i create a simple scene with a cube and a floor for study propose.

i set the delegate to self, but I can't understand why my render stop print out my message after 12 frame.. my I know why it stop? should not running forever since my scene is in view?

here my custom scene:

class GameSceneMain: SCNScene, SCNSceneRendererDelegate, SCNPhysicsContactDelegate {
 
    var camera : SCNCamera?
    var floor : SCNFloor?
    var delegate : SCNSceneRendererDelegate?
    
  
    override init() {
        super.init()
        setupScene()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func setupScene(){ // load sky
      
        let skybox = UIImage(named: "skybox")
        self.background.contents = skybox
        delegate = self
        addCamera()
        addFloor()
        addLight()
        addCube()
    }
    func addCamera(){
        camera = SCNCamera()
        let cameranode = SCNNode()
        cameranode.camera = camera
        cameranode.position = SCNVector3(0, 5, 10)
        cameranode.eulerAngles = SCNVector3(deg2rad(-20), deg2rad(0), 0)
        self.rootNode.addChildNode(cameranode)
    }
    
    func addFloor(){
        floor = SCNFloor()
        guard let floor = floor else {
            return
        }
        floor.reflectivity = 0
        let mat = SCNMaterial()
        mat.diffuse.contents = UIImage(named: "grass")
        mat.diffuse.wrapS = SCNWrapMode.repeat
        mat.diffuse.wrapT = SCNWrapMode.repeat
        floor.materials = [mat]
        let nodeFloor = SCNNode(geometry: floor)
        self.rootNode.addChildNode(nodeFloor)
    }
    
    func addLight(){
        let light = SCNLight()
        light.type = .ambient
        let nodeLight = SCNNode()
        nodeLight.light = light
        self.rootNode.addChildNode(nodeLight)
    }

    
    func  addCube(){
        let box = SCNBox(width: 1.5, height: 2, length: 3, chamferRadius: 0.3)
        let mat = SCNMaterial()
        mat.diffuse.contents = UIColor.blue
        box.materials = [mat]
        let node = SCNNode(geometry: box)
        node.position = SCNVector3(0, 0, 0)
        node.name = "box"
        self.rootNode.addChildNode(node)
    }
    
    var counterFrame = 0
  
    // render STOP why??
    func renderer(_ renderer: SCNSceneRenderer, didRenderScene scene: SCNScene, atTime time: TimeInterval) {
        counterFrame  = 1
        print("run \(counterFrame)")
    }

}

and another class is used for AppManager and load the scene

class AppManager:NSObject, ObservableObject  {
    var sceneView = SCNView()
    var scene : GameSceneMain?
  
    
    
    override init(){
        super.init()
        loadScene()
       
    }
    
    
    func setupView(){
        sceneView.backgroundColor = .black
        sceneView.allowsCameraControl = true
        sceneView.autoenablesDefaultLighting = true
        sceneView.showsStatistics = true
        sceneView.scene = scene
        sceneView.scene?.isPaused = false
        sceneView.delegate = scene?.delegate
       
    }
    

    func loadScene(){
        scene = GameSceneMain()
        guard let scene = scene else {
            return
        }
        sceneView.scene = scene
        
    }
  }

I notice that when the scene load the counter of the frame run until 12 than it stop.. if I move the camera in the simulator than the counter in the renderer continue. But why? Should not run forever since the scene is in view?

Thanks a lot for the help... quite new on SceneKit

CodePudding user response：

This is for performance and energy efficiency reasons. If nothing changes in the scene then rendering the same content again is wasteful.

You can have a look at the rendersContinuously property.