Unity开发笔记-Timeline利用Clip实现Rewind回放

效果展示

除了使用signal，timeline也可以通过自定义clip实现rewind回放

原理：

实现PlayableBehaviour的子类，重写ProcessFrame方法，参数中的Playable对象的GetDuration()和GetTime()可以获得当前clip的总时间和当前时间
如果time接近duration，那么设法取到playableDirector，将time减去当前clip已播放的GetTime()即可

下面是PlayableBehaviour核心代码：

  `public class LoopClipBehavior:PlayableBehaviour
  {
private PlayableDirector director { get; set; }

public override void ProcessFrame(Playable playable, FrameData info, object playerData)
{
    double duration = playable.GetDuration();
    double time = playable.GetTime();
    if (Math.Abs(time- duration)<=0.1f) 
    {
        var diff = playable.GetTime();
        director.time -= diff;
    }
    base.ProcessFrame(playable, info, playerData);
}

public override void OnPlayableCreate(Playable playable)
{
    base.OnPlayableCreate(playable);
    director = (playable.GetGraph().GetResolver() as PlayableDirector);
}
  }
  `

同时也需要实现PlayableAsset和TrackAsset的子类

LoopClipTrack.cs

[TrackClipType(typeof(LoopClip))]
public class LoopClipTrack: TrackAsset
{

}

LoopClip.cs

  `public class LoopClip : PlayableAsset
  {
public LoopClipBehavior template = new LoopClipBehavior();
public override Playable CreatePlayable(PlayableGraph graph, GameObject owner)
{
    var playable = ScriptPlayable<LoopClipBehavior>.Create(graph, template);
    return playable;
}
  }`