Class TrackAsset

A PlayableAsset representing a track inside a timeline.

Inheritance
object
Object
ScriptableObject
PlayableAsset
TrackAsset
ActivationTrack
AnimationTrack
AudioTrack
ControlTrack
GroupTrack
MarkerTrack
PlayableTrack
Implements
Inherited Members
Object.FindObjectsByType<T>(FindObjectsSortMode)
Object.FindObjectsByType<T>(FindObjectsInactive, FindObjectsSortMode)
Object.FindFirstObjectByType<T>()
Object.FindAnyObjectByType<T>()
Object.FindFirstObjectByType<T>(FindObjectsInactive)
Object.FindAnyObjectByType<T>(FindObjectsInactive)
Namespace: UnityEngine.Timeline
Assembly: Unity.Timeline.dll
Syntax
[Serializable]
public abstract class TrackAsset : PlayableAsset, IPlayableAsset, IPropertyPreview, ISerializationCallbackReceiver
Remarks

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

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

Fields

m_Clips

The List of TimelineClips in the track

Declaration
[SerializeField]
[HideInInspector]
protected List<TimelineClip> m_Clips
Field Value
Type Description
List<TimelineClip>
Remarks

This list is not guaranteed to be sorted. Do not add or remove items from this list directly. Use CreateClip(Type) and DeleteClip(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
Overrides

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
bool

hasCurves

Whether this track contains animated properties for the attached PlayableAsset.

Declaration
public bool hasCurves { get; }
Property Value
Type Description
bool
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
bool
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
bool

locked

The local locked state of the track.

Declaration
public bool locked { get; set; }
Property Value
Type Description
bool
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
bool
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
bool
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
bool
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>
Overrides

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 UnityEngine.Playables.INotification.

Declaration
public bool supportsNotifications { get; }
Property Value
Type Description
bool
Remarks

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

timelineAsset

The TimelineAsset that this track belongs to.

Declaration
public TimelineAsset timelineAsset { get; }
Property Value
Type Description
TimelineAsset

Methods

CalculateItemsHash()

Returns a hash which is combination of hashes from clips, animation clips and marker times.

Declaration
protected virtual int CalculateItemsHash()
Returns
Type Description
int

The hash value.

CanCreateTrackMixer()

Whether the track can create a mixer for its own contents.

Declaration
public virtual bool CanCreateTrackMixer()
Returns
Type Description
bool

Returns true if the track's mixer should be included in the playable graph.
Remarks

A return value of true does not guarantee that the mixer will be included in the playable graph. GroupTracks and muted tracks are never included in the graph. A return value of false does not guarantee that the mixer will not be included in the playable graph. If a child track returns true for CanCreateTrackMixer, the parent track will generate the mixer but its own playables will not be included. Override this method to change the conditions for a track to be included in the playable graph.

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

Supported types are determined by TrackClip attributes that decorate the TrackAsset derived class

Exceptions
Type Condition
InvalidOperationException

if T is not supported by the track.

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. When used from the editor, this method attempts to save the created curves clip to the TimelineAsset. The TimelineAsset must already exist in the AssetDatabase to save the curves clip. If the TimelineAsset does not exist, the curves clip is still created but it is not saved.

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 ScriptableObject are supported. Markers that implement the INotification interface cannot be added to tracks that do not support notifications.

Exceptions
Type Condition
InvalidOperationException

Tracks do not support notifications and type implements the INotification interface.
See Also

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 ScriptableObject are supported.

Exceptions
Type Condition
InvalidOperationException

Tracks do not support notifications and T implements the INotification interface.
See Also

CreatePlayable(PlayableGraph, GameObject)

Implement this method to have your asset inject playables into the given graph.

Declaration
public override sealed Playable CreatePlayable(PlayableGraph graph, GameObject go)
Parameters
Type Name Description
PlayableGraph graph

The graph to inject playables into.
GameObject go
Returns
Type Description
Playable

The playable injected into the graph, or the root playable if multiple playables are injected.
Overrides
Remarks

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

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.

Exceptions
Type Condition
ArgumentException

Thrown if the specified PlayableGraph is not valid.
ArgumentNullException

Thrown if the specified TimelineClip is not valid.

CreateTrackMixer(PlayableGraph, GameObject, int)

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.
int 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
bool

Returns true if the removal was successful
Remarks

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

Exceptions
Type Condition
InvalidOperationException

if clip is not a child of the TrackAsset.

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
bool

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

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
int

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(int)

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

Declaration
public IMarker GetMarker(int idx)
Parameters
Type Name Description
int 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
int

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.

Implements

Extension Methods