[csharp] Ported 4.2-beta physics.

CHANGELOG.md

@@ -34,6 +34,22 @@
   * `SkeletonGraphic` now supports automatic scaling based on its `RectTransform` bounds. Automatic scaling can be enabled by setting the added `Layout Scale Mode` Inspector property to either `Width Controls Height`, `Height Controls Width`, `FitInParent` or `EnvelopeParent`. It is set to `None` by default to keep previous behaviour and avoid breaking existing projects. To modify the reference layout bounds, hit the additional `Edit Layout Bounds` toggle button to switch into edit mode, adjust the bounds or hit `Match RectTransform with Mesh`, and hit the button again when done adjusting. The skeleton will now be scaled accordingly to fit the reference layout bounds to the object's `RectTransform`.
   * Added previously missing unlit URP 2D shader variant, available under `Universal Render Pipeline/2D/Spine/Skeleton`.
   * Added support for light cookies at `Universal Render Pipeline/Spine/Sprite` shader.
+  * Timeline extension package: An additional Spine preferences parameter `Timeline` - `Default Mix Duration` has been added, setting newly added `SpineAnimationStateClip` clips accordingly, defaults to false. This Spine preferences parameter can be enabled to default to the previous behaviour before this update.
+  * Tint Black: Added support for [Tint Black](http://en.esotericsoftware.com/spine-slots#Tint-black) functionality at all Spine URP shaders (2D and 3D shaders) and at all standard pipeline `Spine/Sprite` shaders. This feature can be enabled via the `Tint Black` material parameter in the Inspector. Note: The URP Sprite shaders provided in the Spine URP Shaders extension UPM package require the latest version of the spine-unity runtime (package version 4.1.12, 2023-05-31 or newer) to display the added material parameters in the Inspector GUI.
+  * Added `SkeletonGraphic.MeshScale` property to allow access to calculated mesh scale. `MeshScale` is based on (1) Canvas pixels per unit, and (2) `RectTransform` bounds when using `Layout Scale Mode` other than `None` at `SkeletonGraphic` which scales the skeleton mesh to fit the parent `RectTransform` bounds accordingly.
+  * Added `updateSeparatorPartScale` property to `SkeletonGraphic` to let render separator parts follow the scale (lossy scale) of the `SkeletonGraphic` GameObject. Defaults to `false` to maintain existing behaviour.
+  * Added experimental `EditorSkeletonPlayer` component to allow Editor playback of the initial animation set at `SkeletonAnimation` or `SkeletonGraphic` components. Add this component to your skeleton GameObject to enable the in-editor animation preview. Allows configurations for continuous playback when selected, deselected, and alternative single-frame preview by setting `Fixed Track Time` to any value other than 0. Limitations: At skeletons with variable material count the Inspector preview may be too unresponsive. It is then recommended to disable the `EditorSkeletonPlayer` component (at the top of the Inspector) to make it responsive again, then you can disable `Play When Selected` and re-enable the component to preview playback only when deselected.
+  * Added example component `RenderCombinedMesh` to render a combined mesh of multiple meshes or submeshes. This is required by `OutlineOnly` shaders to render a combined outline when using `SkeletonRenderSeparator` or multiple atlas pages which would normally lead to outlines around individual parts. To add a combined outline to your SkeletenRenderer:
+    1) Add a child GameObject and move it a bit back (e.g. position Z = 0.01).
+    2) Add a `RenderCombinedMesh` component, provided in the `Spine Examples/Scripts/Sample Components` directory.
+    3) Copy the original material, add *_Outline* to its name and set the shader to your outline-only shader like `Universal Render Pipeline/Spine/Outline/Skeleton-OutlineOnly` or `Spine/Outline/OutlineOnly-ZWrite`.
+    4) Assign this *_Outline* material at the new child GameObject's `MeshRenderer` component.
+    If you are using `SkeletonRenderSeparator` and need to enable and disable the `SkeletonRenderSeparator` component at runtime, you can increase the `RenderCombinedMesh` `Reference Renderers` array by one and assign the `SkeletonRenderer` itself at the last entry after the parts renderers. Disabled `MeshRenderer` components will be skipped when combining the final mesh, so the combined mesh is automatically filled from the desired active renderers.
+  * Timeline extension package: Added static `EditorEvent` callback to allow editor scripts to react to animation events outside of play-mode. Register to the events via `Spine.Unity.Playables.SpineAnimationStateMixerBehaviour.EditorEvent += YourCallback;`.
+  * URP Shaders: Added `Depth Write` property to shaders `Universal Render Pipeline/Spine/Skeleton` and `Universal Render Pipeline/Spine/Skeleton Lit`. Defaults to false to maintain existing behaviour.
+  * Added `Animation Update` mode (called `UpdateTiming` in code) `In Late Update` for `SkeletonAnimation`, `SkeletonMecanim` and `SkeletonGraphic`. This allows you to update the `SkeletonMecanim` skeleton in the same frame that the Mecanim Animator updated its state, which happens between `Update` and `LateUpdate`.
+  * URP Shaders: Added URP "Blend Mode" shader variants for both URP 3D and URP 2D renderers. They are listed under shader name "Universal Render Pipeline/Spine/Blend Modes/" and "Universal Render Pipeline/2D/Spine/Blend Modes/" respectively.
+  * URP Shaders: Added support for [Tint Black](http://en.esotericsoftware.com/spine-slots#Tint-black) functionality at "Blend Modes" Spine URP shaders (2D and 3D shaders).
 
 * **Breaking changes**
   * Changed `SpineShaderWithOutlineGUI` outline related methods from `private` to `protected virtual` to allow for custom shader GUI subclasses to switch to different outline shaders.