现在我正在测试 ARKit/SceneKit 的实现。基本的屏幕渲染已经有了，接下来我想尝试将屏幕上看到的内容记录为视频。
关于 Scene Kit 的录制，我找到了 这个代码片段：
//
// ViewController.swift
// SceneKitToVideo
//
// Created by Lacy Rhoades on 11/29/16.
// Copyright © 2016 Lacy Rhoades. All rights reserved.
//
import SceneKit
import GPUImage
import Photos
class ViewController: UIViewController {
// Renders a scene (and shows it on the screen)
var scnView: SCNView!
// Another renderer
var secondaryRenderer: SCNRenderer?
// Abducts image data via an OpenGL texture
var textureInput: GPUImageTextureInput?
// Recieves image data from textureInput, shows it on screen
var gpuImageView: GPUImageView!
// Recieves image data from the textureInput, writes to a file
var movieWriter: GPUImageMovieWriter?
// Where to write the output file
let path = NSTemporaryDirectory().appending("tmp.mp4")
// Output file dimensions
let videoSize = CGSize(width: 800.0, height: 600.0)
// EAGLContext in the sharegroup with GPUImage
var eaglContext: EAGLContext!
override func viewDidLoad() {
super.viewDidLoad()
let group = GPUImageContext.sharedImageProcessing().context.sharegroup
self.eaglContext = EAGLContext(api: .openGLES2, sharegroup: group )
let options = ["preferredRenderingAPI": SCNRenderingAPI.openGLES2]
// Main view with 3d in it
self.scnView = SCNView(frame: CGRect.zero, options: options)
self.scnView.preferredFramesPerSecond = 60
self.scnView.eaglContext = eaglContext
self.scnView.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(self.scnView)
// Secondary renderer for rendering to an OpenGL framebuffer
self.secondaryRenderer = SCNRenderer(context: eaglContext, options: options)
// Output of the GPUImage pipeline
self.gpuImageView = GPUImageView()
self.gpuImageView.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(self.gpuImageView)
self.setupConstraints()
self.setupScene()
self.setupMovieWriter()
DispatchQueue.main.async {
self.setupOpenGL()
}
}
func setupConstraints() {
let relativeWidth: CGFloat = 0.8
self.view.addConstraint(NSLayoutConstraint(item: self.scnView, attribute: .width, relatedBy: .equal, toItem: self.view, attribute: .width, multiplier: relativeWidth, constant: 0))
self.view.addConstraint(NSLayoutConstraint(item: self.scnView, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0))
self.view.addConstraint(NSLayoutConstraint(item: self.gpuImageView, attribute: .width, relatedBy: .equal, toItem: self.view, attribute: .width, multiplier: relativeWidth, constant: 0))
self.view.addConstraint(NSLayoutConstraint(item: self.gpuImageView, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-(==30.0)-[scnView]-(==30.0)-[gpuImageView]", options: [], metrics: [:], views: ["gpuImageView": gpuImageView, "scnView": scnView]))
let videoRatio = self.videoSize.width / self.videoSize.height
self.view.addConstraint(NSLayoutConstraint(item: self.scnView, attribute: .width, relatedBy: .equal, toItem: self.scnView, attribute: .height, multiplier: videoRatio, constant: 1))
self.view.addConstraint(NSLayoutConstraint(item: self.gpuImageView, attribute: .width, relatedBy: .equal, toItem: self.gpuImageView, attribute: .height, multiplier: videoRatio, constant: 1))
}
override func viewDidAppear(_ animated: Bool) {
self.cameraBoxNode.runAction(
SCNAction.repeatForever(
SCNAction.rotateBy(x: 0.0, y: -2 * CGFloat.pi, z: 0.0, duration: 8.0)
)
)
self.scnView.isPlaying = true
Timer.scheduledTimer(withTimeInterval: 5.0, repeats: false, block: {
timer in
self.startRecording()
})
}
var scene: SCNScene!
var geometryNode: SCNNode!
var cameraNode: SCNNode!
var cameraBoxNode: SCNNode!
var imageMaterial: SCNMaterial!
func setupScene() {
self.imageMaterial = SCNMaterial()
self.imageMaterial.isDoubleSided = true
self.imageMaterial.diffuse.contentsTransform = SCNMatrix4MakeScale(-1, 1, 1)
self.imageMaterial.diffuse.wrapS = .repeat
self.imageMaterial.diffuse.contents = UIImage(named: "pano_01")
self.scene = SCNScene()
let sphere = SCNSphere(radius: 100.0)
sphere.materials = [imageMaterial!]
self.geometryNode = SCNNode(geometry: sphere)
self.geometryNode.position = SCNVector3Make(0.0, 0.0, 0.0)
scene.rootNode.addChildNode(self.geometryNode)
self.cameraNode = SCNNode()
self.cameraNode.camera = SCNCamera()
self.cameraNode.camera?.yFov = 72.0
self.cameraNode.position = SCNVector3Make(0, 0, 0)
self.cameraNode.eulerAngles = SCNVector3Make(0.0, 0.0, 0.0)
self.cameraBoxNode = SCNNode()
self.cameraBoxNode.addChildNode(self.cameraNode)
scene.rootNode.addChildNode(self.cameraBoxNode)
self.scnView.scene = scene
self.scnView.backgroundColor = UIColor.darkGray
self.scnView.autoenablesDefaultLighting = true
}
func setupMovieWriter() {
let _ = FileUtil.mkdirUsingFile(path)
let _ = FileUtil.unlink(path)
let url = URL(fileURLWithPath: path)
self.movieWriter = GPUImageMovieWriter(movieURL: url, size: self.videoSize)
}
let glRenderQueue = GPUImageContext.sharedContextQueue()!
var outputTexture: GLuint = 0
var outputFramebuffer: GLuint = 0
func setupOpenGL() {
self.glRenderQueue.sync {
let context = EAGLContext.current()
if context != self.eaglContext {
EAGLContext.setCurrent(self.eaglContext)
}
glGenFramebuffers(1, &self.outputFramebuffer)
glBindFramebuffer(GLenum(GL_FRAMEBUFFER), self.outputFramebuffer)
glGenTextures(1, &self.outputTexture)
glBindTexture(GLenum(GL_TEXTURE_2D), self.outputTexture)
}
// Pipe the texture into GPUImage-land
self.textureInput = GPUImageTextureInput(texture: self.outputTexture, size: self.videoSize)
let rotate = GPUImageFilter()
rotate.setInputRotation(kGPUImageFlipVertical, at: 0)
self.textureInput?.addTarget(rotate)
rotate.addTarget(self.gpuImageView)
if let writer = self.movieWriter {
rotate.addTarget(writer)
}
// Call me back on every render
self.scnView.delegate = self
}
func renderToFramebuffer(atTime time: TimeInterval) {
self.glRenderQueue.sync {
let context = EAGLContext.current()
if context != self.eaglContext {
EAGLContext.setCurrent(self.eaglContext)
}
objc_sync_enter(self.eaglContext)
let width = GLsizei(self.videoSize.width)
let height = GLsizei(self.videoSize.height)
glBindFramebuffer(GLenum(GL_FRAMEBUFFER), self.outputFramebuffer)
glBindTexture(GLenum(GL_TEXTURE_2D), self.outputTexture)
glTexImage2D(GLenum(GL_TEXTURE_2D), 0, GL_RGBA, width, height, 0, GLenum(GL_RGBA), GLenum(GL_UNSIGNED_BYTE), nil)
glTexParameteri(GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_MAG_FILTER), GL_LINEAR)
glTexParameteri(GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_MIN_FILTER), GL_LINEAR)
glTexParameteri(GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_WRAP_S), GL_CLAMP_TO_EDGE)
glTexParameteri(GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_WRAP_T), GL_CLAMP_TO_EDGE)
glFramebufferTexture2D(GLenum(GL_FRAMEBUFFER), GLenum(GL_COLOR_ATTACHMENT0), GLenum(GL_TEXTURE_2D), self.outputTexture, 0)
glViewport(0, 0, width, height)
glClear(GLbitfield(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT))
self.secondaryRenderer?.render(atTime: time)
self.videoBuildingQueue.sync {
self.textureInput?.processTexture(withFrameTime: CMTime(seconds: time, preferredTimescale: 100000))
}
objc_sync_exit(self.eaglContext)
}
}
func startRecording() {
self.startRecord()
Timer.scheduledTimer(withTimeInterval: 24.0, repeats: false, block: {
timer in
self.stopRecord()
})
}
let videoBuildingQueue = DispatchQueue.global(qos: .default)
func startRecord() {
self.videoBuildingQueue.sync {
//inOrientation: CGAffineTransform(scaleX: 1.0, y: -1.0)
self.movieWriter?.startRecording()
}
}
var renderStartTime: TimeInterval = 0
func stopRecord() {
self.videoBuildingQueue.sync {
self.movieWriter?.finishRecording(completionHandler: {
self.saveFileToCameraRoll()
})
}
}
func saveFileToCameraRoll() {
assert(FileUtil.fileExists(self.path), "Check for file output")
DispatchQueue.global(qos: .utility).async {
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: URL(fileURLWithPath: self.path))
}) { (done, err) in
if err != nil {
print("Error creating video file in library")
print(err.debugDescription)
} else {
print("Done writing asset to the user's photo library")
}
}
}
}
}
extension ViewController: SCNSceneRendererDelegate {
func renderer(_ renderer: SCNSceneRenderer, didRenderScene scene: SCNScene, atTime time: TimeInterval) {
self.secondaryRenderer?.scene = scene
self.secondaryRenderer?.pointOfView = (renderer as! SCNView).pointOfView
self.renderToFramebuffer(atTime: time)
}
}
但是这并不能呈现设备相机中的图像。
因此，我开始寻找方法来实现它。 到目前为止，我找到了通过访问ARFrame将捕获的图像作为CVImageBufferRef获取的方法。 而苹果的GLCameraRipple示例似乎可以帮助我从中获取OpenGL纹理。
但我的问题是如何在渲染循环中绘制它。 这可能对于有OpenGL经验的人来说很明显，但是我只有非常少关于OpenGL的知识，所以我无法弄清楚如何将其添加到上面的代码中。