Use red damage animation for guns too (#10938)

Content.Client/Weapons/Melee/MeleeWeaponSystem.Effects.cs

@@ -0,0 +1,112 @@
+using Content.Shared.Weapons;
+using Content.Shared.Weapons.Melee;
+using Robust.Client.Animations;
+using Robust.Client.GameObjects;
+using Robust.Shared.Utility;
+
+namespace Content.Client.Weapons.Melee;
+
+public sealed partial class MeleeWeaponSystem
+{
+    private static readonly Animation DefaultDamageAnimation = new()
+    {
+        Length = TimeSpan.FromSeconds(DamageAnimationLength),
+        AnimationTracks =
+        {
+            new AnimationTrackComponentProperty()
+            {
+                ComponentType = typeof(SpriteComponent),
+                Property = nameof(SpriteComponent.Color),
+                KeyFrames =
+                {
+                    new AnimationTrackProperty.KeyFrame(Color.Red, 0f),
+                    new AnimationTrackProperty.KeyFrame(Color.White, DamageAnimationLength)
+                }
+            }
+        }
+    };
+
+    private const float DamageAnimationLength = 0.15f;
+    private const string DamageAnimationKey = "damage-effect";
+
+    private void InitializeEffect()
+    {
+        SubscribeLocalEvent<DamageEffectComponent, AnimationCompletedEvent>(OnEffectAnimation);
+    }
+
+    private void OnEffectAnimation(EntityUid uid, DamageEffectComponent component, AnimationCompletedEvent args)
+    {
+        if (TryComp<SpriteComponent>(uid, out var sprite))
+        {
+            sprite.Color = component.Color;
+        }
+
+        RemCompDeferred<DamageEffectComponent>(uid);
+    }
+
+    /// <summary>
+    /// Gets the red effect animation whenever the server confirms something is hit
+    /// </summary>
+    public Animation? GetDamageAnimation(EntityUid uid, SpriteComponent? sprite = null)
+    {
+        if (!Resolve(uid, ref sprite, false))
+            return null;
+
+        // 90% of them are going to be this so why allocate a new class.
+        if (sprite.Color.Equals(Color.White))
+            return DefaultDamageAnimation;
+
+        return new Animation
+        {
+            Length = TimeSpan.FromSeconds(DamageAnimationLength),
+            AnimationTracks =
+            {
+                new AnimationTrackComponentProperty()
+                {
+                    ComponentType = typeof(SpriteComponent),
+                    Property = nameof(SpriteComponent.Color),
+                    KeyFrames =
+                    {
+                        new AnimationTrackProperty.KeyFrame(Color.Red * sprite.Color, 0f),
+                        new AnimationTrackProperty.KeyFrame(sprite.Color, DamageAnimationLength)
+                    }
+                }
+            }
+        };
+    }
+
+    private void OnDamageEffect(DamageEffectEvent ev)
+    {
+        if (Deleted(ev.Entity))
+            return;
+
+        var player = EnsureComp<AnimationPlayerComponent>(ev.Entity);
+
+        // Need to stop the existing animation first to ensure the sprite color is fixed.
+        // Otherwise we might lerp to a red colour instead.
+        if (_animation.HasRunningAnimation(ev.Entity, player, DamageAnimationKey))
+        {
+            _animation.Stop(ev.Entity, player, DamageAnimationKey);
+        }
+
+        if (!TryComp<SpriteComponent>(ev.Entity, out var sprite))
+        {
+            return;
+        }
+
+        if (TryComp<DamageEffectComponent>(ev.Entity, out var effect))
+        {
+            sprite.Color = effect.Color;
+        }
+
+        var animation = GetDamageAnimation(ev.Entity, sprite);
+
+        if (animation == null)
+            return;
+
+        var comp = EnsureComp<DamageEffectComponent>(ev.Entity);
+        comp.NetSyncEnabled = false;
+        comp.Color = sprite.Color;
+        _animation.Play(player, DefaultDamageAnimation, DamageAnimationKey);
+    }
+}

Content.Client/Weapons/Melee/MeleeWeaponSystem.cs

@@ -13,17 +13,19 @@ using static Content.Shared.Weapons.Melee.MeleeWeaponSystemMessages;
 
 namespace Content.Client.Weapons.Melee
 {
-    [UsedImplicitly]
-    public sealed class MeleeWeaponSystem : EntitySystem
+    public sealed partial class MeleeWeaponSystem : EntitySystem
     {
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
         [Dependency] private readonly IGameTiming _gameTiming = default!;
+        [Dependency] private readonly AnimationPlayerSystem _animation = default!;
         [Dependency] private readonly EffectSystem _effectSystem = default!;
 
         public override void Initialize()
         {
+            InitializeEffect();
             SubscribeNetworkEvent<PlayMeleeWeaponAnimationMessage>(PlayWeaponArc);
             SubscribeNetworkEvent<PlayLungeAnimationMessage>(PlayLunge);
+            SubscribeNetworkEvent<DamageEffectEvent>(OnDamageEffect);
         }
 
         public override void FrameUpdate(float frameTime)