如何在Swift 3中的iOS上的SceneKit中创建循环视频材料？

Question

如何在SceneKit中创建播放循环视频的素材？

Answer 1

使用SpriteKit场景作为几何体的材质,可以在SceneKit中实现此目的.

以下示例将创建SpriteKit场景,使用视频播放器向其添加视频节点,制作视频播放器循环,创建SceneKit场景,添加SceneKit平面,最后将SpriteKit场景添加为平面的漫反射材质.

import UIKit
import SceneKit
import SpriteKit
import AVFoundation

class ViewController: UIViewController, SCNSceneRendererDelegate {

    @IBOutlet weak var sceneView: SCNView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // A SpriteKit scene to contain the SpriteKit video node
        let spriteKitScene = SKScene(size: CGSize(width: sceneView.frame.width, height: sceneView.frame.height))
        spriteKitScene.scaleMode = .aspectFit

        // Create a video player, which will be responsible for the playback of the video material
        let videoUrl = Bundle.main.url(forResource: "videos/video", withExtension: "mp4")!
        let videoPlayer = AVPlayer(url: videoUrl)

        // To make the video loop
        videoPlayer.actionAtItemEnd = .none
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(ViewController.playerItemDidReachEnd),
            name: NSNotification.Name.AVPlayerItemDidPlayToEndTime,
            object: videoPlayer.currentItem)

        // Create the SpriteKit video node, containing the video player
        let videoSpriteKitNode = SKVideoNode(avPlayer: videoPlayer)
        videoSpriteKitNode.position = CGPoint(x: spriteKitScene.size.width / 2.0, y: spriteKitScene.size.height / 2.0)
        videoSpriteKitNode.size = spriteKitScene.size
        videoSpriteKitNode.yScale = -1.0
        videoSpriteKitNode.play()
        spriteKitScene.addChild(videoSpriteKitNode)

        // Create the SceneKit scene
        let scene = SCNScene()
        sceneView.scene = scene
        sceneView.delegate = self
        sceneView.isPlaying = true

        // Create a SceneKit plane and add the SpriteKit scene as its material
        let background = SCNPlane(width: CGFloat(100), height: CGFloat(100))
        background.firstMaterial?.diffuse.contents = spriteKitScene
        let backgroundNode = SCNNode(geometry: background)
        scene.rootNode.addChildNode(backgroundNode)

        ...
    }

    // This callback will restart the video when it has reach its end
    func playerItemDidReachEnd(notification: NSNotification) {
        if let playerItem: AVPlayerItem = notification.object as? AVPlayerItem {
            playerItem.seek(to: kCMTimeZero)
        }
    }

    ...
}

Answer 2

2019年解决方案：

let mat = SCNMaterial()
let videoUrl = Bundle.main.url(forResource: "YourVideo", withExtension: "mp4")!
let player = AVPlayer(url: videoUrl)
mat.diffuse.contents = player
player.actionAtItemEnd = .none
NotificationCenter.default.addObserver(self,
                                       selector: #selector(playerItemDidReachEnd(notification:)),
                                       name: .AVPlayerItemDidPlayToEndTime,
                                       object: player.currentItem)
player.play()

选择器中的方法代码：

@objc private func playerItemDidReachEnd(notification: Notification) {
    if let playerItem = notification.object as? AVPlayerItem {
        playerItem.seek(to: .zero, completionHandler: nil)
    }
}

当对象被释放时，不要忘记移除你的通知观察者！像这样的东西：

NotificationCenter.default.removeObserver(self, name: .AVPlayerItemDidPlayToEndTime, object: player.currentItem)