Class TrackAsset

A PlayableAsset representing a track inside a timeline.

Inheritance

Object

TrackAsset

Namespace: UnityEngine.Timeline

Syntax

public abstract class TrackAsset : ISerializationCallbackReceiver, IPropertyPreview, ICurvesOwner, PlayableAsset

Remarks

Derive from TrackAsset to implement custom timeline tracks. TrackAsset derived classes support the following attributes: HideInMenuAttribute TrackColorAttribute TrackClipTypeAttribute TrackBindingTypeAttribute

Examples

   [TrackColor(1, 0, 0)]
   [TrackBindingType(typeof(Animator))]
   [TrackClipType(typeof(AnimationClip))]
   public class CustomAnimationTrack : TrackAsset {}

Fields

m_Clips

Declaration

protected List<TimelineClip> m_Clips

Field Value

Type	Description
List<TimelineClip>

Properties

curves

An animation clip storing animated properties of the attached PlayableAsset

Declaration

public AnimationClip curves { get; }

Property Value

Type	Description
AnimationClip

duration

The length, in seconds, of this track

Declaration

public override sealed double duration { get; }

Property Value

Type	Description
Double

end

The end time, in seconds, of this track

Declaration

public double end { get; }

Property Value

Type	Description
Double

hasClips

Whether this track contains any TimelineClip.

Declaration

public bool hasClips { get; }

Property Value

Type	Description
Boolean

hasCurves

Whether this track contains animated properties for the attached PlayableAsset.

Declaration

public bool hasCurves { get; }

Property Value

Type	Description
Boolean

Remarks

This property is false if the curves property is null or if it contains no information.

isEmpty

Whether this track is considered empty.

Declaration

public virtual bool isEmpty { get; }

Property Value

Type	Description
Boolean

Remarks

A track is considered empty when it does not contain a TimelineClip, Marker, or Curve.

isSubTrack

Returns whether this track is a subtrack

Declaration

public bool isSubTrack { get; }

Property Value

Type	Description
Boolean

locked

The local locked state of the track.

Declaration

public bool locked { get; set; }

Property Value

Type	Description
Boolean

Remarks

Note that locking a track only affects operations in the Timeline Editor. It does not prevent other API calls from changing a track or it's clips.

This returns or sets the local locked state of the track. A track may still be locked for editing because one or more of it's parent tracks in the hierarchy is locked. Use lockedInHierarchy to test if a track is locked because of it's own locked state or because of a parent tracks locked state.

lockedInHierarchy

The locked state of a track. (RO)

Declaration

public bool lockedInHierarchy { get; }

Property Value

Type	Description
Boolean

Remarks

Note that locking a track only affects operations in the Timeline Editor. It does not prevent other API calls from changing a track or it's clips.

This indicates whether a track is locked in the Timeline Editor because either it's locked property is enabled or a parent track is locked.

muted

Whether the track is muted or not.

Declaration

public bool muted { get; set; }

Property Value

Type	Description
Boolean

Remarks

A muted track is excluded from the generated PlayableGraph

mutedInHierarchy

The muted state of a track.

Declaration

public bool mutedInHierarchy { get; }

Property Value

Type	Description
Boolean

Remarks

A track is also muted when one of its parent tracks are muted.

outputs

Returns a description of the PlayableOutputs that will be created by this track.

Declaration

public override IEnumerable<PlayableBinding> outputs { get; }

Property Value

Type	Description
IEnumerable<PlayableBinding>

parent

The owner of this track.

Declaration

public PlayableAsset parent { get; }

Property Value

Type	Description
PlayableAsset

Remarks

If this track is a subtrack, the parent is a TrackAsset. Otherwise the parent is a TimelineAsset.

start

The start time, in seconds, of this track

Declaration

public double start { get; }

Property Value

Type	Description
Double

supportsNotifications

Indicates if a track accepts markers that implement .

Declaration

public bool supportsNotifications { get; }

Property Value

Type	Description
Boolean

Remarks

Only tracks with a bound object of type or can accept notifications.

timelineAsset

The TimelineAsset that this track belongs to.

Declaration

public TimelineAsset timelineAsset { get; }

Property Value

Type	Description
TimelineAsset

Methods

CalculateItemsHash()

Declaration

protected virtual int CalculateItemsHash()

Returns

Type	Description
Int32

CreateClip<T>()

Creates a clip on the track with a playable asset attached, whose derived type is specified by T

Declaration

public TimelineClip CreateClip<T>()
    where T : ScriptableObject, IPlayableAsset

Returns

Type	Description
TimelineClip	Returns a TimelineClip whose asset is of type T

Type Parameters

Name	Description
T	A PlayableAsset derived type

Remarks

Throws if T is not supported by the track. Supported types are determined by TrackClip attributes that decorate the TrackAsset derived class

CreateCurves(String)

Creates an AnimationClip to store animated properties for the attached PlayableAsset.

Declaration

public void CreateCurves(string curvesClipName)

Parameters

Type	Name	Description
String	curvesClipName	The name of the AnimationClip to create. This method does not ensure unique names. If you want a unique clip name, you must provide one. See ObjectNames.GetUniqueName for information on a method that creates unique names.

Remarks

If curves already exists for this track, this method produces no result regardless of the value specified for curvesClipName.

CreateDefaultClip()

Creates a TimelineClip on this track.

Declaration

public TimelineClip CreateDefaultClip()

Returns

Type	Description
TimelineClip	Returns a new TimelineClip that is attached to the track.

Remarks

The type of the playable asset attached to the clip is determined by TrackClip attributes that decorate the TrackAsset derived class

CreateMarker(Type, Double)

Creates a marker of the requested type, at a specific time, and adds the marker to the current asset.

Declaration

public IMarker CreateMarker(Type type, double time)

Parameters

Type	Name	Description
Type	type	The type of marker.
Double	time	The time where the marker is created.

Returns

Type	Description
IMarker	Returns the instance of the created marker.

Remarks

All markers that implement IMarker and inherit from are supported. Markers that implement the INotification interface cannot be added to tracks that do not support notifications. CreateMarker will throw with tracks that do not support notifications if type implements the INotification interface.

CreateMarker<T>(Double)

Creates a marker of the requested type, at a specific time, and adds the marker to the current asset.

Declaration

public T CreateMarker<T>(double time)
    where T : ScriptableObject, IMarker

Parameters

Type	Name	Description
Double	time	The time where the marker is created.

Returns

Type	Description
T	Returns the instance of the created marker.

Type Parameters

Name	Description
T	The type of marker to create.

Remarks

All markers that implement IMarker and inherit from are supported. CreateMarker will throw with tracks that do not support notifications if T implements the INotification interface.

CreatePlayable(PlayableGraph, GameObject)

Overrides PlayableAsset.CreatePlayable(). Not used in Timeline.

Declaration

public override sealed Playable CreatePlayable(PlayableGraph graph, GameObject go)

Parameters

Type	Name	Description
PlayableGraph	graph
GameObject	go

Returns

Type	Description
Playable

CreatePlayable(PlayableGraph, GameObject, TimelineClip)

Constructs a Playable from a TimelineClip.

Declaration

protected virtual Playable CreatePlayable(PlayableGraph graph, GameObject gameObject, TimelineClip clip)

Parameters

Type	Name	Description
PlayableGraph	graph	PlayableGraph that will own the playable.
GameObject	gameObject	The GameObject that builds the PlayableGraph.
TimelineClip	clip	The TimelineClip to construct a playable for.

Returns

Type	Description
Playable	A playable that will be set as an input to the Track Mixer playable, or Playable.Null if the clip does not have a valid PlayableAsset

Remarks

By default, this method invokes Playable.CreatePlayable, sets animated properties, and sets the speed of the created playable. Override this method to change this default implementation.

CreateTrackMixer(PlayableGraph, GameObject, Int32)

Creates a mixer used to blend playables generated by clips on the track.

Declaration

public virtual Playable CreateTrackMixer(PlayableGraph graph, GameObject go, int inputCount)

Parameters

Type	Name	Description
PlayableGraph	graph	The graph to inject playables into
GameObject	go	The GameObject that requested the graph.
Int32	inputCount	The number of playables from clips that will be inputs to the returned mixer

Returns

Type	Description
Playable	A handle to the [[Playable]] representing the mixer.

Remarks

Override this method to provide a custom playable for mixing clips on a graph.

DeleteClip(TimelineClip)

Delete a clip from this track.

Declaration

public bool DeleteClip(TimelineClip clip)

Parameters

Type	Name	Description
TimelineClip	clip	The clip to delete.

Returns

Type	Description
Boolean	Returns true if the removal was successful

Remarks

This method will delete a clip and any assets owned by the clip.

DeleteMarker(IMarker)

Removes a marker from the current asset.

Declaration

public bool DeleteMarker(IMarker marker)

Parameters

Type	Name	Description
IMarker	marker	The marker instance to be removed.

Returns

Type	Description
Boolean	Returns true if the marker instance was successfully removed. Returns false otherwise.

GatherProperties(PlayableDirector, IPropertyCollector)

Called by the Timeline Editor to gather properties requiring preview.

Declaration

public virtual void GatherProperties(PlayableDirector director, IPropertyCollector driver)

Parameters

Type	Name	Description
PlayableDirector	director	The PlayableDirector invoking the preview
IPropertyCollector	driver	PropertyCollector used to gather previewable properties

Implements

IPropertyPreview.GatherProperties(PlayableDirector, IPropertyCollector)

GetAnimationClipHash(AnimationClip)

Gets the hash code for an AnimationClip.

Declaration

protected static int GetAnimationClipHash(AnimationClip clip)

Parameters

Type	Name	Description
AnimationClip	clip	The animation clip.

Returns

Type	Description
Int32	A 32-bit signed integer that is the hash code for `clip`. Returns 0 if `clip` is null or empty.

GetChildTracks()

The list of subtracks or child tracks attached to this track.

Declaration

public IEnumerable<TrackAsset> GetChildTracks()

Returns

Type	Description
IEnumerable<TrackAsset>	Returns an enumerable list of child tracks owned directly by this track.

Remarks

In the case of GroupTracks, this returns all tracks contained in the group. This will return the all subtracks or override tracks, if supported by the track.

GetClips()

A list of clips owned by this track

Declaration

public IEnumerable<TimelineClip> GetClips()

Returns

Type	Description
IEnumerable<TimelineClip>	Returns an enumerable list of clips owned by the track.

GetMarker(Int32)

Returns the marker at a given position, on the current asset.

Declaration

public IMarker GetMarker(int idx)

Parameters

Type	Name	Description
Int32	idx	The index of the marker to be returned.

Returns

Type	Description
IMarker	The marker.

Remarks

The ordering of the markers is not guaranteed.

GetMarkerCount()

Returns the number of markers on the current asset.

Declaration

public int GetMarkerCount()

Returns

Type	Description
Int32	The number of markers.

GetMarkers()

Returns an enumerable list of markers on the current asset.

Declaration

public IEnumerable<IMarker> GetMarkers()

Returns

Type	Description
IEnumerable<IMarker>	The list of markers on the asset.

OnAfterTrackDeserialize()

Called after a track has been deserialized.

Declaration

protected virtual void OnAfterTrackDeserialize()

OnBeforeTrackSerialize()

Called before a track is serialized.

Declaration

protected virtual void OnBeforeTrackSerialize()

OnCreateClip(TimelineClip)

Called when a clip is created on a track.

Declaration

protected virtual void OnCreateClip(TimelineClip clip)

Parameters

Type	Name	Description
TimelineClip	clip	The timeline clip added to this track

Remarks

Use this method to set default values on a timeline clip, or it's PlayableAsset.

Extension Methods

TrackAssetExtensions.GetGroup(TrackAsset)

TrackAssetExtensions.SetGroup(TrackAsset, GroupTrack)