施加力后的 ARKit 获取节点的位置

Question

与此问题相同的问题 how to track the position of a node after applying force in Arkit 1.5 但未得到解答所以我正在添加新问题

我有我施加力的节点 (SCNSphere)。节点有 dynamic 物理学 body。在滑动时，我使用 physicsBody?.applyForce 对 SCNNode 施加力这一切都很好

问题是施加力后，因为它有 dynamic body 它不断下降，我想跟踪那个位置

在 renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) 我打印了 SCNNode 的 position 但它每次都显示相同的位置，为什么 Y 位置在向下时没有减少？

喜欢

等等？

我是如何添加节点的

        let ballWithOrientation = getNewBallNode() // return ball node + position
        let ballNode = ballWithOrientation.ball // it is the SCNNode
        self.sceneView.scene.rootNode.addChildNode(ballNode ?? SCNNode()) // Added to the scene 
        let cameraPosition =  self.sceneView.pointOfView?.worldFront

        let target =  SCNVector3(Double(cameraPosition?.x ?? 1) * forceVector,Double (cameraPosition?.y  ?? 1) * forceVector,Double(cameraPosition?.z ?? 1) * forceVector) // Vector of direction 
        let throwSpeed = self.calculateBestThrowSpeed(origin: ballNode!.position, target:target , timeToTarget: 0.66)  Calculated vector with velocity 
        ballNode?.physicsBody?.applyForce(throwSpeed, asImpulse: true) // apply force

问题施加力后如何跟踪SCNNode的世界位置？

Answer 1

我找到了非常简单的解决方案

open var presentation: SCNNode { get }

SCNNode 的属性将为您提供当前节点的介绍

所以最后 ballNode.presentation.position 将为您提供节点的当前位置以及所有动画（力）

来自 Apple Docs

When you use implicit animation (see SCNTransaction) to change a node’s properties, those node properties are set immediately to their target values, even though the animated node content appears to transition from the old property values to the new. During the animation SceneKit maintains a copy of the node, called the presentation node, whose properties reflect the transitory values determined by any in-flight animations currently affecting the node.

希望对发现类似问题的人有所帮助

施加力后的 ARKit 获取节点的位置

ARKit after apply force get location of node

ios

swift

scenekit

arkit