Question

我试图通过触摸在SceneKit中移动节点。我在这里使用代码：Move a specific node in SceneKit using touch

我遇到的问题是每次我开始panGesture时，我触摸的对象都会到达场景的左下角以开始移动。将它从该位置移开并释放是可以的，只是在每次平移开始时，对象从左角重置的问题。如果我缩小，它会从这个新缩放级别的角落重置。

我的代码是：

func CGPointToSCNVector3(view: SCNView, depth: Float, point: CGPoint) -> SCNVector3 {
    let projectedOrigin = view.projectPoint(SCNVector3Make(0, 0, depth))
    let locationWithz   = SCNVector3Make(Float(point.x), Float(point.y), projectedOrigin.z)
    return view.unprojectPoint(locationWithz)
}
func dragObject(sender: UIPanGestureRecognizer){
    if(movingNow){
        let translation = sender.translationInView(sender.view!)
        var result : SCNVector3 = CGPointToSCNVector3(objectView, depth: tappedObjectNode.position.z, point: translation)
        tappedObjectNode.position = result
    }
    else{
        let hitResults = objectView.hitTest(sender.locationInView(objectView), options: nil)
        if hitResults.count > 0 {
            movingNow = true
        }
    }
    if(sender.state == UIGestureRecognizerState.Ended) {
    }
}

和

override func viewDidLoad() {
    super.viewDidLoad()
    let scnView = objectView
    scnView.backgroundColor = UIColor.whiteColor()
    scnView.autoenablesDefaultLighting = true
    scnView.allowsCameraControl = true

我暂时禁用allowCameraControl的panning函数，然后调用dragObject：

globalPanRecognizer = UIPanGestureRecognizer(target: self, 
    action:#selector(ViewController.dragObject(_:)))
objectView.addGestureRecognizer(globalPanRecognizer)

这是第一次调用CGPointToSCNVector3时的值：

tappedObjectNode的初始值：SCNVector3（x：0.100000001，y：0.100000001，z：3.0）
projectedOrigin：SCNVector3（x：261.613159，y：285.530396，z：0.949569583） - 这个异常大
CGPointToSCNVector3返回的值：SCNVector3（x：1.03418088，y：1.9734658，z：4.64346933）

我玩过不同版本的CGPointToSCNVector3，但没有运气。这种行为的原因是什么？谢谢，

Answer 1

解决方案是将sender.translationInView(sender.view!)更改为sender.translationInView(self.view!)

Answer 2

Swift 4.1 / Xcode 9.3 / iOS 11.3

// node that you want the user to drag
var tappedObjectNode = SCNNode()

// the SCNView
@IBOutlet weak var sceneView: SCNView!

// the scene
let scene = SCNScene()

//helper
func CGPointToSCNVector3(view: SCNView, depth: Float, point: CGPoint) -> SCNVector3 {
    let projectedOrigin = view.projectPoint(SCNVector3Make(0, 0, depth))
    let locationWithz   = SCNVector3Make(Float(point.x), Float(point.y), projectedOrigin.z)
    return view.unprojectPoint(locationWithz)
}

// gesture handler
var movingNow = false
@objc func dragObject(sender: UIPanGestureRecognizer){
if(movingNow){
        let translation = sender.translation(in: sender.view!)
        var result : SCNVector3 = CGPointToSCNVector3(view: sceneView, depth: tappedObjectNode.position.z, point: translation)    
        tappedObjectNode.position = result
    } else {
        // view is the view containing the sceneView
        let hitResults = sceneView.hitTest(sender.location(in: view), options: nil)
        if hitResults.count > 0 {
            movingNow = true
        }
    }
}


// in viewDidLoad
sceneView.scene = scene

let panner = UIPanGestureRecognizer(target: self, action: #selector(dragObject(sender:)))
sceneView.addGestureRecognizer(panner)

使用触摸在SceneKit中移动节点

2 个答案: