SupportsChildTracksAttribute - custom sub-tracks for custom tracks

Unity Engine
,
1

I wandered around the Playable API amusement park with joy and arrived at a booth called TrackActions. After convincing the guy at the booth to let me play, I created an action to create custom sub-tracks for my custom track. So far so good.

Sadly, I now realized that the SupportsChildTracksAttribute does not allow for multiples. Are there any deeper limitations on why only a single type of sub-track should be supported?
I experimented with adjusting TimelineCreateUtilities.ValidateParentTrack to allow for multiple SupportsChildTracksAttribute applications and it appears to work.

Here’s the relevant part of what I needed to change in TimelineCreateUtilities.ValidateParentTrack:

            foreach (var attr in Attribute.GetCustomAttributes(parent.GetType(), typeof(SupportsChildTracksAttribute)).OfType<SupportsChildTracksAttribute>())
            {
                // group track case, accepts all
                if (attr.childType == null)
                    return true;  

                // specific case. Specifies nesting level
                if (childType == attr.childType)
                {
                    int nestCount = 0;
                    var p = parent;
                    while (p != null && p.isSubTrack)
                    {
                        nestCount++;
                        p = p.parent as TrackAsset;
                    }

                    return nestCount < attr.levels;
                }
            }

Also, convincing the guy at the booth is one thing, messing with his stuff another. Is it possible to let SupportsChildTracksAttribute support multiples in the future? :slight_smile: