swift - 无法区分 ARKit 检测到的平面和使用 HitTest 放置的数字对象

Question

我对 iOS Swift 编程还很陌生。我正在使用 ARKit 构建一个非常基本的应用程序来检测水平面并在其上放置、平移、旋转、修改或删除对象。

我主要关心的是 ARKit 检测到的平面与我放置的数字对象之间的差异。我的想法是使用 hitTest(:options:) 选择对象(如果有的话)并使用 hitTest(:types:) 通过点击手势选择平面。我在下面附上了相关的代码片段。

@objc func tapped(_ gesture: UITapGestureRecognizer){

    let sceneView = gesture.view as! ARSCNView

    let location = gesture.location(in: sceneView)


    let hitTestOptions: [SCNHitTestOption: Any] = [.boundingBoxOnly: true]
    let existingNodeHitTest = sceneView.hitTest(location, options: hitTestOptions)

    if let existingNode = existingNodeHitTest.first?.node {

        // Move, rotate, modify or delete the object

    } else {

        // Option to add other objects

        let hitTest = sceneView.hitTest(location, types: .existingPlaneUsingExtent)

        if !hitTest.isEmpty {

            let node = findNode(at: location)

            if node !== selectedNode {

                self.addItems(hitTestResult: hitTest.first!)


            } 

        }

}

}

func addItems(hitTestResult: ARHitTestResult) {


        let scene = SCNScene(named: "BuildingModels.scnassets/model/model.scn")


        let itemNode = (scene?.rootNode.childNode(withName: "SketchUp", recursively: false))!


        let transform = hitTestResult.worldTransform
        let position = SCNVector3(transform.columns.3.x,transform.columns.3.y,transform.columns.3.z)
        itemNode.position = position
        //            self.sceneView.scene.lightingEnvironment.contents = scene.lightingEnvironment.contents

        self.sceneView.scene.rootNode.addChildNode(itemNode)
        selectedNode = itemNode

}

    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
    guard let planeAnchor = anchor as? ARPlaneAnchor else {return}

    let gridNode = createGrid(planeAnchor: planeAnchor)
    node.addChildNode(gridNode)


}

func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
    guard let planeAnchor = anchor as? ARPlaneAnchor else {return}

    node.enumerateChildNodes { (childNode, _) in
        childNode.removeFromParentNode()
    }

    let gridNode = createGrid(planeAnchor: planeAnchor)
    node.addChildNode(gridNode)

}

当我运行代码时，hitTest(_:options:) 返回检测到的平面。有什么方法可以只选择我放置的 SCNNodes(对象)而不是检测到的平面。我错过了什么吗？非常感谢任何帮助。

谢谢，

苏拉布。

Answer 1

看看你的问题，你已经完成了一半。

完整处理此问题的方法是在 UITapGestureRecognizer 函数中使用以下 HitTest 函数:

(1) ARSCNHitTest，它:

Searches for real-world objects or AR anchors in the captured camera image corresponding to a point in the SceneKit view.

(2) 一个SCNHitTest，它:

Looks for SCNGeometry objects along the ray you specify. For each intersection between the ray and and a geometry, SceneKit creates a hit-test result to provide information about both the SCNNode object containing the geometry and the location of the intersection on the geometry’s surface.

因此，以您的 UITapGestureRecognizer 为例，您可以像这样区分场景中的 ARPlaneAnchor (detectedPlane) 和任何 SCNNode:

@objc func handleTap(_ gesture: UITapGestureRecognizer){

    //1. Get The Current Touch Location
    let currentTouchLocation = gesture.location(in: self.augmentedRealityView)

    //2. Perform An ARNSCNHitTest To See If We Have Hit An ARPlaneAnchor
    if let planeHitTest = augmentedRealityView.hitTest(currentTouchLocation, types: .existingPlane).first,
        let planeAnchor = planeHitTest.anchor as? ARPlaneAnchor{

        print("User Has Tapped On An Existing Plane = \(planeAnchor.identifier)")
        return
    }

    //3. Perform An SCNHitTest To See If We Have Hit An SCNNode
    if let nodeHitTest = augmentedRealityView.hitTest(currentTouchLocation, options: nil).first {

        let nodeTapped = nodeHitTest.node

        print("An SCNNode Has Been Tapped = \(nodeTapped)")
        return
    }

}

如果您为您的任何 SCNNode 使用 name 属性，这也将进一步帮助您，例如:

if let name = nodeTapped.name{
    print("An SCNNode Named \(name) Has Been Tapped")
}

此外，如果您只想检测已添加的对象，例如 SCNNodes，那么您只需删除 getureRecognizer 函数的第二部分即可。

希望对你有帮助