Everything so far

Waveform/GameViewController.swift

@@ -9,21 +9,35 @@
 import SceneKit
 import QuartzCore
 
-class GameViewController: NSViewController {
-    
+class GameViewController: NSViewController, SCNSceneRendererDelegate {
+    static let numberOfBallsPerSide = 41
+
+    private var balls = [SCNNode]()
+
     override func viewDidLoad() {
         super.viewDidLoad()
-        
+
+        guard let sceneView = view as? SCNView else {
+            fatalError("My view isn't a SCNView!")
+        }
+        sceneView.delegate = self
+        sceneView.rendersContinuously = true
+        sceneView.preferredFramesPerSecond = 30
+
         // create a new scene
-        let scene = SCNScene(named: "art.scnassets/ship.scn")!
+        let scene = SCNScene(named: "art.scnassets/blank.scn")!
         
         // create and add a camera to the scene
         let cameraNode = SCNNode()
-        cameraNode.camera = SCNCamera()
+        let camera = SCNCamera()
+        cameraNode.camera = camera
         scene.rootNode.addChildNode(cameraNode)
         
         // place the camera
-        cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
+        cameraNode.position = SCNVector3(x: CGFloat(GameViewController.numberOfBallsPerSide / 7),
+                                         y: 1.5,
+                                         z: CGFloat(GameViewController.numberOfBallsPerSide / 3))
+        cameraNode.look(at: SCNVector3())
         
         // create and add a light to the scene
         let lightNode = SCNNode()
@@ -38,33 +52,44 @@ class GameViewController: NSViewController {
         ambientLightNode.light!.type = .ambient
         ambientLightNode.light!.color = NSColor.darkGray
         scene.rootNode.addChildNode(ambientLightNode)
-        
-        // retrieve the ship node
-        let ship = scene.rootNode.childNode(withName: "ship", recursively: true)!
-        
-        // animate the 3d object
-        ship.runAction(SCNAction.repeatForever(SCNAction.rotateBy(x: 0, y: 2, z: 0, duration: 1)))
-        
-        // retrieve the SCNView
-        let scnView = self.view as! SCNView
+
+        let sphereContainer = SCNNode()
+        scene.rootNode.addChildNode(sphereContainer)
+
+        if let sphere = scene.rootNode.childNode(withName: "sphere", recursively: false) {
+            // Remove it. We're going to copy it all over the place.
+            sphere.removeFromParentNode()
+            for i in 0..<GameViewController.numberOfBallsPerSide {
+                for j in 0..<GameViewController.numberOfBallsPerSide {
+                    let ijSphere = sphere.clone()
+                    balls.append(ijSphere)
+                    ijSphere.worldPosition = SCNVector3(x: CGFloat(-GameViewController.numberOfBallsPerSide / 2) + CGFloat(i),
+                                                        y: 0.0,
+                                                        z: CGFloat(-GameViewController.numberOfBallsPerSide / 2) + CGFloat(j))
+                    sphereContainer.addChildNode(ijSphere)
+                }
+            }
+        }
+
+        sphereContainer.runAction(SCNAction.repeatForever(SCNAction.rotate(by: CGFloat.pi, around: SCNVector3(0, 1, 0), duration: 40.0)))
         
         // set the scene to the view
-        scnView.scene = scene
+        sceneView.scene = scene
         
         // allows the user to manipulate the camera
-        scnView.allowsCameraControl = true
+        sceneView.allowsCameraControl = false
         
         // show statistics such as fps and timing information
-        scnView.showsStatistics = true
+        sceneView.showsStatistics = true
         
         // configure the view
-        scnView.backgroundColor = NSColor.black
+        sceneView.backgroundColor = NSColor.black
         
         // Add a click gesture recognizer
         let clickGesture = NSClickGestureRecognizer(target: self, action: #selector(handleClick(_:)))
-        var gestureRecognizers = scnView.gestureRecognizers
+        var gestureRecognizers = sceneView.gestureRecognizers
         gestureRecognizers.insert(clickGesture, at: 0)
-        scnView.gestureRecognizers = gestureRecognizers
+        sceneView.gestureRecognizers = gestureRecognizers
     }
     
     @objc
@@ -102,4 +127,41 @@ class GameViewController: NSViewController {
             SCNTransaction.commit()
         }
     }
+
+    func delayForSphereAt(x: Int, y: Int) -> Double {
+        return 0.05 * Double(x) + 0.03 * Double(y)
+    }
+
+    // MARK: - SCNRendererDelegate
+
+    static let numberOfSteps = 100
+    var step = 0
+    var maxY = 0.0
+    var minY = 0.0
+
+    func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
+        for z in 0..<GameViewController.numberOfBallsPerSide {
+            for x in 0..<GameViewController.numberOfBallsPerSide {
+                let idx = z * GameViewController.numberOfBallsPerSide + x
+                let node = balls[idx]
+                let delay = delayForSphereAt(x: x, y: z)
+                //let inputX = 2.0 * Double.pi * Double(step) / Double(GameViewController.numberOfSteps) + delay
+
+                let inputX = 2.0 / 3.0 * time + delay
+                let y = sin(inputX) + sin(2.0 * inputX) + sin(4.0 * inputX) + sin(8.0 * inputX)
+
+                node.worldPosition.y = CGFloat(y)
+
+                maxY = max(y, maxY)
+                minY = min(y, minY)
+                let scale = CGFloat(map(y, inMin: minY, inMax: maxY, outMin: 0.0, outMax: 1.0))
+                node.scale = SCNVector3(x: scale, y: scale, z: scale)
+            }
+        }
+        step = (step + 1) % GameViewController.numberOfSteps
+    }
+
+    func map(_ x: Double, inMin: Double, inMax: Double, outMin: Double, outMax: Double) -> Double {
+        return (x - inMin) * (outMax - outMin) / (inMax - inMin) + outMin;
+    }
 }