在 swift spritkit 场景中褪色的视频 [英] fading video over swift spritkit scene

问题描述

我正在将陈列室应用程序从 as3/starling 移植到本机 swift iPad 应用程序.

I am porting a showroom application from as3/starling to a native swift iPad app.

我有两个问题:

1. 如何在我的 spritekit 内容上淡化视频(从 alpha 0 到 1).

1. How can I fade a video over my spritekit content (from alpha 0 to 1).

如何在不显示 iOS 屏幕音量通知图形的情况下使用单个 UI 元素控制 iPad 音量.

How to control the iPad volume with an individual UI element without showing the iOS onscreen-volume notification graphic.

推荐答案

我的第一个答案回答了你最初的问题，这个答案是针对评论中发布的后续问题量身定制的.我觉得这两个答案对社区都有用，而不是组合成一个我认为会令人困惑的答案.

My first answer answers your initial question, and this answer is tailored to the subsequent questions that were posted in the comments. I feel that both answers are useful to the community, instead of combining into just one which I think would be confusing.

在这里，我实现了一个音量滑块和一个控制 VideoNode 的 AVPlayer 对象的擦洗滑块.您可以获得 AVPlayer 的全部功能，但又具有 SKVideoNode 的便利性.另外，播放视频的音量是可控的，无需调整系统音量和后续的灰色音箱弹出:

Here I implement a volume slider and a scrubbing slider that controls the VideoNode's AVPlayer object.. you get the full power of the AVPlayer but with the convenience of the SKVideoNode. Also, the volume for playing video is controlled without having to adjust the system volume and subsequent gray sound box pop-up:

import SpriteKit
import MediaPlayer


class GameScene: SKScene {

  let seekSlider = UISlider(frame: CGRect(x: 0, y: 0, width: 200, height: 15))
  let volSlider  = UISlider(frame: CGRect(x: 0, y: 0, width: 200, height: 15))

  // Because it takes time for us to load the video, we don't know it's duration,
  // hence we don't know what the `.maximumValue` should be for the seekSlider
  let defaultMax = Float(0.123456789)

  var player: AVPlayer!
  var videoNode: SKVideoNode!

  func seekSliderChangedValue(sender: UISlider) {
    // Wait for file to finish loading so we can get accurate end duration:
      if sender.maximumValue == defaultMax {
      if CMTimeGetSeconds(player.currentItem!.duration).isNaN { return }
      else { sender.maximumValue = Float(CMTimeGetSeconds(player.currentItem!.duration)) }
    }

    let value = CMTimeMake(Int64(seekSlider.value), 1)
    player.seek(to: value)
    player.play()
  }

  func volSliderChangedValue(sender: UISlider) {
    player.volume = sender.value
  }

  override func didMove(to view: SKView) {
    removeAllChildren()  // Delete this in your actual project.

    // Add some labels:
    let seekLabel = SKLabelNode(text: "Seek")
    seekLabel.setScale(3)
    seekLabel.verticalAlignmentMode = .center
    seekLabel.position = CGPoint(x: frame.minX + seekLabel.frame.width/2,
                                 y: frame.maxY - seekLabel.frame.height)
    let volLabel  = SKLabelNode(text: "Volume")
    volLabel.setScale(3)
    volLabel.verticalAlignmentMode = .center
    volLabel.position = CGPoint(x: frame.minX + volLabel.frame.width/2,
                                y: frame.minY + volLabel.frame.height + volSlider.frame.height)

    // Make player and node:
    let url = Bundle.main.url(forResource: "sample", withExtension: "mp4")!
    player = AVPlayer(url: url)
    videoNode = SKVideoNode(avPlayer: player!)

    //Configure seek slider:
    seekSlider.addTarget(self, action: #selector(seekSliderChangedValue), for: UIControlEvents.valueChanged)
    seekSlider.maximumValue = defaultMax
    let seekOrigin = convertPoint(toView: CGPoint(x: seekLabel.frame.minX, y: seekLabel.frame.minY))
    seekSlider.frame = CGRect(origin: seekOrigin, size: CGSize(width: 200, height: 15))

    //Configure vol slider:
    volSlider.addTarget(self, action: #selector(volSliderChangedValue), for: UIControlEvents.valueChanged)
    volSlider.value = 1
    let volOrigin = convertPoint(toView: CGPoint(x: volLabel.frame.minX, y: volLabel.frame.minY))
    volSlider.frame = CGRect(origin: volOrigin, size: CGSize(width: 200, height: 15))

    //Scene stuff:
    view.addSubview(seekSlider)
    view.addSubview(volSlider)
    addChild(seekLabel)
    addChild(volLabel)
    addChild(videoNode)

    // Start video and animation:
    videoNode.alpha = 0
    videoNode.play()
    videoNode.run(.fadeIn(withDuration: 5))
  }
}

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