Filter sprites & visualizer (#3008)

Co-authored-by: py01 <pyronetics01@gmail.com>

Content.Client/GameObjects/Components/Atmos/GasFilterVisualizer.cs

@@ -0,0 +1,52 @@
+#nullable enable
+using Content.Shared.GameObjects.Components.Atmos;
+using JetBrains.Annotations;
+using Robust.Client.GameObjects;
+using Robust.Client.Interfaces.GameObjects.Components;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Serialization;
+using Robust.Shared.Utility;
+using YamlDotNet.RepresentationModel;
+
+namespace Content.Client.GameObjects.Components.Atmos
+{
+    [UsedImplicitly]
+    public class GasFilterVisualizer : AppearanceVisualizer
+    {
+        private string _filterEnabledState = default!;
+
+        public override void LoadData(YamlMappingNode node)
+        {
+            base.LoadData(node);
+            var serializer = YamlObjectSerializer.NewReader(node);
+            serializer.DataField(ref _filterEnabledState, "filterEnabledState", "gasFilterOn");
+        }
+
+        public override void InitializeEntity(IEntity entity)
+        {
+            base.InitializeEntity(entity);
+
+            if (!entity.TryGetComponent<ISpriteComponent>(out var sprite)) return;
+
+            sprite.LayerMapReserveBlank(Layer.FilterEnabled);
+            var filterEnabledLayer = sprite.LayerMapGet(Layer.FilterEnabled);
+            sprite.LayerSetState(filterEnabledLayer, _filterEnabledState);
+        }
+
+        public override void OnChangeData(AppearanceComponent component)
+        {
+            base.OnChangeData(component);
+
+            if (!component.Owner.TryGetComponent<ISpriteComponent>(out var sprite)) return;
+            if (!component.TryGetData(FilterVisuals.VisualState, out FilterVisualState filterVisualState)) return;
+
+            var filterEnabledLayer = sprite.LayerMapGet(Layer.FilterEnabled);
+            sprite.LayerSetVisible(filterEnabledLayer, filterVisualState.Enabled);
+        }
+
+        public enum Layer : byte
+        {
+            FilterEnabled,
+        }
+    }
+}