Swift:使用Scenekit中的projectPoint随时间获取并保存更新的SCNNode [英] Swift: Obtain and save the updated SCNNode over time using projectPoint in scenekit

问题描述

我正在尝试使用projectPoint获取Scenekit中更新的SCNNode的2D信息并将其保存.

I am trying to use projectPoint to get the 2D information of the updated SCNNode in scenekit and save them.

基于ignotusverum的建议，我能够将SCNNode保存到按钮中的路径中.

Based on ignotusverum's suggestion, I am able to save the SCNNode in to a path in a button.

     var lastPosition: CGPoint?
     func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
            guard anchor == currentFaceAnchor,
                let contentNode = selectedContentController.contentNode,
                contentNode.parent == node
                else { return }
            for (index, vertex) in vertices.enumerated() {
            let vertex = sceneView.projectPoint(node.convertPosition(SCNVector3(vertex), to: nil))
            let xVertex = CGFloat(vertex.x)
            let yVertex = CGFloat(vertex.y)
            Position = CGPoint(x: xVertex, y: yVertex)
           }
            selectedContentController.session = sceneView?.session
            selectedContentController.sceneView = sceneView
            selectedContentController.renderer(renderer, didUpdate: contentNode, for: anchor)
        }

---

通过开始按钮开始保存:

---

Started saving via a start button:

    private var fpsTimer = Timer()
    private var currentCaptureFrame = 0
    @IBAction private func startPressed() {
        currentCaptureFrame = 0 //inital capture frame
        fpsTimer = Timer.scheduledTimer(withTimeInterval: 1/fps, repeats: true, block: {(timer) -> Void in self.recordData()})
    }

---

通过停止按钮单击保存它们:

---

Saved them via a stop button clicks:

@IBAction private func stopPressed() {
    do {
        fpsTimer.invalidate() //turn off the timer
        let capturedData = captureData.map{$0.stringRepresentation}.joined(separator:"\(lastPosition)>")
        let dir: URL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).last! as URL
        let url = dir.appendingPathComponent("testing.txt")
        try capturedData.appendLineToURL(fileURL: url as URL)
    }
    catch {
        print("Could not write to file")
    }
}

到目前为止，保存点可以正常工作.问题在于，在保存的数据中，我意识到数据仅保存了x和y顶点的一帧.例如:

So far works fine with the points being saved. The problem is that in the saved data, I realized the data is only saving one frame of the x and y vertices. For example:

[(411.0618591308594, 534.4215087890625), (410.7286071777344, 544.9381713867188), (411.5425720214844, 522.1063232421875), (412.0340881347656, 512.1854248046875),... 

[(411.0618591308594, 534.4215087890625), (410.7286071777344, 544.9381713867188), (411.5425720214844, 522.1063232421875), (412.0340881347656, 512.1854248046875)

数据以一帧重复，而不是从单击开始按钮到停止按钮的那一刻起我要保存的时间段.

The data is repeating with one frame rather than the period I want to save from the moment when I click start button to stop button.

我的问题是如何从单击开始按钮到停止按钮的那一刻起保存更新的SCNNode?

提前谢谢！

推荐答案

如果我正确理解了您的问题，那么您希望在每次更新顶点位置时保存它们，以跟踪所有以前的更新以及最近的更新.为此，您只需要将新的顶点位置数组添加到具有已保存数据的全局数组中即可.

If I understand your question correctly you want to save the vertex positions each time they are updated, keeping track of all previous updates as well as the most recent one. In order to do this you simply need to append the new vertex position array to the global array with saved data.

 var savedPositions = [CGPoint]()
 var beginSaving = false

 func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
        guard anchor == currentFaceAnchor,
            let contentNode = selectedContentController.contentNode,
            contentNode.parent == node
            else { return }
        for vertex in vertices {
            let projectedPoint = sceneView.projectPoint(node.convertPosition(SCNVector3(vertex), to: nil))
            if beginSaving {
               savedPositions.append(CGPoint(x: projectedPoint.x, y: projectedPoint.y))
            }
        }
        selectedContentController.session = sceneView?.session
        selectedContentController.sceneView = sceneView
        selectedContentController.renderer(renderer, didUpdate: contentNode, for: anchor)
}

@IBAction private func startPressed() {
    beginSaving = true
}

@IBAction private func stopPressed() {
    beginSaving = false
    ....//do whatever with your array of saved positions
}

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