title: How to I turn off the ambient light in Scene Kit (with Swift)?
body: <p>When I create a new Scene Kit Game using the Swift language, there is already some come which gives this result :
  <img src="https://i.stack.imgur.com/nPWFF.png" alt="enter image description here"><br>
  <strong>I want to turn off the ambient light which is lighting the cube but I don't get how to do that since there isn't any light explicitly attached to any node.</strong></p>
  
  <p>Her's the Game View Controller code : </p>
  
  <pre><code>import SceneKit
  import QuartzCore
  
  class GameViewController: NSViewController {
  
      @IBOutlet var gameView: GameView
  
      override func awakeFromNib(){
          // create a new scene
          let scene = SCNScene()
  
          // create and add a camera to the scene
          let cameraNode = SCNNode()
          cameraNode.camera = SCNCamera()
          scene.rootNode.addChildNode(cameraNode)
  
          // place the camera
          cameraNode.position = SCNVector3(x: 0, y: 0, z: 2)
  
          // create and add a 3d box to the scene
          let boxNode = SCNNode()
          boxNode.geometry = SCNBox(width: 1, height: 1, length: 1, chamferRadius: 0.02)
          scene.rootNode.addChildNode(boxNode)
  
          // create and configure a material
          let material = SCNMaterial()
          material.diffuse.contents = NSImage(named: "texture")
          material.specular.contents = NSColor.whiteColor()
          material.specular.intensity = 0.2
          material.locksAmbientWithDiffuse = true
  
          // set the material to the 3d object geometry
          boxNode.geometry.firstMaterial = material
  
          // animate the 3d object
          let animation: CABasicAnimation = CABasicAnimation(keyPath: "rotation")
          animation.toValue = NSValue(SCNVector4: SCNVector4(x: 1, y: 1, z: 0, w: M_PI*2))
          animation.duration = 5
          animation.repeatCount = MAXFLOAT //repeat forever
          boxNode.addAnimation(animation, forKey: "")
  
          // set the scene to the view
          self.gameView!.scene = scene
  
          // allows the user to manipulate the camera
          self.gameView!.allowsCameraControl = true
  
          // show statistics such as fps and timing information
          self.gameView!.showsStatistics = true
  
          // configure the view
          self.gameView!.backgroundColor = NSColor.blackColor()
      }
  
  }
  </code></pre>