIColor on iOS)

// set a rotation axis (no angle) to be able to
// use a nicer keypath below and avoid needing
// to wrap it in an NSValue
torusNode.rotation = SCNVector4(x: 1.0, y: 1.0, z: 0.0, w: 0.0)

// animate the rotation of the torus
var spin = CABasicAnimation(keyPath: "rotation.w") // only animate the angle
spin.toValue = 2.0*Double.pi
spin.duration = 3
spin.repeatCount = HUGE // for infinity
torusNode.addAnimation(spin, forKey: "spin around")

When I run it, it looks like this:

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Note that to run Scene Kit in an iOS playground, you need to check the "Run in Full Simulator" checkbox.

You find the Playground Setting in the Utilities Pane (⌥⌘0 to hide or show)