錯視の一種リバースパースペクティブを表示するiPhoneアプリのサンプルコードを描いてみます。
import UIKit
import SceneKit
class ViewController: UIViewController {
weak var sceneView : SCNView?
override func viewDidLoad() {
super.viewDidLoad()
setupScene()
createTrapezoid()
createCamera()
}
func setupScene() {
let sv = SCNView(frame: view.bounds)
sv.scene = SCNScene()
sv.backgroundColor = UIColor.blueColor()
sv.allowsCameraControl = true
view.addSubview(sv)
sceneView = sv
}
func createTrapezoid() {
let path = UIBezierPath()
path.moveToPoint(CGPoint(x: –5, y: –10))
path.addLineToPoint(CGPoint(x: 5, y: –6))
path.addLineToPoint(CGPoint(x: 5, y: 6))
path.addLineToPoint(CGPoint(x: –5, y: 10))
path.closePath()
[Int](0…7).each { i in
let t = SCNShape(path: path, extrusionDepth: 0.1)
t.firstMaterial?.diffuse.contents = (i % 2 == 0)
? UIColor(hue: 0.15, saturation: 1, brightness: 1, alpha: 1)
: UIColor(hue: 0.15, saturation: 1, brightness: 0.5, alpha: 1)
let tNode = SCNNode(geometry: t)
tNode.transform = (i % 2 == 0)
? SCNMatrix4Rotate(tNode.transform, 0.8, 0, –1, 0)
: SCNMatrix4Rotate(tNode.transform, Float(M_PI) – 0.8, 0, –1, 0)
tNode.transform = SCNMatrix4Translate(tNode.transform, –Float(i) * 7.0, 0, 0)
self.sceneView?.scene?.rootNode.addChildNode(tNode)
}
}
func createCamera() {
let camera = SCNNode()
camera.name = “camera”
camera.camera = SCNCamera()
camera.position = SCNVector3(x: 0, y: 0, z: 40)
sceneView?.scene?.rootNode.addChildNode(camera)
}
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
let camera = sceneView?.scene?.rootNode.childNodeWithName(“camera”, recursively: false)
camera?.runAction(SCNAction.moveByX(-20, y: 0, z: 0, duration: 10))
}
}
extension Array {
func each(doit:T->Void) {for i in self { doit(i) }}
}