ITileDefinition now has a Path string that ClydeTileDefinitionManager uses (#1860)

* Remove NetMessage boilerplate in favor of virtual properties

* forgot some stuff

.github/workflows/test-content.yml

@@ -38,4 +38,4 @@ jobs:
     - name: Content.Tests
       run: dotnet test --no-build Content.Tests/Content.Tests.csproj -v n
     - name: Content.IntegrationTests
-      run: dotnet test --no-build Content.IntegrationTests/Content.IntegrationTests.csproj -v n
+      run: COMPlus_gcServer=1 dotnet test --no-build Content.IntegrationTests/Content.IntegrationTests.csproj -v n

OpenToolkit.GraphicsLibraryFramework/GLFWNative.cs

@@ -23,12 +23,12 @@ namespace OpenToolkit.GraphicsLibraryFramework
                     return IntPtr.Zero;
                 }
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                if (OperatingSystem.IsLinux())
                 {
                     return NativeLibrary.Load("libglfw.so.3", assembly, path);
                 }
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                if (OperatingSystem.IsMacOS())
                 {
                     return NativeLibrary.Load("libglfw.3.dylib", assembly, path);
                 }

Resources/EngineCredits/Libraries.yml

@@ -23,6 +23,48 @@
     OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+- name: Box2D
+  license:
+    MIT License
+
+    Copyright (c) 2019 Erin Catto
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is 
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+- name: Bullet Physics SDK
+  license:
+    The files in this repository are licensed under the zlib license, except for the files under 'Extras' and examples/ThirdPartyLibs.
+
+    Bullet Continuous Collision Detection and Physics Library
+    http://bulletphysics.org
+
+    This software is provided 'as-is', without any express or implied warranty.
+    In no event will the authors be held liable for any damages arising from the use of this software.
+    Permission is granted to anyone to use this software for any purpose,
+    including commercial applications, and to alter it and redistribute it freely,
+    subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. 
+    If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+    2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+    3. This notice may not be removed or altered from any source distribution. 
+
 - name: Castle Core
   license: |
     Copyright 2004-2016 Castle Project - http://www.castleproject.org/
@@ -317,6 +359,43 @@
     See the License for the specific language governing permissions and
     limitations under the License.
 
+- name: Farseer Physics Engine
+  license:
+    Microsoft Permissive License (Ms-PL)
+
+    This license governs use of the accompanying software.
+    If you use the software, you accept this license.
+    If you do not accept the license, do not use the software.
+
+    1. Definitions
+    The terms "reproduce," "reproduction," "derivative works," and "distribution" have the same meaning here as under U.S. copyright law.
+    A "contribution" is the original software, or any additions or changes to the software.
+    A "contributor" is any person that distributes its contribution under this license.
+    "Licensed patents" are a contributor's patent claims that read directly on its contribution.
+
+    2. Grant of Rights
+    (A) Copyright Grant- Subject to the terms of this license, including the license conditions and limitations in section 3, 
+    each contributor grants you a non-exclusive, worldwide, royalty-free copyright license to reproduce its contribution, 
+    prepare derivative works of its contribution, and distribute its contribution or any derivative works that you create.
+    (B) Patent Grant- Subject to the terms of this license, including the license conditions and limitations in section 3, 
+    each contributor grants you a non-exclusive, worldwide, royalty-free license under its licensed patents to 
+    make, have made, use, sell, offer for sale, import, and/or otherwise dispose of its contribution in the software or 
+    derivative works of the contribution in the software.
+
+    3. Conditions and Limitations
+    (A) No Trademark License- This license does not grant you rights to use any contributors' name, logo, or trademarks.
+    (B) If you bring a patent claim against any contributor over patents that you claim are infringed by the software, 
+    your patent license from such contributor to the software ends automatically.
+    (C) If you distribute any portion of the software, you must retain all copyright, patent, trademark, 
+    and attribution notices that are present in the software.
+    (D) If you distribute any portion of the software in source code form, you may do so only under this license by 
+    including a complete copy of this license with your distribution. If you distribute any portion of the software in 
+    compiled or object code form, you may only do so under a license that complies with this license.
+    (E) The software is licensed "as-is." You bear the risk of using it. The contributors give no express warranties, 
+    guarantees or conditions. You may have additional consumer rights under your local laws which this license cannot change. 
+    To the extent permitted under your local laws, the contributors exclude the implied warranties of 
+    merchantability, fitness for a particular purpose and non-infringement.
+
 - name: Mono.Cecil
   license: |
     Copyright (c) 2008 - 2015 Jb Evain

Resources/Locale/en-US/console.ftl

@@ -1 +0,0 @@
-console-line-edit-placeholder = Command Here

Resources/Locale/en-US/custom-controls.ftl

@@ -0,0 +1,11 @@
+## EntitySpawnWindow
+
+entity-spawn-window-title = Entity Spawn Panel
+entity-spawn-window-search-bar-placeholder = search
+entity-spawn-window-clear-button = Clear
+entity-spawn-window-erase-button-text = Erase Mode
+entity-spawn-window-override-menu-tooltip = Override placement
+
+## Console
+
+console-line-edit-placeholder = Command Here

Resources/Locale/en-US/tab-container.ftl

@@ -0,0 +1 @@
+tab-container-not-tab-title-provided = No title

Resources/Locale/en-US/view-variables.ftl

@@ -0,0 +1,11 @@
+## ViewVariablesInstanceEntity
+
+view-variable-instance-entity-server-components-add-component-button-placeholder = Add Component
+view-variable-instance-entity-client-variables-tab-title = Client Variables
+view-variable-instance-entity-client-components-tab-title = Client Components
+view-variable-instance-entity-server-variables-tab-title = Server Variables
+view-variable-instance-entity-server-components-tab-title = Server Components
+view-variable-instance-entity-client-components-search-bar-placeholder = Search
+view-variable-instance-entity-server-components-search-bar-placeholder = Search
+view-variable-instance-entity-add-window-server-components = Add Component [S]
+view-variable-instance-entity-add-window-client-components = Add Component [C]

Robust.Client.NameGenerator/XamlUiPartialClassGenerator.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Text;
 using Microsoft.CodeAnalysis;
@@ -147,9 +148,10 @@ namespace {nameSpace}
             foreach (var typeSymbol in symbols)
             {
                 var xamlFileName = $"{typeSymbol.Name}.xaml";
-                var relevantXamlFile = context.AdditionalFiles.FirstOrDefault(t => t.Path.EndsWith(xamlFileName));
+                var xamlFileNameSep = $"{Path.DirectorySeparatorChar}{xamlFileName}";
+                var relevantXamlFiles = context.AdditionalFiles.Where(t => t.Path.EndsWith(xamlFileNameSep)).ToArray();
 
-                if (relevantXamlFile == null)
+                if (relevantXamlFiles.Length == 0)
                 {
                     context.ReportDiagnostic(
                         Diagnostic.Create(
@@ -165,13 +167,28 @@ namespace {nameSpace}
                     continue;
                 }
 
-                var txt = relevantXamlFile.GetText()?.ToString();
-                if (txt == null)
+                if (relevantXamlFiles.Length > 1)
                 {
                     context.ReportDiagnostic(
                         Diagnostic.Create(
                             new DiagnosticDescriptor(
                                 "RXN0002",
+                                $"Found multiple candidate XAML files for {typeSymbol}",
+                                $"Multiple files exist with name {xamlFileName}",
+                                "Usage",
+                                DiagnosticSeverity.Error,
+                                true),
+                            typeSymbol.Locations[0]));
+                    continue;
+                }
+
+                var txt = relevantXamlFiles[0].GetText()?.ToString();
+                if (txt == null)
+                {
+                    context.ReportDiagnostic(
+                        Diagnostic.Create(
+                            new DiagnosticDescriptor(
+                                "RXN0004",
                                 $"Unexpected empty Xaml-File was found at {xamlFileName}",
                                 "Expected Content due to a Class with the same name being annotated with [GenerateTypedNameReferences].",
                                 "Usage",
@@ -192,7 +209,7 @@ namespace {nameSpace}
                     context.ReportDiagnostic(
                         Diagnostic.Create(
                             new DiagnosticDescriptor(
-                                "AXN0003",
+                                "RXN0003",
                                 "Unhandled exception occured while generating typed Name references.",
                                 $"Unhandled exception occured while generating typed Name references: {e}",
                                 "Usage",

Robust.Client/Audio/Midi/MidiManager.cs

@@ -225,7 +225,7 @@ namespace Robust.Client.Audio.Midi
                 // Since the last loaded soundfont takes priority, we load the fallback soundfont before the soundfont.
                 renderer.LoadSoundfont(FallbackSoundfont);
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                if (OperatingSystem.IsLinux())
                 {
                     foreach (var filepath in LinuxSoundfonts)
                     {
@@ -243,12 +243,12 @@ namespace Robust.Client.Audio.Midi
                         break;
                     }
                 }
-                else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                else if (OperatingSystem.IsMacOS())
                 {
                     if (File.Exists(OsxSoundfont) && SoundFont.IsSoundFont(OsxSoundfont))
                         renderer.LoadSoundfont(OsxSoundfont, true);
                 }
-                else if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                else if (OperatingSystem.IsWindows())
                 {
                     if (File.Exists(WindowsSoundfont) && SoundFont.IsSoundFont(WindowsSoundfont))
                         renderer.LoadSoundfont(WindowsSoundfont, true);

Robust.Client/Audio/Midi/MidiRenderer.cs

@@ -628,10 +628,15 @@ namespace Robust.Client.Audio.Midi
         void IMidiRenderer.InternalDispose()
         {
             Source?.Dispose();
+            _driver?.Dispose();
+
+            // Do NOT dispose of the sequencer after the synth or it'll cause a segfault for some fucking reason.
+            _sequencer?.UnregisterClient(_debugRegister);
+            _sequencer?.UnregisterClient(_synthRegister);
+            _sequencer?.Dispose();
+            
             _synth?.Dispose();
             _player?.Dispose();
-            _driver?.Dispose();
-            _sequencer?.Dispose();
         }
     }
 }

Robust.Client/ClientIoC.cs

@@ -46,13 +46,15 @@ namespace Robust.Client
             IoCManager.Register<IClientMapManager, ClientMapManager>();
             IoCManager.Register<IEntityManager, ClientEntityManager>();
             IoCManager.Register<IEntityLookup, EntityLookup>();
+            IoCManager.Register<IReflectionManager, ClientReflectionManager>();
+            IoCManager.Register<IConsoleHost, ClientConsoleHost>();
+            IoCManager.Register<IClientConsoleHost, ClientConsoleHost>();
             IoCManager.Register<IComponentFactory, ClientComponentFactory>();
             IoCManager.Register<ITileDefinitionManager, ClydeTileDefinitionManager>();
             IoCManager.Register<IClydeTileDefinitionManager, ClydeTileDefinitionManager>();
             IoCManager.Register<GameController, GameController>();
             IoCManager.Register<IGameController, GameController>();
             IoCManager.Register<IGameControllerInternal, GameController>();
-            IoCManager.Register<IReflectionManager, ClientReflectionManager>();
             IoCManager.Register<IResourceManager, ResourceCache>();
             IoCManager.Register<IResourceManagerInternal, ResourceCache>();
             IoCManager.Register<IResourceCache, ResourceCache>();
@@ -72,8 +74,6 @@ namespace Robust.Client
             IoCManager.Register<IDebugDrawingManager, DebugDrawingManager>();
             IoCManager.Register<ILightManager, LightManager>();
             IoCManager.Register<IDiscordRichPresence, DiscordRichPresence>();
-            IoCManager.Register<IClientConsoleHost, ClientConsoleHost>();
-            IoCManager.Register<IConsoleHost, ClientConsoleHost>();
             IoCManager.Register<IMidiManager, MidiManager>();
             IoCManager.Register<IAuthManager, AuthManager>();
             switch (mode)

Robust.Client/Console/ClientConsoleHost.cs

@@ -49,7 +49,11 @@ namespace Robust.Client.Console
             NetManager.RegisterNetMessage<MsgConCmdAck>(HandleConCmdAck);
             NetManager.RegisterNetMessage<MsgConCmd>(ProcessCommand);
 
-            Reset();
+            _requestedCommands = false;
+            NetManager.Connected += OnNetworkConnected;
+
+            LoadConsoleCommands();
+            SendServerCommandRequest();
             LogManager.RootSawmill.AddHandler(new DebugConsoleLogHandler(this));
         }
 
@@ -61,17 +65,6 @@ namespace Robust.Client.Console
             ExecuteCommand(null, text);
         }
 
-        /// <inheritdoc />
-        public void Reset()
-        {
-            AvailableCommands.Clear();
-            _requestedCommands = false;
-            NetManager.Connected += OnNetworkConnected;
-
-            LoadConsoleCommands();
-            SendServerCommandRequest();
-        }
-
         /// <inheritdoc />
         public event EventHandler<AddStringArgs>? AddString;
 
@@ -97,7 +90,7 @@ namespace Robust.Client.Console
                 return;
 
             // echo the command locally
-            WriteError(null, "> " + command);
+            WriteLine(null, "> " + command);
 
             //Commands are processed locally and then sent to the server to be processed there again.
             var args = new List<string>();
@@ -142,6 +135,9 @@ namespace Robust.Client.Console
         private void OutputText(string text, bool local, bool error)
         {
             AddString?.Invoke(this, new AddStringArgs(text, local, error));
+
+            var level = error ? LogLevel.Warning : LogLevel.Info;
+            Logger.LogS(level, "CON", text);
         }
 
         private void OnNetworkConnected(object? sender, NetChannelArgs netChannelArgs)

Robust.Client/Console/Commands/Debug.cs

@@ -77,7 +77,7 @@ namespace Robust.Client.Console.Commands
                     message.Append($"net ID: {registration.NetID}");
                 }
 
-                message.Append($", NSE: {registration.NetworkSynchronizeExistence}, references:");
+                message.Append($", References:");
 
                 shell.WriteLine(message.ToString());
 

Robust.Client/Console/Commands/LightBBCommand.cs

@@ -0,0 +1,19 @@
+#if DEBUG
+using Robust.Client.GameObjects;
+using Robust.Shared.Console;
+using Robust.Shared.GameObjects;
+
+namespace Robust.Client.Console.Commands
+{
+    internal sealed class LightDebugCommand : IConsoleCommand
+    {
+        public string Command => "lightbb";
+        public string Description => "Toggles whether to show light bounding boxes";
+        public string Help => $"{Command}";
+        public void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            EntitySystem.Get<DebugLightTreeSystem>().Enabled ^= true;
+        }
+    }
+}
+#endif

Robust.Client/Console/Commands/Scripting.cs

@@ -1,6 +1,5 @@
 using Robust.Shared.Console;
 using Robust.Shared.IoC;
-using Robust.Shared.Localization;
 
 namespace Robust.Client.Console.Commands
 {
@@ -41,7 +40,7 @@ namespace Robust.Client.Console.Commands
             var mgr = IoCManager.Resolve<IScriptClient>();
             if (!mgr.CanScript)
             {
-                shell.WriteError(Loc.GetString("You do not have server side scripting permission."));
+                shell.WriteError("You do not have server side scripting permission.");
                 return;
             }
 

Robust.Client/Console/IClientConsoleHost.cs

@@ -11,11 +11,6 @@ namespace Robust.Client.Console
         /// </summary>
         void Initialize();
 
-        /// <summary>
-        /// Resets the console to a post-initialized state.
-        /// </summary>
-        void Reset();
-
         event EventHandler<AddStringArgs> AddString;
         event EventHandler<AddFormattedMessageArgs> AddFormatted;
 

Robust.Client/Console/ScriptConsoleClient.cs

@@ -1,5 +1,4 @@
 #if CLIENT_SCRIPTING
-using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
@@ -14,7 +13,6 @@ using Microsoft.CodeAnalysis.Text;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.ViewVariables;
 using Robust.Shared.IoC;
-using Robust.Shared.Localization;
 using Robust.Shared.Maths;
 using Robust.Shared.Reflection;
 using Robust.Shared.Scripting;
@@ -43,14 +41,14 @@ namespace Robust.Client.Console
 
         public ScriptConsoleClient()
         {
-            Title = Loc.GetString("Robust C# Interactive (CLIENT)");
+            Title = "Robust C# Interactive (CLIENT)";
             ScriptInstanceShared.InitDummy();
 
             _globals = new ScriptGlobalsImpl(this);
 
             IoCManager.InjectDependencies(this);
 
-            OutputPanel.AddText(Loc.GetString(@"Robust C# interactive console (CLIENT)."));
+            OutputPanel.AddText("Robust C# interactive console (CLIENT).");
             OutputPanel.AddText(">");
         }
 

Robust.Client/Console/WatchWindow.cs

@@ -8,8 +8,6 @@ using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Shared.IoC;
-using Robust.Shared.Localization;
-using Robust.Shared.Maths;
 using Robust.Shared.Reflection;
 using Robust.Shared.Scripting;
 using Robust.Shared.Timing;
@@ -31,7 +29,7 @@ namespace Robust.Client.Console
 
             ScriptInstanceShared.InitDummy();
 
-            Title = Loc.GetString("Watch Window");
+            Title = "Watch Window";
 
             var mainVBox = new VBoxContainer
             {
@@ -49,11 +47,11 @@ namespace Robust.Client.Console
                             (_addWatchEdit = new HistoryLineEdit
                             {
                                 HorizontalExpand = true,
-                                PlaceHolder = Loc.GetString("Add watch (C# interactive)")
+                                PlaceHolder = "Add watch (C# interactive)"
                             }),
                             (_addWatchButton = new Button
                             {
-                                Text = Loc.GetString("Add")
+                                Text = "Add"
                             })
                         }
                     }
@@ -118,7 +116,7 @@ namespace Robust.Client.Console
                         }),
                         (delButton = new Button
                         {
-                            Text = Loc.GetString("Remove")
+                            Text = "Remove"
                         }),
                     }
                 });
@@ -178,7 +176,7 @@ namespace Robust.Client.Console
                             ClipText = true,
                             HorizontalExpand = true
                         },
-                        (delButton = new Button {Text = Loc.GetString("Remove")})
+                        (delButton = new Button {Text = "Remove"})
                     }
                 });
 

Robust.Client/ContentStart.cs

@@ -7,13 +7,13 @@ namespace Robust.Client
 #if FULL_RELEASE
             throw new System.InvalidOperationException("ContentStart.Start is not available on a full release.");
 #else
-            GameController.Start(args, true);
+            GameController.Start(args, new GameControllerOptions(), true);
 #endif
         }
 
         public static void StartLibrary(string[] args, GameControllerOptions options)
         {
-            GameController.Start(args, true, null, options);
+            GameController.Start(args, options, true, null);
         }
     }
 }

Robust.Client/Debugging/DebugDrawing.cs

@@ -130,17 +130,17 @@ namespace Robust.Client.Debugging
                 {
                     if (body != _hoverBodies[0])
                     {
-                        DrawString(screenHandle, _font, drawPos + new Vector2(0, row * lineHeight), "------");
+                        screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), "------");
                         row++;
                     }
 
-                    DrawString(screenHandle, _font, drawPos + new Vector2(0, row * lineHeight), $"Ent: {body.Owner}");
+                    screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), $"Ent: {body.Owner}");
                     row++;
-                    DrawString(screenHandle, _font, drawPos + new Vector2(0, row * lineHeight), $"Layer: {Convert.ToString(body.CollisionLayer, 2)}");
+                    screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), $"Layer: {Convert.ToString(body.CollisionLayer, 2)}");
                     row++;
-                    DrawString(screenHandle, _font, drawPos + new Vector2(0, row * lineHeight), $"Mask: {Convert.ToString(body.CollisionMask, 2)}");
+                    screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), $"Mask: {Convert.ToString(body.CollisionMask, 2)}");
                     row++;
-                    DrawString(screenHandle, _font, drawPos + new Vector2(0, row * lineHeight), $"Enabled: {body.CanCollide}, Hard: {body.Hard}, Anchored: {(body).BodyType == BodyType.Static}");
+                    screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), $"Enabled: {body.CanCollide}, Hard: {body.Hard}, Anchored: {(body).BodyType == BodyType.Static}");
                     row++;
                 }
 
@@ -177,8 +177,9 @@ namespace Robust.Client.Debugging
                     foreach (var fixture in physBody.Fixtures)
                     {
                         var shape = fixture.Shape;
-                        var sleepPercent = physBody.Awake ? physBody.SleepTime / sleepThreshold : 1.0f;
+                        var sleepPercent = physBody.Awake ? 0.0f : 1.0f;
                         shape.DebugDraw(drawing, transform.WorldMatrix, in viewport, sleepPercent);
+                        drawing.SetTransform(in Matrix3.Identity);
                     }
 
                     foreach (var joint in physBody.Joints)
@@ -187,6 +188,7 @@ namespace Robust.Client.Debugging
                         drawnJoints.Add(joint);
 
                         joint.DebugDraw(drawing, in viewport);
+                        drawing.SetTransform(in Matrix3.Identity);
                     }
 
                     if (worldBox.Contains(mouseWorldPos))
@@ -199,17 +201,6 @@ namespace Robust.Client.Debugging
                 }
             }
 
-            private static void DrawString(DrawingHandleScreen handle, Font font, Vector2 pos, string str)
-            {
-                var baseLine = new Vector2(pos.X, font.GetAscent(1) + pos.Y);
-
-                foreach (var rune in str.EnumerateRunes())
-                {
-                    var advance = font.DrawChar(handle, rune, baseLine, 1, Color.White);
-                    baseLine += new Vector2(advance, 0);
-                }
-            }
-
             private class PhysDrawingAdapter : DebugDrawingHandle
             {
                 private readonly DrawingHandleWorld _handle;

Robust.Client/GameController/GameController.Loader.cs

@@ -11,7 +11,7 @@ namespace Robust.Client
         {
             public void Main(IMainArgs args)
             {
-                Start(args.Args, contentStart: false, args);
+                Start(args.Args, new GameControllerOptions(), contentStart: false, args);
             }
         }
     }

Robust.Client/GameController/GameController.Standalone.cs

@@ -22,10 +22,10 @@ namespace Robust.Client
 
         public static void Main(string[] args)
         {
-            Start(args);
+            Start(args, new GameControllerOptions());
         }
 
-        public static void Start(string[] args, bool contentStart = false, IMainArgs? loaderArgs=null, GameControllerOptions? options = null)
+        public static void Start(string[] args, GameControllerOptions options, bool contentStart = false, IMainArgs? loaderArgs=null)
         {
             if (_hasStarted)
             {
@@ -40,7 +40,7 @@ namespace Robust.Client
             }
         }
 
-        private static void ParsedMain(CommandLineArgs args, bool contentStart, IMainArgs? loaderArgs, GameControllerOptions? options)
+        private static void ParsedMain(CommandLineArgs args, bool contentStart, IMainArgs? loaderArgs, GameControllerOptions options)
         {
             IoCManager.InitThread();
 
@@ -51,15 +51,13 @@ namespace Robust.Client
             var gc = IoCManager.Resolve<GameController>();
             gc.SetCommandLineArgs(args);
             gc._loaderArgs = loaderArgs;
-            if(options != null)
-                gc.Options = options;
 
             // When the game is ran with the startup executable being content,
             // we have to disable the separate load context.
             // Otherwise the content assemblies will be loaded twice which causes *many* fun bugs.
             gc.ContentStart = contentStart;
 
-            gc.Run(mode);
+            gc.Run(mode, options);
         }
 
         public void OverrideMainLoop(IGameLoop gameLoop)
@@ -67,9 +65,9 @@ namespace Robust.Client
             _mainLoop = gameLoop;
         }
 
-        public void Run(DisplayMode mode, Func<ILogHandler>? logHandlerFactory = null)
+        public void Run(DisplayMode mode, GameControllerOptions options, Func<ILogHandler>? logHandlerFactory = null)
         {
-            if (!StartupSystemSplash(logHandlerFactory))
+            if (!StartupSystemSplash(options, logHandlerFactory))
             {
                 Logger.Fatal("Failed to start game controller!");
                 return;

Robust.Client/GameController/GameController.cs

@@ -75,14 +75,12 @@ namespace Robust.Client
         public GameControllerOptions Options { get; private set; } = new();
         public InitialLaunchState LaunchState { get; private set; } = default!;
 
-        public bool LoadConfigAndUserData { get; set; } = true;
-
         public void SetCommandLineArgs(CommandLineArgs args)
         {
             _commandLineArgs = args;
         }
 
-        private bool StartupContinue(DisplayMode displayMode)
+        internal bool StartupContinue(DisplayMode displayMode)
         {
             _clyde.InitializePostWindowing();
             _clyde.SetWindowTitle(Options.DefaultWindowTitle);
@@ -95,7 +93,7 @@ namespace Robust.Client
             _modLoader.SetUseLoadContext(!ContentStart);
             _modLoader.SetEnableSandboxing(Options.Sandboxing);
 
-            if (!_modLoader.TryLoadModulesFrom(new ResourcePath("/Assemblies/"), Options.ContentModulePrefix))
+            if (!_modLoader.TryLoadModulesFrom(Options.AssemblyDirectory, Options.ContentModulePrefix))
             {
                 Logger.Fatal("Errors while loading content assemblies.");
                 return false;
@@ -196,8 +194,9 @@ namespace Robust.Client
             return true;
         }
 
-        private bool StartupSystemSplash(Func<ILogHandler>? logHandlerFactory)
+        internal bool StartupSystemSplash(GameControllerOptions options, Func<ILogHandler>? logHandlerFactory)
         {
+            Options = options;
             ReadInitialLaunchState();
 
             SetupLogging(_logManager, logHandlerFactory ?? (() => new ConsoleLogHandler()));
@@ -234,7 +233,7 @@ namespace Robust.Client
             _configurationManager.LoadCVarsFromAssembly(typeof(GameController).Assembly); // Client
             _configurationManager.LoadCVarsFromAssembly(typeof(IConfigurationManager).Assembly); // Shared
 
-            if (LoadConfigAndUserData)
+            if (Options.LoadConfigAndUserData)
             {
                 var configFile = Path.Combine(userDataDir, Options.ConfigFileName);
                 if (File.Exists(configFile))
@@ -258,13 +257,13 @@ namespace Robust.Client
 
             ProfileOptSetup.Setup(_configurationManager);
 
-            _resourceCache.Initialize(LoadConfigAndUserData ? userDataDir : null);
+            _resourceCache.Initialize(Options.LoadConfigAndUserData ? userDataDir : null);
 
             var mountOptions = _commandLineArgs != null
                 ? MountOptions.Merge(_commandLineArgs.MountOptions, Options.MountOptions) : Options.MountOptions;
 
-            ProgramShared.DoMounts(_resourceCache, mountOptions, Options.ContentBuildDirectory,
-                _loaderArgs != null && !Options.ResourceMountDisabled, ContentStart);
+            ProgramShared.DoMounts(_resourceCache, mountOptions, Options.ContentBuildDirectory, Options.AssemblyDirectory,
+                Options.LoadContentResources, _loaderArgs != null && !Options.ResourceMountDisabled, ContentStart);
 
             if (_loaderArgs != null)
             {
@@ -471,7 +470,7 @@ namespace Robust.Client
             Clyde,
         }
 
-        private void Cleanup()
+        internal void Cleanup()
         {
             _networkManager.Shutdown("Client shutting down");
             _midiManager.Shutdown();

Robust.Client/GameControllerOptions.cs

@@ -42,6 +42,11 @@ namespace Robust.Client
         /// </summary>
         public string ContentBuildDirectory { get; init; } = "Content.Client";
 
+        /// <summary>
+        ///     Directory to load all assemblies from.
+        /// </summary>
+        public ResourcePath AssemblyDirectory { get; init; } = new(@"/Assemblies/");
+
         /// <summary>
         ///     Directory to load all prototypes from.
         /// </summary>
@@ -52,6 +57,16 @@ namespace Robust.Client
         /// </summary>
         public bool ResourceMountDisabled { get; init; } = false;
 
+        /// <summary>
+        ///     Whether to mount content resources when not on FULL_RELEASE.
+        /// </summary>
+        public bool LoadContentResources { get; init; } = true;
+
+        /// <summary>
+        ///     Whether to load config and user data.
+        /// </summary>
+        public bool LoadConfigAndUserData { get; init; } = true;
+
         /// <summary>
         ///     Whether to disable command line args server auto-connecting.
         /// </summary>

Robust.Client/GameObjects/ClientComponentFactory.cs

@@ -1,12 +1,15 @@
+using Robust.Shared.Console;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
-using Robust.Shared.Physics;
+using Robust.Shared.IoC;
+using Robust.Shared.Reflection;
 
 namespace Robust.Client.GameObjects
 {
-    public class ClientComponentFactory : ComponentFactory
+    internal class ClientComponentFactory : ComponentFactory
     {
-        public ClientComponentFactory()
+        public ClientComponentFactory(IDynamicTypeFactoryInternal typeFactory, IReflectionManager reflectionManager, IConsoleHost conHost)
+            : base(typeFactory, reflectionManager, conHost)
         {
             // Required for the engine to work
             RegisterIgnore("KeyBindingInput");

Robust.Client/GameObjects/ClientEntityManager.cs

@@ -109,13 +109,15 @@ namespace Robust.Client.GameObjects
         [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
         public void SendComponentNetworkMessage(INetChannel? channel, IEntity entity, IComponent component, ComponentMessage message)
         {
-            if (!component.NetID.HasValue)
+            var netId = ComponentFactory.GetRegistration(component.GetType()).NetID;
+
+            if (!netId.HasValue)
                 throw new ArgumentException($"Component {component.Name} does not have a NetID.", nameof(component));
 
             var msg = _networkManager.CreateNetMessage<MsgEntity>();
             msg.Type = EntityMessageType.ComponentMessage;
             msg.EntityUid = entity.Uid;
-            msg.NetId = component.NetID.Value;
+            msg.NetId = netId.Value;
             msg.ComponentMessage = message;
             msg.SourceTick = _gameTiming.CurTick;
 

Robust.Client/GameObjects/Components/Appearance/AppearanceComponent.cs

@@ -104,7 +104,7 @@ namespace Robust.Client.GameObjects
             _appearanceDirty = false;
         }
 
-        public override void Initialize()
+        protected override void Initialize()
         {
             base.Initialize();
 

Robust.Client/GameObjects/Components/Eye/EyeComponent.cs

@@ -116,7 +116,7 @@ namespace Robust.Client.GameObjects
         public MapCoordinates? Position => _eye?.Position;
 
         /// <inheritdoc />
-        public override void Initialize()
+        protected override void Initialize()
         {
             base.Initialize();
 
@@ -156,7 +156,7 @@ namespace Robust.Client.GameObjects
             VisibilityMask = state.VisibilityMask;
         }
 
-        public override void OnRemove()
+        protected override void OnRemove()
         {
             base.OnRemove();
 

Robust.Client/GameObjects/Components/Light/ClientOccluderComponent.cs

@@ -34,11 +34,11 @@ namespace Robust.Client.GameObjects
 
             if (Owner.Transform.Anchored)
             {
-                SnapGridOnPositionChanged();
+                AnchorStateChanged();
             }
         }
 
-        public void SnapGridOnPositionChanged()
+        public void AnchorStateChanged()
         {
             SendDirty();
 

Robust.Client/GameObjects/Components/Light/PointLightComponent.cs

@@ -1,10 +1,13 @@
-using System;
+using System;
 using System.Collections.Generic;
 using Robust.Client.Graphics;
 using Robust.Client.ResourceManagement;
 using Robust.Shared.Animations;
+using Robust.Shared.Configuration;
 using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
+using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Serialization;
@@ -15,12 +18,12 @@ namespace Robust.Client.GameObjects
 {
     [RegisterComponent]
     [ComponentReference(typeof(IPointLightComponent))]
+    [NetworkedComponent()]
     public class PointLightComponent : Component, IPointLightComponent, ISerializationHooks
     {
         [Dependency] private readonly IResourceCache _resourceCache = default!;
 
         public override string Name => "PointLight";
-        public override uint? NetID => NetIDs.POINT_LIGHT;
 
         internal bool TreeUpdateQueued { get; set; }
 
@@ -135,30 +138,13 @@ namespace Robust.Client.GameObjects
         public bool VisibleNested
         {
             get => _visibleNested;
-            set
-            {
-                if (_visibleNested == value) return;
-                _visibleNested = value;
-                if (value)
-                {
-                    if (Owner.Transform.Parent == null) return;
-
-                    _lightOnParent = true;
-                }
-                else
-                {
-                    if (!_lightOnParent) return;
-
-                    _lightOnParent = false;
-                }
-            }
+            set => _visibleNested = value;
         }
 
         [DataField("radius")]
         private float _radius = 5f;
         [DataField("nestedvisible")]
         private bool _visibleNested = true;
-        private bool _lightOnParent;
         [DataField("color")]
         private Color _color = Color.White;
         [DataField("offset")]
@@ -185,6 +171,8 @@ namespace Robust.Client.GameObjects
             get => _radius;
             set
             {
+                if (MathHelper.CloseTo(value, _radius)) return;
+
                 _radius = MathF.Max(value, 0.01f); // setting radius to 0 causes exceptions, so just use a value close enough to zero that it's unnoticeable.
                 Owner.EntityManager.EventBus.RaiseEvent(EventSource.Local, new PointLightRadiusChangedEvent(this));
             }
@@ -198,17 +186,8 @@ namespace Robust.Client.GameObjects
                 Mask = null;
         }
 
-        /// <summary>
-        /// What MapId we are intersecting for RenderingTreeSystem.
-        /// </summary>
         [ViewVariables]
-        internal MapId IntersectingMapId { get; set; } = MapId.Nullspace;
-
-        /// <summary>
-        /// What grids we're on for RenderingTreeSystem.
-        /// </summary>
-        [ViewVariables]
-        internal List<GridId> IntersectingGrids = new();
+        internal RenderingTreeComponent? RenderTree { get; set; }
 
         void ISerializationHooks.AfterDeserialization()
         {
@@ -218,42 +197,13 @@ namespace Robust.Client.GameObjects
             }
         }
 
-        public override void Initialize()
+        protected override void Initialize()
         {
             base.Initialize();
             UpdateMask();
         }
 
-        /// <inheritdoc />
-        public override void HandleMessage(ComponentMessage message, IComponent? component)
-        {
-            base.HandleMessage(message, component);
-
-            if (message is ParentChangedMessage msg)
-            {
-                HandleTransformParentChanged(msg);
-            }
-        }
-
-        private void HandleTransformParentChanged(ParentChangedMessage obj)
-        {
-            // TODO: this does not work for things nested multiply layers deep.
-            if (!VisibleNested)
-            {
-                return;
-            }
-
-            if (obj.NewParent != null && obj.NewParent.IsValid())
-            {
-                _lightOnParent = true;
-            }
-            else
-            {
-                _lightOnParent = false;
-            }
-        }
-
-        public override void OnRemove()
+        protected override void OnRemove()
         {
             base.OnRemove();
 

Robust.Client/GameObjects/Components/Renderable/SpriteComponent.cs

@@ -46,6 +46,7 @@ namespace Robust.Client.GameObjects
             {
                 if (_visible == value) return;
                 _visible = value;
+
                 Owner.EntityManager.EventBus.RaiseLocalEvent(Owner.Uid, new SpriteUpdateEvent());
             }
         }
@@ -130,17 +131,8 @@ namespace Robust.Client.GameObjects
         [DataField("directional")]
         private bool _directional = true;
 
-        /// <summary>
-        /// What MapId we are intersecting for RenderingTreeSystem.
-        /// </summary>
         [ViewVariables]
-        internal MapId IntersectingMapId { get; set; } = MapId.Nullspace;
-
-        /// <summary>
-        /// What grids we're on for RenderingTreeSystem.
-        /// </summary>
-        [ViewVariables]
-        internal List<GridId> IntersectingGrids { get; } = new();
+        internal RenderingTreeComponent? RenderTree { get; set; } = null;
 
         [DataField("layerDatums")]
         private List<PrototypeLayerData> LayerDatums
@@ -271,7 +263,7 @@ namespace Robust.Client.GameObjects
                 }
 
                 _layerMapShared = true;
-                UpdateIsInert();
+                QueueUpdateIsInert();
             }
         }
 
@@ -336,6 +328,8 @@ namespace Robust.Client.GameObjects
         [ViewVariables(VVAccess.ReadWrite)]
         public bool TreeUpdateQueued { get; set; }
 
+        [ViewVariables(VVAccess.ReadWrite)] private bool _inertUpdateQueued;
+
         [ViewVariables(VVAccess.ReadWrite)]
         public ShaderInstance? PostShader { get; set; }
 
@@ -636,7 +630,7 @@ namespace Robust.Client.GameObjects
                 index = Layers.Count - 1;
             }
 
-            UpdateIsInert();
+            QueueUpdateIsInert();
             return index;
         }
 
@@ -663,7 +657,7 @@ namespace Robust.Client.GameObjects
                 }
             }
 
-            UpdateIsInert();
+            QueueUpdateIsInert();
         }
 
         public void RemoveLayer(object layerKey)
@@ -1514,8 +1508,20 @@ namespace Robust.Client.GameObjects
             };
         }
 
-        private void UpdateIsInert()
+        private void QueueUpdateIsInert()
         {
+            if (_inertUpdateQueued)
+                return;
+
+            _inertUpdateQueued = true;
+            // Yes that null check is valid because of that stupid fucking dummy IEntity.
+            // Who thought that was a good idea.
+            Owner?.EntityManager?.EventBus?.RaiseEvent(EventSource.Local, new SpriteUpdateInertEvent {Sprite = this});
+        }
+
+        internal void DoUpdateIsInert()
+        {
+            _inertUpdateQueued = false;
             IsInert = true;
 
             foreach (var layer in Layers)
@@ -1865,14 +1871,14 @@ namespace Robust.Client.GameObjects
             {
                 AutoAnimated = value;
 
-                _parent.UpdateIsInert();
+                _parent.QueueUpdateIsInert();
             }
 
             public void SetVisible(bool value)
             {
                 Visible = value;
 
-                _parent.UpdateIsInert();
+                _parent.QueueUpdateIsInert();
             }
 
             public void SetRsi(RSI? rsi)
@@ -1904,7 +1910,7 @@ namespace Robust.Client.GameObjects
                     }
                 }
 
-                _parent.UpdateIsInert();
+                _parent.QueueUpdateIsInert();
             }
 
             public void SetState(RSI.StateId stateId)
@@ -1936,7 +1942,7 @@ namespace Robust.Client.GameObjects
                 AnimationTime = 0;
                 AnimationTimeLeft = state.GetDelay(0);
 
-                _parent.UpdateIsInert();
+                _parent.QueueUpdateIsInert();
             }
 
             public void SetTexture(Texture? texture)
@@ -1944,7 +1950,7 @@ namespace Robust.Client.GameObjects
                 State = default;
                 Texture = texture;
 
-                _parent.UpdateIsInert();
+                _parent.QueueUpdateIsInert();
             }
 
             public void SetOffset(Vector2 offset)
@@ -2235,4 +2241,9 @@ namespace Robust.Client.GameObjects
     {
 
     }
+
+    internal struct SpriteUpdateInertEvent
+    {
+        public SpriteComponent Sprite;
+    }
 }

Robust.Client/GameObjects/Components/RenderingTreeComponent.cs

@@ -0,0 +1,43 @@
+using Robust.Shared.GameObjects;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics;
+
+namespace Robust.Client.GameObjects
+{
+    [RegisterComponent]
+    public sealed class RenderingTreeComponent : Component
+    {
+        public override string Name => "RenderingTree";
+
+        internal DynamicTree<SpriteComponent> SpriteTree { get; private set; } = new(SpriteAabbFunc);
+        internal DynamicTree<PointLightComponent> LightTree { get; private set; } = new(LightAabbFunc);
+
+        private static Box2 SpriteAabbFunc(in SpriteComponent value)
+        {
+            var worldPos = value.Owner.Transform.WorldPosition;
+            return new Box2(worldPos, worldPos);
+        }
+
+        private static Box2 LightAabbFunc(in PointLightComponent value)
+        {
+            var worldPos = value.Owner.Transform.WorldPosition;
+
+            var boxSize = value.Radius * 2;
+            return Box2.CenteredAround(worldPos, (boxSize, boxSize));
+        }
+
+        internal static Box2 SpriteAabbFunc(SpriteComponent value, Vector2? worldPos = null)
+        {
+            worldPos ??= value.Owner.Transform.WorldPosition;
+
+            return new Box2(worldPos.Value, worldPos.Value);
+        }
+
+        internal static Box2 LightAabbFunc(PointLightComponent value, Vector2? worldPos = null)
+        {
+            worldPos ??= value.Owner.Transform.WorldPosition;
+            var boxSize = value.Radius * 2;
+            return Box2.CenteredAround(worldPos.Value, (boxSize, boxSize));
+        }
+    }
+}

Robust.Client/GameObjects/EntitySystems/ClientOccluderSystem.cs

@@ -35,7 +35,7 @@ namespace Robust.Client.GameObjects
 
             SubscribeLocalEvent<OccluderDirtyEvent>(HandleDirtyEvent);
 
-            SubscribeLocalEvent<ClientOccluderComponent, SnapGridPositionChangedEvent>(HandleSnapGridMove);
+            SubscribeLocalEvent<ClientOccluderComponent, AnchorStateChangedEvent>(HandleAnchorChanged);
         }
 
         public override void FrameUpdate(float frameTime)
@@ -62,9 +62,9 @@ namespace Robust.Client.GameObjects
             }
         }
 
-        private static void HandleSnapGridMove(EntityUid uid, ClientOccluderComponent component, SnapGridPositionChangedEvent args)
+        private static void HandleAnchorChanged(EntityUid uid, ClientOccluderComponent component, AnchorStateChangedEvent args)
         {
-            component.SnapGridOnPositionChanged();
+            component.AnchorStateChanged();
         }
 
         private void HandleDirtyEvent(OccluderDirtyEvent ev)

Robust.Client/GameObjects/EntitySystems/DebugLightTreeSystem.cs

@@ -0,0 +1,84 @@
+#if DEBUG
+using Robust.Client.Graphics;
+using Robust.Shared.Enums;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+
+namespace Robust.Client.GameObjects
+{
+    internal sealed class DebugLightTreeSystem : EntitySystem
+    {
+        private DebugLightOverlay? _lightOverlay;
+
+        public bool Enabled
+        {
+            get => _enabled;
+            set
+            {
+                if (_enabled == value) return;
+
+                _enabled = value;
+                var overlayManager = IoCManager.Resolve<IOverlayManager>();
+
+                if (_enabled)
+                {
+                    _lightOverlay = new DebugLightOverlay(
+                        IoCManager.Resolve<IEntityLookup>(),
+                        IoCManager.Resolve<IEyeManager>(),
+                        IoCManager.Resolve<IMapManager>(),
+                        Get<RenderingTreeSystem>());
+
+                    overlayManager.AddOverlay(_lightOverlay);
+                }
+                else
+                {
+                    overlayManager.RemoveOverlay(_lightOverlay!);
+                    _lightOverlay = null;
+                }
+            }
+        }
+
+        private bool _enabled;
+
+        private sealed class DebugLightOverlay : Overlay
+        {
+            private IEntityLookup _lookup;
+            private IEyeManager _eyeManager;
+            private IMapManager _mapManager;
+
+            private RenderingTreeSystem _tree;
+
+            public override OverlaySpace Space => OverlaySpace.WorldSpace;
+
+            public DebugLightOverlay(IEntityLookup lookup, IEyeManager eyeManager, IMapManager mapManager, RenderingTreeSystem tree)
+            {
+                _lookup = lookup;
+                _eyeManager = eyeManager;
+                _mapManager = mapManager;
+                _tree = tree;
+            }
+
+            protected internal override void Draw(in OverlayDrawArgs args)
+            {
+                var map = _eyeManager.CurrentMap;
+                if (map == MapId.Nullspace) return;
+
+                var viewport = _eyeManager.GetWorldViewport();
+
+                foreach (var tree in _tree.GetLightTrees(map, viewport))
+                {
+                    foreach (var light in tree)
+                    {
+                        var aabb = _lookup.GetWorldAabbFromEntity(light.Owner);
+                        if (!aabb.Intersects(viewport)) continue;
+
+                        args.WorldHandle.DrawRect(aabb, Color.Green.WithAlpha(0.1f));
+                    }
+                }
+            }
+        }
+    }
+}
+#endif

Robust.Client/GameObjects/EntitySystems/RenderingTreeSystem.cs

@@ -3,8 +3,11 @@ using System.Drawing;
 using System.Linq;
 using JetBrains.Annotations;
 using Robust.Client.Physics;
+using Robust.Shared;
+using Robust.Shared.Configuration;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
+using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Physics;
@@ -18,25 +21,58 @@ namespace Robust.Client.GameObjects
     [UsedImplicitly]
     public sealed class RenderingTreeSystem : EntitySystem
     {
+        internal const string LoggerSawmill = "rendertree";
+
         // Nullspace is not indexed. Keep that in mind.
 
-        [Dependency] private readonly IMapManagerInternal _mapManager = default!;
-
-        private readonly Dictionary<MapId, Dictionary<GridId, MapTrees>> _gridTrees = new();
+        [Dependency] private readonly IMapManager _mapManager = default!;
 
         private readonly List<SpriteComponent> _spriteQueue = new();
         private readonly List<PointLightComponent> _lightQueue = new();
 
         private HashSet<EntityUid> _checkedChildren = new();
 
-        internal DynamicTree<SpriteComponent> GetSpriteTreeForMap(MapId map, GridId grid)
+        /// <summary>
+        /// <see cref="CVars.MaxLightRadius"/>
+        /// </summary>
+        public float MaxLightRadius { get; private set; }
+
+        internal IEnumerable<RenderingTreeComponent> GetRenderTrees(MapId mapId, Box2 worldAABB)
         {
-            return _gridTrees[map][grid].SpriteTree;
+            if (mapId == MapId.Nullspace) yield break;
+
+            var enclosed = false;
+
+            foreach (var grid in _mapManager.FindGridsIntersecting(mapId, worldAABB))
+            {
+                yield return EntityManager.GetEntity(grid.GridEntityId).GetComponent<RenderingTreeComponent>();
+
+                // if we're enclosed then we know no other grids relevant + don't need the map's rendertree
+                if (grid.WorldBounds.Encloses(in worldAABB))
+                {
+                    enclosed = true;
+                    break;
+                }
+            }
+
+            if (!enclosed)
+                yield return _mapManager.GetMapEntity(mapId).GetComponent<RenderingTreeComponent>();
         }
 
-        internal DynamicTree<PointLightComponent> GetLightTreeForMap(MapId map, GridId grid)
+        internal IEnumerable<DynamicTree<SpriteComponent>> GetSpriteTrees(MapId mapId, Box2 worldAABB)
         {
-            return _gridTrees[map][grid].LightTree;
+            foreach (var comp in GetRenderTrees(mapId, worldAABB))
+            {
+                yield return comp.SpriteTree;
+            }
+        }
+
+        internal IEnumerable<DynamicTree<PointLightComponent>> GetLightTrees(MapId mapId, Box2 worldAABB)
+        {
+            foreach (var comp in GetRenderTrees(mapId, worldAABB))
+            {
+                yield return comp.LightTree;
+            }
         }
 
         public override void Initialize()
@@ -48,9 +84,7 @@ namespace Robust.Client.GameObjects
             UpdatesAfter.Add(typeof(PhysicsSystem));
 
             _mapManager.MapCreated += MapManagerOnMapCreated;
-            _mapManager.MapDestroyed += MapManagerOnMapDestroyed;
             _mapManager.OnGridCreated += MapManagerOnGridCreated;
-            _mapManager.OnGridRemoved += MapManagerOnGridRemoved;
 
             // Due to how recursion works, this must be done.
             SubscribeLocalEvent<MoveEvent>(AnythingMoved);
@@ -65,6 +99,11 @@ namespace Robust.Client.GameObjects
             SubscribeLocalEvent<PointLightComponent, PointLightRadiusChangedEvent>(PointLightRadiusChanged);
             SubscribeLocalEvent<PointLightComponent, RenderTreeRemoveLightEvent>(RemoveLight);
             SubscribeLocalEvent<PointLightComponent, PointLightUpdateEvent>(HandleLightUpdate);
+
+            SubscribeLocalEvent<RenderingTreeComponent, ComponentRemove>(HandleTreeRemove);
+
+            var configManager = IoCManager.Resolve<IConfigurationManager>();
+            configManager.OnValueChanged(CVars.MaxLightRadius, value => MaxLightRadius = value, true);
         }
 
         private void HandleLightUpdate(EntityUid uid, PointLightComponent component, PointLightUpdateEvent args)
@@ -88,12 +127,12 @@ namespace Robust.Client.GameObjects
         {
             // To avoid doing redundant updates (and we don't need to update a grid's children ever)
             if (!_checkedChildren.Add(sender.Owner.Uid) ||
-                sender.Owner.HasComponent<MapGridComponent>() ||
-                sender.Owner.HasComponent<MapComponent>()) return;
+                sender.Owner.HasComponent<RenderingTreeComponent>()) return;
 
             // This recursive search is needed, as MoveEvent is defined to not care about indirect events like children.
             // WHATEVER YOU DO, DON'T REPLACE THIS WITH SPAMMING EVENTS UNLESS YOU HAVE A GUARANTEE IT WON'T LAG THE GC.
             // (Struct-based events ok though)
+            // Ironically this was lagging the GC lolz
             if (sender.Owner.TryGetComponent(out SpriteComponent? sprite))
                 QueueSpriteUpdate(sprite);
 
@@ -129,16 +168,10 @@ namespace Robust.Client.GameObjects
 
         private void ClearSprite(SpriteComponent component)
         {
-            if (_gridTrees.TryGetValue(component.IntersectingMapId, out var gridTrees))
-            {
-                foreach (var gridId in component.IntersectingGrids)
-                {
-                    if (!gridTrees.TryGetValue(gridId, out var tree)) continue;
-                    tree.SpriteTree.Remove(component);
-                }
-            }
+            if (component.RenderTree == null) return;
 
-            component.IntersectingGrids.Clear();
+            component.RenderTree.SpriteTree.Remove(component);
+            component.RenderTree = null;
         }
 
         private void QueueSpriteUpdate(SpriteComponent component)
@@ -173,16 +206,10 @@ namespace Robust.Client.GameObjects
 
         private void ClearLight(PointLightComponent component)
         {
-            if (_gridTrees.TryGetValue(component.IntersectingMapId, out var gridTrees))
-            {
-                foreach (var gridId in component.IntersectingGrids)
-                {
-                    if (!gridTrees.TryGetValue(gridId, out var tree)) continue;
-                    tree.LightTree.Remove(component);
-                }
-            }
+            if (component.RenderTree == null) return;
 
-            component.IntersectingGrids.Clear();
+            component.RenderTree.LightTree.Remove(component);
+            component.RenderTree = null;
         }
 
         private void QueueLightUpdate(PointLightComponent component)
@@ -198,31 +225,23 @@ namespace Robust.Client.GameObjects
         {
             base.Shutdown();
             _mapManager.MapCreated -= MapManagerOnMapCreated;
-            _mapManager.MapDestroyed -= MapManagerOnMapDestroyed;
             _mapManager.OnGridCreated -= MapManagerOnGridCreated;
-            _mapManager.OnGridRemoved -= MapManagerOnGridRemoved;
         }
 
-        private void MapManagerOnMapDestroyed(object? sender, MapEventArgs e)
+        private void HandleTreeRemove(EntityUid uid, RenderingTreeComponent component, ComponentRemove args)
         {
-            foreach (var (_, gridTree) in _gridTrees[e.Map])
+            foreach (var sprite in component.SpriteTree)
             {
-                foreach (var comp in gridTree.LightTree)
-                {
-                    comp.IntersectingGrids.Clear();
-                }
-
-                foreach (var comp in gridTree.SpriteTree)
-                {
-                    comp.IntersectingGrids.Clear();
-                }
-
-                // Just in case?
-                gridTree.LightTree.Clear();
-                gridTree.SpriteTree.Clear();
+                sprite.RenderTree = null;
             }
 
-            _gridTrees.Remove(e.Map);
+            foreach (var light in component.LightTree)
+            {
+                light.RenderTree = null;
+            }
+
+            component.SpriteTree.Clear();
+            component.LightTree.Clear();
         }
 
         private void MapManagerOnMapCreated(object? sender, MapEventArgs e)
@@ -232,35 +251,31 @@ namespace Robust.Client.GameObjects
                 return;
             }
 
-            _gridTrees.Add(e.Map, new Dictionary<GridId, MapTrees>
-            {
-                {GridId.Invalid, new MapTrees()}
-            });
+            _mapManager.GetMapEntity(e.Map).EnsureComponent<RenderingTreeComponent>();
         }
 
         private void MapManagerOnGridCreated(MapId mapId, GridId gridId)
         {
-            _gridTrees[mapId].Add(gridId, new MapTrees());
+            EntityManager.GetEntity(_mapManager.GetGrid(gridId).GridEntityId).EnsureComponent<RenderingTreeComponent>();
         }
 
-        private void MapManagerOnGridRemoved(MapId mapId, GridId gridId)
+        private RenderingTreeComponent? GetRenderTree(IEntity entity)
         {
-            var gridTree = _gridTrees[mapId][gridId];
 
-            foreach (var sprite in gridTree.SpriteTree)
+            if (entity.Transform.MapID == MapId.Nullspace ||
+                entity.HasComponent<RenderingTreeComponent>()) return null;
+
+            var parent = entity.Transform.Parent?.Owner;
+
+            while (true)
             {
-                sprite.IntersectingGrids.Remove(gridId);
+                if (parent == null) break;
+
+                if (parent.TryGetComponent(out RenderingTreeComponent? comp)) return comp;
+                parent = parent.Transform.Parent?.Owner;
             }
 
-            foreach (var light in gridTree.LightTree)
-            {
-                light.IntersectingGrids.Remove(gridId);
-            }
-
-            // Clear in case
-            gridTree.LightTree.Clear();
-            gridTree.SpriteTree.Clear();
-            _gridTrees[mapId].Remove(gridId);
+            return null;
         }
 
         public override void FrameUpdate(float frameTime)
@@ -270,55 +285,43 @@ namespace Robust.Client.GameObjects
             foreach (var sprite in _spriteQueue)
             {
                 sprite.TreeUpdateQueued = false;
-                var mapId = sprite.Owner.Transform.MapID;
-
                 if (!sprite.Visible || sprite.ContainerOccluded)
                 {
                     ClearSprite(sprite);
                     continue;
                 }
 
-                // If we're on a new map then clear the old one.
-                if (sprite.IntersectingMapId != mapId)
+                var oldMapTree = sprite.RenderTree;
+                var newMapTree = GetRenderTree(sprite.Owner);
+                // TODO: Temp PVS guard
+                var worldPos = sprite.Owner.Transform.WorldPosition;
+
+                if (float.IsNaN(worldPos.X) || float.IsNaN(worldPos.Y))
                 {
                     ClearSprite(sprite);
+                    continue;
                 }
 
-                sprite.IntersectingMapId = mapId;
+                var treePos = newMapTree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+                var aabb = RenderingTreeComponent.SpriteAabbFunc(sprite, worldPos).Translated(-treePos);
 
-                if (mapId == MapId.Nullspace) continue;
-
-                var mapTree = _gridTrees[mapId];
-                var aabb = MapTrees.SpriteAabbFunc(sprite);
-                var intersectingGrids = _mapManager.FindGridIdsIntersecting(mapId, aabb, true).ToList();
-
-                // Remove from old
-                foreach (var gridId in sprite.IntersectingGrids)
+                // If we're on a new map then clear the old one.
+                if (oldMapTree != newMapTree)
                 {
-                    if (intersectingGrids.Contains(gridId)) continue;
-                    mapTree[gridId].SpriteTree.Remove(sprite);
+                    ClearSprite(sprite);
+                    newMapTree?.SpriteTree.Add(sprite, aabb);
                 }
-
-                // Rebuild in the update below
-                sprite.IntersectingGrids.Clear();
-
-                // Update / add to new
-                foreach (var gridId in intersectingGrids)
+                else
                 {
-                    var translated = aabb.Translated(gridId == GridId.Invalid
-                        ? Vector2.Zero
-                        : -_mapManager.GetGrid(gridId).WorldPosition);
-
-                    mapTree[gridId].SpriteTree.AddOrUpdate(sprite, translated);
-
-                    sprite.IntersectingGrids.Add(gridId);
+                    newMapTree?.SpriteTree.Update(sprite, aabb);
                 }
+
+                sprite.RenderTree = newMapTree;
             }
 
             foreach (var light in _lightQueue)
             {
                 light.TreeUpdateQueued = false;
-                var mapId = light.Owner.Transform.MapID;
 
                 if (!light.Enabled || light.ContainerOccluded)
                 {
@@ -326,72 +329,44 @@ namespace Robust.Client.GameObjects
                     continue;
                 }
 
-                // If we're on a new map then clear the old one.
-                if (light.IntersectingMapId != mapId)
+                var oldMapTree = light.RenderTree;
+                var newMapTree = GetRenderTree(light.Owner);
+                // TODO: Temp PVS guard
+                var worldPos = light.Owner.Transform.WorldPosition;
+
+                if (float.IsNaN(worldPos.X) || float.IsNaN(worldPos.Y))
                 {
                     ClearLight(light);
+                    continue;
                 }
 
-                light.IntersectingMapId = mapId;
-
-                if (mapId == MapId.Nullspace) continue;
-
-                var mapTree = _gridTrees[mapId];
-                var aabb = MapTrees.LightAabbFunc(light);
-                var intersectingGrids = _mapManager.FindGridIdsIntersecting(mapId, aabb, true).ToList();
-
-                // Remove from old
-                foreach (var gridId in light.IntersectingGrids)
+                // TODO: Events need a bit of cleanup so we only validate this on initialize and radius changed events
+                // this is fine for now IMO as it's 1 float check for every light that moves
+                if (light.Radius > MaxLightRadius)
                 {
-                    if (intersectingGrids.Contains(gridId)) continue;
-                    mapTree[gridId].LightTree.Remove(light);
+                    Logger.WarningS(LoggerSawmill, $"Light radius for {light.Owner} set above max radius of {MaxLightRadius}. This may lead to pop-in.");
                 }
 
-                // Rebuild in the update below
-                light.IntersectingGrids.Clear();
+                var treePos = newMapTree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+                var aabb = RenderingTreeComponent.LightAabbFunc(light, worldPos).Translated(-treePos);
 
-                // Update / add to new
-                foreach (var gridId in intersectingGrids)
+                // If we're on a new map then clear the old one.
+                if (oldMapTree != newMapTree)
                 {
-                    var translated = aabb.Translated(gridId == GridId.Invalid
-                        ? Vector2.Zero
-                        : -_mapManager.GetGrid(gridId).WorldPosition);
-
-                    mapTree[gridId].LightTree.AddOrUpdate(light, translated);
-                    light.IntersectingGrids.Add(gridId);
+                    ClearLight(light);
+                    newMapTree?.LightTree.Add(light, aabb);
                 }
+                else
+                {
+                    newMapTree?.LightTree.Update(light, aabb);
+                }
+
+                light.RenderTree = newMapTree;
             }
 
             _spriteQueue.Clear();
             _lightQueue.Clear();
         }
-
-        private sealed class MapTrees
-        {
-            public readonly DynamicTree<SpriteComponent> SpriteTree;
-            public readonly DynamicTree<PointLightComponent> LightTree;
-
-            public MapTrees()
-            {
-                SpriteTree = new DynamicTree<SpriteComponent>(SpriteAabbFunc);
-                LightTree = new DynamicTree<PointLightComponent>(LightAabbFunc);
-            }
-
-            internal static Box2 SpriteAabbFunc(in SpriteComponent value)
-            {
-                var worldPos = value.Owner.Transform.WorldPosition;
-
-                return new Box2(worldPos, worldPos);
-            }
-
-            internal static Box2 LightAabbFunc(in PointLightComponent value)
-            {
-                var worldPos = value.Owner.Transform.WorldPosition;
-
-                var boxSize = value.Radius * 2;
-                return Box2.CenteredAround(worldPos, (boxSize, boxSize));
-            }
-        }
     }
 
     internal class RenderTreeRemoveLightEvent : EntityEventArgs

Robust.Client/GameObjects/EntitySystems/SpriteSystem.cs

@@ -1,9 +1,9 @@
-using JetBrains.Annotations;
+using System.Collections.Generic;
+using JetBrains.Annotations;
 using Robust.Client.Graphics;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
-using Robust.Shared.Maths;
 
 namespace Robust.Client.GameObjects
 {
@@ -17,16 +17,29 @@ namespace Robust.Client.GameObjects
         [Dependency] private readonly IMapManager _mapManager = default!;
 
         private RenderingTreeSystem _treeSystem = default!;
+        private readonly Queue<SpriteComponent> _inertUpdateQueue = new();
 
         public override void Initialize()
         {
             base.Initialize();
+
             _treeSystem = Get<RenderingTreeSystem>();
+            SubscribeLocalEvent<SpriteUpdateInertEvent>(QueueUpdateInert);
+        }
+
+        private void QueueUpdateInert(SpriteUpdateInertEvent ev)
+        {
+            _inertUpdateQueue.Enqueue(ev.Sprite);
         }
 
         /// <inheritdoc />
         public override void FrameUpdate(float frameTime)
         {
+            while (_inertUpdateQueue.TryDequeue(out var sprite))
+            {
+                sprite.DoUpdateIsInert();
+            }
+
             // So we could calculate the correct size of the entities based on the contents of their sprite...
             // Or we can just assume that no entity is larger than 10x10 and get a stupid easy check.
             var pvsBounds = _eyeManager.GetWorldViewport().Enlarged(5);
@@ -37,13 +50,11 @@ namespace Robust.Client.GameObjects
                 return;
             }
 
-            foreach (var gridId in _mapManager.FindGridIdsIntersecting(currentMap, pvsBounds, true))
+            foreach (var comp in _treeSystem.GetRenderTrees(currentMap, pvsBounds))
             {
-                var gridBounds = gridId == GridId.Invalid ? pvsBounds : pvsBounds.Translated(-_mapManager.GetGrid(gridId).WorldPosition);
+                var bounds = pvsBounds.Translated(-comp.Owner.Transform.WorldPosition);
 
-                var mapTree = _treeSystem.GetSpriteTreeForMap(currentMap, gridId);
-
-                mapTree.QueryAabb(ref frameTime, (ref float state, in SpriteComponent value) =>
+                comp.SpriteTree.QueryAabb(ref frameTime, (ref float state, in SpriteComponent value) =>
                 {
                     if (value.IsInert)
                     {
@@ -52,7 +63,7 @@ namespace Robust.Client.GameObjects
 
                     value.FrameUpdate(state);
                     return true;
-                }, gridBounds, approx: true);
+                }, bounds, true);
             }
         }
     }

Robust.Client/GameObjects/IClientEntityManager.cs

@@ -1,4 +1,3 @@
-using System.Collections.Generic;
 using Robust.Shared.GameObjects;
 
 namespace Robust.Client.GameObjects

Robust.Client/GameObjects/PlayerMessages.cs

@@ -1,17 +0,0 @@
-using System;
-using Robust.Shared.GameObjects;
-
-namespace Robust.Client.GameObjects
-{
-    [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
-    public class PlayerAttachedMsg : ComponentMessage
-    {
-
-    }
-
-    [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
-    public class PlayerDetachedMsg : ComponentMessage
-    {
-
-    }
-}

Robust.Client/GameStates/ClientGameStateManager.cs

@@ -4,6 +4,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
+using JetBrains.Annotations;
 using Robust.Client.GameObjects;
 using Robust.Client.Input;
 using Robust.Client.Map;
@@ -25,6 +26,7 @@ using Robust.Shared.Utility;
 namespace Robust.Client.GameStates
 {
     /// <inheritdoc />
+    [UsedImplicitly]
     public class ClientGameStateManager : IClientGameStateManager
     {
         private GameStateProcessor _processor = default!;
@@ -36,6 +38,8 @@ namespace Robust.Client.GameStates
             _pendingSystemMessages
                 = new();
 
+        private uint _metaCompNetId;
+
         [Dependency] private readonly IComponentFactory _compFactory = default!;
         [Dependency] private readonly IClientEntityManagerInternal _entities = default!;
         [Dependency] private readonly IEntityLookup _lookup = default!;
@@ -99,6 +103,12 @@ namespace Robust.Client.GameStates
             Predicting = _config.GetCVar(CVars.NetPredict);
             PredictTickBias = _config.GetCVar(CVars.NetPredictTickBias);
             PredictLagBias = _config.GetCVar(CVars.NetPredictLagBias);
+
+            var metaId = _compFactory.GetRegistration(typeof(MetaDataComponent)).NetID;
+            if (!metaId.HasValue)
+                throw new InvalidOperationException("MetaDataComponent does not have a NetId.");
+
+            _metaCompNetId = metaId.Value;
         }
 
         /// <inheritdoc />
@@ -210,6 +220,11 @@ namespace Robust.Client.GameStates
                     ResetPredictedEntities(_timing.CurTick);
                 }
 
+                if (!curState.Extrapolated)
+                {
+                    _processor.UpdateFullRep(curState);
+                }
+
                 // Store last tick we got from the GameStateProcessor.
                 _lastProcessedTick = _timing.CurTick;
 
@@ -338,11 +353,11 @@ namespace Robust.Client.GameStates
                 }
 
                 // TODO: handle component deletions/creations.
-                foreach (var comp in _componentManager.GetNetComponents(entity.Uid))
+                foreach (var (netId, comp) in _componentManager.GetNetComponents(entity.Uid))
                 {
-                    DebugTools.AssertNotNull(comp.NetID);
+                    DebugTools.AssertNotNull(netId);
 
-                    if (comp.LastModifiedTick < curTick || !last.TryGetValue(comp.NetID!.Value, out var compState))
+                    if (comp.LastModifiedTick < curTick || !last.TryGetValue(netId, out var compState))
                     {
                         continue;
                     }
@@ -363,24 +378,22 @@ namespace Robust.Client.GameStates
             // so that we can later roll back to it (if necessary).
             var outputData = new Dictionary<EntityUid, Dictionary<uint, ComponentState>>();
 
+            Debug.Assert(_players.LocalPlayer != null, "_players.LocalPlayer != null");
+            var player = _players.LocalPlayer.Session;
+
             foreach (var createdEntity in createdEntities)
             {
                 var compData = new Dictionary<uint, ComponentState>();
                 outputData.Add(createdEntity, compData);
 
-                foreach (var component in _componentManager.GetNetComponents(createdEntity))
+                foreach (var (netId, component) in _componentManager.GetNetComponents(createdEntity))
                 {
-                    Debug.Assert(_players.LocalPlayer != null, "_players.LocalPlayer != null");
-
-                    var player = _players.LocalPlayer.Session;
                     var state = component.GetComponentState(player);
 
-                    if (state.GetType() == typeof(ComponentState))
-                    {
+                    if(state.GetType() == typeof(ComponentState))
                         continue;
-                    }
 
-                    compData.Add(state.NetID, state);
+                    compData.Add(netId, state);
                 }
             }
 
@@ -422,16 +435,17 @@ namespace Robust.Client.GameStates
                     //Known entities
                     if (_entities.TryGetEntity(es.Uid, out var entity))
                     {
+                        // Logger.Debug($"[{IGameTiming.TickStampStatic}] MOD {es.Uid}");
                         toApply.Add(entity, (es, null));
                     }
                     else //Unknown entities
                     {
-                        var metaState = (MetaDataComponentState?) es.ComponentStates
-                            ?.FirstOrDefault(c => c.NetID == NetIDs.META_DATA);
+                        var metaState = (MetaDataComponentState?) es.ComponentChanges?.FirstOrDefault(c => c.NetID == _metaCompNetId).State;
                         if (metaState == null)
                         {
                             throw new InvalidOperationException($"Server sent new entity state for {es.Uid} without metadata component!");
                         }
+                        // Logger.Debug($"[{IGameTiming.TickStampStatic}] CREATE {es.Uid} {metaState.PrototypeId}");
                         var newEntity = (Entity)_entities.CreateEntity(metaState.PrototypeId, es.Uid);
                         toApply.Add(newEntity, (es, null));
                         toInitialize.Add(newEntity);
@@ -471,6 +485,7 @@ namespace Robust.Client.GameStates
 
             foreach (var id in deletions)
             {
+                // Logger.Debug($"[{IGameTiming.TickStampStatic}] DELETE {id}");
                 _entities.DeleteEntity(id);
             }
 
@@ -535,7 +550,7 @@ namespace Robust.Client.GameStates
         private void HandleEntityState(IComponentManager compMan, IEntity entity, EntityEventBus bus, EntityState? curState,
             EntityState? nextState)
         {
-            var compStateWork = new Dictionary<uint, (ComponentState? curState, ComponentState? nextState)>();
+            var compStateWork = new Dictionary<ushort, (ComponentState? curState, ComponentState? nextState)>();
             var entityUid = entity.Uid;
 
             if (curState?.ComponentChanges != null)
@@ -551,42 +566,46 @@ namespace Robust.Client.GameStates
                     }
                     else
                     {
+                        //Right now we just assume every state from an unseen entity is added
+
                         if (compMan.HasComponent(entityUid, compChange.NetID))
                             continue;
 
-                        var newComp = (Component) _compFactory.GetComponent(compChange.ComponentName!);
+                        var newComp = (Component) _compFactory.GetComponent(compChange.NetID);
                         newComp.Owner = entity;
                         compMan.AddComponent(entity, newComp, true);
+
+                        compStateWork[compChange.NetID] = (compChange.State, null);
                     }
                 }
             }
 
-            if (curState?.ComponentStates != null)
+            if (curState?.ComponentChanges != null)
             {
-                foreach (var compState in curState.ComponentStates)
+                foreach (var compChange in curState.ComponentChanges)
                 {
-                    compStateWork[compState.NetID] = (compState, null);
+                    compStateWork[compChange.NetID] = (compChange.State, null);
                 }
             }
 
-            if (nextState?.ComponentStates != null)
+            if (nextState?.ComponentChanges != null)
             {
-                foreach (var compState in nextState.ComponentStates)
+                foreach (var compState in nextState.ComponentChanges)
                 {
                     if (compStateWork.TryGetValue(compState.NetID, out var state))
                     {
-                        compStateWork[compState.NetID] = (state.curState, compState);
+                        compStateWork[compState.NetID] = (state.curState, compState.State);
                     }
                     else
                     {
-                        compStateWork[compState.NetID] = (null, compState);
+                        compStateWork[compState.NetID] = (null, compState.State);
                     }
                 }
             }
 
             foreach (var (netId, (cur, next)) in compStateWork)
             {
-                if (compMan.TryGetComponent(entityUid, netId, out var component))
+                if (compMan.TryGetComponent(entityUid, (ushort) netId, out var component))
                 {
                     try
                     {

Robust.Client/GameStates/GameStateProcessor.cs

@@ -1,4 +1,4 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Robust.Shared.GameObjects;
@@ -149,11 +149,6 @@ namespace Robust.Client.GameStates
                 {
                     Logger.DebugS("net.state", $"Applying State:  ext={curState!.Extrapolated}, cTick={_timing.CurTick}, fSeq={curState.FromSequence}, tSeq={curState.ToSequence}, buf={_stateBuffer.Count}");
                 }
-
-                if (!curState!.Extrapolated)
-                {
-                    UpdateFullRep(curState);
-                }
             }
 
             var cState = curState!;
@@ -162,8 +157,10 @@ namespace Robust.Client.GameStates
             return applyNextState;
         }
 
-        private void UpdateFullRep(GameState state)
+        public void UpdateFullRep(GameState state)
         {
+            // Logger.Debug($"UPDATE FULL REP: {string.Join(", ", state.EntityStates?.Select(e => e.Uid) ?? Enumerable.Empty<EntityUid>())}");
+
             if (state.FromSequence == GameTick.Zero)
             {
                 // Full state.
@@ -198,14 +195,10 @@ namespace Robust.Client.GameStates
                             {
                                 compData.Remove(change.NetID);
                             }
-                        }
-                    }
-
-                    if (entityState.ComponentStates != null)
-                    {
-                        foreach (var compState in entityState.ComponentStates)
-                        {
-                            compData[compState.NetID] = compState;
+                            else if (change.State is not null)
+                            {
+                                compData[change.NetID] = change.State;
+                            }
                         }
                     }
                 }

Robust.Client/GameStates/NetEntityOverlay.cs

@@ -178,7 +178,7 @@ namespace Robust.Client.GameStates
                 var yPos = 10 + _lineHeight * i;
                 var name = $"({netEnt.Id}) {ent.Prototype?.ID}";
                 var color = CalcTextColor(ref netEnt);
-                DrawString(screenHandle, _font, new Vector2(xPos + (TrafficHistorySize + 4), yPos), name, color);
+                screenHandle.DrawString(_font, new Vector2(xPos + (TrafficHistorySize + 4), yPos), name, color);
                 DrawTrafficBox(screenHandle, ref netEnt, xPos, yPos);
             }
         }
@@ -223,17 +223,6 @@ namespace Robust.Client.GameStates
             base.DisposeBehavior();
         }
 
-        private static void DrawString(DrawingHandleScreen handle, Font font, Vector2 pos, string str, Color textColor)
-        {
-            var baseLine = new Vector2(pos.X, font.GetAscent(1) + pos.Y);
-
-            foreach (var rune in str.EnumerateRunes())
-            {
-                var advance = font.DrawChar(handle, rune, baseLine, 1, textColor);
-                baseLine += new Vector2(advance, 0);
-            }
-        }
-
         private struct NetEntity
         {
             public GameTick LastUpdate;

Robust.Client/GameStates/NetGraphOverlay.cs

@@ -21,6 +21,7 @@ namespace Robust.Client.GameStates
         [Dependency] private readonly IGameTiming _gameTiming = default!;
         [Dependency] private readonly IClientNetManager _netManager = default!;
         [Dependency] private readonly IClientGameStateManager _gameStateManager = default!;
+        [Dependency] private readonly IComponentFactory _componentFactory = default!;
 
         private const int HistorySize = 60 * 3; // number of ticks to keep in history.
         private const int TargetPayloadBps = 56000 / 8; // Target Payload size in Bytes per second. A mind-numbing fifty-six thousand bits per second, who would ever need more?
@@ -90,17 +91,14 @@ namespace Robust.Client.GameStates
                             sb.Append($"\n  Changes:");
                             foreach (var compChange in entState.ComponentChanges)
                             {
-                                var del = compChange.Deleted ? 'D' : 'C';
-                                sb.Append($"\n    [{del}]{compChange.NetID}:{compChange.ComponentName}");
-                            }
-                        }
+                                var registration = _componentFactory.GetRegistration(compChange.NetID);
+                                var create = compChange.Created ? 'C' : '\0';
+                                var mod = !(compChange.Created || compChange.Created) ? 'M' : '\0';
+                                var del = compChange.Deleted ? 'D' : '\0';
+                                sb.Append($"\n    [{create}{mod}{del}]{compChange.NetID}:{registration.Name}");
 
-                        if (entState.ComponentStates is not null)
-                        {
-                            sb.Append($"\n  States:");
-                            foreach (var compState in entState.ComponentStates)
-                            {
-                                sb.Append($"\n    {compState.NetID}:{compState.GetType().Name}");
+                                if(compChange.State is not null)
+                                    sb.Append($"\n      STATE:{compChange.State.GetType().Name}");
                             }
                         }
                     }
@@ -184,7 +182,7 @@ namespace Robust.Client.GameStates
                 // Draw size if above average
                 if (drawSizeThreshold * 1.5 < state.Payload)
                 {
-                    DrawString(handle, _font, new Vector2(xOff, yoff - _font.GetLineHeight(1)), state.Payload.ToString());
+                    handle.DrawString(_font, new Vector2(xOff, yoff - _font.GetLineHeight(1)), state.Payload.ToString());
                 }
 
                 // second tick marks
@@ -224,14 +222,14 @@ namespace Robust.Client.GameStates
             handle.DrawLine(new Vector2(leftMargin, midYoff), new Vector2(leftMargin + width, midYoff), Color.DarkGray.WithAlpha(0.8f));
 
             // payload text
-            DrawString(handle, _font, new Vector2(leftMargin + width, warnYoff), "56K");
-            DrawString(handle, _font, new Vector2(leftMargin + width, midYoff), "33.6K");
+            handle.DrawString(_font, new Vector2(leftMargin + width, warnYoff), "56K");
+            handle.DrawString(_font, new Vector2(leftMargin + width, midYoff), "33.6K");
 
             // interp text info
             if(lastLagY != -1)
-                DrawString(handle, _font, new Vector2(leftMargin + width, lastLagY), $"{lastLagMs.ToString()}ms");
+                handle.DrawString(_font, new Vector2(leftMargin + width, lastLagY), $"{lastLagMs.ToString()}ms");
 
-            DrawString(handle, _font, new Vector2(leftMargin, height + LowerGraphOffset), $"{_gameStateManager.CurrentBufferSize.ToString()} states");
+            handle.DrawString(_font, new Vector2(leftMargin, height + LowerGraphOffset), $"{_gameStateManager.CurrentBufferSize.ToString()} states");
         }
 
         protected override void DisposeBehavior()
@@ -241,17 +239,6 @@ namespace Robust.Client.GameStates
             base.DisposeBehavior();
         }
 
-        private void DrawString(DrawingHandleScreen handle, Font font, Vector2 pos, string str)
-        {
-            var baseLine = new Vector2(pos.X, font.GetAscent(1) + pos.Y);
-
-            foreach (var rune in str.EnumerateRunes())
-            {
-                var advance = font.DrawChar(handle, rune, baseLine, 1, Color.White);
-                baseLine += new Vector2(advance, 0);
-            }
-        }
-
         private class NetShowGraphCommand : IConsoleCommand
         {
             public string Command => "net_graph";

Robust.Client/Graphics/Clyde/Clyde.DllMap.cs

@@ -11,7 +11,7 @@ namespace Robust.Client.Graphics.Clyde
     {
         static Clyde()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) &&
+            if (OperatingSystem.IsWindows() &&
                 RuntimeInformation.ProcessArchitecture == Architecture.X64 &&
                 Environment.GetEnvironmentVariable("ROBUST_INTEGRATED_GPU") != "1")
             {
@@ -28,20 +28,20 @@ namespace Robust.Client.Graphics.Clyde
                 }
             }
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return;
             }
 
             NativeLibrary.SetDllImportResolver(typeof(GL).Assembly, (name, assembly, path) =>
             {
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
+                if (OperatingSystem.IsLinux()
                     && _dllMapLinux.TryGetValue(name, out var mappedName))
                 {
                     return NativeLibrary.Load(mappedName);
                 }
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX)
+                if (OperatingSystem.IsMacOS()
                     && _dllMapMacOS.TryGetValue(name, out mappedName))
                 {
                     return NativeLibrary.Load(mappedName);

Robust.Client/Graphics/Clyde/Clyde.HLR.cs

@@ -366,24 +366,11 @@ namespace Robust.Client.Graphics.Clyde
         private void ProcessSpriteEntities(MapId map, Box2 worldBounds,
             RefList<(SpriteComponent sprite, Matrix3 matrix, Angle worldRot, float yWorldPos)> list)
         {
-            var spriteSystem = _entitySystemManager.GetEntitySystem<RenderingTreeSystem>();
-
-            foreach (var gridId in _mapManager.FindGridIdsIntersecting(map, worldBounds, true))
+            foreach (var comp in _entitySystemManager.GetEntitySystem<RenderingTreeSystem>().GetRenderTrees(map, worldBounds))
             {
-                Box2 gridBounds;
+                var bounds = worldBounds.Translated(-comp.Owner.Transform.WorldPosition);
 
-                if (gridId == GridId.Invalid)
-                {
-                    gridBounds = worldBounds;
-                }
-                else
-                {
-                    gridBounds = worldBounds.Translated(-_mapManager.GetGrid(gridId).WorldPosition);
-                }
-
-                var tree = spriteSystem.GetSpriteTreeForMap(map, gridId);
-
-                tree.QueryAabb(ref list, ((
+                comp.SpriteTree.QueryAabb(ref list, ((
                     ref RefList<(SpriteComponent sprite, Matrix3 matrix, Angle worldRot, float yWorldPos)> state,
                     in SpriteComponent value) =>
                 {
@@ -398,7 +385,7 @@ namespace Robust.Client.Graphics.Clyde
                     entry.yWorldPos = worldPos.Y;
                     return true;
 
-                }), gridBounds, approx: true);
+                }), bounds, true);
             }
         }
 

Robust.Client/Graphics/Clyde/Clyde.LightRendering.cs

@@ -494,24 +494,16 @@ namespace Robust.Client.Graphics.Clyde
             GetLightsToRender(MapId map, in Box2 worldBounds)
         {
             var renderingTreeSystem = _entitySystemManager.GetEntitySystem<RenderingTreeSystem>();
+            var enlargedBounds = worldBounds.Enlarged(renderingTreeSystem.MaxLightRadius);
+
+            // Use worldbounds for this one as we only care if the light intersects our actual bounds
             var state = (this, worldBounds, count: 0);
 
-            foreach (var gridId in _mapManager.FindGridIdsIntersecting(map, worldBounds, true))
+            foreach (var comp in renderingTreeSystem.GetRenderTrees(map, enlargedBounds))
             {
-                Box2 gridBounds;
+                var bounds = worldBounds.Translated(-comp.Owner.Transform.WorldPosition);
 
-                if (gridId == GridId.Invalid)
-                {
-                    gridBounds = worldBounds;
-                }
-                else
-                {
-                    gridBounds = worldBounds.Translated(-_mapManager.GetGrid(gridId).WorldPosition);
-                }
-
-                var lightTree = renderingTreeSystem.GetLightTreeForMap(map, gridId);
-
-                lightTree.QueryAabb(ref state, (ref (Clyde clyde, Box2 worldBounds, int count) state, in PointLightComponent light) =>
+                comp.LightTree.QueryAabb(ref state, (ref (Clyde clyde, Box2 worldBounds, int count) state, in PointLightComponent light) =>
                 {
                     var transform = light.Owner.Transform;
 
@@ -535,7 +527,7 @@ namespace Robust.Client.Graphics.Clyde
                     state.clyde._lightsToRenderList[state.count++] = (light, lightPos, distanceSquared);
 
                     return true;
-                }, gridBounds);
+                }, bounds);
             }
 
             if (state.count > _maxLightsPerScene)

Robust.Client/Graphics/Clyde/Clyde.Windowing.cs

@@ -131,7 +131,7 @@ namespace Robust.Client.Graphics.Clyde
 
             if (!succeeded)
             {
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                 {
                     var msgBoxContent = "Failed to create the game window. " +
                                         "This probably means your GPU is too old to play the game. " +
@@ -164,7 +164,7 @@ namespace Robust.Client.Graphics.Clyde
 
         private IEnumerable<Image<Rgba32>> LoadWindowIcons()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            if (OperatingSystem.IsMacOS())
             {
                 // Does nothing on macOS so don't bother.
                 yield break;

Robust.Client/Graphics/Clyde/Windowing/Glfw.WindowThread.cs

@@ -1,4 +1,4 @@
-using System.Runtime.InteropServices;
+using System;
 using System.Threading.Channels;
 using System.Threading.Tasks;
 using OpenToolkit.GraphicsLibraryFramework;
@@ -13,11 +13,6 @@ namespace Robust.Client.Graphics.Clyde
     {
         private sealed partial class GlfwWindowingImpl
         {
-            // glfwPostEmptyEvent is broken on macOS and crashes when not called from the main thread
-            // (despite what the docs claim, and yes this makes it useless).
-            // Because of this, we just forego it and use glfwWaitEventsTimeout on macOS instead.
-            private static readonly bool IsMacOS = RuntimeInformation.IsOSPlatform(OSPlatform.OSX);
-
             private bool _windowingRunning;
             private ChannelWriter<CmdBase> _cmdWriter = default!;
             private ChannelReader<CmdBase> _cmdReader = default!;
@@ -53,7 +48,10 @@ namespace Robust.Client.Graphics.Clyde
 
                 while (_windowingRunning)
                 {
-                    if (IsMacOS)
+                    // glfwPostEmptyEvent is broken on macOS and crashes when not called from the main thread
+                    // (despite what the docs claim, and yes this makes it useless).
+                    // Because of this, we just forego it and use glfwWaitEventsTimeout on macOS instead.
+                    if (OperatingSystem.IsMacOS())
                         GLFW.WaitEventsTimeout(0.008);
                     else
                         GLFW.WaitEvents();
@@ -157,7 +155,7 @@ namespace Robust.Client.Graphics.Clyde
                 _cmdWriter.TryWrite(cmd);
 
                 // Post empty event to unstuck WaitEvents if necessary.
-                if (!IsMacOS)
+                if (!OperatingSystem.IsMacOS())
                     GLFW.PostEmptyEvent();
             }
 

Robust.Client/Graphics/Clyde/Windowing/Glfw.Windows.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.InteropServices;
+using System.Runtime.Loader;
 using System.Threading.Tasks;
 using OpenToolkit;
 using OpenToolkit.Graphics.OpenGL4;
@@ -33,6 +34,7 @@ namespace Robust.Client.Graphics.Clyde
             private GlfwWindowReg? _mainWindow;
             private GlfwBindingsContext _mainGraphicsContext = default!;
             private int _nextWindowId = 1;
+            private static bool _eglLoaded;
 
             public async Task<WindowHandle> WindowCreate(WindowCreateParameters parameters)
             {
@@ -474,6 +476,20 @@ namespace Robust.Client.Graphics.Clyde
                     GLFW.WindowHint(WindowHintContextApi.ContextCreationApi, ContextApi.EglContextApi);
                     GLFW.WindowHint(WindowHintOpenGlProfile.OpenGlProfile, OpenGlProfile.Any);
                     GLFW.WindowHint(WindowHintBool.SrgbCapable, false);
+
+                    if (!_eglLoaded && OperatingSystem.IsWindows())
+                    {
+                        // On non-published builds (so, development), GLFW can't find libEGL.dll
+                        // because it'll be in runtimes/<rid>/native/ instead of next to the actual executable.
+                        // We manually preload the library here so that GLFW will find it when it does its thing.
+                        NativeLibrary.TryLoad(
+                            "libEGL.dll",
+                            typeof(Clyde).Assembly,
+                            DllImportSearchPath.SafeDirectories,
+                            out _);
+
+                        _eglLoaded = true;
+                    }
                 }
 
 

Robust.Client/Graphics/Drawing/DrawingHandleScreen.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Text;
 using Robust.Shared.Maths;
 
 namespace Robust.Client.Graphics
@@ -39,5 +40,57 @@ namespace Robust.Client.Graphics
             DrawPrimitiveTopology type = filled ? DrawPrimitiveTopology.TriangleFan : DrawPrimitiveTopology.LineStrip;
             DrawPrimitives(type, buffer, color);
         }
+
+        /// <summary>
+        ///     Draw a simple string to the screen at the specified position.
+        /// </summary>
+        /// <remarks>
+        ///     This method is primarily intended for debug purposes and does not handle things like UI scaling.
+        /// </remarks>
+        /// <returns>
+        ///     The space taken up (horizontal and vertical) by the text.
+        /// </returns>
+        /// <param name="font">The font to render with.</param>
+        /// <param name="pos">The top-left corner to start drawing text at.</param>
+        /// <param name="str">The text to draw.</param>
+        /// <param name="color">The color of text to draw.</param>
+        public Vector2 DrawString(Font font, Vector2 pos, string str, Color color)
+        {
+            var advanceTotal = Vector2.Zero;
+            var baseLine = new Vector2(pos.X, font.GetAscent(1) + pos.Y);
+            var lineHeight = font.GetLineHeight(1);
+
+            foreach (var rune in str.EnumerateRunes())
+            {
+                if (rune == new Rune('\n'))
+                {
+                    baseLine.X = pos.X;
+                    baseLine.Y += lineHeight;
+                    advanceTotal.Y += lineHeight;
+                    continue;
+                }
+
+                var advance = font.DrawChar(this, rune, baseLine, 1, color);
+                advanceTotal.X += advance;
+                baseLine += new Vector2(advance, 0);
+            }
+
+            return advanceTotal;
+        }
+
+        /// <summary>
+        ///     Draw a simple string to the screen at the specified position.
+        /// </summary>
+        /// <remarks>
+        ///     This method is primarily intended for debug purposes and does not handle things like UI scaling.
+        /// </remarks>
+        /// <returns>
+        ///     The space taken up (horizontal and vertical) by the text.
+        /// </returns>
+        /// <param name="font">The font to render with.</param>
+        /// <param name="pos">The top-left corner to start drawing text at.</param>
+        /// <param name="str">The text to draw.</param>
+        public Vector2 DrawString(Font font, Vector2 pos, string str)
+            => DrawString(font, pos, str, Color.White);
     }
 }

Robust.Client/IGameControllerInternal.cs

@@ -10,8 +10,7 @@ namespace Robust.Client
         GameControllerOptions Options { get; }
         bool ContentStart { get; set; }
         void SetCommandLineArgs(CommandLineArgs args);
-        bool LoadConfigAndUserData { get; set; }
-        void Run(GameController.DisplayMode mode, Func<ILogHandler>? logHandlerFactory = null);
+        void Run(GameController.DisplayMode mode, GameControllerOptions options, Func<ILogHandler>? logHandlerFactory = null);
         void KeyDown(KeyEventArgs keyEvent);
         void KeyUp(KeyEventArgs keyEvent);
         void TextEntered(TextEventArgs textEvent);

Robust.Client/Input/InputDevices.cs

@@ -1,7 +1,6 @@
-using System.Collections.Generic;
-using System.Runtime.InteropServices;
+using System;
+using System.Collections.Generic;
 using Robust.Shared.Localization;
-using Robust.Shared.Map;
 
 namespace Robust.Client.Input
 {
@@ -179,9 +178,9 @@ namespace Robust.Client.Input
             var locId = $"input-key-{key}";
             if (key == Key.LSystem || key == Key.RSystem)
             {
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                     locId += "-win";
-                else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                else if (OperatingSystem.IsMacOS())
                     locId += "-mac";
                 else
                     locId += "-linux";

Robust.Client/Map/ClientMapManager.cs

@@ -32,12 +32,12 @@ namespace Robust.Client.Map
                     //get shared euid of map comp entity
                     foreach (var entityState in entityStates!)
                     {
-                        if(entityState.ComponentStates is null)
+                        if(entityState.ComponentChanges is null)
                             continue;
 
-                        foreach (var compState in entityState.ComponentStates)
+                        foreach (var compChange in entityState.ComponentChanges)
                         {
-                            if (compState is not MapComponentState mapCompState || mapCompState.MapId != mapId)
+                            if (compChange.State is not MapComponentState mapCompState || mapCompState.MapId != mapId)
                                 continue;
 
                             mapEuid = entityState.Uid;
@@ -67,12 +67,12 @@ namespace Robust.Client.Map
                     //get shared euid of map comp entity
                     foreach (var entityState in entityStates!)
                     {
-                        if(entityState.ComponentStates is null)
+                        if (entityState.ComponentChanges is null)
                             continue;
 
-                        foreach (var compState in entityState.ComponentStates)
+                        foreach (var compState in entityState.ComponentChanges)
                         {
-                            if (compState is not MapGridComponentState gridCompState || gridCompState.GridIndex != gridId)
+                            if (compState.State is not MapGridComponentState gridCompState || gridCompState.GridIndex != gridId)
                                 continue;
 
                             gridEuid = entityState.Uid;

Robust.Client/Map/ClydeTileDefinitionManager.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using Robust.Client.Graphics;
 using Robust.Client.ResourceManagement;
@@ -17,7 +18,7 @@ namespace Robust.Client.Map
         [Dependency] private readonly IResourceCache _resourceCache = default!;
 
         private Texture? _tileTextureAtlas;
-        
+
         public Texture TileTextureAtlas => _tileTextureAtlas ?? Texture.Transparent;
 
         private readonly Dictionary<ushort, Box2> _tileRegions = new();
@@ -61,7 +62,7 @@ namespace Robust.Client.Map
                 var row = i / dimensionX;
 
                 Image<Rgba32> image;
-                using (var stream = _resourceCache.ContentFileRead($"/Textures/Constructible/Tiles/{def.SpriteName}.png"))
+                using (var stream = _resourceCache.ContentFileRead(Path.Join(def.Path, $"{def.SpriteName}.png")))
                 {
                     image = Image.Load<Rgba32>(stream);
                 }

Robust.Client/Player/LocalPlayer.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using Robust.Client.GameObjects;
 using Robust.Shared.Enums;
 using Robust.Shared.GameObjects;
@@ -70,11 +70,9 @@ namespace Robust.Client.Player
             eye.Current = true;
 
             EntityAttached?.Invoke(new EntityAttachedEventArgs(entity));
-            entity.SendMessage(null, new PlayerAttachedMsg());
 
             // notify ECS Systems
             ControlledEntity.EntityManager.EventBus.RaiseEvent(EventSource.Local, new PlayerAttachSysMessage(ControlledEntity));
-
             ControlledEntity.EntityManager.EventBus.RaiseLocalEvent(ControlledEntity.Uid, new PlayerAttachedEvent(ControlledEntity));
         }
 
@@ -87,11 +85,9 @@ namespace Robust.Client.Player
             if (previous is {Initialized: true, Deleted: false})
             {
                 previous.GetComponent<EyeComponent>().Current = false;
-                previous.SendMessage(null, new PlayerDetachedMsg());
 
                 // notify ECS Systems
                 previous.EntityManager.EventBus.RaiseEvent(EventSource.Local, new PlayerAttachSysMessage(null));
-
                 previous.EntityManager.EventBus.RaiseLocalEvent(previous.Uid, new PlayerDetachedEvent(previous));
             }
 

Robust.Client/UserInterface/Controls/Button.cs

@@ -10,7 +10,7 @@ namespace Robust.Client.UserInterface.Controls
     {
         public Label Label { get; }
 
-        public Button() : base()
+        public Button()
         {
             AddStyleClass(StyleClassButton);
             Label = new Label

Robust.Client/UserInterface/Controls/CheckBox.cs

@@ -14,7 +14,7 @@ namespace Robust.Client.UserInterface.Controls
         public Label Label { get; }
         public TextureRect TextureRect { get; }
 
-        public CheckBox() : base()
+        public CheckBox()
         {
             ToggleMode = true;
 

Robust.Client/UserInterface/Controls/ContainerButton.cs

@@ -13,7 +13,7 @@ namespace Robust.Client.UserInterface.Controls
         public const string StylePseudoClassHover = "hover";
         public const string StylePseudoClassDisabled = "disabled";
 
-        public ContainerButton() : base()
+        public ContainerButton()
         {
             DrawModeChanged();
         }

Robust.Client/UserInterface/Controls/ItemList.cs

@@ -318,6 +318,8 @@ namespace Robust.Client.UserInterface.Controls
         {
             base.Draw(handle);
 
+            var sizeBox = PixelSizeBox;
+
             var font = ActualFont;
             var listBg = ActualBackground;
             var iconBg = ActualItemBackground;
@@ -346,31 +348,38 @@ namespace Robust.Client.UserInterface.Controls
                     itemHeight = item.IconSize.Y;
                 }
 
-                itemHeight = Math.Max(itemHeight, ActualFont.GetHeight(UIScale));
+                itemHeight = Math.Max(itemHeight, font.GetHeight(UIScale));
                 itemHeight += ActualItemBackground.MinimumSize.Y;
 
-                item.Region = UIBox2.FromDimensions(0, offset, PixelWidth, itemHeight);
+                var region = UIBox2.FromDimensions(0, offset, PixelWidth, itemHeight);
+                item.Region = region;
 
-                bg.Draw(handle, item.Region.Value);
-
-                var contentBox = bg.GetContentBox(item.Region.Value);
-                var drawOffset = contentBox.TopLeft;
-                if (item.Icon != null)
+                if (region.Intersects(sizeBox))
                 {
-                    if (item.IconRegion.Size == Vector2.Zero)
-                    {
-                        handle.DrawTextureRect(item.Icon, UIBox2.FromDimensions(drawOffset, item.Icon.Size), item.IconModulate);
-                    }
-                    else
-                    {
-                        handle.DrawTextureRectRegion(item.Icon, UIBox2.FromDimensions(drawOffset, item.Icon.Size), item.IconRegion, item.IconModulate);
-                    }
-                }
+                    bg.Draw(handle, item.Region.Value);
 
-                if (item.Text != null)
-                {
-                    var textBox = new UIBox2(contentBox.Left + item.IconSize.X, contentBox.Top, contentBox.Right, contentBox.Bottom);
-                    DrawTextInternal(handle, item.Text, textBox);
+                    var contentBox = bg.GetContentBox(item.Region.Value);
+                    var drawOffset = contentBox.TopLeft;
+                    if (item.Icon != null)
+                    {
+                        if (item.IconRegion.Size == Vector2.Zero)
+                        {
+                            handle.DrawTextureRect(item.Icon, UIBox2.FromDimensions(drawOffset, item.Icon.Size),
+                                item.IconModulate);
+                        }
+                        else
+                        {
+                            handle.DrawTextureRectRegion(item.Icon, UIBox2.FromDimensions(drawOffset, item.Icon.Size),
+                                item.IconRegion, item.IconModulate);
+                        }
+                    }
+
+                    if (item.Text != null)
+                    {
+                        var textBox = new UIBox2(contentBox.Left + item.IconSize.X, contentBox.Top, contentBox.Right,
+                            contentBox.Bottom);
+                        DrawTextInternal(handle, item.Text, textBox);
+                    }
                 }
 
                 offset += itemHeight;

Robust.Client/UserInterface/Controls/SpinBox.cs

@@ -52,7 +52,7 @@ namespace Robust.Client.UserInterface.Controls
 
         public event EventHandler<ValueChangedEventArgs>? ValueChanged;
 
-        public SpinBox() : base()
+        public SpinBox()
         {
             MouseFilter = MouseFilterMode.Pass;
 

Robust.Client/UserInterface/Controls/TabContainer.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using Robust.Client.Graphics;
 using Robust.Shared.Input;
 using Robust.Shared.Localization;
@@ -75,7 +75,7 @@ namespace Robust.Client.UserInterface.Controls
             var control = GetChild(tab);
             var title = control.GetValue(TabTitleProperty);
 
-            return title ?? control.Name ?? Loc.GetString("No title");
+            return title ?? control.Name ?? Loc.GetString("tab-container-not-tab-title-provided");
         }
 
         public static string? GetTabTitle(Control control)

Robust.Client/UserInterface/CustomControls/EntitySpawnWindow.cs

@@ -65,7 +65,7 @@ namespace Robust.Client.UserInterface.CustomControls
             this.prototypeManager = prototypeManager;
             this.resourceCache = resourceCache;
 
-            Title = Loc.GetString("Entity Spawn Panel");
+            Title = Loc.GetString("entity-spawn-window-title");
 
 
             SetSize = (250, 300);
@@ -83,13 +83,13 @@ namespace Robust.Client.UserInterface.CustomControls
                             (SearchBar = new LineEdit
                             {
                                 HorizontalExpand = true,
-                                PlaceHolder = Loc.GetString("Search")
+                                PlaceHolder = Loc.GetString("entity-spawn-window-search-bar-placeholder")
                             }),
 
                             (ClearButton = new Button
                             {
                                 Disabled = true,
-                                Text = Loc.GetString("Clear"),
+                                Text = Loc.GetString("entity-spawn-window-clear-button"),
                             })
                         }
                     },
@@ -109,13 +109,13 @@ namespace Robust.Client.UserInterface.CustomControls
                             (EraseButton = new Button
                             {
                                 ToggleMode = true,
-                                Text = Loc.GetString("Erase Mode")
+                                Text = Loc.GetString("entity-spawn-window-erase-button-text")
                             }),
 
                             (OverrideMenu = new OptionButton
                             {
                                 HorizontalExpand = true,
-                                ToolTip = Loc.GetString("Override placement")
+                                ToolTip = Loc.GetString("entity-spawn-window-override-menu-tooltip")
                             })
                         }
                     },

Robust.Client/UserInterface/CustomControls/ScriptConsole.cs

@@ -1,6 +1,5 @@
 using Robust.Client.Graphics;
 using Robust.Client.UserInterface.Controls;
-using Robust.Shared.Localization;
 using Robust.Shared.Maths;
 
 namespace Robust.Client.UserInterface.CustomControls
@@ -37,9 +36,9 @@ namespace Robust.Client.UserInterface.CustomControls
                             (InputBar = new HistoryLineEdit
                             {
                                 HorizontalExpand = true,
-                                PlaceHolder = Loc.GetString("Your C# code here.")
+                                PlaceHolder = "Your C# code here."
                             }),
-                            (RunButton = new Button {Text = Loc.GetString("Run")})
+                            (RunButton = new Button {Text = "Run"})
                         }
                     },
                 }

Robust.Client/UserInterface/FileDialogManager.cs

@@ -148,7 +148,7 @@ namespace Robust.Client.UserInterface
         // ReSharper disable once MemberCanBeMadeStatic.Local
         private Task<string?> RunAsyncMaybe(Func<string?> action)
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            if (OperatingSystem.IsMacOS())
             {
                 // macOS seems pretty annoying about having the file dialog opened from the main thread.
                 // So we are forced to execute this synchronously on the main thread.
@@ -326,7 +326,7 @@ namespace Robust.Client.UserInterface
 
         private async Task<bool> IsKDialogAvailable()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            if (!OperatingSystem.IsLinux())
                 return false;
 
             if (!_checkedKDialogAvailable)

Robust.Client/ViewVariables/Instances/ViewVariablesInstanceEntity.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
@@ -120,7 +120,7 @@ namespace Robust.Client.ViewVariables.Instances
 
             var clientVBox = new VBoxContainer {SeparationOverride = 0};
             _tabs.AddChild(clientVBox);
-            _tabs.SetTabTitle(TabClientVars, "Client Variables");
+            _tabs.SetTabTitle(TabClientVars, Loc.GetString("view-variable-instance-entity-client-variables-tab-title"));
 
             var first = true;
             foreach (var group in LocalPropertyList(obj, ViewVariablesManager, _robustSerializer))
@@ -138,7 +138,7 @@ namespace Robust.Client.ViewVariables.Instances
 
             _clientComponents = new VBoxContainer {SeparationOverride = 0};
             _tabs.AddChild(_clientComponents);
-            _tabs.SetTabTitle(TabClientComponents, "Client Components");
+            _tabs.SetTabTitle(TabClientComponents, Loc.GetString("view-variable-instance-entity-client-components-tab-title"));
 
             PopulateClientComponents();
 
@@ -146,11 +146,11 @@ namespace Robust.Client.ViewVariables.Instances
             {
                 _serverVariables = new VBoxContainer {SeparationOverride = 0};
                 _tabs.AddChild(_serverVariables);
-                _tabs.SetTabTitle(TabServerVars, "Server Variables");
+                _tabs.SetTabTitle(TabServerVars, Loc.GetString("view-variable-instance-entity-server-variables-tab-title"));
 
                 _serverComponents = new VBoxContainer {SeparationOverride = 0};
                 _tabs.AddChild(_serverComponents);
-                _tabs.SetTabTitle(TabServerComponents, "Server Components");
+                _tabs.SetTabTitle(TabServerComponents, Loc.GetString("view-variable-instance-entity-server-components-tab-title"));
 
                 PopulateServerComponents(false);
             }
@@ -162,13 +162,13 @@ namespace Robust.Client.ViewVariables.Instances
 
             _clientComponents.AddChild(_clientComponentsSearchBar = new LineEdit
             {
-                PlaceHolder = Loc.GetString("Search"),
+                PlaceHolder = Loc.GetString("view-variable-instance-entity-client-components-search-bar-placeholder"),
                 HorizontalExpand = true,
             });
 
             _clientComponents.AddChild(_clientComponentsAddButton = new Button()
             {
-                Text = Loc.GetString("Add Component"),
+                Text = Loc.GetString("view-variable-instance-entity-server-components-add-component-button-placeholder"),
                 HorizontalExpand = true,
             });
 
@@ -198,13 +198,13 @@ namespace Robust.Client.ViewVariables.Instances
 
             _serverComponents.AddChild(_serverComponentsSearchBar = new LineEdit
             {
-                PlaceHolder = Loc.GetString("Search"),
+                PlaceHolder = Loc.GetString("view-variable-instance-entity-server-components-search-bar-placeholder"),
                 HorizontalExpand = true,
             });
 
             _serverComponents.AddChild(_serverComponentsAddButton = new Button()
             {
-                Text = Loc.GetString("Add Component"),
+                Text = Loc.GetString("view-variable-instance-entity-server-components-add-component-button-placeholder"),
                 HorizontalExpand = true,
             });
 
@@ -336,7 +336,7 @@ namespace Robust.Client.ViewVariables.Instances
         {
             _addComponentWindow?.Dispose();
 
-            _addComponentWindow = new ViewVariablesAddWindow(GetValidComponentsForAdding(), "Add Component [C]");
+            _addComponentWindow = new ViewVariablesAddWindow(GetValidComponentsForAdding(), Loc.GetString("view-variable-instance-entity-add-window-client-components"));
             _addComponentWindow.AddButtonPressed += TryAdd;
             _addComponentServer = false;
 
@@ -349,7 +349,7 @@ namespace Robust.Client.ViewVariables.Instances
 
             if (_entitySession == null) return;
 
-            _addComponentWindow = new ViewVariablesAddWindow(await GetValidServerComponentsForAdding(), "Add Component [S]");
+            _addComponentWindow = new ViewVariablesAddWindow(await GetValidServerComponentsForAdding(), Loc.GetString("view-variable-instance-entity-add-window-server-components"));
             _addComponentWindow.AddButtonPressed += TryAdd;
             _addComponentServer = true;
 

Robust.Client/ViewVariables/ViewVariablesCommand.cs

@@ -33,6 +33,9 @@ namespace Robust.Client.ViewVariables
             var valArg = args[0];
             if (valArg.StartsWith("SI"))
             {
+                if (valArg.StartsWith("SIoC"))
+                    valArg = valArg.Substring(4);
+
                 // Server-side IoC selector.
                 var selector = new ViewVariablesIoCSelector(valArg.Substring(1));
                 vvm.OpenVV(selector);
@@ -41,6 +44,9 @@ namespace Robust.Client.ViewVariables
 
             if (valArg.StartsWith("I"))
             {
+                if (valArg.StartsWith("IoC"))
+                    valArg = valArg.Substring(3);
+
                 // Client-side IoC selector.
                 var reflection = IoCManager.Resolve<IReflectionManager>();
                 if (!reflection.TryLooseGetType(valArg, out var type))

Robust.Server/BaseServer.cs

@@ -102,6 +102,8 @@ namespace Robust.Server
 
         private readonly ManualResetEventSlim _shutdownEvent = new(false);
 
+        public ServerOptions Options { get; private set; } = new();
+
         /// <inheritdoc />
         public int MaxPlayers => _config.GetCVar(CVars.GameMaxPlayers);
 
@@ -114,7 +116,7 @@ namespace Robust.Server
             Logger.InfoS("srv", "Restarting Server...");
 
             Cleanup();
-            Start(_logHandlerFactory);
+            Start(Options, _logHandlerFactory);
         }
 
         /// <inheritdoc />
@@ -141,15 +143,16 @@ namespace Robust.Server
         }
 
         /// <inheritdoc />
-        public bool Start(Func<ILogHandler>? logHandlerFactory = null)
+        public bool Start(ServerOptions options, Func<ILogHandler>? logHandlerFactory = null)
         {
+            Options = options;
             var profilePath = Path.Join(Environment.CurrentDirectory, "AAAAAAAA");
             ProfileOptimization.SetProfileRoot(profilePath);
             ProfileOptimization.StartProfile("AAAAAAAAAA");
 
             _config.Initialize(true);
 
-            if (LoadConfigAndUserData)
+            if (Options.LoadConfigAndUserData)
             {
                 // Sets up the configMgr
                 // If a config file path was passed, use it literally.
@@ -269,22 +272,26 @@ namespace Robust.Server
                 return true;
             }
 
-            var dataDir = LoadConfigAndUserData
+            var dataDir = Options.LoadConfigAndUserData
                 ? _commandLineArgs?.DataDir ?? PathHelpers.ExecutableRelativeFile("data")
                 : null;
 
             // Set up the VFS
             _resources.Initialize(dataDir);
 
-            ProgramShared.DoMounts(_resources, _commandLineArgs?.MountOptions, "Content.Server", contentStart:ContentStart);
+            var mountOptions = _commandLineArgs != null
+                ? MountOptions.Merge(_commandLineArgs.MountOptions, Options.MountOptions) : Options.MountOptions;
+
+            ProgramShared.DoMounts(_resources, mountOptions, Options.ContentBuildDirectory, Options.AssemblyDirectory,
+                Options.LoadContentResources, Options.ResourceMountDisabled, ContentStart);
 
             // When the game is ran with the startup executable being content,
             // we have to disable the separate load context.
             // Otherwise the content assemblies will be loaded twice which causes *many* fun bugs.
             _modLoader.SetUseLoadContext(!ContentStart);
-            _modLoader.SetEnableSandboxing(false);
+            _modLoader.SetEnableSandboxing(Options.Sandboxing);
 
-            if (!_modLoader.TryLoadModulesFrom(new ResourcePath("/Assemblies/"), "Content."))
+            if (!_modLoader.TryLoadModulesFrom(Options.AssemblyDirectory, Options.ContentModulePrefix))
             {
                 Logger.Fatal("Errors while loading content assemblies.");
                 return true;
@@ -335,13 +342,23 @@ namespace Robust.Server
             // otherwise the prototypes will be cleared
             var prototypeManager = IoCManager.Resolve<IPrototypeManager>();
             prototypeManager.Initialize();
-            prototypeManager.LoadDirectory(new ResourcePath(@"/Prototypes"));
+            prototypeManager.LoadDirectory(Options.PrototypeDirectory);
             prototypeManager.Resync();
 
             IoCManager.Resolve<IServerConsoleHost>().Initialize();
             _entityManager.Startup();
             IoCManager.Resolve<IEntityLookup>().Startup();
             _stateManager.Initialize();
+
+            // sometime after content init
+            {
+                var reg = _entityManager.ComponentFactory.GetRegistration<TransformComponent>();
+                if (!reg.NetID.HasValue)
+                    throw new InvalidOperationException("TransformComponent does not have a NetId.");
+
+                _stateManager.SetTransformNetId(reg.NetID.Value);
+            }
+
             _scriptHost.Initialize();
 
             _modLoader.BroadcastRunLevel(ModRunLevel.PostInit);
@@ -355,7 +372,7 @@ namespace Robust.Server
             AddFinalStringsToSerializer();
             _stringSerializer.LockStrings();
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && _config.GetCVar(CVars.SysWinTickPeriod) >= 0)
+            if (OperatingSystem.IsWindows() && _config.GetCVar(CVars.SysWinTickPeriod) >= 0)
             {
                 WindowsTickPeriod.TimeBeginPeriod((uint) _config.GetCVar(CVars.SysWinTickPeriod));
             }
@@ -449,8 +466,7 @@ namespace Robust.Server
             }
         }
 
-        /// <inheritdoc />
-        public void MainLoop()
+        internal void SetupMainLoop()
         {
             if (_mainLoop == null)
             {
@@ -472,16 +488,27 @@ namespace Robust.Server
 
             // set GameLoop.Running to false to return from this function.
             _time.Paused = false;
-            _mainLoop.Run();
+        }
 
+        internal void FinishMainLoop()
+        {
             _time.InSimulation = true;
             Cleanup();
 
             _shutdownEvent.Set();
         }
 
+        /// <inheritdoc />
+        public void MainLoop()
+        {
+            SetupMainLoop();
+
+            _mainLoop.Run();
+
+            FinishMainLoop();
+        }
+
         public bool ContentStart { get; set; }
-        public bool LoadConfigAndUserData { private get; set; } = true;
 
         public void OverrideMainLoop(IGameLoop gameLoop)
         {
@@ -560,7 +587,7 @@ namespace Robust.Server
 
             //TODO: This should prob shutdown all managers in a loop.
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && _config.GetCVar(CVars.SysWinTickPeriod) >= 0)
+            if (OperatingSystem.IsWindows() && _config.GetCVar(CVars.SysWinTickPeriod) >= 0)
             {
                 WindowsTickPeriod.TimeEndPeriod((uint) _config.GetCVar(CVars.SysWinTickPeriod));
             }

Robust.Server/ContentStart.cs

@@ -7,13 +7,13 @@ namespace Robust.Server
 #if FULL_RELEASE
             throw new System.InvalidOperationException("ContentStart.Start is not available on a full release.");
 #else
-            Program.Start(args, true);
+            Program.Start(args, new ServerOptions(), true);
 #endif
         }
 
-        public static void StartLibrary(string[] args)
+        public static void StartLibrary(string[] args, ServerOptions options)
         {
-            Program.Start(args, true);
+            Program.Start(args, options, true);
         }
     }
 }

Robust.Server/GameObjects/Components/Actor/ActorComponent.cs

@@ -1,4 +1,3 @@
-using System;
 using Robust.Server.Player;
 using Robust.Shared.GameObjects;
 using Robust.Shared.ViewVariables;
@@ -12,34 +11,4 @@ namespace Robust.Server.GameObjects
         [ViewVariables]
         public IPlayerSession PlayerSession { get; internal set; } = default!;
     }
-
-    /// <summary>
-    ///     Raised on an entity whenever a player attaches to this entity.
-    /// </summary>
-    [Serializable]
-    [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
-    public class PlayerAttachedMsg : ComponentMessage
-    {
-        public IPlayerSession NewPlayer { get; }
-
-        public PlayerAttachedMsg(IPlayerSession newPlayer)
-        {
-            NewPlayer = newPlayer;
-        }
-    }
-
-    /// <summary>
-    ///     Raised on an entity whenever a player detaches from this entity.
-    /// </summary>
-    [Serializable]
-    [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
-    public class PlayerDetachedMsg : ComponentMessage
-    {
-        public IPlayerSession OldPlayer { get; }
-
-        public PlayerDetachedMsg(IPlayerSession oldPlayer)
-        {
-            OldPlayer = oldPlayer;
-        }
-    }
 }

Robust.Server/GameObjects/Components/Eye/EyeComponent.cs

@@ -1,4 +1,5 @@
 using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
 using Robust.Shared.Maths;
 using Robust.Shared.Prototypes;
 using Robust.Shared.Players;

Robust.Server/GameObjects/Components/Light/PointLightComponent.cs

@@ -1,4 +1,5 @@
 using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
 using Robust.Shared.Maths;
 using Robust.Shared.Prototypes;
 using Robust.Shared.Players;
@@ -10,6 +11,7 @@ namespace Robust.Server.GameObjects
 {
     [RegisterComponent]
     [ComponentReference(typeof(IPointLightComponent))]
+    [NetworkedComponent()]
     public class PointLightComponent : Component, IPointLightComponent
     {
         [DataField("color")]
@@ -22,7 +24,6 @@ namespace Robust.Server.GameObjects
         private Vector2 _offset = Vector2.Zero;
 
         public override string Name => "PointLight";
-        public override uint? NetID => NetIDs.POINT_LIGHT;
 
         [ViewVariables(VVAccess.ReadWrite)]
         public Color Color

Robust.Server/GameObjects/EntitySystems/ActorSystem.cs

@@ -80,9 +80,6 @@ namespace Robust.Server.GameObjects
             actor.PlayerSession = player;
             player.SetAttachedEntity(entity);
 
-            // TODO: Remove component message.
-            entity.SendMessage(actor, new PlayerAttachedMsg(player));
-
             // The player is fully attached now, raise an event!
             RaiseLocalEvent(uid, new PlayerAttachedEvent(entity, player, forceKicked));
             return true;
@@ -129,9 +126,6 @@ namespace Robust.Server.GameObjects
 
             var entity = EntityManager.GetEntity(uid);
 
-            // TODO: Remove component message.
-            entity.SendMessage(component, new PlayerDetachedMsg(component.PlayerSession));
-
             // The player is fully detached now that the component has shut down.
             RaiseLocalEvent(uid, new PlayerDetachedEvent(entity, component.PlayerSession));
         }

Robust.Server/GameObjects/EntitySystems/TileLookup/GridTileLookupNode.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Maths;
 
@@ -7,7 +8,7 @@ namespace Robust.Server.GameObjects
     internal sealed class GridTileLookupNode
     {
         internal GridTileLookupChunk ParentChunk { get; }
-        
+
         internal Vector2i Indices { get; }
 
         internal IEnumerable<IEntity> Entities
@@ -17,7 +18,18 @@ namespace Robust.Server.GameObjects
                 foreach (var entity in _entities)
                 {
                     if (!entity.Deleted)
+                    {
                         yield return entity;
+                    }
+
+                    if (!entity.TryGetComponent(out ContainerManagerComponent? containerManager)) continue;
+                    foreach (var container in containerManager.GetAllContainers())
+                    {
+                        foreach (var child in container.ContainedEntities)
+                        {
+                            yield return child;
+                        }
+                    }
                 }
             }
         }
@@ -29,7 +41,7 @@ namespace Robust.Server.GameObjects
             ParentChunk = parentChunk;
             Indices = indices;
         }
-        
+
         internal void AddEntity(IEntity entity)
         {
             _entities.Add(entity);

Robust.Server/GameObjects/EntitySystems/TileLookup/GridTileLookupSystem.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using JetBrains.Annotations;
+using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
@@ -212,6 +213,8 @@ namespace Robust.Server.GameObjects
             SubscribeNetworkEvent<RequestGridTileLookupMessage>(HandleRequest);
             #endif
             SubscribeLocalEvent<MoveEvent>(HandleEntityMove);
+            SubscribeLocalEvent<EntInsertedIntoContainerMessage>(HandleContainerInsert);
+            SubscribeLocalEvent<EntRemovedFromContainerMessage>(HandleContainerRemove);
             SubscribeLocalEvent<EntityInitializedMessage>(HandleEntityInitialized);
             SubscribeLocalEvent<EntityDeletedMessage>(HandleEntityDeleted);
             _mapManager.OnGridCreated += HandleGridCreated;
@@ -219,6 +222,16 @@ namespace Robust.Server.GameObjects
             _mapManager.TileChanged += HandleTileChanged;
         }
 
+        private void HandleContainerRemove(EntRemovedFromContainerMessage ev)
+        {
+            HandleEntityAdd(ev.Entity);
+        }
+
+        private void HandleContainerInsert(EntInsertedIntoContainerMessage ev)
+        {
+            HandleEntityRemove(ev.Entity);
+        }
+
         public override void Shutdown()
         {
             base.Shutdown();
@@ -238,6 +251,11 @@ namespace Robust.Server.GameObjects
 
         private void HandleEntityInitialized(EntityInitializedMessage message)
         {
+            if (message.Entity.IsInContainer())
+            {
+                return;
+            }
+
             HandleEntityAdd(message.Entity);
         }
 

Robust.Server/GameObjects/ServerComponentFactory.cs

@@ -1,11 +1,15 @@
+using Robust.Shared.Console;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Reflection;
 
 namespace Robust.Server.GameObjects
 {
-    public class ServerComponentFactory : ComponentFactory
+    internal class ServerComponentFactory : ComponentFactory
     {
-        public ServerComponentFactory()
+        public ServerComponentFactory(IDynamicTypeFactoryInternal typeFactory, IReflectionManager reflectionManager, IConsoleHost conHost)
+            : base(typeFactory, reflectionManager, conHost)
         {
             RegisterIgnore("Input");
             RegisterIgnore("AnimationPlayer");

Robust.Server/GameObjects/ServerEntityManager.cs

@@ -75,7 +75,7 @@ namespace Robust.Server.GameObjects
                 // As such, we can reset the modified ticks to Zero,
                 // which indicates "not different from client's own deserialization".
                 // So the initial data for the component or even the creation doesn't have to be sent over the wire.
-                foreach (var component in ComponentManager.GetNetComponents(entity.Uid))
+                foreach (var (netId, component) in ComponentManager.GetNetComponents(entity.Uid))
                 {
                     // Make sure to ONLY get components that are defined in the prototype.
                     // Others could be instantiated directly by AddComponent (e.g. ContainerManager).
@@ -143,13 +143,15 @@ namespace Robust.Server.GameObjects
             if (_networkManager.IsClient)
                 return;
 
-            if (!component.NetID.HasValue)
+            var netId = ComponentFactory.GetRegistration(component.GetType()).NetID;
+
+            if (!netId.HasValue)
                 throw new ArgumentException($"Component {component.Name} does not have a NetID.", nameof(component));
 
             var msg = _networkManager.CreateNetMessage<MsgEntity>();
             msg.Type = EntityMessageType.ComponentMessage;
             msg.EntityUid = entity.Uid;
-            msg.NetId = component.NetID.Value;
+            msg.NetId = netId.Value;
             msg.ComponentMessage = message;
             msg.SourceTick = _gameTiming.CurTick;
 

Robust.Server/GameStates/EntityViewCulling.cs

@@ -39,6 +39,8 @@ namespace Robust.Server.GameStates
         private readonly ObjectPool<HashSet<EntityUid>> _viewerEntsPool
             = new DefaultObjectPool<HashSet<EntityUid>>(new DefaultPooledObjectPolicy<HashSet<EntityUid>>(), MaxVisPoolSize);
 
+        private ushort _transformNetId = 0;
+
         /// <summary>
         /// Is view culling enabled, or will we send the whole map?
         /// </summary>
@@ -58,6 +60,11 @@ namespace Robust.Server.GameStates
             _lookup = lookup;
         }
 
+        public void SetTransformNetId(ushort value)
+        {
+            _transformNetId = value;
+        }
+
         // Not thread safe
         public void EntityDeleted(EntityUid e)
         {
@@ -204,16 +211,14 @@ namespace Robust.Server.GameStates
                 var oldState = (TransformComponent.TransformComponentState) xform.GetComponentState(session);
 
                 entityStates.Add(new EntityState(entityUid,
-                    new ComponentChanged[]
+                    new[]
                     {
-                        new(false, NetIDs.TRANSFORM, "Transform")
-                    },
-                    new ComponentState[]
-                    {
-                        new TransformComponent.TransformComponentState(Vector2NaN,
-                            oldState.Rotation,
-                            oldState.ParentID,
-                            oldState.NoLocalRotation)
+                        ComponentChange.Changed(_transformNetId,
+                            new TransformComponent.TransformComponentState(Vector2NaN,
+                                oldState.Rotation,
+                                oldState.ParentID,
+                                oldState.NoLocalRotation,
+                                oldState.Anchored)),
                     }));
             }
 

Robust.Server/GameStates/IServerGameStateManager.cs

@@ -17,5 +17,6 @@ namespace Robust.Server.GameStates
 
         bool PvsEnabled { get; set; }
         float PvsRange { get; set; }
+        void SetTransformNetId(ushort netId);
     }
 }

Robust.Server/GameStates/ServerGameStateManager.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
+using JetBrains.Annotations;
 using Robust.Server.GameObjects;
 using Robust.Server.Map;
 using Robust.Server.Player;
@@ -21,6 +22,7 @@ using Robust.Shared.Utility;
 namespace Robust.Server.GameStates
 {
     /// <inheritdoc cref="IServerGameStateManager"/>
+    [UsedImplicitly]
     public class ServerGameStateManager : IServerGameStateManager, IPostInjectInit
     {
         // Mapping of net UID of clients -> last known acked state.
@@ -53,6 +55,11 @@ namespace Robust.Server.GameStates
             set => _configurationManager.SetCVar(CVars.NetMaxUpdateRange, value);
         }
 
+        public void SetTransformNetId(ushort netId)
+        {
+            _entityView.SetTransformNetId(netId);
+        }
+
         public void PostInject()
         {
             _logger = Logger.GetSawmill("PVS");
@@ -183,6 +190,8 @@ namespace Robust.Server.GameStates
                     oldestAck = lastAck;
                 }
 
+                DebugTools.Assert(state.MapData?.CreatedMaps is null || (state.MapData?.CreatedMaps is not null && state.EntityStates is not null), "Sending new maps, but no entity state.");
+
                 // actually send the state
                 var stateUpdateMessage = _networkManager.CreateNetMessage<MsgState>();
                 stateUpdateMessage.State = state;
@@ -247,38 +256,44 @@ namespace Robust.Server.GameStates
         /// <returns>New entity State for the given entity.</returns>
         internal static EntityState GetEntityState(IComponentManager compMan, ICommonSession player, EntityUid entityUid, GameTick fromTick)
         {
-            var compStates = new List<ComponentState>();
-            var changed = new List<ComponentChanged>();
+            var changed = new List<ComponentChange>();
 
-            foreach (var comp in compMan.GetNetComponents(entityUid))
+            foreach (var (netId, component) in compMan.GetNetComponents(entityUid))
             {
-                DebugTools.Assert(comp.Initialized);
+                DebugTools.Assert(component.Initialized);
 
                 // NOTE: When LastModifiedTick or CreationTick are 0 it means that the relevant data is
                 // "not different from entity creation".
                 // i.e. when the client spawns the entity and loads the entity prototype,
                 // the data it deserializes from the prototype SHOULD be equal
-                // to what the component state / ComponentChanged would send.
+                // to what the component state / ComponentChange would send.
                 // As such, we can avoid sending this data in this case since the client "already has it".
 
-                if (comp.NetSyncEnabled && comp.LastModifiedTick != GameTick.Zero && comp.LastModifiedTick >= fromTick)
-                    compStates.Add(comp.GetComponentState(player));
+                DebugTools.Assert(component.LastModifiedTick >= component.CreationTick);
 
-                if (comp.CreationTick != GameTick.Zero && comp.CreationTick >= fromTick && !comp.Deleted)
+                if (component.CreationTick != GameTick.Zero && component.CreationTick >= fromTick && !component.Deleted)
                 {
+                    ComponentState? state = null;
+                    if (component.NetSyncEnabled && component.LastModifiedTick != GameTick.Zero && component.LastModifiedTick >= fromTick)
+                        state = component.GetComponentState(player);
+
                     // Can't be null since it's returned by GetNetComponents
                     // ReSharper disable once PossibleInvalidOperationException
-                    changed.Add(ComponentChanged.Added(comp.NetID!.Value, comp.Name));
+                    changed.Add(ComponentChange.Added(netId, state));
                 }
-                else if (comp.Deleted && comp.LastModifiedTick >= fromTick)
+                else if (component.NetSyncEnabled && component.LastModifiedTick != GameTick.Zero && component.LastModifiedTick >= fromTick)
+                {
+                    changed.Add(ComponentChange.Changed(netId, component.GetComponentState(player)));
+                }
+                else if (component.Deleted && component.LastModifiedTick >= fromTick)
                 {
                     // Can't be null since it's returned by GetNetComponents
                     // ReSharper disable once PossibleInvalidOperationException
-                    changed.Add(ComponentChanged.Removed(comp.NetID!.Value));
+                    changed.Add(ComponentChange.Removed(netId));
                 }
             }
 
-            return new EntityState(entityUid, changed.ToArray(), compStates.ToArray());
+            return new EntityState(entityUid, changed.ToArray());
         }
 
         /// <summary>
@@ -296,10 +311,8 @@ namespace Robust.Server.GameStates
 
                 DebugTools.Assert(entity.Initialized);
 
-                if (entity.LastModifiedTick <= fromTick)
-                    continue;
-
-                stateEntities.Add(GetEntityState(entityMan.ComponentManager, player, entity.Uid, fromTick));
+                if (entity.LastModifiedTick >= fromTick)
+                    stateEntities.Add(GetEntityState(entityMan.ComponentManager, player, entity.Uid, fromTick));
             }
 
             // no point sending an empty collection

Robust.Server/IBaseServer.cs

@@ -23,7 +23,7 @@ namespace Robust.Server
         ///     Sets up the server, loads the game, gets ready for client connections.
         /// </summary>
         /// <returns></returns>
-        bool Start(Func<ILogHandler>? logHandler = null);
+        bool Start(ServerOptions options, Func<ILogHandler>? logHandler = null);
 
         /// <summary>
         ///     Hard restarts the server, shutting it down, kicking all players, and starting the server again.
@@ -44,11 +44,10 @@ namespace Robust.Server
 
     internal interface IBaseServerInternal : IBaseServer
     {
+        ServerOptions Options { get; }
         bool ContentStart { set; }
-        bool LoadConfigAndUserData { set; }
 
         void OverrideMainLoop(IGameLoop gameLoop);
-
         void SetCommandLineArgs(CommandLineArgs args);
     }
 }

Robust.Server/Maps/MapLoader.cs

@@ -409,7 +409,7 @@ namespace Robust.Server.Maps
                         continue;
                     }
 
-                    foreach (var component in _componentManager.GetNetComponents(entity.Uid))
+                    foreach (var (netId, component) in _componentManager.GetNetComponents(entity.Uid))
                     {
                         var castComp = (Component) component;
 

Robust.Server/Program.cs

@@ -21,10 +21,10 @@ namespace Robust.Server
 
         internal static void Main(string[] args)
         {
-            Start(args);
+            Start(args, new ServerOptions());
         }
 
-        internal static void Start(string[] args, bool contentStart = false)
+        internal static void Start(string[] args, ServerOptions options, bool contentStart = false)
         {
             if (_hasStarted)
             {
@@ -47,11 +47,11 @@ namespace Robust.Server
                     TaskCreationOptions.LongRunning,
                     TaskContinuationOptions.None,
                     RobustTaskScheduler.Instance
-                ).StartNew(() => ParsedMain(parsed, contentStart))
+                ).StartNew(() => ParsedMain(parsed, contentStart, options))
                 .GetAwaiter().GetResult();
         }
 
-        private static void ParsedMain(CommandLineArgs args, bool contentStart)
+        private static void ParsedMain(CommandLineArgs args, bool contentStart, ServerOptions options)
         {
             Thread.CurrentThread.Name = "Main Thread";
             IoCManager.InitThread();
@@ -67,7 +67,7 @@ namespace Robust.Server
 
             Logger.Info("Server -> Starting");
 
-            if (server.Start())
+            if (server.Start(options))
             {
                 Logger.Fatal("Server -> Can not start server");
                 //Not like you'd see this, haha. Perhaps later for logging.
@@ -98,7 +98,7 @@ namespace Robust.Server
 
         internal static void SetupLogging()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
 #if WINDOWS_USE_UTF8_CONSOLE
                 System.Console.OutputEncoding = Encoding.UTF8;

Robust.Server/ServerIoC.cs

@@ -37,11 +37,13 @@ namespace Robust.Server
 
             IoCManager.Register<IBaseServer, BaseServer>();
             IoCManager.Register<IBaseServerInternal, BaseServer>();
+            IoCManager.Register<BaseServer, BaseServer>();
             IoCManager.Register<IGameTiming, GameTiming>();
+            IoCManager.Register<IReflectionManager, ServerReflectionManager>();
+            IoCManager.Register<IConsoleHost, ServerConsoleHost>();
+            IoCManager.Register<IServerConsoleHost, ServerConsoleHost>();
             IoCManager.Register<IComponentFactory, ServerComponentFactory>();
             IoCManager.Register<IConGroupController, ConGroupController>();
-            IoCManager.Register<IServerConsoleHost, ServerConsoleHost>();
-            IoCManager.Register<IConsoleHost, ServerConsoleHost>();
             IoCManager.Register<IMapManager, ServerMapManager>();
             IoCManager.Register<IMapManagerInternal, ServerMapManager>();
             IoCManager.Register<IServerMapManager, ServerMapManager>();
@@ -54,7 +56,6 @@ namespace Robust.Server
             IoCManager.Register<IPlayerManager, PlayerManager>();
             IoCManager.Register<ISharedPlayerManager, PlayerManager>();
             IoCManager.Register<IPrototypeManager, ServerPrototypeManager>();
-            IoCManager.Register<IReflectionManager, ServerReflectionManager>();
             IoCManager.Register<IResourceManager, ResourceManager>();
             IoCManager.Register<IResourceManagerInternal, ResourceManager>();
             IoCManager.Register<IServerEntityManager, ServerEntityManager>();

Robust.Server/ServerOptions.cs

@@ -0,0 +1,54 @@
+using Robust.Shared;
+using Robust.Shared.Utility;
+
+namespace Robust.Server
+{
+    public class ServerOptions
+    {
+        /// <summary>
+        ///     Whether content sandboxing will be enabled & enforced.
+        /// </summary>
+        public bool Sandboxing { get; init; } = false;
+
+        // TODO: Expose mounting methods to games using Robust as a library.
+        /// <summary>
+        ///     Lists of mount options to mount.
+        /// </summary>
+        public MountOptions MountOptions { get; init; } = new();
+
+        /// <summary>
+        ///     Assemblies with this prefix will be loaded.
+        /// </summary>
+        public string ContentModulePrefix { get; init; } = "Content.";
+
+        /// <summary>
+        ///     Name of the content build directory, for game pack mounting purposes.
+        /// </summary>
+        public string ContentBuildDirectory { get; init; } = "Content.Server";
+
+        /// <summary>
+        ///     Directory to load all assemblies from.
+        /// </summary>
+        public ResourcePath AssemblyDirectory { get; init; } = new(@"/Assemblies/");
+
+        /// <summary>
+        ///     Directory to load all prototypes from.
+        /// </summary>
+        public ResourcePath PrototypeDirectory { get; init; } = new(@"/Prototypes/");
+
+        /// <summary>
+        ///     Whether to disable mounting the "Resources/" folder on FULL_RELEASE.
+        /// </summary>
+        public bool ResourceMountDisabled { get; init; } = false;
+
+        /// <summary>
+        ///     Whether to mount content resources when not on FULL_RELEASE.
+        /// </summary>
+        public bool LoadContentResources { get; init; } = true;
+
+        /// <summary>
+        ///     Whether to load config and user data.
+        /// </summary>
+        public bool LoadConfigAndUserData { get; init; } = true;
+    }
+}

Robust.Server/Utility/WindowsTickPeriod.cs

@@ -11,7 +11,7 @@ namespace Robust.Server.Utility
 
         public static void TimeBeginPeriod(uint period)
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (!OperatingSystem.IsWindows())
                 throw new InvalidOperationException();
 
             var ret = timeBeginPeriod(period);
@@ -21,7 +21,7 @@ namespace Robust.Server.Utility
 
         public static void TimeEndPeriod(uint period)
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (!OperatingSystem.IsWindows())
                 throw new InvalidOperationException();
 
             var ret = timeEndPeriod(period);

Robust.Shared.Maths/Box2Rotated.cs

@@ -149,6 +149,26 @@ namespace Robust.Shared.Maths
             return new Box2(X0, Y0, X1, Y1);
         }
 
+        public bool Contains(Vector2 worldPoint)
+        {
+            // Get the worldpoint in our frame of reference so we can do a faster AABB check.
+            var localPoint = GetLocalPoint(worldPoint);
+            return Box.Contains(localPoint);
+        }
+
+        /// <summary>
+        /// Convert a point in world-space coordinates to our local coordinates.
+        /// </summary>
+        private Vector2 GetLocalPoint(Vector2 point)
+        {
+            // Could make this more efficient but works for now I guess...
+            var boxCenter = Box.Center;
+
+            var result = point - boxCenter;
+            result = Origin + Rotation.RotateVec(result - Origin);
+            return result + boxCenter;
+        }
+
         #region Equality
 
         /// <inheritdoc />

Robust.Shared/Asynchronous/TaskManager.cs

@@ -14,6 +14,11 @@ namespace Robust.Shared.Asynchronous
         public void Initialize()
         {
             _mainThreadContext = new RobustSynchronizationContext(_runtimeLog);
+            ResetSynchronizationContext();
+        }
+
+        public void ResetSynchronizationContext()
+        {
             SynchronizationContext.SetSynchronizationContext(_mainThreadContext);
         }
 

Robust.Shared/CVars.cs

@@ -73,7 +73,7 @@ namespace Robust.Shared
         // just has the Lidgren thread go absolute brr polling.
         public static readonly CVarDef<float> NetPredictLagBias = CVarDef.Create(
                 "net.predict_lag_bias",
-                RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? 0.016f : 0,
+                OperatingSystem.IsWindows() ? 0.016f : 0,
                 CVar.ARCHIVE);
 
         public static readonly CVarDef<int> NetStateBufMergeThreshold =
@@ -211,6 +211,21 @@ namespace Robust.Shared
         public static readonly CVarDef<bool> LogRuntimeLog =
             CVarDef.Create("log.runtimelog", true, CVar.ARCHIVE | CVar.SERVERONLY);
 
+        /*
+         * Light
+         */
+
+        /// <summary>
+        /// This is the maximum the viewport is enlarged to check for any intersecting render-trees for lights.
+        /// This should be set to your maximum light radius.
+        /// </summary>
+        /// <remarks>
+        /// If this value is too small it just means there may be pop-in where a light is located on a render-tree
+        /// outside of our viewport.
+        /// </remarks>
+        public static readonly CVarDef<float> MaxLightRadius =
+            CVarDef.Create("light.max_radius", 20.0f, CVar.CLIENTONLY);
+
         /*
          * LOKI
          */

Robust.Shared/Containers/BaseContainer.cs

@@ -68,6 +68,10 @@ namespace Robust.Shared.Containers
             InternalInsert(toinsert);
             transform.AttachParent(Owner.Transform);
 
+            // This is an edge case where the parent grid is the container being inserted into, so AttachParent would not unanchor.
+            if (transform.Anchored)
+                transform.Anchored = false;
+
             // spatially move the object to the location of the container. If you don't want this functionality, the
             // calling code can save the local position before calling this function, and apply it afterwords.
             transform.LocalPosition = Vector2.Zero;
@@ -147,7 +151,6 @@ namespace Robust.Shared.Containers
 
             Owner.EntityManager.EventBus.RaiseLocalEvent(Owner.Uid, new EntInsertedIntoContainerMessage(toinsert, this));
             Owner.EntityManager.EventBus.RaiseEvent(EventSource.Local, new UpdateContainerOcclusionMessage(toinsert));
-            Manager.Owner.SendMessage(Manager, new ContainerContentsModifiedMessage(this, toinsert, false));
             Manager.Dirty();
         }
 
@@ -164,7 +167,6 @@ namespace Robust.Shared.Containers
 
             Owner.EntityManager.EventBus.RaiseLocalEvent(Owner.Uid, new EntRemovedFromContainerMessage(toremove, this));
             Owner.EntityManager.EventBus.RaiseEvent(EventSource.Local, new UpdateContainerOcclusionMessage(toremove));
-            Manager.Owner.SendMessage(Manager, new ContainerContentsModifiedMessage(this, toremove, true));
             Manager.Dirty();
         }
     }

Robust.Shared/Containers/ContainerContentsModifiedMessage.cs

@@ -1,40 +0,0 @@
-using System;
-using Robust.Shared.GameObjects;
-
-namespace Robust.Shared.Containers
-{
-    /// <summary>
-    /// The contents of this container have been changed.
-    /// </summary>
-    [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
-    public class ContainerContentsModifiedMessage : ComponentMessage
-    {
-        /// <summary>
-        /// Container whose contents were modified.
-        /// </summary>
-        public IContainer Container { get; }
-
-        /// <summary>
-        /// Entity that was added or removed from the container.
-        /// </summary>
-        public IEntity Entity { get; }
-
-        /// <summary>
-        /// If true, the entity was removed. If false, it was added to the container.
-        /// </summary>
-        public bool Removed { get; }
-
-        /// <summary>
-        /// Constructs a new instance of <see cref="ContainerContentsModifiedMessage"/>.
-        /// </summary>
-        /// <param name="container">Container whose contents were modified.</param>
-        /// <param name="entity">Entity that was added or removed in the container.</param>
-        /// <param name="removed">If true, the entity was removed. If false, it was added to the container.</param>
-        public ContainerContentsModifiedMessage(IContainer container, IEntity entity, bool removed)
-        {
-            Container = container;
-            Entity = entity;
-            Removed = removed;
-        }
-    }
-}

Robust.Shared/Containers/ContainerManagerComponent.cs

@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Players;
 using Robust.Shared.Serialization;
@@ -17,6 +18,7 @@ namespace Robust.Shared.Containers
     /// Holds data about a set of entity containers on this entity.
     /// </summary>
     [ComponentReference(typeof(IContainerManager))]
+    [NetworkedComponent()]
     public class ContainerManagerComponent : Component, IContainerManager
     {
         [Dependency] private readonly IRobustSerializer _serializer = default!;
@@ -30,10 +32,7 @@ namespace Robust.Shared.Containers
         public sealed override string Name => "ContainerContainer";
 
         /// <inheritdoc />
-        public sealed override uint? NetID => NetIDs.CONTAINER_MANAGER;
-
-        /// <inheritdoc />
-        public override void OnRemove()
+        protected override void OnRemove()
         {
             base.OnRemove();
 
@@ -47,7 +46,7 @@ namespace Robust.Shared.Containers
         }
 
         /// <inheritdoc />
-        public override void Initialize()
+        protected override void Initialize()
         {
             base.Initialize();
 
@@ -281,7 +280,7 @@ namespace Robust.Shared.Containers
         {
             public List<ContainerData> ContainerSet;
 
-            public ContainerManagerComponentState(List<ContainerData> containers) : base(NetIDs.CONTAINER_MANAGER)
+            public ContainerManagerComponentState(List<ContainerData> containers)
             {
                 ContainerSet = containers;
             }

Robust.Shared/ContentPack/PathHelpers.cs

@@ -60,8 +60,8 @@ namespace Robust.Shared.ContentPack
 
         // TODO: gaf
         public static bool IsFileSystemCaseSensitive() =>
-            !RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
-            && !RuntimeInformation.IsOSPlatform(OSPlatform.OSX);
+            !OperatingSystem.IsWindows()
+            && !OperatingSystem.IsMacOS();
 
     }
 }

Robust.Shared/DllMapHelper.cs

@@ -33,12 +33,12 @@ namespace Robust.Shared
                     return IntPtr.Zero;
                 }
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                if (OperatingSystem.IsLinux())
                 {
                     return NativeLibrary.Load(linuxName, assembly, path);
                 }
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                if (OperatingSystem.IsMacOS())
                 {
                     return NativeLibrary.Load(macName, assembly, path);
                 }

Robust.Shared/GameObjects/Component.cs

@@ -1,4 +1,5 @@
 using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.Network;
 using Robust.Shared.Players;
 using Robust.Shared.Reflection;
@@ -18,14 +19,6 @@ namespace Robust.Shared.GameObjects
         [ViewVariables]
         public abstract string Name { get; }
 
-        /// <inheritdoc />
-        [ViewVariables]
-        public virtual uint? NetID => null;
-
-        /// <inheritdoc />
-        [ViewVariables]
-        public virtual bool NetworkSynchronizeExistence => false;
-
         /// <inheritdoc />
         [ViewVariables]
         [DataField("netsync")]
@@ -41,31 +34,94 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [ViewVariables]
-        public bool Initialized { get; private set; }
+        public ComponentLifeStage LifeStage { get; private set; } = ComponentLifeStage.PreAdd;
 
-        private bool _running;
-        /// <inheritdoc />
-        [ViewVariables(VVAccess.ReadWrite)]
-        public bool Running
+        /// <summary>
+        /// Increases the life stage from <see cref="ComponentLifeStage.PreAdd" /> to <see cref="ComponentLifeStage.Added" />,
+        /// calling <see cref="OnAdd" />.
+        /// </summary>
+        internal void LifeAddToEntity()
         {
-            get => _running;
-            set
-            {
-                if(_running == value)
-                    return;
+            DebugTools.Assert(LifeStage == ComponentLifeStage.PreAdd);
 
-                if(value)
-                    Startup();
-                else
-                    Shutdown();
+            LifeStage = ComponentLifeStage.Adding;
+            OnAdd();
 
-                _running = value;
-            }
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Added, $"Component {this.GetType().Name} did not call base {nameof(OnAdd)} in derived method.");
+        }
+
+        /// <summary>
+        /// Increases the life stage from <see cref="ComponentLifeStage.Added" /> to <see cref="ComponentLifeStage.Initialized" />,
+        /// calling <see cref="Initialize" />.
+        /// </summary>
+        internal void LifeInitialize()
+        {
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Added);
+
+            LifeStage = ComponentLifeStage.Initializing;
+            Initialize();
+
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Initialized, $"Component {this.GetType().Name} did not call base {nameof(Initialize)} in derived method.");
+        }
+
+        /// <summary>
+        /// Increases the life stage from <see cref="ComponentLifeStage.Initialized" /> to
+        /// <see cref="ComponentLifeStage.Running" />, calling <see cref="Startup" />.
+        /// </summary>
+        internal void LifeStartup()
+        {
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Initialized);
+
+            LifeStage = ComponentLifeStage.Starting;
+            Startup();
+
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Running, $"Component {this.GetType().Name} did not call base {nameof(Startup)} in derived method.");
+        }
+
+        /// <summary>
+        /// Increases the life stage from <see cref="ComponentLifeStage.Running" /> to <see cref="ComponentLifeStage.Stopped" />,
+        /// calling <see cref="Shutdown" />.
+        /// </summary>
+        /// <remarks>
+        /// Components are allowed to remove themselves in their own Startup function.
+        /// </remarks>
+        internal void LifeShutdown()
+        {
+            // Starting allows a component to remove itself in it's own Startup function.
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Starting || LifeStage == ComponentLifeStage.Running);
+
+            LifeStage = ComponentLifeStage.Stopping;
+            Shutdown();
+
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Stopped, $"Component {this.GetType().Name} did not call base {nameof(Shutdown)} in derived method.");
+        }
+
+        /// <summary>
+        /// Increases the life stage from <see cref="ComponentLifeStage.Stopped" /> to <see cref="ComponentLifeStage.Deleted" />,
+        /// calling <see cref="OnRemove" />.
+        /// </summary>
+        internal void LifeRemoveFromEntity()
+        {
+            // can be called at any time after PreAdd, including inside other life stage events.
+            DebugTools.Assert(LifeStage != ComponentLifeStage.PreAdd);
+
+            LifeStage = ComponentLifeStage.Removing;
+            OnRemove();
+
+            DebugTools.Assert(LifeStage == ComponentLifeStage.Deleted, $"Component {this.GetType().Name} did not call base {nameof(OnRemove)} in derived method.");
         }
 
         /// <inheritdoc />
         [ViewVariables]
-        public bool Deleted { get; private set; }
+        public bool Initialized => LifeStage >= ComponentLifeStage.Initializing;
+
+        /// <inheritdoc />
+        [ViewVariables]
+        public bool Running => ComponentLifeStage.Starting <= LifeStage && LifeStage <= ComponentLifeStage.Stopping;
+
+        /// <inheritdoc />
+        [ViewVariables]
+        public bool Deleted => LifeStage >= ComponentLifeStage.Removing;
 
         /// <inheritdoc />
         [ViewVariables]
@@ -91,87 +147,56 @@ namespace Robust.Shared.GameObjects
             return (EntityEventBus) Owner.EntityManager.EventBus;
         }
 
-        /// <inheritdoc />
-        public virtual void OnRemove()
+        /// <summary>
+        /// Called when the component gets added to an entity.
+        /// </summary>
+        protected virtual void OnAdd()
         {
-            if (Running)
-                throw new InvalidOperationException("Cannot Remove a running entity!");
-
-            // We have been marked for deletion by the Component Manager.
-            Deleted = true;
-            GetBus().RaiseComponentEvent(this, CompRemoveInstance);
+            CreationTick = Owner.EntityManager.CurrentTick;
+            GetBus().RaiseComponentEvent(this, CompAddInstance);
+            LifeStage = ComponentLifeStage.Added;
         }
 
         /// <summary>
-        ///     Called when the component gets added to an entity.
+        /// Called when all of the entity's other components have been added and are available,
+        /// But are not necessarily initialized yet. DO NOT depend on the values of other components to be correct.
         /// </summary>
-        public virtual void OnAdd()
+        protected virtual void Initialize()
         {
-            if (Initialized)
-                throw new InvalidOperationException("Cannot Add an Initialized component!");
-
-            if (Running)
-                throw new InvalidOperationException("Cannot Add a running component!");
-
-            if (Deleted)
-                throw new InvalidOperationException("Cannot Add a Deleted component!");
-
-            CreationTick = Owner.EntityManager.CurrentTick;
-            GetBus().RaiseComponentEvent(this, CompAddInstance);
-        }
-
-        /// <inheritdoc />
-        public virtual void Initialize()
-        {
-            if (Initialized)
-                throw new InvalidOperationException("Component already Initialized!");
-
-            if (Running)
-                throw new InvalidOperationException("Cannot Initialize a running component!");
-
-            if (Deleted)
-                throw new InvalidOperationException("Cannot Initialize a Deleted component!");
-
-            Initialized = true;
             GetBus().RaiseComponentEvent(this, CompInitInstance);
+            LifeStage = ComponentLifeStage.Initialized;
         }
 
         /// <summary>
         ///     Starts up a component. This is called automatically after all components are Initialized and the entity is Initialized.
-        ///     This can be called multiple times during the component's life, and at any time.
         /// </summary>
+        /// <remarks>
+        /// Components are allowed to remove themselves in their own Startup function.
+        /// </remarks>
         protected virtual void Startup()
         {
-            if (!Initialized)
-                throw new InvalidOperationException("Cannot Start an uninitialized component!");
-
-            if (Running)
-                throw new InvalidOperationException("Cannot Startup a running component!");
-
-            if (Deleted)
-                throw new InvalidOperationException("Cannot Start a Deleted component!");
-
-            _running = true;
             GetBus().RaiseComponentEvent(this, CompStartupInstance);
+            LifeStage = ComponentLifeStage.Running;
         }
 
         /// <summary>
-        ///     Shuts down the component. The is called Automatically by OnRemove. This can be called multiple times during
-        ///     the component's life, and at any time.
+        ///     Shuts down the component. The is called Automatically by OnRemove.
         /// </summary>
         protected virtual void Shutdown()
         {
-            if (!Initialized)
-                throw new InvalidOperationException("Cannot Shutdown an uninitialized component!");
-
-            if (!Running)
-                throw new InvalidOperationException("Cannot Shutdown an unstarted component!");
-
-            if (Deleted)
-                throw new InvalidOperationException("Cannot Shutdown a Deleted component!");
-
-            _running = false;
             GetBus().RaiseComponentEvent(this, CompShutdownInstance);
+            LifeStage = ComponentLifeStage.Stopped;
+        }
+
+        /// <summary>
+        /// Called when the component is removed from an entity.
+        /// Shuts down the component.
+        /// The component has already been marked as deleted in the component manager.
+        /// </summary>
+        protected virtual void OnRemove()
+        {
+            GetBus().RaiseComponentEvent(this, CompRemoveInstance);
+            LifeStage = ComponentLifeStage.Deleted;
         }
 
         /// <inheritdoc />
@@ -217,14 +242,16 @@ namespace Robust.Shared.GameObjects
         [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
         public virtual void HandleNetworkMessage(ComponentMessage message, INetChannel netChannel, ICommonSession? session = null) { }
 
+        private static readonly ComponentState DefaultComponentState = new();
+
         /// <param name="player"></param>
         /// <inheritdoc />
         public virtual ComponentState GetComponentState(ICommonSession player)
         {
-            if (NetID == null)
-                throw new InvalidOperationException($"Cannot make state for component without Net ID: {GetType()}");
+            if (!(Attribute.GetCustomAttribute(GetType(), typeof(NetworkedComponentAttribute)) is NetworkedComponentAttribute))
+                throw new InvalidOperationException($"Calling base {nameof(GetComponentState)} without being networked.");
 
-            return new ComponentState(NetID.Value);
+            return DefaultComponentState;
         }
 
         /// <inheritdoc />
@@ -244,6 +271,67 @@ namespace Robust.Shared.GameObjects
         }
     }
 
+    /// <summary>
+    /// The life stages of an ECS component.
+    /// </summary>
+    public enum ComponentLifeStage
+    {
+        /// <summary>
+        /// The component has just been allocated.
+        /// </summary>
+        PreAdd = 0,
+
+        /// <summary>
+        /// Currently being added to an entity.
+        /// </summary>
+        Adding,
+
+        /// <summary>
+        /// Has been added to an entity.
+        /// </summary>
+        Added,
+
+        /// <summary>
+        /// Currently being initialized.
+        /// </summary>
+        Initializing,
+
+        /// <summary>
+        /// Has been initialized.
+        /// </summary>
+        Initialized,
+
+        /// <summary>
+        /// Currently being started up.
+        /// </summary>
+        Starting,
+
+        /// <summary>
+        /// Has started up.
+        /// </summary>
+        Running,
+
+        /// <summary>
+        /// Currently shutting down.
+        /// </summary>
+        Stopping,
+
+        /// <summary>
+        /// Has been shut down.
+        /// </summary>
+        Stopped,
+
+        /// <summary>
+        /// Currently being removed from it's entity.
+        /// </summary>
+        Removing,
+
+        /// <summary>
+        /// Removed from it's entity, and is deleted.
+        /// </summary>
+        Deleted,
+    }
+
     /// <summary>
     /// The component has been added to the entity. This is the first function
     /// to be called after the component has been allocated and (optionally) deserialized.

Robust.Shared/GameObjects/ComponentFactory.cs

@@ -3,31 +3,33 @@ using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.Serialization;
+using JetBrains.Annotations;
+using Robust.Shared.Console;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Reflection;
+using Robust.Shared.Utility;
 
 namespace Robust.Shared.GameObjects
 {
-    public class ComponentFactory : IComponentFactory
+    internal class ComponentFactory : IComponentFactory
     {
-        [Dependency] private readonly IDynamicTypeFactoryInternal _typeFactory = default!;
-        [Dependency] private readonly IReflectionManager _reflectionManager = default!;
+        private readonly IDynamicTypeFactoryInternal _typeFactory;
+        private readonly IReflectionManager _reflectionManager;
 
         private class ComponentRegistration : IComponentRegistration
         {
             public string Name { get; }
-            public uint? NetID { get; }
-            public bool NetworkSynchronizeExistence { get; }
+            public ushort? NetID { get; set; }
             public Type Type { get; }
             internal readonly List<Type> References = new();
             IReadOnlyList<Type> IComponentRegistration.References => References;
 
-            public ComponentRegistration(string name, Type type, uint? netID, bool networkSynchronizeExistence)
+            public ComponentRegistration(string name, Type type)
             {
                 Name = name;
-                NetID = netID;
-                NetworkSynchronizeExistence = networkSynchronizeExistence;
+                NetID = null;
                 Type = type;
                 References.Add(type);
             }
@@ -52,7 +54,7 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         /// Mapping of network ID to type.
         /// </summary>
-        private readonly Dictionary<uint, ComponentRegistration> netIDs = new();
+        private List<IComponentRegistration>? _networkedComponents;
 
         /// <summary>
         /// Mapping of concrete component types to their registration.
@@ -76,8 +78,34 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public IEnumerable<Type> AllRegisteredTypes => types.Keys;
 
+        /// <inheritdoc />
+        public IReadOnlyList<IComponentRegistration>? NetworkedComponents => _networkedComponents;
+
         private IEnumerable<ComponentRegistration> AllRegistrations => types.Values;
 
+        public ComponentFactory(IDynamicTypeFactoryInternal typeFactory, IReflectionManager reflectionManager, IConsoleHost conHost)
+        {
+            _typeFactory = typeFactory;
+            _reflectionManager = reflectionManager;
+
+            conHost.RegisterCommand("dump_net_comps", "Prints the table of networked components.", "dump_net_comps", (shell, argStr, args) =>
+            {
+                if (_networkedComponents is null)
+                {
+                    shell.WriteError("Registration still writeable, network ids have not been generated.");
+                    return;
+                }
+
+                shell.WriteLine("Networked Component Registrations:");
+
+                for (int netId = 0; netId < _networkedComponents.Count; netId++)
+                {
+                    var registration = _networkedComponents[netId];
+                    shell.WriteLine($"  [{netId,4}] {registration.Name,-16} {registration.Type.Name}");
+                }
+            });
+        }
+
         [Obsolete("Use RegisterClass and Attributes instead of the Register/RegisterReference combo")]
         public void Register<T>(bool overwrite = false) where T : IComponent, new()
         {
@@ -86,6 +114,9 @@ namespace Robust.Shared.GameObjects
 
         private void Register(Type type, bool overwrite = false)
         {
+            if (_networkedComponents is not null)
+                throw new ComponentRegistrationLockException();
+
             if (types.ContainsKey(type))
             {
                 throw new InvalidOperationException($"Type is already registered: {type}");
@@ -97,8 +128,6 @@ namespace Robust.Shared.GameObjects
 
             var name = dummy.Name;
             var lowerCaseName = name.ToLowerInvariant();
-            var netID = dummy.NetID;
-            var netSyncExist = dummy.NetworkSynchronizeExistence;
 
             if (IgnoredComponentNames.Contains(name))
             {
@@ -128,24 +157,11 @@ namespace Robust.Shared.GameObjects
                 }
             }
 
-            if (netID != null && netIDs.ContainsKey(netID.Value))
-            {
-                if (!overwrite)
-                {
-                    throw new InvalidOperationException($"{name} has duplicate network ID {netID}, previous: {netIDs[netID.Value]}");
-                }
-
-                RemoveComponent(netIDs[netID.Value].Name);
-            }
-
-            var registration = new ComponentRegistration(name, type, netID, netSyncExist);
+            var registration = new ComponentRegistration(name, type);
             names[name] = registration;
             _lowerCaseNames[lowerCaseName] = name;
             types[type] = registration;
-            if (netID != null)
-            {
-                netIDs[netID.Value] = registration;
-            }
+
             ComponentAdded?.Invoke(registration);
         }
 
@@ -157,6 +173,9 @@ namespace Robust.Shared.GameObjects
 
         private void RegisterReference(Type target, Type @interface)
         {
+            if (_networkedComponents is not null)
+                throw new ComponentRegistrationLockException();
+
             if (!types.ContainsKey(target))
             {
                 throw new InvalidOperationException($"Unregistered type: {target}");
@@ -194,15 +213,14 @@ namespace Robust.Shared.GameObjects
 
         private void RemoveComponent(string name)
         {
+            if (_networkedComponents is not null)
+                throw new ComponentRegistrationLockException();
+
             var registration = names[name];
             
             names.Remove(registration.Name);
             _lowerCaseNames.Remove(registration.Name.ToLowerInvariant());
             types.Remove(registration.Type);
-            if (registration.NetID != null)
-            {
-                netIDs.Remove(registration.NetID.Value);
-            }
         }
 
         public ComponentAvailability GetComponentAvailability(string componentName, bool ignoreCase = false)
@@ -253,7 +271,7 @@ namespace Robust.Shared.GameObjects
             return _typeFactory.CreateInstanceUnchecked<IComponent>(GetRegistration(componentName).Type);
         }
 
-        public IComponent GetComponent(uint netId)
+        public IComponent GetComponent(ushort netId)
         {
             return _typeFactory.CreateInstanceUnchecked<IComponent>(GetRegistration(netId).Type);
         }
@@ -275,11 +293,14 @@ namespace Robust.Shared.GameObjects
             }
         }
 
-        public IComponentRegistration GetRegistration(uint netID)
+        public IComponentRegistration GetRegistration(ushort netID)
         {
+            if (_networkedComponents is null)
+                throw new ComponentRegistrationLockException();
+
             try
             {
-                return netIDs[netID];
+                return _networkedComponents[netID];
             }
             catch (KeyNotFoundException)
             {
@@ -343,9 +364,9 @@ namespace Robust.Shared.GameObjects
             return TryGetRegistration(typeof(T), out registration);
         }
 
-        public bool TryGetRegistration(uint netID, [NotNullWhen(true)] out IComponentRegistration? registration)
+        public bool TryGetRegistration(ushort netID, [NotNullWhen(true)] out IComponentRegistration? registration)
         {
-            if (netIDs.TryGetValue(netID, out var tempRegistration))
+            if (_networkedComponents is not null && _networkedComponents.TryGetValue(netID, out var tempRegistration))
             {
                 registration = tempRegistration;
                 return true;
@@ -406,15 +427,36 @@ namespace Robust.Shared.GameObjects
             return AllRegistrations.SelectMany(r => r.References).Distinct();
         }
 
-        public IEnumerable<uint> GetAllNetIds()
+        /// <inheritdoc />
+        public void GenerateNetIds()
         {
-            foreach (var registration in AllRegistrations)
+            // assumptions:
+            // component names are guaranteed to be unique
+            // component names are 1:1 with component concrete types
+
+            // a subset of component names are networked
+            var networkedRegs = new List<IComponentRegistration>(names.Count);
+
+            foreach (var kvRegistration in names)
             {
-                if (registration.NetID != null)
+                var registration = kvRegistration.Value;
+                if (Attribute.GetCustomAttribute(registration.Type, typeof(NetworkedComponentAttribute)) is NetworkedComponentAttribute)
                 {
-                    yield return registration.NetID.Value;
+                    networkedRegs.Add(registration);
                 }
             }
+
+            // The sorting implementation is unstable, but there are no duplicate names, so that isn't a problem.
+            // Ordinal comparison is used so that the resulting order is always identical on every computer.
+            networkedRegs.Sort((a, b) => string.Compare(a.Name, b.Name, StringComparison.Ordinal));
+
+            for (ushort i = 0; i < networkedRegs.Count; i++)
+            {
+                var registration = (ComponentRegistration) networkedRegs[i];
+                registration.NetID = i;
+            }
+
+            _networkedComponents = networkedRegs;
         }
     }
 
@@ -434,4 +476,6 @@ namespace Robust.Shared.GameObjects
           SerializationInfo info,
           StreamingContext context) : base(info, context) { }
     }
+
+    public class ComponentRegistrationLockException : Exception { }
 }

Robust.Shared/GameObjects/ComponentManager.cs

@@ -1,8 +1,10 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using Internal.TypeSystem;
 using Robust.Shared.Exceptions;
 using Robust.Shared.Physics;
 using Robust.Shared.Serialization;
@@ -28,7 +30,7 @@ namespace Robust.Shared.GameObjects
         private const int EntityCapacity = 1024;
         private const int NetComponentCapacity = 8;
 
-        private readonly Dictionary<EntityUid, Dictionary<uint, Component>> _netComponents
+        private readonly Dictionary<EntityUid, Dictionary<ushort, Component>> _netComponents
             = new(EntityCapacity);
 
         private readonly Dictionary<Type, Dictionary<EntityUid, Component>> _entTraitDict
@@ -144,14 +146,14 @@ namespace Robust.Shared.GameObjects
             }
 
             // add the component to the netId grid
-            if (component.NetID != null)
+            if (reg.NetID != null)
             {
                 // the main comp grid keeps this in sync
-                var netId = component.NetID.Value;
+                var netId = reg.NetID.Value;
 
                 if (!_netComponents.TryGetValue(uid, out var netSet))
                 {
-                    netSet = new Dictionary<uint, Component>(NetComponentCapacity);
+                    netSet = new Dictionary<ushort, Component>(NetComponentCapacity);
                     _netComponents.Add(uid, netSet);
                 }
                 netSet.Add(netId, component);
@@ -164,19 +166,15 @@ namespace Robust.Shared.GameObjects
 
             _componentDependencyManager.OnComponentAdd(entity.Uid, component);
 
-            component.OnAdd();
+            component.LifeAddToEntity();
 
-            if (!entity.Initialized && !entity.Initializing) return;
+            if (!entity.Initialized && !entity.Initializing)
+                return;
 
-            component.Initialize();
-
-            DebugTools.Assert(component.Initialized, "Component is not initialized after calling Initialize(). "
-                                                     + "Did you forget to call base.Initialize() in an override?");
+            component.LifeInitialize();
 
             if (entity.Initialized)
-            {
-                component.Running = true;
-            }
+                component.LifeStartup();
         }
 
         /// <inheritdoc />
@@ -190,14 +188,14 @@ namespace Robust.Shared.GameObjects
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void RemoveComponent(EntityUid uid, Type type)
         {
-            RemoveComponentDeferred((Component) GetComponent(uid, type), uid, false);
+            RemoveComponentDeferred((Component)GetComponent(uid, type), uid, false);
         }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void RemoveComponent(EntityUid uid, uint netId)
+        public void RemoveComponent(EntityUid uid, ushort netId)
         {
-            RemoveComponentDeferred((Component) GetComponent(uid, netId), uid, false);
+            RemoveComponentDeferred((Component)GetComponent(uid, netId), uid, false);
         }
 
         /// <inheritdoc />
@@ -209,7 +207,7 @@ namespace Robust.Shared.GameObjects
             if (component.Owner == null || component.Owner.Uid != uid)
                 throw new InvalidOperationException("Component is not owned by entity.");
 
-            RemoveComponentDeferred((Component) component, uid, false);
+            RemoveComponentDeferred((Component)component, uid, false);
         }
 
         private static IEnumerable<Component> InSafeOrder(IEnumerable<Component> comps, bool forCreation = false)
@@ -260,23 +258,26 @@ namespace Robust.Shared.GameObjects
             try
             {
 #endif
-                // these two components are required on all entities and cannot be removed normally.
-                if (!removeProtected && (component is ITransformComponent || component is IMetaDataComponent))
-                {
-                    DebugTools.Assert("Tried to remove a protected component.");
-                    return;
-                }
+            // these two components are required on all entities and cannot be removed normally.
+            if (!removeProtected && (component is ITransformComponent || component is IMetaDataComponent))
+            {
+                DebugTools.Assert("Tried to remove a protected component.");
+                return;
+            }
 
-                if (!_deleteSet.Add(component))
-                {
-                    // already deferred deletion
-                    return;
-                }
+            if (!_deleteSet.Add(component))
+            {
+                // already deferred deletion
+                return;
+            }
 
-                component.Running = false;
-                component.OnRemove();
-                _componentDependencyManager.OnComponentRemove(uid, component);
-                ComponentRemoved?.Invoke(this, new RemovedComponentEventArgs(component, uid));
+            if (component.Running)
+                component.LifeShutdown();
+
+            if (component.LifeStage != ComponentLifeStage.PreAdd)
+                component.LifeRemoveFromEntity();
+            _componentDependencyManager.OnComponentRemove(uid, component);
+            ComponentRemoved?.Invoke(this, new RemovedComponentEventArgs(component, uid));
 #if EXCEPTION_TOLERANCE
             }
             catch (Exception e)
@@ -300,8 +301,12 @@ namespace Robust.Shared.GameObjects
                     return;
                 }
 
-                component.Running = false;
-                component.OnRemove(); // Sets delete
+                if (component.Running)
+                    component.LifeShutdown();
+
+                if (component.LifeStage != ComponentLifeStage.PreAdd)
+                    component.LifeRemoveFromEntity(); // Sets delete
+
                 ComponentRemoved?.Invoke(this, new RemovedComponentEventArgs(component, component.Owner.Uid));
 
             }
@@ -332,13 +337,13 @@ namespace Robust.Shared.GameObjects
             }
 
             // ReSharper disable once InvertIf
-            if (component.NetID != null)
+            if (reg.NetID != null)
             {
                 var netSet = _netComponents[entityUid];
                 if (netSet.Count == 1)
                     _netComponents.Remove(entityUid);
                 else
-                    netSet.Remove(component.NetID.Value);
+                    netSet.Remove(reg.NetID.Value);
 
                 component.Owner.Dirty();
             }
@@ -364,7 +369,7 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool HasComponent(EntityUid uid, uint netId)
+        public bool HasComponent(EntityUid uid, ushort netId)
         {
             return _netComponents.TryGetValue(uid, out var netSet)
                    && netSet.ContainsKey(netId);
@@ -374,7 +379,7 @@ namespace Robust.Shared.GameObjects
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public T GetComponent<T>(EntityUid uid)
         {
-            return (T) GetComponent(uid, typeof(T));
+            return (T)GetComponent(uid, typeof(T));
         }
 
         /// <inheritdoc />
@@ -394,7 +399,7 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public IComponent GetComponent(EntityUid uid, uint netId)
+        public IComponent GetComponent(EntityUid uid, ushort netId)
         {
             return _netComponents[uid][netId];
         }
@@ -406,7 +411,7 @@ namespace Robust.Shared.GameObjects
             {
                 if (!comp.Deleted)
                 {
-                    component = (T) comp;
+                    component = (T)comp;
                     return true;
                 }
             }
@@ -433,7 +438,7 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public bool TryGetComponent(EntityUid uid, uint netId, [MaybeNullWhen(false)] out IComponent component)
+        public bool TryGetComponent(EntityUid uid, ushort netId, [MaybeNullWhen(false)] out IComponent component)
         {
             if (_netComponents.TryGetValue(uid, out var netSet)
                 && netSet.TryGetValue(netId, out var comp))
@@ -471,9 +476,9 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public IEnumerable<IComponent> GetNetComponents(EntityUid uid)
+        public NetComponentEnumerable GetNetComponents(EntityUid uid)
         {
-            return _netComponents[uid].Values;
+            return new NetComponentEnumerable(_netComponents[uid]);
         }
 
         #region Join Functions
@@ -486,7 +491,7 @@ namespace Robust.Shared.GameObjects
             {
                 if (comp.Deleted || !includePaused && comp.Paused) continue;
 
-                yield return (T) (object) comp;
+                yield return (T)(object)comp;
             }
         }
 
@@ -507,7 +512,7 @@ namespace Robust.Shared.GameObjects
                 if (!trait2.TryGetValue(uid, out var t2Comp) || t2Comp.Deleted || !includePaused && kvComp.Value.Paused)
                     continue;
 
-                yield return ((TComp1) (object) kvComp.Value, (TComp2) (object) t2Comp);
+                yield return ((TComp1)(object)kvComp.Value, (TComp2)(object)t2Comp);
             }
         }
 
@@ -531,9 +536,9 @@ namespace Robust.Shared.GameObjects
                 if (!trait3.TryGetValue(uid, out var t3Comp) || t3Comp.Deleted)
                     continue;
 
-                yield return ((TComp1) (object) kvComp.Value,
-                    (TComp2) (object) t2Comp,
-                    (TComp3) (object) t3Comp);
+                yield return ((TComp1)(object)kvComp.Value,
+                    (TComp2)(object)t2Comp,
+                    (TComp3)(object)t3Comp);
             }
         }
 
@@ -562,10 +567,10 @@ namespace Robust.Shared.GameObjects
                 if (!trait4.TryGetValue(uid, out var t4Comp) || t4Comp.Deleted)
                     continue;
 
-                yield return ((TComp1) (object) kvComp.Value,
-                    (TComp2) (object) t2Comp,
-                    (TComp3) (object) t3Comp,
-                    (TComp4) (object) t4Comp);
+                yield return ((TComp1)(object)kvComp.Value,
+                    (TComp2)(object)t2Comp,
+                    (TComp3)(object)t3Comp,
+                    (TComp4)(object)t4Comp);
             }
         }
 
@@ -594,4 +599,30 @@ namespace Robust.Shared.GameObjects
             }
         }
     }
+
+    public readonly struct NetComponentEnumerable
+    {
+        private readonly Dictionary<ushort, Component> _dictionary;
+
+        public NetComponentEnumerable(Dictionary<ushort, Component> dictionary) => _dictionary = dictionary;
+        public NetComponentEnumerator GetEnumerator() => new(_dictionary);
+    }
+
+    public struct NetComponentEnumerator
+    {
+        // DO NOT MAKE THIS READONLY
+        private Dictionary<ushort, Component>.Enumerator _dictEnum;
+
+        public NetComponentEnumerator(Dictionary<ushort, Component> dictionary) => _dictEnum = dictionary.GetEnumerator();
+        public bool MoveNext() => _dictEnum.MoveNext();
+        public (ushort netId, IComponent component) Current
+        {
+            get
+            {
+                var val = _dictEnum.Current;
+                return (val.Key, val.Value);
+            }
+        }
+
+    }
 }

Robust.Shared/GameObjects/ComponentMessages/Messages.cs

@@ -1,45 +0,0 @@
-using System;
-using JetBrains.Annotations;
-
-namespace Robust.Shared.GameObjects
-{
-    [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
-    public class RelayMovementEntityMessage : ComponentMessage
-    {
-        [PublicAPI]
-        public readonly IEntity Entity;
-
-        public RelayMovementEntityMessage(IEntity entity)
-        {
-            Entity = entity;
-        }
-    }
-
-    /// <summary>
-    ///     The entity transform parent has been changed.
-    /// </summary>
-    [Obsolete("Component Messages are deprecated, use Entity Events instead.")]
-    public class ParentChangedMessage : ComponentMessage
-    {
-        /// <summary>
-        ///     The new parent of the transform.
-        /// </summary>
-        public IEntity? NewParent { get; }
-
-        /// <summary>
-        ///     The old parent of the transform.
-        /// </summary>
-        public IEntity? OldParent { get; }
-
-        /// <summary>
-        ///     Constructs a new instance of <see cref="ParentChangedMessage"/>.
-        /// </summary>
-        /// <param name="newParent">The new parent of the transform.</param>
-        /// <param name="oldParent">The old parent of the transform.</param>
-        public ParentChangedMessage(IEntity? newParent, IEntity? oldParent)
-        {
-            NewParent = newParent;
-            OldParent = oldParent;
-        }
-    }
-}

Robust.Shared/GameObjects/ComponentState.cs

@@ -1,18 +1,10 @@
-using Robust.Shared.Serialization;
 using System;
 using Robust.Shared.Analyzers;
+using Robust.Shared.Serialization;
 
 namespace Robust.Shared.GameObjects
 {
     [RequiresSerializable]
     [Serializable, NetSerializable]
-    public class ComponentState
-    {
-        public uint NetID { get; }
-
-        public ComponentState(uint netID)
-        {
-            NetID = netID;
-        }
-    }
+    public class ComponentState { }
 }

Robust.Shared/GameObjects/Components/Appearance/SharedAppearanceComponent.cs

@@ -1,6 +1,7 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using Robust.Shared.GameStates;
 using Robust.Shared.Serialization;
 
 namespace Robust.Shared.GameObjects
@@ -11,10 +12,10 @@ namespace Robust.Shared.GameObjects
     ///     The data works using a simple key/value system. It is recommended to use enum keys to prevent errors.
     ///     Visualization works client side with overrides of the <c>AppearanceVisualizer</c> class.
     /// </summary>
+    [NetworkedComponent()]
     public abstract class SharedAppearanceComponent : Component
     {
         public override string Name => "Appearance";
-        public override uint? NetID => NetIDs.APPEARANCE;
 
         public abstract void SetData(string key, object value);
         public abstract void SetData(Enum key, object value);
@@ -30,7 +31,7 @@ namespace Robust.Shared.GameObjects
         {
             public readonly Dictionary<object, object> Data;
 
-            public AppearanceComponentState(Dictionary<object, object> data) : base(NetIDs.APPEARANCE)
+            public AppearanceComponentState(Dictionary<object, object> data)
             {
                 Data = data;
             }

Robust.Shared/GameObjects/Components/ClickableComponentState.cs

@@ -9,7 +9,7 @@ namespace Robust.Shared.GameObjects
     {
         public Box2? LocalBounds { get; }
 
-        public ClickableComponentState(Box2? localBounds) : base(NetIDs.CLICKABLE)
+        public ClickableComponentState(Box2? localBounds)
         {
             LocalBounds = localBounds;
         }

Robust.Shared/GameObjects/Components/Collidable/PhysicsComponent.Physics.cs

@@ -26,6 +26,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using Robust.Shared.Containers;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Map;
@@ -44,6 +45,7 @@ using Robust.Shared.ViewVariables;
 namespace Robust.Shared.GameObjects
 {
     [ComponentReference(typeof(IPhysBody))]
+    [NetworkedComponent()]
     public sealed class PhysicsComponent : Component, IPhysBody, ISerializationHooks
     {
         [DataField("status", readOnly: true)]
@@ -52,9 +54,6 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public override string Name => "Physics";
 
-        /// <inheritdoc />
-        public override uint? NetID => NetIDs.PHYSICS;
-
         /// <summary>
         ///     Has this body been added to an island previously in this tick.
         /// </summary>
@@ -62,8 +61,9 @@ namespace Robust.Shared.GameObjects
 
         /// <summary>
         ///     Store the body's index within the island so we can lookup its data.
+        ///     Key is Island's ID and value is our index.
         /// </summary>
-        public int IslandIndex { get; set; }
+        public Dictionary<int, int> IslandIndex { get; set; } = new();
 
         // TODO: Actually implement after the initial pr dummy
         /// <summary>
@@ -833,6 +833,32 @@ namespace Robust.Shared.GameObjects
         [DataField("angularDamping")]
         private float _angularDamping = 0.02f;
 
+        /// <summary>
+        /// Get the linear and angular velocities at the same time.
+        /// </summary>
+        public (Vector2 Linear, float Angular) MapVelocities
+        {
+            get
+            {
+                var linearVelocity = _linVelocity;
+                var angularVelocity = _angVelocity;
+                var parent = Owner.Transform.Parent?.Owner;
+
+                while (parent != null)
+                {
+                    if (parent.TryGetComponent(out PhysicsComponent? body))
+                    {
+                        linearVelocity += body.LinearVelocity;
+                        angularVelocity += body.AngularVelocity;
+                    }
+
+                    parent = parent.Transform.Parent?.Owner;
+                }
+
+                return (linearVelocity, angularVelocity);
+            }
+        }
+
         /// <summary>
         ///     Current linear velocity of the entity in meters per second.
         /// </summary>
@@ -861,6 +887,33 @@ namespace Robust.Shared.GameObjects
 
         private Vector2 _linVelocity;
 
+        /// <summary>
+        /// Get the body's LinearVelocity in map terms.
+        /// </summary>
+        /// <remarks>
+        /// Consider using <see cref="MapVelocities"/> if you need linear and angular at the same time.
+        /// </remarks>
+        public Vector2 MapLinearVelocity
+        {
+            get
+            {
+                var velocity = _linVelocity;
+                var parent = Owner.Transform.Parent?.Owner;
+
+                while (parent != null)
+                {
+                    if (parent.TryGetComponent(out PhysicsComponent? body))
+                    {
+                        velocity += body.LinearVelocity;
+                    }
+
+                    parent = parent.Transform.Parent?.Owner;
+                }
+
+                return velocity;
+            }
+        }
+
         /// <summary>
         ///     Current angular velocity of the entity in radians per sec.
         /// </summary>
@@ -889,6 +942,33 @@ namespace Robust.Shared.GameObjects
 
         private float _angVelocity;
 
+        /// <summary>
+        /// Get the body's AngularVelocity in map terms.
+        /// </summary>
+        /// <remarks>
+        /// Consider using <see cref="MapVelocities"/> if you need linear and angular at the same time.
+        /// </remarks>
+        public float MapAngularVelocity
+        {
+            get
+            {
+                var velocity = _angVelocity;
+                var parent = Owner.Transform.Parent?.Owner;
+
+                while (parent != null)
+                {
+                    if (parent.TryGetComponent(out PhysicsComponent? body))
+                    {
+                        velocity += body.AngularVelocity;
+                    }
+
+                    parent = parent.Transform.Parent?.Owner;
+                }
+
+                return velocity;
+            }
+        }
+
         /// <summary>
         ///     Current momentum of the entity in kilogram meters per second
         /// </summary>
@@ -1148,7 +1228,7 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public override void Initialize()
+        protected override void Initialize()
         {
             base.Initialize();
 
@@ -1253,7 +1333,7 @@ namespace Robust.Shared.GameObjects
             Logger.DebugS("physics", $"Removed joint id: {joint.ID} type: {joint.GetType().Name} from {Owner}");
         }
 
-        public override void OnRemove()
+        protected override void OnRemove()
         {
             base.OnRemove();
             // Need to do these immediately in case collision behaviors deleted the body