## Spine UI Toolkit Extension [Experimental]

This experimental plugin provides integration of UI Toolkit for the spine-unity runtime. Please be sure to test this package first and create backups of your project before using.
The plugin adds a `SpineVisualElement` control element to be used with UI Toolkit, providing functionality similar to `SkeletonGraphic` to add your Spine skeletons to a Visual Tree Asset via UI Toolkit's UI Builder.

### Usage

For usage of the `SpineVisualElement` control element, you can check out the included `UI Toolkit Example.unity` example scene and `SpineUIToolkit.uxml` file which can be installed via the `Samples` tab in the Unity Package Manager window.
The new `SpineVisualElement` can be found in the Unity `UI Builder` window under `Library - Project - Custom Controls` `Spine - Unity - SpineVisualElement`. It can be added to your hierarchy and configured as normal UI Toolkit elements while providing Spine skeleton attributes as well.

### Limitations

Premultiply-alpha (PMA) atlas textures are not supported due to limitations of the UI Toolkit `VisualElement` API, not allowing custom shaders. Please export your atlas textures as straight alpha to avoid artifacts.

Custom slot blend modes (additive, muliply, screen) are not supported due to the same custom shader limitation.