SceneKitSample.swift

import UIKit
import SceneKit

class ViewController: UIViewController {
    @IBOutlet weak var sceneView: SCNView!

    override func loadView() {
        super.loadView()
        let scene = SCNScene()
        self.sceneView.scene = scene
        sceneView.autoenablesDefaultLighting = true
        setupScene(scene)
        let y:Float = 8

        //反発係数を変えた3つ球体を追加
        scene.rootNode.addChildNode(createSphere(SCNVector3Make(-1.5, y, 0), restitution: 0.5))
        scene.rootNode.addChildNode(createSphere(SCNVector3Make(0, y, 0), restitution: 1.0))
        scene.rootNode.addChildNode(createSphere(SCNVector3Make(1.5, y, 0), restitution: 1.5))
        
        //4秒後にもう一つ球体を追加
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(4 * Double(NSEC_PER_SEC))), dispatch_get_main_queue(), {
            scene.rootNode.addChildNode(self.createSphere(SCNVector3Make(-1, y, 0), restitution: 1.0))
        })
    }

    private func setupScene(scene:SCNScene) {
        //カメラ追加
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        cameraNode.position = SCNVector3(x: 0, y: 1, z: 15)
        scene.rootNode.addChildNode(cameraNode)

        //床を作成
        let floor = SCNFloor()
        floor.reflectivity = 0.25
        let floorNode = SCNNode(geometry: floor)
        let floorShape = SCNPhysicsShape(geometry: floor, options: nil)
        let floorBody = SCNPhysicsBody(type: .Static, shape: floorShape)
        floorNode.physicsBody = floorBody
        scene.rootNode.addChildNode(floorNode)
    }
    
    //球体を作成
    private func createSphere(position:SCNVector3, restitution:CGFloat) -> SCNNode {
        let sphere = SCNSphere(radius: 0.5)
        let node = SCNNode(geometry: sphere)
        node.position = position
        if let material = node.geometry?.firstMaterial {
            material.diffuse.contents = UIColor.redColor()
            material.specular.contents = UIColor.whiteColor()
        }
        let physicsShape = SCNPhysicsShape(geometry: sphere, options: nil)
        let physicsBody = SCNPhysicsBody(type: .Dynamic, shape: physicsShape)
        physicsBody.restitution = restitution
        node.physicsBody = physicsBody
        return node
    }
}