Flickering only when enabled via Unity Animation

calvin-tl

We have some Game Objects with Skeleton Graphics on them and a script that plays the Spine animations from their beginning whenever the Game Object is activated.

Here's what that code looks like, stripped down:

private void OnEnable()
{
    Play();
}

public void Play(string spineAnimationName = null, string animationTrigger = null, Action onAnimationCompleted = null)
{
    foreach (IAnimationStateComponent spineObject in spineArray)
    {
        int trackIndex = 0;

    foreach (TrackEntry track in spineObject.AnimationState.Tracks)
    {
        // Rewinds the Spine animation
        track.TrackTime = 0;

        if (spineAnimationName.HasValue())
        {
            spineObject.AnimationState.SetAnimation(trackIndex++, spineAnimationName, false);
        }
    }
}
}

The problem we're seeing is that when the Game Object is activated by a Unity animation, we see a single frame flicker of the last frame that the Spine Animation was in when it was previously deactivated.

There is no flicker if you manually activate and deactivate the Game Object through the Inspector.

It feels like maybe Unity is evaluating native animations one frame faster than Spine is evaluating the updated mesh / bone positions? So the Game Object becomes active and visible, but Spine hasn't had a chance to reflect the updated TrackTime.

Anyway, we've tried all kinds of stuff, like Update, LateUpdate, Reset, etc. and we're out of ideas.

Thanks for your help!

Also, sorry if this is too similar to this recent topic: http://esotericsoftware.com/forum/Animation-flickers-on-enable-9407

I wasn't sure if our situation applied, considering we aren't calling any Animator commands.

We did try the Update and LateUpdate suggestions from that topic and it just caused our Spine animations to stop playing properly.

Pharan

If you enable something via a separate Update loop (such as Unity's internal animation update), you need to make sure the order of things that happen is correct.

Update is the "Update Spine Internals" method. It progresses AnimationState, and poses the internal Skeleton according to the AnimationState.
LateUpdate is the "Generate Mesh" method. It translates the internal skeleton into a new, visible Unity mesh.

You can imagine that if your code runs in between SkeletonAnimation.Update and SkeletonAnimation.LateUpdate, the latest pose will not have been applied to the skeleton when LateUpdate happens. So what you see is the previous pose.

If your code doesn't run BEFORE "Update Spine Internals" happens, you have to call it yourself.
That's skeletonAnimation.Update(0);

calvin-tl

Thanks for your help Pharan!

We had tried calling Update before, but maybe there were some other confounding variables preventing it from working. This time around everything's working great.

Thanks again!