Better fix for waddle animation.

Content.Client/Movement/Systems/ClientWaddleAnimationSystem.cs

@@ -0,0 +1,144 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Numerics;
+using Content.Client.Buckle;
+using Content.Client.Gravity;
+using Content.Shared.ActionBlocker;
+using Content.Shared.Mobs.Systems;
+using Content.Shared.Movement.Components;
+using Content.Shared.Movement.Systems;
+using Robust.Client.Animations;
+using Robust.Client.GameObjects;
+using Robust.Shared.Animations;
+
+namespace Content.Client.Movement.Systems;
+
+public sealed class ClientWaddleAnimationSystem : SharedWaddleAnimationSystem
+{
+    [Dependency] private readonly AnimationPlayerSystem _animation = default!;
+    [Dependency] private readonly GravitySystem _gravity = default!;
+    [Dependency] private readonly ActionBlockerSystem _actionBlocker = default!;
+    [Dependency] private readonly BuckleSystem _buckle = default!;
+    [Dependency] private readonly MobStateSystem _mobState = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        // Start waddling
+        SubscribeAllEvent<StartedWaddlingEvent>((msg, args) => StartWaddling(args.SenderSession.AttachedEntity));
+
+        // Handle concluding animations
+        SubscribeLocalEvent<WaddleAnimationComponent, AnimationCompletedEvent>(OnAnimationCompleted);
+
+        // Stop waddling
+        SubscribeAllEvent<StoppedWaddlingEvent>((msg, args) => StopWaddling(args.SenderSession.AttachedEntity));
+    }
+
+    private void StartWaddling(EntityUid? uid)
+    {
+        if (
+            !EntityIsValid(uid, out var entity, out var component) ||
+            _animation.HasRunningAnimation(entity.Value, component.KeyName) ||
+            _gravity.IsWeightless(entity.Value) ||
+            _buckle.IsBuckled(entity.Value) ||
+            _mobState.IsIncapacitated(entity.Value) ||
+            !TryComp<InputMoverComponent>(entity, out var mover) ||
+            !_actionBlocker.CanMove(entity.Value, mover)
+        )
+            return;
+
+        PlayWaddleAnimationUsing(entity.Value, component, CalculateAnimationLength(component, mover), CalculateTumbleIntensity(component));
+    }
+
+    private static float CalculateTumbleIntensity(WaddleAnimationComponent component)
+    {
+        return component.LastStep ? 360 - component.TumbleIntensity : component.TumbleIntensity;
+    }
+
+    private static float CalculateAnimationLength(WaddleAnimationComponent component, InputMoverComponent mover)
+    {
+        return mover.Sprinting ? component.AnimationLength * component.RunAnimationLengthMultiplier : component.AnimationLength;
+    }
+
+    private void OnAnimationCompleted(EntityUid uid, WaddleAnimationComponent component, AnimationCompletedEvent args)
+    {
+        if (args.Key != component.KeyName)
+            return;
+
+        if (!TryComp<InputMoverComponent>(uid, out var mover))
+            return;
+
+        PlayWaddleAnimationUsing(uid, component, CalculateAnimationLength(component, mover), CalculateTumbleIntensity(component));
+    }
+
+    private void StopWaddling(EntityUid? uid)
+    {
+        if (
+            !EntityIsValid(uid, out var entity, out var component) ||
+            !_animation.HasRunningAnimation(entity.Value, component.KeyName)
+        )
+            return;
+
+        _animation.Stop(entity.Value, component.KeyName);
+
+        if (!TryComp<SpriteComponent>(entity.Value, out var sprite))
+            return;
+
+        // Note that this is a hard-write to this sprite, not some layer-based operation. If this is called whilst a sprite
+        // is lying down, it will make the sprite stand up, which usually looks wrong.
+        sprite.Offset = new Vector2();
+        sprite.Rotation = Angle.FromDegrees(0);
+    }
+
+    private bool EntityIsValid(EntityUid? uid, [NotNullWhen(true)] out EntityUid? entity, [NotNullWhen(true)] out WaddleAnimationComponent? component)
+    {
+        entity = null;
+        component = null;
+
+        if (!uid.HasValue)
+            return false;
+
+        entity = uid.Value;
+
+        return TryComp(entity, out component);
+    }
+
+    private void PlayWaddleAnimationUsing(EntityUid uid, WaddleAnimationComponent component, float len, float tumbleIntensity)
+    {
+        component.LastStep = !component.LastStep;
+
+        var anim = new Animation()
+        {
+            Length = TimeSpan.FromSeconds(len),
+            AnimationTracks =
+            {
+                new AnimationTrackComponentProperty()
+                {
+                    ComponentType = typeof(SpriteComponent),
+                    Property = nameof(SpriteComponent.Rotation),
+                    InterpolationMode = AnimationInterpolationMode.Linear,
+                    KeyFrames =
+                    {
+                        new AnimationTrackProperty.KeyFrame(Angle.FromDegrees(0), 0),
+                        new AnimationTrackProperty.KeyFrame(Angle.FromDegrees(tumbleIntensity), len/2),
+                        new AnimationTrackProperty.KeyFrame(Angle.FromDegrees(0), len/2),
+                    }
+                },
+                new AnimationTrackComponentProperty()
+                {
+                    ComponentType = typeof(SpriteComponent),
+                    Property = nameof(SpriteComponent.Offset),
+                    InterpolationMode = AnimationInterpolationMode.Linear,
+                    KeyFrames =
+                    {
+                        new AnimationTrackProperty.KeyFrame(new Vector2(), 0),
+                        new AnimationTrackProperty.KeyFrame(component.HopIntensity, len/2),
+                        new AnimationTrackProperty.KeyFrame(new Vector2(), len/2),
+                    }
+                }
+            }
+        };
+
+        _animation.Play(uid, anim, component.KeyName);
+    }
+}

Content.Server/Movement/Systems/ServerWaddleAnimationSystem.cs

@@ -0,0 +1,5 @@
+using Content.Shared.Movement.Systems;
+
+namespace Content.Server.Movement.Systems;
+
+public sealed class ServerWaddleAnimationSystem : SharedWaddleAnimationSystem;

Content.Client/Clothing/Systems/WaddleClothingSystem.cs → Content.Shared/Clothing/EntitySystems/WaddleClothingSystem.cs

@@ -1,8 +1,8 @@
 using Content.Shared.Clothing.Components;
-using Content.Shared.Movement.Components;
 using Content.Shared.Inventory.Events;
+using Content.Shared.Movement.Components;
 
-namespace Content.Client.Clothing.Systems;
+namespace Content.Shared.Clothing.EntitySystems;
 
 public sealed class WaddleClothingSystem : EntitySystem
 {