Re-organize all projects (#4166)

Content.Client/Window/WindowSystem.cs

@@ -0,0 +1,71 @@
+using System.Collections.Generic;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+
+namespace Content.Client.Window
+{
+    [UsedImplicitly]
+    public sealed class WindowSystem : EntitySystem
+    {
+        private readonly Queue<IEntity> _dirtyEntities = new();
+
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            SubscribeLocalEvent<WindowSmoothDirtyEvent>(HandleDirtyEvent);
+            SubscribeLocalEvent<WindowComponent, SnapGridPositionChangedEvent>(HandleSnapGridMove);
+        }
+
+        public override void Shutdown()
+        {
+            base.Shutdown();
+
+            UnsubscribeLocalEvent<WindowSmoothDirtyEvent>();
+            UnsubscribeLocalEvent<WindowComponent, SnapGridPositionChangedEvent>(HandleSnapGridMove);
+        }
+
+        private void HandleDirtyEvent(WindowSmoothDirtyEvent ev)
+        {
+            if (ev.Sender.HasComponent<WindowComponent>())
+            {
+                _dirtyEntities.Enqueue(ev.Sender);
+            }
+        }
+
+        private static void HandleSnapGridMove(EntityUid uid, WindowComponent component, SnapGridPositionChangedEvent args)
+        {
+            component.SnapGridOnPositionChanged();
+        }
+
+        public override void FrameUpdate(float frameTime)
+        {
+            base.FrameUpdate(frameTime);
+
+            // Performance: This could be spread over multiple updates, or made parallel.
+            while (_dirtyEntities.Count > 0)
+            {
+                var entity = _dirtyEntities.Dequeue();
+                if (entity.Deleted)
+                {
+                    continue;
+                }
+
+                entity.GetComponent<WindowComponent>().UpdateSprite();
+            }
+        }
+    }
+
+    /// <summary>
+    ///     Event raised by a <see cref="WindowComponent"/> when it needs to be recalculated.
+    /// </summary>
+    public sealed class WindowSmoothDirtyEvent : EntityEventArgs
+    {
+        public IEntity Sender { get; }
+
+        public WindowSmoothDirtyEvent(IEntity sender)
+        {
+            Sender = sender;
+        }
+    }
+}