是否将一个scenekit节点附加到ARAnchor只是将节点的变换设置为锚的变换？

1 回答

• 0

  ARKit管理锚点的位置，并通过任何必要的变换扩展连接到它们的节点 . 因此，基本相连的节点的相对位置保持不变，但是锚的位置可能会改变 . 您还可以设置约束，以使旋转始终与摄像机或其他节点相同 .

  所以，问题＃1：它可以是相对于锚变换的任何变换 . 问题＃2：看到上面的解释，节点到锚点的相对变换保持不变但是锚点位置可能会改变 .

  在锚位置添加球体的示例以及在其上方始终面向相机的文本标签：

  func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode? {
  
      guard let featureAnchor = anchor as? FeatureAnchor else {
          return nil
      }
      let feature = featureAnchor.feature
  
      let billboardConstraint = SCNBillboardConstraint()
      billboardConstraint.freeAxes = SCNBillboardAxis.Y
  
      let sphere = SCNSphere(radius: Global.dotRadius)
      sphere.firstMaterial?.transparency = Global.annotationTransparency
      sphere.firstMaterial?.diffuse.contents = UIColor.yellow
      sphere.firstMaterial?.specular.contents = UIColor.white
      let node = SCNNode(geometry: sphere)
      node.constraints = [billboardConstraint]
  
      let text = SCNText(string: feature.description, extrusionDepth: Global.textDepth)
      text.chamferRadius = Global.textDepth
      text.firstMaterial?.transparency = Global.annotationTransparency
      text.firstMaterial?.diffuse.contents = UIColor.green
      text.firstMaterial?.specular.contents = UIColor.white
      text.firstMaterial?.isDoubleSided = true
      text.font = Global.textFont
      text.alignmentMode = kCAAlignmentCenter
  
      let (min, max) = text.boundingBox
      let dx: Float = (max.x - min.x) / 2.0 // x = center
      let dy: Float = min.y // y = bottom
      let dz: Float = Float(Global.textDepth) / 2.0 // z = center
  
      let textNode = SCNNode(geometry: text)
      textNode.pivot = SCNMatrix4MakeTranslation(dx, dy, dz)
      textNode.scale = SCNVector3Make(Global.textScale, Global.textScale, Global.textScale)
  
      node.addChildNode(textNode)
  
      return node
  }
  

  回复于 2024-04-19T11:47:57+08:00