README: MinimalistTLBinder

Plugin to bind objects to a PlayableAsset used on Timelines and load your Timeline in runtime.

Motivation

By default, a PlayableAsset can hold references to elements that coexist in the same scope as them.

Let's suppose that we have a Timeline that has a reference to the Main Camera of the scene. If this Timeline exists on the scene the reference will be there and the timeline will be able to manipulate the referenced camera.

Now, if we move the Timeline to a prefab that will be loaded at runtime, the Main Camera reference will be lost. To solve this issue we would have to bind the element by code.

This plugin helps with the process of binding elements in runtime.

How to use it

To make it work, we have to create our Timeline and assign the references on Edit mode, then we will use the plugin to wire the objects that are referenced on it.

And we should be ready to go.

Detailed steps

1.- Work on a Timeline and add object references to it, as usual. So a timeline like this:

Also, you can see on Unity Inspector the current bindings:

2.- Add a PlayableDirectorBinder component and assign the PlaybleDirector component to it on the Director field.

3.- Wire the elements using the button that says Wire bindings! on the PlayableDirectorBinder component.

This will do two things;

• First, Add a BindableAsset component to each of the referenced objects. This new component will hold a unique identifier and a reference to the bound object.
• Second, update the names of each one of the tracks on the Timeline to include that unique identifier (later this name will be parsed to look for the object with that unique Id).

Updated track names:

New BindableAsset component:

4.- Save your changes and load your Timeline in runtime. By default, PlayableDirectorBinder will try to bind elements on Awake but this option can be disabled (this would require a manual invocation of SearchAndBindObjectsOnScene() on PlayableDirectorBinder).

Other actions

There are other buttons on the PlayableDirectorBinder component besides Wire bindings!. Those are useful for testing or cleaning up things:

• Wire bindings!: Add a BindableAsset component to referenced objects and update the track name accordingly. If there is already a BindableAsset component on the referenced object, it will just update the track name. In the case that the unique Id on the BindableAsset doesn't match the specified Id on the track name, the track name will be updated.
• Search and bind scene objects: Search on the current scene and try to bind elements using the unique Id specified on the track name.
• Cleanup binding references: Unbind all the references. Useful if, after Wire the bindings you want to see if everything is working. (ie; First Wire... the bindings, then Cleanup..., then Search and bind.... If you are in the scene where the timeline will be loaded, all the references should be re-bound).
• Reset track names with assigned components: Reset the name on all the tracks that have an assigned component. So you always can wire and the track names should go back to their previous values.
• Reset *ALL* track names: Rest the name on all tracks, without filtering those that have or have no references. If you reset the name of a track that has nothing assigned to it, it will be on you to reassign a valid reference.

Known issues

• The process to obtain the BindableAsset references relies on Finding Objects Of Type All that exist on a loaded scene (Resources.FindObjectsOfTypeAll<BindableAsset>().Where(ba => ba.gameObject.scene.isLoaded);). This can cause issues with the PlayableDirectorBinder option Try Bind on Awake if the PlayableDirectorBinder is being instantiated at the same time. In other words, the current way to look up BindableAsset cannot retrieve them during Awake if they are also being instantiated. So make sure that you have the required BindableAsset elements already loaded before loading a PlayableDirectorBinder. A workaround for this is to manually invoke the SearchAndBindObjectsOnScene() method after the scene is loaded with both elements.

Future improvements

• Improve the lookup function; FindObjectsOfTypeAll can be expensive.
• Improve assignment function: Currently, after retrieving all the BindableAsset we try to bind each one of them. A better solution would be to a dictionary.