swift SceneKit 拒绝节点移动

Question

我创建了一个球体节点，我需要用户只能旋转（左/右，上/下）和放大/缩小节点，但默认情况下他可以从中心移动节点（使用两个手指） - 是否可以禁止用户将节点从中心移开？感谢您的帮助

sceneView.scene = scene

cameraOrbit = SCNNode()
cameraNode = SCNNode()
camera = SCNCamera()

// camera stuff
camera.usesOrthographicProjection = true
camera.orthographicScale = 5
camera.zNear = 1
camera.zFar = 100

cameraNode.position = SCNVector3(x: 0, y: 0, z: 70)
cameraNode.camera = camera
cameraOrbit = SCNNode()
cameraOrbit.addChildNode(cameraNode)
scene.rootNode.addChildNode(cameraNode)

let sphere = SCNSphere(radius: 2)
sphere.firstMaterial?.diffuse.contents = UIColor.red
let earthNode = SCNNode(geometry: sphere)
earthNode.name = "sphere"
earthNode.geometry?.materials = [blueMaterial]
scene.rootNode.addChildNode(earthNode)
earthNode.rotation = SCNVector4(0, 1, 0, 0)

let lightNode = SCNNode()
let light = SCNLight()
light.type = .ambient
light.intensity = 200
lightNode.light = light
scene.rootNode.addChildNode(lightNode)

sceneView.allowsCameraControl = true
sceneView.backgroundColor = UIColor.clear
sceneView.cameraControlConfiguration.allowsTranslation = true
sceneView.cameraControlConfiguration.rotationSensitivity = 0.4

Answer 1

是的，所有这些都是可行的。首先，创建您自己的相机 class 并关闭 allowsCameraControl。然后就可以实现zoom/strafe/whatever.

这里有一些可能有用的示例，只需在堆栈搜索栏中搜索这些数字并找到我的 answers/examples。

57018359 - 这个 post 告诉您如何触摸 2d 屏幕（点击）并将其转换为 3d 坐标，同时您决定深度 (z)，就像您想要点击屏幕并放置一样3d 中的对象 space.

57003908 - 此 post 告诉您如何 select 使用 hitTest（点击）的对象。例如，如果您显示带有门的房屋正面并点击它，那么该函数将 return 您的门节点，前提是您将节点命名为“门”并在它被触摸时采取某种动作。然后你可以根据那个位置重新定位你的相机。您需要遍历所有结果，因为可能存在重叠或加 Z 节点

55129224 - 此 post 为您提供了创建相机的快速示例 class。您可以使用它来重新定位您的相机或前后移动它等。

双指拖动：

func dragBegins(vRecognizer: UIPanGestureRecognizer)
    {
        if(data.gameState == .run)
        {
            if(vRecognizer.numberOfTouches == 2) { dragMode = .strafe }
        }
    }


class Camera
{
    var data = Data.sharedInstance
    var util = Util.sharedInstance
    var gameDefaults = Defaults()
    
    var cameraEye = SCNNode()
    var cameraFocus = SCNNode()
    
    var centerX: Int = 100
    var strafeDelta: Float = 0.8
    var zoomLevel: Int = 35
    var zoomLevelMax: Int = 35              // Max number of zoom levels
    
    //********************************************************************
    init()
    {
        cameraEye.name = "Camera Eye"
        cameraFocus.name = "Camera Focus"
        
        cameraFocus.isHidden = true
        cameraFocus.position  =  SCNVector3(x: 0, y: 0, z: 0)
        
        cameraEye.camera = SCNCamera()
        cameraEye.constraints = []
        cameraEye.position = SCNVector3(x: 0, y: 15, z: 0.1)
        
        let vConstraint = SCNLookAtConstraint(target: cameraFocus)
        vConstraint.isGimbalLockEnabled = true
        cameraEye.constraints = [vConstraint]
    }
    //********************************************************************
    func reset()
    {
        centerX = 100
        cameraFocus.position  =  SCNVector3(x: 0, y: 0, z: 0)
        cameraEye.constraints = []
        cameraEye.position = SCNVector3(x: 0, y: 32, z: 0.1)
        cameraFocus.position = SCNVector3Make(0, 0, 0)
        
        let vConstraint = SCNLookAtConstraint(target: cameraFocus)
        vConstraint.isGimbalLockEnabled = true
        cameraEye.constraints = [vConstraint]
    }
    //********************************************************************
    func strafeRight()
    {
        if(centerX + 1 < 112)
        {
            centerX += 1
            cameraEye.position.x += strafeDelta
            cameraFocus.position.x += strafeDelta
        }
    }
    //********************************************************************
    func strafeLeft()
    {
        if(centerX - 1 > 90)
        {
            centerX -= 1
            cameraEye.position.x -= strafeDelta
            cameraFocus.position.x -= strafeDelta
        }
    }
    //********************************************************************
}


//********************************************************************
    func lerp(start: SCNVector3, end: SCNVector3, percent: Float) -> SCNVector3
    {
        let v3 = cgVecSub(v1: end, v2: start)
        let v4 = cgVecScalarMult(v: v3, s: percent)
        return cgVecAdd(v1: start, v2: v4)
    }

Answer 2

您可以将类似的代码放入您的 UIViewController 中：

//**************************************************************************
    // Gesture Recognizers
    // MARK: Gesture Recognizers
    //**************************************************************************
    @objc func handleTap(recognizer: UITapGestureRecognizer)
    {
        if(data.isNavigationOff == true) { return }         // No panel select if Add, Update, EndWave, or EndGame
        if(gameMenuTableView.isHidden == false) { return }  // No panel if game menu is showing
        
        let location: CGPoint = recognizer.location(in: gameScene)
        
        if(data.isAirStrikeModeOn == true)
        {
            let projectedPoint = gameScene.projectPoint(SCNVector3(0, 0, 0))
            let scenePoint = gameScene.unprojectPoint(SCNVector3(location.x, location.y, CGFloat(projectedPoint.z)))
            gameControl.airStrike(position: scenePoint)
        }
        else
        {
            let hitResults = gameScene.hitTest(location, options: hitTestOptions)
            for vHit in hitResults
            {
                if(vHit.node.name?.prefix(5) == "Panel")
                {
                    // May have selected an invalid panel or auto upgrade was on
                    if(gameControl.selectPanel(vPanel: vHit.node.name!) == false) { return }
                    return
                }
            }
        }
    }
    //**************************************************************************
    @objc func handlePan(recognizer: UIPanGestureRecognizer)
    {
        if(data.gameState != .run || data.isGamePaused == true) { return }
        
        currentLocation = recognizer.location(in: gameScene)
        
        switch recognizer.state
        {
        case UIGestureRecognizer.State.began:
            beginLocation = recognizer.location(in: gameScene)
            break
        case UIGestureRecognizer.State.changed:
            if(currentLocation.x > beginLocation.x * 1.1)
            {
                beginLocation.x = currentLocation.x
                gNodes.camera.strafeLeft()
            }
            if(currentLocation.x < beginLocation.x * 0.9)
            {
                beginLocation.x = currentLocation.x
                gNodes.camera.strafeRight()
            }
            break
        case UIGestureRecognizer.State.ended:
            break
        default:
            break
        }
    }

swift SceneKit 拒绝节点移动

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