Add pointlight to flashbangs (#15785)

Content.Client/Light/EntitySystems/LightFadeSystem.cs

@@ -0,0 +1,46 @@
+using Content.Client.Light.Components;
+using Robust.Client.Animations;
+using Robust.Client.GameObjects;
+using Robust.Shared.Animations;
+
+namespace Content.Client.Light.EntitySystems;
+
+public sealed class LightFadeSystem : EntitySystem
+{
+    [Dependency] private readonly AnimationPlayerSystem _player = default!;
+
+    private const string FadeTrack = "light-fade";
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<LightFadeComponent, ComponentStartup>(OnFadeStartup);
+    }
+
+    private void OnFadeStartup(EntityUid uid, LightFadeComponent component, ComponentStartup args)
+    {
+        if (!TryComp<PointLightComponent>(uid, out var light))
+            return;
+
+        var animation = new Animation()
+        {
+            Length = TimeSpan.FromSeconds(component.Duration),
+            AnimationTracks =
+            {
+                new AnimationTrackComponentProperty()
+                {
+                    Property = nameof(PointLightComponent.Energy),
+                    ComponentType = typeof(PointLightComponent),
+                    InterpolationMode = AnimationInterpolationMode.Cubic,
+                    KeyFrames =
+                    {
+                        new AnimationTrackProperty.KeyFrame(light.Energy, 0f),
+                        new AnimationTrackProperty.KeyFrame(0f, component.Duration)
+                    }
+                }
+            }
+        };
+
+        _player.Play(uid, animation, FadeTrack);
+    }
+}