将 SCNNode 或 UIView 添加到 SCNView 的中心，以便检测其他 SCNNode答案

【问题标题】：Add SCNNode or UIView to the center of SCNView in order to detect other SCNNodes将 SCNNode 或 UIView 添加到 SCNView 的中心，以便检测其他 SCNNode
【发布时间】：2019-06-14 22:47:48
【问题描述】：

我正在尝试将 UIView 居中到我的 SCNView 的中心，以便检测场景中其他添加的 SCNTorus 节点。

我在我的场景视图的中心添加了一个视图，如下所示

var focusPoint: CGPoint {
    return CGPoint(
        x: sceneView.bounds.size.width / 2,
        y: sceneView.bounds.size.height - (sceneView.bounds.size.height / 1.618))
}

然后我尝试了两种方法：

1 -

    func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {

        DispatchQueue.main.async { [weak self] in

            guard let strongSelf = self else { return }

            if !strongSelf.inEditMode { return }

            for node in strongSelf.selectionRingsNodes {

                let projectedPoint = renderer.projectPoint(node.position)
                let projectedCGPoint = CGPoint(x: CGFloat(projectedPoint.x), y: CGFloat(projectedPoint.y))

                let distance = projectedCGPoint.distance(to: strongSelf.focusPoint)


                if distance < 20 {
                    print(node.name)
                }

            }
        }
    }

2 -

    func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {

        DispatchQueue.main.async { [weak self] in

            guard let strongSelf = self else { return }

            if !strongSelf.inEditMode { return }

            for node in strongSelf.selectionRingsNodes {

                let (min, max) = node.boundingBox
                let projectedMinPoint = renderer.projectPoint(min)
                let projectedMinCGPoint = CGPoint(x: CGFloat(projectedMinPoint.x), y: CGFloat(projectedMinPoint.y))

                let projectedMaxPoint = renderer.projectPoint(max)
                let projectedMaxCGPoint = CGPoint(x: CGFloat(projectedMaxPoint.x), y: CGFloat(projectedMaxPoint.y))

                let minX = CGFloat(projectedMinCGPoint.x)
                let maxX = CGFloat(projectedMaxCGPoint.x)
                let minY = CGFloat(projectedMinCGPoint.y)
                let maxY = CGFloat(projectedMaxCGPoint.y)

                let nodeRect = CGRect(x: minX, y: minY, width: maxX - minX, height: maxY - minY)

                if nodeRect.contains(strongSelf.focusPoint) {
                    print(node.name)
                }
            }
        }
    }

这两个方法返回错误的结果，距离很大，x和y也很大。

【问题讨论】：

标签： swift scenekit arkit

【解决方案1】：

我终于找到了解决方案！

原来我应该把位置转换成场景的世界坐标空间，用这个方法convertPosition(SCNVector3,to:)

这里是完整的代码：

func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {

        DispatchQueue.main.async { [weak self] in

            guard let strongSelf = self else { return }

            if !strongSelf.inEditMode { return }

            for node in strongSelf.selectionRingsNodes {

                let position = node.convertPosition(SCNVector3Zero, to: nil)
                let projectedPoint = renderer.projectPoint(position)
                let projectedCGPoint = CGPoint(x: CGFloat(projectedPoint.x), y: CGFloat(projectedPoint.y))
                let distance = projectedCGPoint.distance(to: strongSelf.focusPoint)
                if distance < 50 {
                    strongSelf.showToast(message: node.getTopMostParentNode().name!, font: .systemFont(ofSize: 30))
                }
            }
        }
    }

【讨论】：