From d5585a30fdcea6acd06a59ed1aa89a60a33cebff Mon Sep 17 00:00:00 2001
From: Wojciech Figat <wojtek@figat.pl>
Date: Fri, 10 Dec 2021 12:42:11 +0100
Subject: [PATCH] Fix missing root motion preview in Animation preview panels
 (with option to disable it)

---
 .../Viewport/Previews/AnimatedModelPreview.cs | 12 +++++++--
 .../Viewport/Previews/AnimationPreview.cs     | 27 +++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/Source/Editor/Viewport/Previews/AnimatedModelPreview.cs b/Source/Editor/Viewport/Previews/AnimatedModelPreview.cs
index f3b1d263e..7337bd78b 100644
--- a/Source/Editor/Viewport/Previews/AnimatedModelPreview.cs
+++ b/Source/Editor/Viewport/Previews/AnimatedModelPreview.cs
@@ -23,6 +23,11 @@ namespace FlaxEditor.Viewport.Previews
         private bool _playAnimation, _playAnimationOnce;
         private float _playSpeed = 1.0f;
 
+        /// <summary>
+        /// Snaps the preview actor to the world origin.
+        /// </summary>
+        protected bool _snapToOrigin = true;
+
         /// <summary>
         /// Gets or sets the skinned model asset to preview.
         /// </summary>
@@ -249,8 +254,11 @@ namespace FlaxEditor.Viewport.Previews
         {
             if (!ScaleToFit)
             {
-                _previewModel.Scale = Vector3.One;
-                _previewModel.Position = Vector3.Zero;
+                if (_snapToOrigin)
+                {
+                    _previewModel.Scale = Vector3.One;
+                    _previewModel.Position = Vector3.Zero;
+                }
                 return;
             }
 
diff --git a/Source/Editor/Viewport/Previews/AnimationPreview.cs b/Source/Editor/Viewport/Previews/AnimationPreview.cs
index 6e7903c7b..9ef6fedb9 100644
--- a/Source/Editor/Viewport/Previews/AnimationPreview.cs
+++ b/Source/Editor/Viewport/Previews/AnimationPreview.cs
@@ -1,5 +1,6 @@
 // Copyright (c) 2012-2021 Wojciech Figat. All rights reserved.
 
+using FlaxEditor.GUI.ContextMenu;
 using FlaxEditor.GUI.Input;
 using FlaxEngine;
 using FlaxEditor.Viewport.Widgets;
@@ -15,6 +16,20 @@ namespace FlaxEditor.Viewport.Previews
     {
         private ViewportWidgetButton _playPauseButton;
 
+        /// <summary>
+        /// Gets or sets a value indicating whether enable root motion.
+        /// </summary>
+        public bool RootMotion
+        {
+            get => !_snapToOrigin;
+            set
+            {
+                if (!_snapToOrigin == value)
+                    return;
+                _snapToOrigin = !value;
+            }
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="AnimationPreview"/> class.
         /// </summary>
@@ -24,6 +39,7 @@ namespace FlaxEditor.Viewport.Previews
         {
             PlayAnimation = true;
             PlayAnimationChanged += OnPlayAnimationChanged;
+            _snapToOrigin = false;
 
             // Playback Speed
             {
@@ -48,6 +64,17 @@ namespace FlaxEditor.Viewport.Previews
                 playPauseWidget.Parent = this;
             }
 
+            // Play Root Motion
+            {
+                var button = ViewWidgetButtonMenu.AddButton("Root Motion");
+                var buttonValue = new CheckBox(90, 2, !_snapToOrigin)
+                {
+                    Parent = button
+                };
+                buttonValue.StateChanged += checkbox => RootMotion = !RootMotion;
+                ViewWidgetButtonMenu.VisibleChanged += control => buttonValue.Checked = RootMotion;
+            }
+
             // Enable shadows
             PreviewLight.ShadowsMode = ShadowsCastingMode.All;
             PreviewLight.CascadeCount = 2;