将节点放置在 ARKit World 中的触摸位置

Question

我想在距离用户相机 10 厘米的地方放置一个节点。该节点应放置在用户触摸屏幕的位置（未投影）。但不幸的是，我的代码不起作用。您知道缺少什么吗？我该怎么办？

这是我的代码：

func getDirection(for point: CGPoint, in view: SCNView) -> SCNVector3 {
        let farPoint  = view.unprojectPoint(SCNVector3Make(Float(point.x), Float(point.y), -0.1))
        let nearPoint = view.unprojectPoint(SCNVector3Make(Float(point.x), Float(point.y), 0))

        return SCNVector3Make(farPoint.x - nearPoint.x, farPoint.y - nearPoint.y, farPoint.z - nearPoint.z)
    }

Answer 1

1.首先添加一个点击手势识别器：

    func addTapGestureToSceneView() {
        let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(didReceiveTapGesture(_:)))
        sceneView.addGestureRecognizer(tapGestureRecognizer)
    }

    func didReceiveTapGesture(_ sender: UITapGestureRecognizer) {
        let location = sender.location(in: sceneView)
        guard let hitTestResult = sceneView.hitTest(location, types: [.featurePoint, .estimatedHorizontalPlane]).first
            else { return }
        let anchor = ARAnchor(transform: hitTestResult.worldTransform)
        sceneView.session.add(anchor: anchor)
    }

2。实现 ARSCNViewDelegate ：

extension ViewController: ARSCNViewDelegate {

    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
        guard !(anchor is ARPlaneAnchor) else { return }
        let sphereNode = generateSphereNode()
        DispatchQueue.main.async {
            node.addChildNode(sphereNode)
        }
    }
}

    func generateSphereNode() -> SCNNode {
        let node = SCNNode(geometry: SCNSphere(radius: 0.05))
        node.geometry?.firstMaterial?.diffuse.contents = UIColor.blue
        return node
    }