Ios SceneKit场景时间偏移不工作

我正在尝试复制WWDC 2013 skinning.m幻灯片，但我在CCAnimationGroup上的时间偏移功能方面遇到了问题。当我在代码中实现时间偏移时，它不会像在Apple代码中那样偏移时间，它只是从动画的开始开始，不管我做什么

苹果所做的和我所做的有什么区别

以下是苹果公司的一段代码：

- (void)extractAnimationsFromSceneSource:(SCNSceneSource *)sceneSource
{


// In this scene objects are animated separately using long animations
// playing 3 successive animations. We will group these long animations
// and then split the group in 3 different animation groups.
// We could also have used three DAEs (one per animation).

NSArray *animationIDs = [sceneSource identifiersOfEntriesWithClass:[CAAnimation class]];

NSUInteger animationCount = [animationIDs count];
NSMutableArray *longAnimations = [[NSMutableArray alloc] initWithCapacity:animationCount];

CFTimeInterval maxDuration = 0;

for (NSInteger index = 0; index < animationCount; index++) {
    CAAnimation *animation = [sceneSource entryWithIdentifier:animationIDs[index] withClass:[CAAnimation class]];
    if (animation) {
        maxDuration = MAX(maxDuration, animation.duration);
        [longAnimations addObject:animation];
     //   NSLog(@"%@",[longAnimations description]);
    }
}

CAAnimationGroup *longAnimationsGroup = [[CAAnimationGroup alloc] init];
longAnimationsGroup.animations = longAnimations;
longAnimationsGroup.duration = maxDuration;

CAAnimationGroup *idleAnimationGroup = [longAnimationsGroup copy];
idleAnimationGroup.timeOffset = 6.45833333333333;
_idleAnimationGroup = [CAAnimationGroup animation];
_idleAnimationGroup.animations = @[idleAnimationGroup];
_idleAnimationGroup.duration = 24.71 - 6.45833333333333;
_idleAnimationGroup.repeatCount = FLT_MAX;
_idleAnimationGroup.autoreverses = YES;

无论我如何更改时间偏移量，它总是从0开始。我看到苹果复制了一个带有时间偏移的动画组，然后用它来实例化一个基于该偏移的新动画组。正如您所看到的，我已经尝试在我的代码中这样做，但它并没有改变任何事情

目前我唯一能想到的是iOS不支持timeoffset属性？？也许它只支持可可豆

---

谢谢你能提供的任何帮助

似乎在for循环中重新声明了

maxDuration

，所以最后

maxDuration

仍然是0，我真是太感谢你了！！！这解决了我的问题。我已经拔头发好几天了！！

class myViewController: UIViewController,
var _idleAnimationGroup = CAAnimationGroup()

...

  func extractAnimationsFromSceneSource(sceneSource: SCNSceneSource)

    {

    var animationsIDs = sceneSource.identifiersOfEntriesWithClass(CAAnimation.self) as [String]

    var animationCount = animationsIDs.count

    var longAnimations:[CAAnimation] = []
    var maxDuration : CFTimeInterval = 0;

    for animationID in animationsIDs {
        if let animation = sceneSource.entryWithIdentifier(animationID, withClass: CAAnimation.self) as? CAAnimation {
            var maxDuration = max(maxDuration, animation.duration);
          longAnimations.append(animation)
        }

    }

        var longAnimationsGroup = CAAnimationGroup()
        longAnimationsGroup.animations = longAnimations
        longAnimationsGroup.duration = maxDuration

        var idleAnimationGroup :CAAnimationGroup = longAnimationsGroup.copy() as CAAnimationGroup

        idleAnimationGroup.timeOffset = 2.5

        _idleAnimationGroup.animations = [idleAnimationGroup]
        _idleAnimationGroup.duration = 1.0


}