如何在SceneKit中在用户点击位置渲染球体？

huangapple
go评论108阅读模式
英文:

How to render spheres in SceneKit at user's tap position?

问题

我正在使用Swift和SceneKit开发iOS应用程序。当用户点击屏幕时，我希望在SceneKit中的用户点击位置渲染一个点。我该如何实现这个功能？

我正在使用unprojectPoint()方法，但是我的对象没有渲染在预期的位置。

我有一个SceneView，摄像机设置如下：

  1. cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)

然后，我通过以下方式在点击位置渲染点：

  1. func handleTap(_ gestureRecognize: UIGestureRecognizer) {
  2.     // 获取SCNView
  3.     let scnView = self.view as! SCNView
  4.     
  5.     // 创建点
  6.     let geo = SCNSphere(radius: CGFloat(0.1))
  7.     geo.firstMaterial?.diffuse.contents = UIColor.red
  8.     let dotNode = SCNNode(geometry: geo)
  9.     
  10.     let p = gestureRecognize.location(in: scnView)
  11.     let uP = scnView.unprojectPoint(SCNVector3(p.x, p.y, 5))
  12.     // 在这里 - 如何设置点的位置？
  13.     dotNode.position = SCNVector3(uP.x, uP.y, 5)
  14.     
  15.     scnView.scene?.rootNode.addChildNode(dotNode)
  16. }

这是我的Github仓库链接：https://github.com/rudyhuynh/SceneKitExample

英文:

I am working on an iOS app with Swift and SceneKit. When user taps on screen, I want to render a dot in SceneKit at the location that user just tapped. How can I do that?

I am using unprojectPoint() method but my object is not rendered at expected location.

I am having a SceneView, with the camera like this:

  1. cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)

And then I render the dot at tap position like this:

  1. func handleTap(_ gestureRecognize: UIGestureRecognizer) {
  2.     // retrieve the SCNView
  3.     let scnView = self.view as! SCNView
  4.     
  5.     // create dot
  6.     let geo = SCNSphere(radius: CGFloat(0.1))
  7.     geo.firstMaterial?.diffuse.contents = UIColor.red
  8.     let dotNode = SCNNode(geometry: geo)
  9.     
  10.     let p = gestureRecognize.location(in: scnView)
  11.     let uP = scnView.unprojectPoint(SCNVector3(p.x, p.y, 5))
  12.     // HERE - how to set position for the dot ?
  13.     dotNode.position = SCNVector3(uP.x, uP.y, 5)
  14.     
  15.     scnView.scene?.rootNode.addChildNode(dotNode)
  16. }

Here is my Github repo: https://github.com/rudyhuynh/SceneKitExample

答案1

得分: 1

反投影一个点

为了在预期位置渲染点节点，请使用以下方法。不要忘记你正在使用透视投影查看场景。对具有 Z 坐标为 0.0 的点进行反投影会返回位于近裁剪平面上的点。对具有 Z 坐标为 1.0 的点进行反投影会返回位于远裁剪平面上的点。

  1. import SceneKit
  3. class GameViewController: UIViewController {
  5.     override func viewDidLoad() {
  6.         super.viewDidLoad()
  7.         let sceneView = self.view as! SCNView
  8.         sceneView.scene = SCNScene()
  9.         sceneView.backgroundColor = UIColor.black
  11.         let cameraNode = SCNNode()
  12.         cameraNode.camera = SCNCamera()
  13.         cameraNode.simdPosition = simd_float3(0, 0, 1)
  14.         sceneView.scene?.rootNode.addChildNode(cameraNode)
  16.         let tapGesture = UITapGestureRecognizer(target: self,
  17.                                                 action: #selector(tap))
  18.         sceneView.addGestureRecognizer(tapGesture)
  19.     }
  21.     @objc func tap(_ gestureRecognizer: UITapGestureRecognizer) {
  22.         let scnView = self.view as! SCNView
  24.         let geo = SCNSphere(radius: 0.01)
  25.         geo.firstMaterial?.diffuse.contents = UIColor.white
  26.         let dotNode = SCNNode(geometry: geo)
  28.         let point = gestureRecognizer.location(in: scnView)
  29.         let unprojected = scnView.unprojectPoint(.init(point.x, point.y, 0))
  31.         dotNode.position = SCNVector3(unprojected.x, unprojected.y, -0.01)
  32.         scnView.scene?.rootNode.addChildNode(dotNode)
  33.     }
  34. }

要在正交投影下运行相机，请使用：

  1. cameraNode.camera?.usesOrthographicProjection = true
英文:

Unprojecting a Point

To render dot nodes at expected position, use the following approach. Don't forget that you are looking at the scene in perspective projection. Unprojecting a point whose Z-coordinate is 0.0 returns a point on the near clipping plane. Unprojecting a point whose Z-coordinate is 1.0 returns a point on the far clipping plane.

  1. import SceneKit
  3. class GameViewController: UIViewController {
  5.     override func viewDidLoad() {
  6.         super.viewDidLoad()            
  7.         let sceneView = self.view as! SCNView
  8.         sceneView.scene = SCNScene()
  9.         sceneView.backgroundColor = UIColor.black
  10.                 
  11.         let cameraNode = SCNNode()
  12.         cameraNode.camera = SCNCamera()
  13.         cameraNode.simdPosition = simd_float3(0, 0, 1)
  14.         sceneView.scene?.rootNode.addChildNode(cameraNode)
  15.         
  16.         let tapGesture = UITapGestureRecognizer(target: self,
  17.                                                 action: #selector(tap))
  18.         sceneView.addGestureRecognizer(tapGesture)
  19.     }
  21.     @objc func tap(_ gestureRecognizer: UITapGestureRecognizer) {
  22.         let scnView = self.view as! SCNView
  23.         
  24.         let geo = SCNSphere(radius: 0.01)
  25.         geo.firstMaterial?.diffuse.contents = UIColor.white
  26.         let dotNode = SCNNode(geometry: geo)
  28.         let point = gestureRecognizer.location(in: scnView)
  29.         let unprojected = scnView.unprojectPoint(.init(point.x, point.y, 0))
  30.  
  31.         dotNode.position = SCNVector3(unprojected.x, unprojected.y, -0.01)
  32.         scnView.scene?.rootNode.addChildNode(dotNode)
  33.     }
  34. }

如何在SceneKit中在用户点击位置渲染球体？

To run a camera in orthographic projection, use:

  1. cameraNode.camera?.usesOrthographicProjection = true

huangapple
  • 本文由 发表于 2023年6月14日 23:29:57
  • 转载请务必保留本文链接：https://go.coder-hub.com/76475229.html
  • ios
  • scenekit
  • swift
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定