Add tile entity occlusion (#14626)

Content.Client/Movement/Systems/FloorOcclusionSystem.cs

@@ -0,0 +1,55 @@
+using Content.Shared.Movement.Components;
+using Content.Shared.Movement.Systems;
+using Robust.Client.GameObjects;
+using Robust.Client.Graphics;
+using Robust.Shared.Prototypes;
+
+namespace Content.Client.Movement.Systems;
+
+public sealed class FloorOcclusionSystem : SharedFloorOcclusionSystem
+{
+    [Dependency] private readonly IPrototypeManager _proto = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<FloorOcclusionComponent, ComponentStartup>(OnOcclusionStartup);
+        SubscribeLocalEvent<FloorOcclusionComponent, AfterAutoHandleStateEvent>(OnOcclusionAuto);
+    }
+
+    private void OnOcclusionAuto(EntityUid uid, FloorOcclusionComponent component, ref AfterAutoHandleStateEvent args)
+    {
+        SetEnabled(uid, component, component.Enabled);
+    }
+
+    private void OnOcclusionStartup(EntityUid uid, FloorOcclusionComponent component, ComponentStartup args)
+    {
+        if (component.Enabled && TryComp<SpriteComponent>(uid, out var sprite))
+            SetShader(sprite, true);
+    }
+
+    protected override void SetEnabled(EntityUid uid, FloorOcclusionComponent component, bool enabled)
+    {
+        if (component.Enabled == enabled)
+            return;
+
+        base.SetEnabled(uid, component, enabled);
+
+        if (!TryComp<SpriteComponent>(uid, out var sprite))
+            return;
+
+        SetShader(sprite, enabled);
+    }
+
+    private void SetShader(SpriteComponent sprite, bool enabled)
+    {
+        if (enabled)
+        {
+            sprite.PostShader = _proto.Index<ShaderPrototype>("HorizontalCut").Instance();
+        }
+        else
+        {
+            sprite.PostShader = null;
+        }
+    }
+}