如何使用Swift scenekit在IOS上绘制摄像机视频作为背景？ [英] How to draw camera video as background on IOS using Swift scenekit?

问题描述

我正在尝试使用ios上的swift和scenekit开发增强现实应用程序。有没有办法将设备摄像头捕获的视频作为场景背景绘制？

I am trying to develop an augmented reality app using swift and scenekit on ios. Is there a way to draw the video captured by the device camera as a background of the scene?

推荐答案

这对我有用，

我使用 AVFoundation 来捕获设备相机的视频输入：

I used AVFoundation to capture the video input of the device camera:

   let captureSession = AVCaptureSession()
   let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill

    if let videoDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo) {
        var err: NSError? = nil
        if let videoIn : AVCaptureDeviceInput = AVCaptureDeviceInput.deviceInputWithDevice(videoDevice, error: &err) as? AVCaptureDeviceInput {
            if(err == nil){
                if (captureSession.canAddInput(videoIn as AVCaptureInput)){
                    captureSession.addInput(videoIn as AVCaptureDeviceInput)
                }
                else {
                    println("Failed to add video input.")
                }
            }
            else {
                println("Failed to create video input.")
            }
        }
        else {
            println("Failed to create video capture device.")
        }
    }
    captureSession.startRunning()

此时，基于Apple的​​background SCNScene 的属性，我预计会添加 AVCaptureV的实例ideoPreviewLayer 到 SCNScene 的 background.contents ，其中包括：

At this point, based on Apple's documentation of the background property of SCNScene, I expected to add the instance of AVCaptureVideoPreviewLayer to an SCNScene's background.contents, with something like:

   previewLayer.frame = sceneView.bounds
   sceneView.scene.background.contents = previewLayer 

这会将场景的背景颜色从默认白色更改为黑色，但不提供视频输入。 这可能是一个iOS错误？。
所以计划B.相反，我添加了'AVCaptureVideoPreviewLayer'作为 UIView的子层的图层：

This changed the background color of my scene from default white to black, but offered no video input. This may be an iOS bug?. So Plan B. Instead, I added the 'AVCaptureVideoPreviewLayer' as a sublayer of a UIView's layer:

 previewLayer.frame = self.view.bounds
 self.view.layer.addSublayer(previewLayer)

然后我将 SCNView 设置为相同 UIView 的子视图，设置 SCNView 的背景颜色以清除：

I then set an SCNView as a subview of that same UIView, setting the SCNView's background color to clear:

    let sceneView = SCNView()
    sceneView.frame = self.view.bounds
    sceneView.backgroundColor = UIColor.clearColor()
    self.view.addSubview(sceneView)

设备相机的视频现在可以看作背景现场。

The device camera's video is now visible as the background of the scene.

我创建了一个小的演示。

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