Fixes SpriteComponent error reporting

* Grid fixtures

* termp

* Fixes

* Test reversion reversion?

* Tests

* Fix Equals

* Slight box2i cleanup

* Better initializer

* Also add static grid assert

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

@@ -4,4 +4,8 @@ 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
+entity-spawn-window-override-menu-tooltip = Override placement
+
+## Console
+
+console-line-edit-placeholder = Command Here

Robust.Client/BaseClient.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Net;
 using Robust.Client.Debugging;
 using Robust.Client.GameObjects;

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/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

@@ -13,10 +13,11 @@ using Microsoft.CodeAnalysis.Text;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.ViewVariables;
 using Robust.Shared.IoC;
-using Robust.Shared.Maths;
 using Robust.Shared.Reflection;
 using Robust.Shared.Scripting;
 using Robust.Shared.Utility;
+using SixLabors.ImageSharp;
+using Color = Robust.Shared.Maths.Color;
 
 #nullable enable
 
@@ -116,7 +117,7 @@ namespace Robust.Client.Console
             }
             else
             {
-                var options = ScriptInstanceShared.GetScriptOptions(_reflectionManager);
+                var options = ScriptInstanceShared.GetScriptOptions(_reflectionManager).AddReferences(typeof(Image).Assembly);
                 newScript = CSharpScript.Create(code, options, typeof(ScriptGlobals));
             }
 

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

@@ -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))

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

@@ -75,8 +75,6 @@ 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;
@@ -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;
         }
 
-        internal 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)
             {

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/Light/PointLightComponent.cs

@@ -5,6 +5,7 @@ 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;
@@ -17,12 +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; }
 

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

@@ -365,7 +365,7 @@ namespace Robust.Client.GameObjects
                     }
                     else
                     {
-                        Logger.ErrorS(LogCategory, "Unable to load RSI '{0}'. Trace:\n{1}", rsiPath);
+                        Logger.ErrorS(LogCategory, "Unable to load RSI '{0}'.", rsiPath);
                     }
                 }
             }

Robust.Client/GameObjects/Components/RenderingTreeComponent.cs

@@ -15,29 +15,43 @@ namespace Robust.Client.GameObjects
         private static Box2 SpriteAabbFunc(in SpriteComponent value)
         {
             var worldPos = value.Owner.Transform.WorldPosition;
-            return new Box2(worldPos, worldPos);
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
+
+            var pos = worldPos - tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return new Box2(pos, pos);
         }
 
         private static Box2 LightAabbFunc(in PointLightComponent value)
         {
             var worldPos = value.Owner.Transform.WorldPosition;
-
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
             var boxSize = value.Radius * 2;
-            return Box2.CenteredAround(worldPos, (boxSize, boxSize));
+
+            var pos = worldPos - tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return Box2.CenteredAround(pos, (boxSize, boxSize));
         }
 
         internal static Box2 SpriteAabbFunc(SpriteComponent value, Vector2? worldPos = null)
         {
             worldPos ??= value.Owner.Transform.WorldPosition;
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
 
-            return new Box2(worldPos.Value, worldPos.Value);
+            var pos = worldPos - tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return new Box2(pos, pos);
         }
 
         internal static Box2 LightAabbFunc(PointLightComponent value, Vector2? worldPos = null)
         {
             worldPos ??= value.Owner.Transform.WorldPosition;
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
             var boxSize = value.Radius * 2;
-            return Box2.CenteredAround(worldPos.Value, (boxSize, boxSize));
+
+            var pos = worldPos - tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return Box2.CenteredAround(pos, (boxSize, boxSize));
         }
     }
 }

Robust.Client/GameObjects/EntitySystems/RenderingTreeSystem.cs

@@ -41,22 +41,12 @@ namespace Robust.Client.GameObjects
         {
             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>();
+            yield return _mapManager.GetMapEntity(mapId).GetComponent<RenderingTreeComponent>();
         }
 
         internal IEnumerable<DynamicTree<SpriteComponent>> GetSpriteTrees(MapId mapId, Box2 worldAABB)
@@ -259,9 +249,8 @@ namespace Robust.Client.GameObjects
             EntityManager.GetEntity(_mapManager.GetGrid(gridId).GridEntityId).EnsureComponent<RenderingTreeComponent>();
         }
 
-        private RenderingTreeComponent? GetRenderTree(IEntity entity)
+        internal static RenderingTreeComponent? GetRenderTree(IEntity entity)
         {
-
             if (entity.Transform.MapID == MapId.Nullspace ||
                 entity.HasComponent<RenderingTreeComponent>()) return null;
 
@@ -302,8 +291,7 @@ namespace Robust.Client.GameObjects
                     continue;
                 }
 
-                var treePos = newMapTree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
-                var aabb = RenderingTreeComponent.SpriteAabbFunc(sprite, worldPos).Translated(-treePos);
+                var aabb = RenderingTreeComponent.SpriteAabbFunc(sprite, worldPos);
 
                 // If we're on a new map then clear the old one.
                 if (oldMapTree != newMapTree)
@@ -348,7 +336,7 @@ namespace Robust.Client.GameObjects
                 }
 
                 var treePos = newMapTree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
-                var aabb = RenderingTreeComponent.LightAabbFunc(light, worldPos).Translated(-treePos);
+                var aabb = RenderingTreeComponent.LightAabbFunc(light, worldPos);
 
                 // If we're on a new map then clear the old one.
                 if (oldMapTree != newMapTree)

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 />
@@ -343,11 +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;
                     }
@@ -368,24 +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);
                 }
             }
 
@@ -432,8 +440,7 @@ namespace Robust.Client.GameStates
                     }
                     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!");
@@ -543,7 +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)
@@ -559,42 +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;
@@ -195,14 +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/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}");
                             }
                         }
                     }

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

@@ -210,11 +210,11 @@ namespace Robust.Client.Graphics.Clyde
             _windowing!.WindowRequestAttention(_windowing.MainWindow!);
         }
 
-        public async Task<IClydeWindow> CreateWindow(WindowCreateParameters parameters)
+        public IClydeWindow CreateWindow(WindowCreateParameters parameters)
         {
             DebugTools.AssertNotNull(_windowing);
 
-            return await _windowing!.WindowCreate(parameters);
+            return _windowing!.WindowCreate(parameters);
         }
 
         private void DoDestroyWindow(WindowReg reg)

Robust.Client/Graphics/Clyde/ClydeHeadless.cs

@@ -210,7 +210,7 @@ namespace Robust.Client.Graphics.Clyde
             yield break;
         }
 
-        public Task<IClydeWindow> CreateWindow(WindowCreateParameters parameters)
+        public IClydeWindow CreateWindow(WindowCreateParameters parameters)
         {
             var window = new DummyWindow(CreateRenderTarget((123, 123), default))
             {
@@ -218,7 +218,7 @@ namespace Robust.Client.Graphics.Clyde
             };
             _windows.Add(window);
 
-            return Task.FromResult<IClydeWindow>(window);
+            return window;
         }
 
         public ClydeHandle LoadShader(ParsedShader shader, string? name = null)

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

@@ -22,8 +22,7 @@ namespace Robust.Client.Graphics.Clyde
 {
     internal partial class Clyde
     {
-        // Wait for it.
-        private sealed partial class GlfwWindowingImpl
+        private unsafe sealed partial class GlfwWindowingImpl
         {
             private readonly List<GlfwWindowReg> _windows = new();
 
@@ -36,45 +35,23 @@ namespace Robust.Client.Graphics.Clyde
             private int _nextWindowId = 1;
             private static bool _eglLoaded;
 
-            public async Task<WindowHandle> WindowCreate(WindowCreateParameters parameters)
+            public WindowHandle WindowCreate(WindowCreateParameters parameters)
             {
-                // tfw await not allowed in unsafe contexts
-
-                // GL APIs don't take kindly to making a new window without unbinding the main context. Great.
-                // Leaving code for async path in, in case it works on like GLX.
-                var unbindContextAndBlock = true;
-
                 DebugTools.AssertNotNull(_mainWindow);
 
-                Task<GlfwWindowCreateResult> task;
-                unsafe
-                {
-                    if (unbindContextAndBlock)
-                        GLFW.MakeContextCurrent(null);
+                GLFW.MakeContextCurrent(null);
 
-                    task = SharedWindowCreate(
-                        _clyde._chosenRenderer,
-                        parameters,
-                        _mainWindow!.GlfwWindow);
-                }
+                var task = SharedWindowCreate(
+                    _clyde._chosenRenderer,
+                    parameters,
+                    _mainWindow!.GlfwWindow);
 
-                if (unbindContextAndBlock)
-                {
-                    unsafe
-                    {
-                        // Block the main thread (to avoid stuff like texture uploads being problematic).
-                        WaitWindowCreate(task);
+                // Block the main thread (to avoid stuff like texture uploads being problematic).
+                WaitWindowCreate(task);
 
-                        if (unbindContextAndBlock)
-                            GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
-                    }
-                }
-                else
-                {
-                    await task;
-                }
+                GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
 
-                var (reg, error) = await task;
+                var (reg, error) = task.Result;
 
                 if (reg == null)
                 {
@@ -85,18 +62,11 @@ namespace Robust.Client.Graphics.Clyde
                 _clyde.CreateWindowRenderTexture(reg);
                 _clyde.InitWindowBlitThread(reg);
 
-                unsafe
-                {
-                    GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
-                }
+                GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
 
                 return reg.Handle;
             }
-        }
 
-        // Yes, you read that right.
-        private sealed unsafe partial class GlfwWindowingImpl
-        {
             public bool TryInitMainWindow(Renderer renderer, [NotNullWhen(false)] out string? error)
             {
                 var width = _cfg.GetCVar(CVars.DisplayWidth);
@@ -167,6 +137,21 @@ namespace Robust.Client.Graphics.Clyde
                 WindowCreateParameters parameters,
                 Window* share)
             {
+                //
+                // IF YOU'RE WONDERING WHY THIS IS TASK-BASED:
+                // I originally wanted this to be async so we could avoid blocking the main thread
+                // while the OS takes its stupid 100~ms just to initialize a fucking GL context.
+                // This doesn't *work* because
+                // we have to release the GL context while the shared context is being created.
+                // (at least on WGL, I didn't test other platforms and I don't care to.)
+                // Not worth it to avoid a main thread blockage by allowing Clyde to temporarily release the GL context,
+                // because rendering would be locked up *anyways*.
+                //
+                // Basically what I'm saying is that everything about OpenGL is a fucking mistake
+                // and I should get on either Veldrid or Vulkan some time.
+                // Probably Veldrid tbh.
+                //
+
                 // Yes we ping-pong this TCS through the window thread and back, deal with it.
                 var tcs = new TaskCompletionSource<GlfwWindowCreateResult>();
                 SendCmd(new CmdWinCreate(
@@ -525,7 +510,6 @@ namespace Robust.Client.Graphics.Clyde
                 }
 
 
-
                 return window;
             }
 

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

@@ -38,7 +38,7 @@ namespace Robust.Client.Graphics.Clyde
             void WindowRequestAttention(WindowReg window);
             void WindowSwapBuffers(WindowReg window);
             uint? WindowGetX11Id(WindowReg window);
-            Task<WindowHandle> WindowCreate(WindowCreateParameters parameters);
+            WindowHandle WindowCreate(WindowCreateParameters parameters);
             void WindowDestroy(WindowReg reg);
 
             string KeyGetName(Keyboard.Key key);

Robust.Client/Graphics/IClyde.cs

@@ -130,6 +130,6 @@ namespace Robust.Client.Graphics
 
         IEnumerable<IClydeMonitor> EnumerateMonitors();
 
-        Task<IClydeWindow> CreateWindow(WindowCreateParameters parameters);
+        IClydeWindow CreateWindow(WindowCreateParameters parameters);
     }
 }

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/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/UserInterface/Controls/BoxContainer.cs

@@ -6,20 +6,31 @@ namespace Robust.Client.UserInterface.Controls
 {
     /// <summary>
     ///     A container that lays out its children sequentially.
-    ///     Use <see cref="VBoxContainer"/> or <see cref="HBoxContainer"/> for an implementation.
     /// </summary>
-    public abstract class BoxContainer : Container
+    public class BoxContainer : Container
     {
+        private LayoutOrientation _orientation;
         public const string StylePropertySeparation = "separation";
 
         private const int DefaultSeparation = 0;
-        private protected abstract bool Vertical { get; }
 
         /// <summary>
         ///     Specifies "where" the controls should be laid out.
         /// </summary>
         public AlignMode Align { get; set; }
 
+        private bool Vertical => Orientation == LayoutOrientation.Vertical;
+
+        public LayoutOrientation Orientation
+        {
+            get => _orientation;
+            set
+            {
+                _orientation = value;
+                InvalidateMeasure();
+            }
+        }
+
         private int ActualSeparation
         {
             get
@@ -237,5 +248,11 @@ namespace Robust.Client.UserInterface.Controls
             /// </summary>
             End = 2
         }
+
+        public enum LayoutOrientation : byte
+        {
+            Horizontal,
+            Vertical
+        }
     }
 }

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/HBoxContainer.cs

@@ -1,10 +1,16 @@
-namespace Robust.Client.UserInterface.Controls
+using System;
+
+namespace Robust.Client.UserInterface.Controls
 {
     /// <summary>
     ///     Container that lays its children out horizontally: from left to right.
     /// </summary>
+    [Obsolete("Use BoxContainer and set Orientation instead")]
     public class HBoxContainer : BoxContainer
     {
-        private protected override bool Vertical => false;
+        public HBoxContainer()
+        {
+            Orientation = LayoutOrientation.Horizontal;
+        }
     }
 }

Robust.Client/UserInterface/Controls/HSplitContainer.cs

@@ -1,7 +1,13 @@
+using System;
+
 namespace Robust.Client.UserInterface.Controls
 {
+    [Obsolete("Use SplitContainer directly and set Orientation")]
     public class HSplitContainer : SplitContainer
     {
-        private protected sealed override bool Vertical => false;
+        public HSplitContainer()
+        {
+            Orientation = SplitOrientation.Horizontal;
+        }
     }
 }

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/SplitContainer.cs

@@ -4,7 +4,7 @@ using Robust.Shared.Maths;
 
 namespace Robust.Client.UserInterface.Controls
 {
-    public abstract class SplitContainer : Container
+    public class SplitContainer : Container
     {
         /// <summary>
         /// Defines how user-initiated moving of the split should work. See documentation
@@ -22,11 +22,10 @@ namespace Robust.Client.UserInterface.Controls
         /// </summary>
         public float SplitEdgeSeparation { get; set; }
 
-        private protected abstract bool Vertical { get; }
-
         private float _splitCenter;
         private SplitState _splitState;
         private bool _dragging;
+        private SplitOrientation _orientation;
 
         // min / max x and y extents in relative virtual pixels of where the split can go regardless
         // of anything else.
@@ -35,6 +34,18 @@ namespace Robust.Client.UserInterface.Controls
         private float SplitMax =>
             Vertical ? Height - (SplitWidth + SplitEdgeSeparation) : Width - (SplitWidth + SplitEdgeSeparation);
 
+        private bool Vertical => Orientation == SplitOrientation.Vertical;
+
+        public SplitOrientation Orientation
+        {
+            get => _orientation;
+            set
+            {
+                _orientation = value;
+                InvalidateMeasure();
+            }
+        }
+
         public SplitContainer()
         {
             MouseFilter = MouseFilterMode.Stop;
@@ -264,5 +275,11 @@ namespace Robust.Client.UserInterface.Controls
             /// </summary>
             Manual = 1
         }
+
+        public enum SplitOrientation : byte
+        {
+            Horizontal,
+            Vertical
+        }
     }
 }

Robust.Client/UserInterface/Controls/VBoxContainer.cs

@@ -1,10 +1,16 @@
-namespace Robust.Client.UserInterface.Controls
+using System;
+
+namespace Robust.Client.UserInterface.Controls
 {
     /// <summary>
     ///     Container that lays its children out vertically: from top to bottom.
     /// </summary>
+    [Obsolete("Use BoxContainer and set Orientation instead")]
     public class VBoxContainer : BoxContainer
     {
-        private protected override bool Vertical => true;
+        public VBoxContainer()
+        {
+            Orientation = LayoutOrientation.Vertical;
+        }
     }
 }

Robust.Client/UserInterface/Controls/VSplitContainer.cs

@@ -1,7 +1,13 @@
+using System;
+
 namespace Robust.Client.UserInterface.Controls
 {
+    [Obsolete("Use SplitContainer directly and set Orientation")]
     public class VSplitContainer : SplitContainer
     {
-        private protected sealed override bool Vertical => true;
+        public VSplitContainer()
+        {
+            Orientation = SplitOrientation.Vertical;
+        }
     }
 }

Robust.Client/UserInterface/DevWindow.xaml.cs

@@ -24,7 +24,7 @@ namespace Robust.Client.UserInterface
                 monitor = clyde.EnumerateMonitors().Single(m => m.Id == id);
             }
 
-            var window = await clyde.CreateWindow(new WindowCreateParameters
+            var window = clyde.CreateWindow(new WindowCreateParameters
             {
                 Maximized = true,
                 Title = "SS14 Debug Window",

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);
@@ -492,7 +509,6 @@ namespace Robust.Server
         }
 
         public bool ContentStart { get; set; }
-        public bool LoadConfigAndUserData { private get; set; } = true;
 
         public void OverrideMainLoop(IGameLoop gameLoop)
         {

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/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/PhysicsSystem.cs

@@ -1,24 +1,22 @@
-using JetBrains.Annotations;
+using JetBrains.Annotations;
 using Robust.Shared;
 using Robust.Shared.Configuration;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
-using Robust.Shared.Physics.Collision.Shapes;
-using Robust.Shared.Physics.Dynamics;
+using Robust.Shared.Physics;
 
 namespace Robust.Server.GameObjects
 {
     [UsedImplicitly]
     public class PhysicsSystem : SharedPhysicsSystem
     {
-        [Dependency] private readonly IMapManager _mapManager = default!;
         [Dependency] private readonly IConfigurationManager _configurationManager = default!;
 
         public override void Initialize()
         {
             base.Initialize();
-            _mapManager.OnGridCreated += HandleGridCreated;
+            SubscribeLocalEvent<GridInitializeEvent>(HandleGridInit);
             LoadMetricCVar();
             _configurationManager.OnValueChanged(CVars.MetricsEnabled, _ => LoadMetricCVar());
         }
@@ -28,19 +26,14 @@ namespace Robust.Server.GameObjects
             MetricsEnabled = _configurationManager.GetCVar(CVars.MetricsEnabled);
         }
 
-        public override void Shutdown()
+        private void HandleGridInit(GridInitializeEvent ev)
         {
-            base.Shutdown();
-            _mapManager.OnGridCreated -= HandleGridCreated;
-        }
+            var guid = ev.EntityUid;
 
-        private void HandleGridCreated(MapId mapId, GridId gridId)
-        {
-            if (!EntityManager.TryGetEntity(_mapManager.GetGrid(gridId).GridEntityId, out var gridEntity)) return;
-            var grid = _mapManager.GetGrid(gridId);
-            var collideComp = gridEntity.AddComponent<PhysicsComponent>();
+            if (!EntityManager.TryGetEntity(guid, out var gridEntity)) return;
+            var collideComp = gridEntity.EnsureComponent<PhysicsComponent>();
             collideComp.CanCollide = true;
-            collideComp.AddFixture(new Fixture(collideComp, new PhysShapeGrid(grid)) {CollisionMask = MapGridHelpers.CollisionGroup, CollisionLayer = MapGridHelpers.CollisionGroup});
+            collideComp.BodyType = BodyType.Static;
         }
 
         /// <inheritdoc />

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)
         {
@@ -204,17 +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,
-                            oldState.Anchored)
+                        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");
@@ -249,38 +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>

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/Physics/GridFixtureSystem.cs

@@ -0,0 +1,136 @@
+using System.Collections.Generic;
+using Robust.Server.GameObjects;
+using Robust.Shared;
+using Robust.Shared.Configuration;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics;
+using Robust.Shared.Physics.Broadphase;
+using Robust.Shared.Physics.Collision.Shapes;
+using Robust.Shared.Physics.Dynamics;
+
+namespace Robust.Server.Physics
+{
+    /// <summary>
+    /// Handles generating fixtures for MapGrids.
+    /// </summary>
+    internal sealed class GridFixtureSystem : EntitySystem
+    {
+        [Dependency] private readonly IMapManager _mapManager = default!;
+
+        private SharedBroadPhaseSystem _broadphase = default!;
+
+        // Is delaying fixture updates a good idea? IDEK. We definitely can't do them on every tile changed
+        // because if someone changes 50 tiles that will kill perf. We could probably just run it every Update
+        // (and at specific times due to race condition stuff).
+        // At any rate, cooldown given here if someone wants it. CD of 0 just runs it every tick.
+        private float _cooldown;
+        private float _accumulator;
+
+        private HashSet<MapChunk> _queuedChunks = new();
+
+        public override void Initialize()
+        {
+            base.Initialize();
+            UpdatesBefore.Add(typeof(PhysicsSystem));
+            SubscribeLocalEvent<RegenerateChunkCollisionEvent>(HandleCollisionRegenerate);
+            _broadphase = Get<SharedBroadPhaseSystem>();
+
+            var configManager = IoCManager.Resolve<IConfigurationManager>();
+            configManager.OnValueChanged(CVars.GridFixtureUpdateRate, value => _cooldown = value, true);
+        }
+
+        public override void Update(float frameTime)
+        {
+            base.Update(frameTime);
+
+            _accumulator += frameTime;
+            if (_accumulator < _cooldown) return;
+
+            _accumulator -= _cooldown;
+            Process();
+        }
+
+        /// <summary>
+        /// Go through every dirty chunk and re-generate their fixtures.
+        /// </summary>
+        public void Process()
+        {
+            foreach (var chunk in _queuedChunks)
+            {
+                RegenerateCollision(chunk);
+            }
+
+            _queuedChunks.Clear();
+        }
+
+        /// <summary>
+        /// Queue the chunk to generate (if cooldown > 0) or immediately process it.
+        /// </summary>
+        /// <param name="ev"></param>
+        private void HandleCollisionRegenerate(RegenerateChunkCollisionEvent ev)
+        {
+            if (_cooldown <= 0f)
+            {
+                RegenerateCollision(ev.Chunk);
+                return;
+            }
+
+            _queuedChunks.Add(ev.Chunk);
+        }
+
+        private void RegenerateCollision(MapChunk chunk)
+        {
+            // Currently this is gonna be hella simple.
+            if (!_mapManager.TryGetGrid(chunk.GridId, out var grid) ||
+                !EntityManager.TryGetEntity(grid.GridEntityId, out var gridEnt) ||
+                !gridEnt.TryGetComponent(out PhysicsComponent? physicsComponent)) return;
+
+            // TODO: Lots of stuff here etc etc, make changes to mapgridchunk.
+            var bounds = chunk.CalcLocalBounds();
+
+            // So something goes on with the chunk's internal bounds caching where if there's no data the bound is 0 or something?
+            if (bounds.IsEmpty()) return;
+
+            var origin = chunk.Indices * chunk.ChunkSize;
+            bounds = bounds.Translated(origin);
+
+            var oldFixture = chunk.Fixture;
+
+            var newFixture = new Fixture(
+                new PolygonShape
+                {
+                    Vertices = new List<Vector2>
+                    {
+                        bounds.BottomRight,
+                        bounds.TopRight,
+                        bounds.TopLeft,
+                        bounds.BottomLeft,
+                    }
+                },
+                MapGridHelpers.CollisionGroup,
+                MapGridHelpers.CollisionGroup,
+                true) {ID = $"grid-{grid.Index}_chunk-{chunk.Indices.X}-{chunk.Indices.Y}",
+                Body = physicsComponent};
+
+            // TODO: Chunk will likely need multiple fixtures but future sloth problem lmao fucking dickhead
+            if (oldFixture?.Equals(newFixture) == true) return;
+
+            if (oldFixture != null)
+                physicsComponent.RemoveFixture(oldFixture);
+
+            physicsComponent.AddFixture(newFixture);
+            chunk.Fixture = newFixture;
+
+            EntityManager.EventBus.RaiseLocalEvent(gridEnt.Uid,new GridFixtureChangeEvent {OldFixture = oldFixture, NewFixture = newFixture});
+        }
+    }
+
+    public sealed class GridFixtureChangeEvent : EntityEventArgs
+    {
+        public Fixture? OldFixture { get; init; }
+        public Fixture? NewFixture { get; init; }
+    }
+}

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.

Robust.Server/ServerIoC.cs

@@ -39,10 +39,11 @@ namespace Robust.Server
             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>();
@@ -55,7 +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.Shared.Maths/Box2.cs

@@ -316,7 +316,7 @@ namespace Robust.Shared.Maths
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static float Area(in Box2 box)
+        public static float Area(in Box2 box)
             => box.Width * box.Height;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

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.Maths/Box2i.cs

@@ -66,6 +66,11 @@ namespace Robust.Shared.Maths
             return xOk && yOk;
         }
 
+        public readonly bool IsEmpty()
+        {
+            return Bottom == Top || Left == Right;
+        }
+
         /// <summary>Returns a UIBox2 translated by the given amount.</summary>
         public readonly Box2i Translated(Vector2i point)
         {

Robust.Shared/CVars.cs

@@ -226,6 +226,17 @@ namespace Robust.Shared
         public static readonly CVarDef<float> MaxLightRadius =
             CVarDef.Create("light.max_radius", 20.0f, CVar.CLIENTONLY);
 
+        /*
+         * Lookup
+         */
+
+        /// <summary>
+        /// Like MaxLightRadius this is how far we enlarge lookups to find intersecting components.
+        /// This should be set to your maximum entity size.
+        /// </summary>
+        public static readonly CVarDef<float> LookupEnlargementRange =
+            CVarDef.Create("lookup.enlargement_range", 10.0f, CVar.ARCHIVE | CVar.REPLICATED | CVar.CHEAT);
+
         /*
          * LOKI
          */
@@ -451,6 +462,13 @@ namespace Robust.Shared
         public static readonly CVarDef<float> MaxAngVelocity =
             CVarDef.Create("physics.maxangvelocity", 15f);
 
+        /// <summary>
+        /// How frequently grid fixtures are updated. Given grid updates can be expensive they aren't run immediately.
+        /// Set to 0 to run them immediately.
+        /// </summary>
+        public static readonly CVarDef<float> GridFixtureUpdateRate =
+            CVarDef.Create("physics.grid_fixture_update_rate", 0.2f);
+
         /*
          * DISCORD
          */

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!;
@@ -29,9 +31,6 @@ namespace Robust.Shared.Containers
         /// <inheritdoc />
         public sealed override string Name => "ContainerContainer";
 
-        /// <inheritdoc />
-        public sealed override uint? NetID => NetIDs.CONTAINER_MANAGER;
-
         /// <inheritdoc />
         protected override void OnRemove()
         {
@@ -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/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")]
@@ -249,14 +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 />

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);
@@ -191,7 +193,7 @@ namespace Robust.Shared.GameObjects
 
         /// <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);
         }
@@ -335,13 +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();
             }
@@ -367,7 +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);
@@ -397,7 +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];
         }
@@ -436,7 +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))
@@ -474,9 +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
@@ -597,4 +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/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>
@@ -74,6 +73,23 @@ namespace Robust.Shared.GameObjects
 
         public bool IgnoreCCD { get; set; }
 
+        [ViewVariables]
+        public int ContactCount
+        {
+            get
+            {
+                var count = 0;
+                var edge = ContactEdges;
+                while (edge != null)
+                {
+                    edge = edge.Next;
+                    count++;
+                }
+
+                return count;
+            }
+        }
+
         /// <summary>
         ///     Linked-list of all of our contacts.
         /// </summary>
@@ -834,6 +850,32 @@ 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>
@@ -862,6 +904,33 @@ 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>
@@ -890,6 +959,33 @@ 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>

Robust.Shared/GameObjects/Components/Collidable/PhysicsComponentState.cs

@@ -44,7 +44,6 @@ namespace Robust.Shared.GameObjects
             Vector2 linearVelocity,
             float angularVelocity,
             BodyType bodyType)
-            : base(NetIDs.PHYSICS)
         {
             CanCollide = canCollide;
             SleepingAllowed = sleepingAllowed;

Robust.Shared/GameObjects/Components/CollisionWakeComponent.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using Robust.Shared.GameStates;
 using Robust.Shared.Physics;
 using Robust.Shared.Players;
 using Robust.Shared.Serialization;
@@ -11,10 +12,10 @@ namespace Robust.Shared.GameObjects
     /// <summary>
     ///     An optimisation component for stuff that should be set as collidable when it's awake and non-collidable when asleep.
     /// </summary>
+    [NetworkedComponent()]
     public sealed class CollisionWakeComponent : Component
     {
         public override string Name => "CollisionWake";
-        public override uint? NetID => NetIDs.COLLISION_WAKE;
 
         [DataField("enabled")]
         private bool _enabled = true;
@@ -64,7 +65,7 @@ namespace Robust.Shared.GameObjects
         {
             public bool Enabled { get; }
 
-            public CollisionWakeState(bool enabled) : base(NetIDs.COLLISION_WAKE)
+            public CollisionWakeState(bool enabled)
             {
                 Enabled = enabled;
             }

Robust.Shared/GameObjects/Components/EntityLookupComponent.cs

@@ -0,0 +1,12 @@
+using Robust.Shared.Physics;
+
+namespace Robust.Shared.GameObjects
+{
+    [RegisterComponent]
+    public sealed class EntityLookupComponent : Component
+    {
+        public override string Name => "EntityLookup";
+
+        internal DynamicTree<IEntity> Tree = default!;
+    }
+}

Robust.Shared/GameObjects/Components/Eye/SharedEyeComponent.cs

@@ -1,14 +1,15 @@
 using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.Maths;
 using Robust.Shared.Serialization;
 using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.GameObjects
 {
+    [NetworkedComponent()]
     public class SharedEyeComponent : Component
     {
         public override string Name => "Eye";
-        public override uint? NetID => NetIDs.EYE;
 
         [ViewVariables(VVAccess.ReadWrite)]
         public virtual bool DrawFov { get; set; }
@@ -39,7 +40,7 @@ namespace Robust.Shared.GameObjects
         public Angle Rotation { get; }
         public uint VisibilityMask { get; }
 
-        public EyeComponentState(bool drawFov, Vector2 zoom, Vector2 offset, Angle rotation, uint visibilityMask) : base(NetIDs.EYE)
+        public EyeComponentState(bool drawFov, Vector2 zoom, Vector2 offset, Angle rotation, uint visibilityMask)
         {
             DrawFov = drawFov;
             Zoom = zoom;

Robust.Shared/GameObjects/Components/Light/OccluderComponent.cs

@@ -1,4 +1,5 @@
 using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Prototypes;
@@ -9,10 +10,10 @@ using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.GameObjects
 {
+    [NetworkedComponent()]
     public class OccluderComponent : Component
     {
         public sealed override string Name => "Occluder";
-        public sealed override uint? NetID => NetIDs.OCCLUDER;
 
         [DataField("enabled")]
         private bool _enabled = true;
@@ -94,7 +95,7 @@ namespace Robust.Shared.GameObjects
             public bool Enabled { get; }
             public Box2 BoundingBox { get; }
 
-            public OccluderComponentState(bool enabled, Box2 boundingBox) : base(NetIDs.OCCLUDER)
+            public OccluderComponentState(bool enabled, Box2 boundingBox)
             {
                 Enabled = enabled;
                 BoundingBox = boundingBox;

Robust.Shared/GameObjects/Components/Light/PointLightComponentState.cs

@@ -14,7 +14,6 @@ namespace Robust.Shared.GameObjects
         public readonly Vector2 Offset;
 
         public PointLightComponentState(bool enabled, Color color, float radius, Vector2 offset)
-            : base(NetIDs.POINT_LIGHT)
         {
             Enabled = enabled;
             Color = color;

Robust.Shared/GameObjects/Components/Localization/GrammarComponent.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Robust.Shared.Enums;
+using Robust.Shared.GameStates;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.ViewVariables;
 
@@ -10,10 +11,10 @@ namespace Robust.Shared.GameObjects.Components.Localization
     ///     Overrides grammar attributes specified in prototypes or localization files.
     /// </summary>
     [RegisterComponent]
+    [NetworkedComponent()]
     public class GrammarComponent : Component
     {
         public override string Name => "Grammar";
-        public override uint? NetID => NetIDs.GRAMMAR;
 
         [ViewVariables]
         [DataField("attributes")]

Robust.Shared/GameObjects/Components/Map/MapComponent.cs

@@ -1,4 +1,5 @@
-using System;
+using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.Map;
 using Robust.Shared.Players;
 using Robust.Shared.Serialization;
@@ -18,6 +19,7 @@ namespace Robust.Shared.GameObjects
 
     /// <inheritdoc cref="IMapComponent"/>
     [ComponentReference(typeof(IMapComponent))]
+    [NetworkedComponent()]
     public class MapComponent : Component, IMapComponent
     {
         [ViewVariables(VVAccess.ReadOnly)]
@@ -27,9 +29,6 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public override string Name => "Map";
 
-        /// <inheritdoc />
-        public override uint? NetID => NetIDs.MAP_MAP;
-
         /// <inheritdoc />
         public MapId WorldMap
         {
@@ -73,7 +72,6 @@ namespace Robust.Shared.GameObjects
         public MapId MapId { get; }
 
         public MapComponentState(MapId mapId)
-            : base(NetIDs.MAP_MAP)
         {
             MapId = mapId;
         }

Robust.Shared/GameObjects/Components/Map/MapGridComponent.cs

@@ -1,4 +1,5 @@
 using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
@@ -25,6 +26,7 @@ namespace Robust.Shared.GameObjects
 
     /// <inheritdoc cref="IMapGridComponent"/>
     [ComponentReference(typeof(IMapGridComponent))]
+    [NetworkedComponent()]
     internal class MapGridComponent : Component, IMapGridComponent
     {
         [Dependency] private readonly IMapManager _mapManager = default!;
@@ -36,9 +38,6 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public override string Name => "MapGrid";
 
-        /// <inheritdoc />
-        public override uint? NetID => NetIDs.MAP_GRID;
-
         /// <inheritdoc />
         public GridId GridIndex
         {
@@ -145,7 +144,6 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         /// <param name="gridIndex">Index of the grid this component is linked to.</param>
         public MapGridComponentState(GridId gridIndex)
-            : base(NetIDs.MAP_GRID)
         {
             GridIndex = gridIndex;
         }

Robust.Shared/GameObjects/Components/MetaDataComponent.cs

@@ -1,4 +1,5 @@
-using System;
+using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Players;
 using Robust.Shared.Prototypes;
@@ -35,7 +36,6 @@ namespace Robust.Shared.GameObjects
         /// <param name="description">The in-game description of this entity.</param>
         /// <param name="prototypeId">The prototype this entity was created from, if any.</param>
         public MetaDataComponentState(string? name, string? description, string? prototypeId)
-            : base(NetIDs.META_DATA)
         {
             Name = name;
             Description = description;
@@ -66,6 +66,7 @@ namespace Robust.Shared.GameObjects
 
     /// <inheritdoc cref="IMetaDataComponent"/>
     [ComponentReference(typeof(IMetaDataComponent))]
+    [NetworkedComponent()]
     internal class MetaDataComponent : Component, IMetaDataComponent
     {
         [Dependency] private readonly IPrototypeManager _prototypes = default!;
@@ -79,9 +80,6 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public override string Name => "MetaData";
 
-        /// <inheritdoc />
-        public override uint? NetID => NetIDs.META_DATA;
-
         /// <inheritdoc />
         [ViewVariables(VVAccess.ReadWrite)]
         public string EntityName

Robust.Shared/GameObjects/Components/NetIDs.cs

@@ -1,21 +0,0 @@
-namespace Robust.Shared.GameObjects
-{
-    public static class NetIDs
-    {
-        public const uint MAP_MAP = 1;
-        public const uint MAP_GRID = 2;
-        public const uint META_DATA = 4;
-        public const uint TRANSFORM = 5;
-        public const uint SPRITE = 8;
-        public const uint POINT_LIGHT = 10;
-        public const uint PHYSICS = 12;
-        public const uint CLICKABLE = 14;
-        public const uint APPEARANCE = 22;
-        public const uint USERINTERFACE = 24;
-        public const uint CONTAINER_MANAGER = 25;
-        public const uint OCCLUDER = 26;
-        public const uint EYE = 28;
-        public const uint GRAMMAR = 29;
-        public const uint COLLISION_WAKE = 30;
-    }
-}

Robust.Shared/GameObjects/Components/Renderable/SharedSpriteComponent.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Robust.Shared.GameStates;
 using Robust.Shared.Maths;
 using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
@@ -7,10 +8,10 @@ using Robust.Shared.Utility;
 
 namespace Robust.Shared.GameObjects
 {
+    [NetworkedComponent()]
     public abstract class SharedSpriteComponent : Component
     {
         public override string Name => "Sprite";
-        public override uint? NetID => NetIDs.SPRITE;
 
         public abstract bool Visible { get; set; }
 
@@ -42,7 +43,6 @@ namespace Robust.Shared.GameObjects
                 string? baseRsiPath,
                 List<PrototypeLayerData> layers,
                 uint renderOrder)
-                : base(NetIDs.SPRITE)
             {
                 Visible = visible;
                 DrawDepth = drawDepth;

Robust.Shared/GameObjects/Components/Transform/TransformComponent.cs

@@ -4,6 +4,7 @@ using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Robust.Shared.Animations;
 using Robust.Shared.Containers;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
@@ -16,6 +17,7 @@ using Robust.Shared.ViewVariables;
 namespace Robust.Shared.GameObjects
 {
     [ComponentReference(typeof(ITransformComponent))]
+    [NetworkedComponent()]
     internal class TransformComponent : Component, ITransformComponent, IComponentDebug
     {
         [DataField("parent")]
@@ -54,9 +56,6 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public override string Name => "Transform";
 
-        /// <inheritdoc />
-        public sealed override uint? NetID => NetIDs.TRANSFORM;
-
         /// <inheritdoc />
         [ViewVariables]
         public MapId MapID { get; private set; }
@@ -896,7 +895,6 @@ namespace Robust.Shared.GameObjects
             /// <param name="parentId">Current parent transform of this entity.</param>
             /// <param name="noLocalRotation"></param>
             public TransformComponentState(Vector2 localPosition, Angle rotation, EntityUid parentId, bool noLocalRotation, bool anchored)
-                : base(NetIDs.TRANSFORM)
             {
                 LocalPosition = localPosition;
                 Rotation = rotation;

Robust.Shared/GameObjects/Components/UserInterface/SharedUserInterfaceComponent.cs

@@ -1,4 +1,5 @@
 using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Reflection;
 using Robust.Shared.Serialization;
@@ -6,10 +7,10 @@ using Robust.Shared.Serialization.Manager.Attributes;
 
 namespace Robust.Shared.GameObjects
 {
+    [NetworkedComponent()]
     public abstract class SharedUserInterfaceComponent : Component
     {
         public sealed override string Name => "UserInterface";
-        public sealed override uint? NetID => NetIDs.USERINTERFACE;
 
         [DataDefinition]
         public sealed class PrototypeData : ISerializationHooks

Robust.Shared/GameObjects/EntityEventBus.Directed.cs

@@ -400,7 +400,7 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public void ClearEventTables()
         {
-            _eventTables.ClearEntities();
+            _eventTables.Clear();
         }
 
         public void Dispose()

Robust.Shared/GameObjects/EntityManager.cs

@@ -21,7 +21,7 @@ namespace Robust.Shared.GameObjects
 
         [IoC.Dependency] protected readonly IPrototypeManager PrototypeManager = default!;
         [IoC.Dependency] protected readonly IEntitySystemManager EntitySystemManager = default!;
-        [IoC.Dependency] private readonly IComponentFactory ComponentFactory = default!;
+        [IoC.Dependency] protected readonly IComponentFactory ComponentFactory = default!;
         [IoC.Dependency] private readonly IComponentManager _componentManager = default!;
         [IoC.Dependency] private readonly IMapManager _mapManager = default!;
         [IoC.Dependency] private readonly IGameTiming _gameTiming = default!;
@@ -32,6 +32,8 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public GameTick CurrentTick => _gameTiming.CurTick;
 
+        IComponentFactory IEntityManager.ComponentFactory => ComponentFactory;
+
         /// <inheritdoc />
         public IComponentManager ComponentManager => _componentManager;
 
@@ -479,7 +481,7 @@ namespace Robust.Shared.GameObjects
             var uid = netMsg.EntityUid;
             if (compMsg.Directed)
             {
-                if (_componentManager.TryGetComponent(uid, netMsg.NetId, out var component))
+                if (_componentManager.TryGetComponent(uid, (ushort) netMsg.NetId, out var component))
                     component.HandleNetworkMessage(compMsg, compChannel, session);
             }
             else

Robust.Shared/GameObjects/EntityState.cs

@@ -7,61 +7,71 @@ namespace Robust.Shared.GameObjects
     public sealed class EntityState
     {
         public EntityUid Uid { get; }
-        public ComponentChanged[]? ComponentChanges { get; }
-        public ComponentState[]? ComponentStates { get; }
 
-        public bool Empty => ComponentChanges is null && ComponentStates is null;
+        public ComponentChange[]? ComponentChanges { get; }
 
-        public EntityState(EntityUid uid, ComponentChanged[]? changedComponents, ComponentState[]? componentStates)
+        public bool Empty => ComponentChanges is null;
+
+        public EntityState(EntityUid uid, ComponentChange[]? changedComponents)
         {
             Uid = uid;
 
             // empty lists are 5 bytes each
             ComponentChanges = changedComponents == null || changedComponents.Length == 0 ? null : changedComponents;
-            ComponentStates = componentStates == null || componentStates.Length == 0 ? null : componentStates;
         }
     }
 
     [Serializable, NetSerializable]
-    public readonly struct ComponentChanged
+    public readonly struct ComponentChange
     {
         // 15ish bytes to create a component (strings are big), 5 bytes to remove one
 
         /// <summary>
-        ///     Was the component added or removed from the entity.
+        ///     Was the component removed from the entity.
         /// </summary>
         public readonly bool Deleted;
 
         /// <summary>
-        ///     The Network ID of the component to remove.
+        /// Was the component added to the entity.
         /// </summary>
-        public readonly uint NetID;
+        public readonly bool Created;
 
         /// <summary>
-        ///     The prototype name of the component to add.
+        /// State data for the created/modified component, if any.
         /// </summary>
-        public readonly string? ComponentName;
+        public readonly ComponentState? State;
 
-        public ComponentChanged(bool deleted, uint netId, string? componentName)
+        /// <summary>
+        ///     The Network ID of the component to remove.
+        /// </summary>
+        public readonly ushort NetID;
+
+        public ComponentChange(ushort netId, bool created, bool deleted, ComponentState? state)
         {
             Deleted = deleted;
+            State = state;
             NetID = netId;
-            ComponentName = componentName;
+            Created = created;
         }
 
         public override string ToString()
         {
-            return $"{(Deleted ? "D" : "C")} {NetID} {ComponentName}";
+            return $"{(Deleted ? "D" : "C")} {NetID} {State?.GetType().Name}";
         }
 
-        public static ComponentChanged Added(uint netId, string componentName)
+        public static ComponentChange Added(ushort netId, ComponentState? state)
         {
-            return new(false, netId, componentName);
+            return new(netId, true, false, state);
         }
 
-        public static ComponentChanged Removed(uint netId)
+        public static ComponentChange Changed(ushort netId, ComponentState state)
         {
-            return new(true, netId, null);
+            return new(netId, false, false, state);
+        }
+
+        public static ComponentChange Removed(ushort netId)
+        {
+            return new(netId, false, true, null);
         }
     }
 }

Robust.Shared/GameObjects/IComponent.cs

@@ -1,7 +1,7 @@
 using System;
+using Robust.Shared.GameStates;
 using Robust.Shared.Network;
 using Robust.Shared.Players;
-using Robust.Shared.Serialization;
 using Robust.Shared.Timing;
 
 namespace Robust.Shared.GameObjects
@@ -13,16 +13,6 @@ namespace Robust.Shared.GameObjects
     /// </remarks>
     public interface IComponent
     {
-        /// <summary>
-        ///     Represents the network ID for the component.
-        ///     The network ID is used to determine which component will receive the component state
-        ///     on the other side of the network.
-        ///     If this is <c>null</c>, the component is not replicated across the network.
-        /// </summary>
-        /// <seealso cref="NetworkSynchronizeExistence" />
-        /// <seealso cref="IComponentRegistration.NetID" />
-        uint? NetID { get; }
-
         /// <summary>
         ///     Name that this component is represented with in prototypes.
         /// </summary>
@@ -40,21 +30,11 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         ComponentLifeStage LifeStage { get; }
 
-        /// <summary>
-        ///     Whether the client should synchronize component additions and removals.
-        ///     If this is false and the component gets added or removed server side, the client will not do the same.
-        ///     If this is true and the server adds or removes the component, the client will do as such too.
-        ///     This flag has no effect if <see cref="NetID" /> is <c>null</c>.
-        ///     This is disabled by default, usually the client builds their instance from a prototype.
-        /// </summary>
-        /// <seealso cref="IComponentRegistration.NetworkSynchronizeExistence" />
-        bool NetworkSynchronizeExistence { get; }
-
         /// <summary>
         ///     Whether this component should be synchronized with clients when modified.
         ///     If this is true, the server will synchronize all client instances with the data in this instance.
         ///     If this is false, clients can modify the data in their instances without being overwritten by the server.
-        ///     This flag has no effect if <see cref="NetID" /> is <c>null</c>.
+        ///     This flag has no effect if <see cref="NetworkedComponentAttribute" /> is not defined on the component.
         ///     This is enabled by default.
         /// </summary>
         bool NetSyncEnabled { get; }

Robust.Shared/GameObjects/IComponentFactory.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using Robust.Shared.GameStates;
 using Robust.Shared.Prototypes;
 
 namespace Robust.Shared.GameObjects
@@ -58,6 +59,16 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         IEnumerable<Type> AllRegisteredTypes { get; }
 
+        /// <summary>
+        /// The subset of all registered components that are networked, so that they can be
+        /// referenced between the client and the server.
+        /// </summary>
+        /// <remarks>
+        /// This will be null if the network Ids have not been generated yet.
+        /// </remarks>
+        /// <seealso cref="GenerateNetIds"/>
+        IReadOnlyList<IComponentRegistration>? NetworkedComponents { get; }
+
         /// <summary>
         /// Get whether a component is available right now.
         /// </summary>
@@ -142,7 +153,7 @@ namespace Robust.Shared.GameObjects
         /// <exception cref="UnknownComponentException">
         ///     Thrown if no component exists with the given id <see cref="netId"/>.
         /// </exception>
-        IComponent GetComponent(uint netId);
+        IComponent GetComponent(ushort netId);
 
         /// <summary>
         ///     Gets the registration belonging to a component, throwing an exception if it does not exist.
@@ -181,7 +192,7 @@ namespace Robust.Shared.GameObjects
         /// <exception cref="UnknownComponentException">
         ///     Thrown if no component with id <see cref="netID"/> exists.
         /// </exception>
-        IComponentRegistration GetRegistration(uint netID);
+        IComponentRegistration GetRegistration(ushort netID);
 
         /// <summary>
         ///     Gets the registration of a component, throwing an exception if
@@ -225,7 +236,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="netID">The network ID corresponding to the component.</param>
         /// <param name="registration">The registration if found, null otherwise.</param>
         /// <returns>true it found, false otherwise.</returns>
-        bool TryGetRegistration(uint netID, [NotNullWhen(true)] out IComponentRegistration? registration);
+        bool TryGetRegistration(ushort netID, [NotNullWhen(true)] out IComponentRegistration? registration);
 
         /// <summary>
         ///     Tries to get the registration of a component.
@@ -241,8 +252,7 @@ namespace Robust.Shared.GameObjects
         void DoAutoRegistrations();
 
         IEnumerable<Type> GetAllRefTypes();
-
-        IEnumerable<uint> GetAllNetIds();
+        void GenerateNetIds();
     }
 
     /// <summary>
@@ -263,18 +273,8 @@ namespace Robust.Shared.GameObjects
         /// ID used to reference the component type across the network.
         /// If null, no network synchronization will be available for this component.
         /// </summary>
-        /// <seealso cref="IComponent.NetID" />
-        uint? NetID { get; }
-
-        /// <summary>
-        /// True if the addition and removal of the component will be synchronized to clients.
-        /// This means that if the server adds or removes the component outside of prototype-based creation,
-        /// the client will update accordingly.
-        /// If false the client will ignore missing components even when the net ID checks out and could be instantiated.
-        /// and the client won't delete the component if no state was sent for it.
-        /// </summary>
-        /// <seealso cref="IComponent.NetworkSynchronizeExistence" />
-        bool NetworkSynchronizeExistence { get; }
+        /// <seealso cref="NetworkedComponentAttribute" />
+        ushort? NetID { get; }
 
         /// <summary>
         /// The type that will be instantiated if this component is created.

Robust.Shared/GameObjects/IComponentManager.cs

@@ -72,7 +72,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         /// <param name="uid">Entity UID to modify.</param>
         /// <param name="netID">Network ID of the component to remove.</param>
-        void RemoveComponent(EntityUid uid, uint netID);
+        void RemoveComponent(EntityUid uid, ushort netID);
 
         /// <summary>
         ///     Removes the specified component.
@@ -118,7 +118,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to check.</param>
         /// <param name="netId">Network ID to check for.</param>
         /// <returns>True if the entity has a component with the given network ID, otherwise false.</returns>
-        bool HasComponent(EntityUid uid, uint netId);
+        bool HasComponent(EntityUid uid, ushort netId);
 
         /// <summary>
         ///     Returns the component of a specific type.
@@ -143,7 +143,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to look on.</param>
         /// <param name="netId">Network ID of the component to retrieve.</param>
         /// <returns>The component with the specified network id.</returns>
-        IComponent GetComponent(EntityUid uid, uint netId);
+        IComponent GetComponent(EntityUid uid, ushort netId);
 
         /// <summary>
         ///     Returns the component of a specific type.
@@ -171,7 +171,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="netId">Component Network ID to check for.</param>
         /// <param name="component">Component with the specified network id.</param>
         /// <returns>If the component existed in the entity.</returns>
-        bool TryGetComponent(EntityUid uid, uint netId, [NotNullWhen(true)] out IComponent? component);
+        bool TryGetComponent(EntityUid uid, ushort netId, [NotNullWhen(true)] out IComponent? component);
 
         /// <summary>
         ///     Returns ALL component type instances on an entity. A single component instance
@@ -195,7 +195,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         /// <param name="uid">Entity UID to look on.</param>
         /// <returns>All components that have a network ID.</returns>
-        IEnumerable<IComponent> GetNetComponents(EntityUid uid);
+        NetComponentEnumerable GetNetComponents(EntityUid uid);
 
         /// <summary>
         ///     Returns ALL component instances of a specified type.

Robust.Shared/GameObjects/IEntityManager.cs

@@ -24,6 +24,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         void FrameUpdate(float frameTime);
 
+        IComponentFactory ComponentFactory { get; }
         IComponentManager ComponentManager { get; }
         IEntitySystemManager EntitySysManager { get; }
         IEntityNetworkManager? EntityNetManager { get; }

Robust.Shared/GameObjects/Systems/EntityLookup.cs

@@ -3,6 +3,8 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using JetBrains.Annotations;
+using Robust.Shared.Configuration;
+using Robust.Shared.IoC;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Physics;
@@ -66,15 +68,24 @@ namespace Robust.Shared.GameObjects
     [UsedImplicitly]
     public class EntityLookup : IEntityLookup, IEntityEventSubscriber
     {
+        private readonly IComponentManager _compManager;
         private readonly IEntityManager _entityManager;
         private readonly IMapManager _mapManager;
 
-        private readonly Dictionary<MapId, DynamicTree<IEntity>> _entityTreesPerMap = new();
+        private const int GrowthRate = 256;
+
+        private const float PointEnlargeRange = .00001f / 2;
 
         // Using stacks so we always use latest data (given we only run it once per entity).
         private readonly Stack<MoveEvent> _moveQueue = new();
         private readonly Stack<RotateEvent> _rotateQueue = new();
-        private readonly Queue<EntMapIdChangedMessage> _mapChangeQueue = new();
+        private readonly Queue<EntParentChangedMessage> _parentChangeQueue = new();
+
+        /// <summary>
+        /// Like RenderTree we need to enlarge our lookup range for EntityLookupComponent as an entity is only ever on
+        /// 1 EntityLookupComponent at a time (hence it may overlap without another lookup).
+        /// </summary>
+        private float _lookupEnlargementRange;
 
         /// <summary>
         /// Move and rotate events generate the same update so no point duplicating work in the same tick.
@@ -83,10 +94,17 @@ namespace Robust.Shared.GameObjects
 
         // TODO: Should combine all of the methods that check for IPhysBody and just use the one GetWorldAabbFromEntity method
 
+        // TODO: Combine GridTileLookupSystem and entity anchoring together someday.
+        // Queries are a bit of spaghet rn but ideally you'd just have:
+        // A) The fast tile-based one
+        // B) The physics-only one (given physics needs it to be fast af)
+        // C) A generic use one that covers anything not caught in the above.
+
         public bool Started { get; private set; } = false;
 
-        public EntityLookup(IEntityManager entityManager, IMapManager mapManager)
+        public EntityLookup(IComponentManager compManager, IEntityManager entityManager, IMapManager mapManager)
         {
+            _compManager = compManager;
             _entityManager = entityManager;
             _mapManager = mapManager;
         }
@@ -98,14 +116,21 @@ namespace Robust.Shared.GameObjects
                 throw new InvalidOperationException("Startup() called multiple times.");
             }
 
+            var configManager = IoCManager.Resolve<IConfigurationManager>();
+            configManager.OnValueChanged(CVars.LookupEnlargementRange, value => _lookupEnlargementRange = value, true);
+
             var eventBus = _entityManager.EventBus;
             eventBus.SubscribeEvent<MoveEvent>(EventSource.Local, this, ev => _moveQueue.Push(ev));
             eventBus.SubscribeEvent<RotateEvent>(EventSource.Local, this, ev => _rotateQueue.Push(ev));
-            eventBus.SubscribeEvent<EntMapIdChangedMessage>(EventSource.Local, this, ev => _mapChangeQueue.Enqueue(ev));
+            eventBus.SubscribeEvent<EntParentChangedMessage>(EventSource.Local, this, ev => _parentChangeQueue.Enqueue(ev));
+
+            eventBus.SubscribeLocalEvent<EntityLookupComponent, ComponentInit>(HandleLookupInit);
+            eventBus.SubscribeLocalEvent<EntityLookupComponent, ComponentShutdown>(HandleLookupShutdown);
+            eventBus.SubscribeEvent<GridInitializeEvent>(EventSource.Local, this, HandleGridInit);
+
             _entityManager.EntityDeleted += HandleEntityDeleted;
             _entityManager.EntityStarted += HandleEntityStarted;
             _mapManager.MapCreated += HandleMapCreated;
-            _mapManager.MapDestroyed += HandleMapDestroyed;
             Started = true;
         }
 
@@ -118,17 +143,43 @@ namespace Robust.Shared.GameObjects
             _moveQueue.Clear();
             _rotateQueue.Clear();
             _handledThisTick.Clear();
-            _mapChangeQueue.Clear();
-            _entityTreesPerMap.Clear();
+            _parentChangeQueue.Clear();
 
-            _entityManager.EventBus.UnsubscribeEvents(this);
             _entityManager.EntityDeleted -= HandleEntityDeleted;
             _entityManager.EntityStarted -= HandleEntityStarted;
             _mapManager.MapCreated -= HandleMapCreated;
-            _mapManager.MapDestroyed -= HandleMapDestroyed;
             Started = false;
         }
 
+        private void HandleLookupShutdown(EntityUid uid, EntityLookupComponent component, ComponentShutdown args)
+        {
+            component.Tree.Clear();
+        }
+
+        private void HandleGridInit(GridInitializeEvent ev)
+        {
+            _entityManager.GetEntity(ev.EntityUid).EnsureComponent<EntityLookupComponent>();
+        }
+
+        private void HandleLookupInit(EntityUid uid, EntityLookupComponent component, ComponentInit args)
+        {
+            var capacity = (int) Math.Min(256, Math.Ceiling(component.Owner.Transform.ChildCount / (float) GrowthRate) * GrowthRate);
+
+            component.Tree = new DynamicTree<IEntity>(
+                GetRelativeAABBFromEntity,
+                capacity: capacity,
+                growthFunc: x => x == GrowthRate ? GrowthRate * 8 : x + GrowthRate
+            );
+        }
+
+        private static Box2 GetRelativeAABBFromEntity(in IEntity entity)
+        {
+            var aabb = GetWorldAABB(entity);
+            var tree = GetLookup(entity);
+
+            return aabb.Translated(-tree?.Owner.Transform.WorldPosition ?? Vector2.Zero);
+        }
+
         private void HandleEntityDeleted(object? sender, EntityUid uid)
         {
             RemoveFromEntityTrees(_entityManager.GetEntity(uid));
@@ -141,63 +192,78 @@ namespace Robust.Shared.GameObjects
 
         private void HandleMapCreated(object? sender, MapEventArgs eventArgs)
         {
-            _entityTreesPerMap[eventArgs.Map] = new DynamicTree<IEntity>(
-                GetWorldAabbFromEntity,
-                capacity: 16,
-                growthFunc: x => x == 16 ? 3840 : x + 256
-            );
-        }
+            if (eventArgs.Map == MapId.Nullspace) return;
 
-        private void HandleMapDestroyed(object? sender, MapEventArgs eventArgs)
-        {
-            _entityTreesPerMap.Remove(eventArgs.Map);
+            _mapManager.GetMapEntity(eventArgs.Map).EnsureComponent<EntityLookupComponent>();
         }
 
         public void Update()
         {
             // Acruid said he'd deal with Update being called around IEntityManager later.
-            _handledThisTick.Clear();
 
-            while (_mapChangeQueue.TryDequeue(out var mapChangeEvent))
+            // Could be more efficient but essentially nuke their old lookup and add to new lookup if applicable.
+            while (_parentChangeQueue.TryDequeue(out var mapChangeEvent))
             {
-                if (mapChangeEvent.Entity.Deleted) continue;
-                RemoveFromEntityTree(mapChangeEvent.Entity, mapChangeEvent.OldMapId);
-                UpdateEntityTree(mapChangeEvent.Entity, GetWorldAabbFromEntity(mapChangeEvent.Entity));
                 _handledThisTick.Add(mapChangeEvent.Entity.Uid);
+                RemoveFromEntityTrees(mapChangeEvent.Entity);
+
+                if (mapChangeEvent.Entity.Deleted) continue;
+                UpdateEntityTree(mapChangeEvent.Entity, GetWorldAabbFromEntity(mapChangeEvent.Entity));
             }
 
             while (_moveQueue.TryPop(out var moveEvent))
             {
-                if (moveEvent.Sender.Deleted || _handledThisTick.Contains(moveEvent.Sender.Uid)) continue;
+                if (moveEvent.Sender.Deleted || !_handledThisTick.Add(moveEvent.Sender.Uid)) continue;
 
                 UpdateEntityTree(moveEvent.Sender, moveEvent.WorldAABB);
-                _handledThisTick.Add(moveEvent.Sender.Uid);
             }
 
             while (_rotateQueue.TryPop(out var rotateEvent))
             {
-                if (rotateEvent.Sender.Deleted || _handledThisTick.Contains(rotateEvent.Sender.Uid)) continue;
+                if (rotateEvent.Sender.Deleted || !_handledThisTick.Add(rotateEvent.Sender.Uid)) continue;
 
                 UpdateEntityTree(rotateEvent.Sender, rotateEvent.WorldAABB);
             }
+
+            _handledThisTick.Clear();
         }
 
         #region Spatial Queries
 
+        private IEnumerable<EntityLookupComponent> GetLookupsIntersecting(MapId mapId, Box2 worldAABB)
+        {
+            if (mapId == MapId.Nullspace) yield break;
+
+            // TODO: Recursive and all that.
+            foreach (var grid in _mapManager.FindGridsIntersecting(mapId, worldAABB.Enlarged(_lookupEnlargementRange)))
+            {
+                yield return _entityManager.GetEntity(grid.GridEntityId).GetComponent<EntityLookupComponent>();
+            }
+
+            yield return _mapManager.GetMapEntity(mapId).GetComponent<EntityLookupComponent>();
+        }
+
         /// <inheritdoc />
         public bool AnyEntitiesIntersecting(MapId mapId, Box2 box, bool approximate = false)
         {
             var found = false;
-            _entityTreesPerMap[mapId].QueryAabb(ref found, (ref bool found, in IEntity ent) =>
-            {
-                if (!ent.Deleted)
-                {
-                    found = true;
-                    return false;
-                }
 
-                return true;
-            }, box, approximate);
+            foreach (var lookup in GetLookupsIntersecting(mapId, box))
+            {
+                var offsetBox = box.Translated(-lookup.Owner.Transform.WorldPosition);
+
+                lookup.Tree.QueryAabb(ref found, (ref bool found, in IEntity ent) =>
+                {
+                    if (!ent.Deleted)
+                    {
+                        found = true;
+                        return false;
+                    }
+
+                    return true;
+                }, offsetBox, approximate);
+            }
+
             return found;
         }
 
@@ -205,31 +271,34 @@ namespace Robust.Shared.GameObjects
         [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         public void FastEntitiesIntersecting(in MapId mapId, ref Box2 position, EntityQueryCallback callback)
         {
-            if (mapId == MapId.Nullspace)
-                return;
+            foreach (var lookup in GetLookupsIntersecting(mapId, position))
+            {
+                var offsetBox = position.Translated(-lookup.Owner.Transform.WorldPosition);
 
-            _entityTreesPerMap[mapId]._b2Tree
-                .FastQuery(ref position, (ref IEntity data) => callback(data));
+                lookup.Tree._b2Tree.FastQuery(ref offsetBox, (ref IEntity data) => callback(data));
+            }
         }
 
         /// <inheritdoc />
         public IEnumerable<IEntity> GetEntitiesIntersecting(MapId mapId, Box2 position, bool approximate = false)
         {
-            if (!_entityTreesPerMap.TryGetValue(mapId, out var mapTree))
-            {
-                return Enumerable.Empty<IEntity>();
-            }
+            if (mapId == MapId.Nullspace) return Enumerable.Empty<IEntity>();
 
             var list = new List<IEntity>();
 
-            mapTree.QueryAabb(ref list, (ref List<IEntity> list, in IEntity ent) =>
+            foreach (var lookup in GetLookupsIntersecting(mapId, position))
             {
-                if (!ent.Deleted)
+                var offsetBox = position.Translated(-lookup.Owner.Transform.WorldPosition);
+
+                lookup.Tree.QueryAabb(ref list, (ref List<IEntity> list, in IEntity ent) =>
                 {
-                    list.Add(ent);
-                }
-                return true;
-            }, position, approximate);
+                    if (!ent.Deleted)
+                    {
+                        list.Add(ent);
+                    }
+                    return true;
+                }, offsetBox, approximate);
+            }
 
             return list;
         }
@@ -237,25 +306,25 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public IEnumerable<IEntity> GetEntitiesIntersecting(MapId mapId, Vector2 position, bool approximate = false)
         {
-            const float range = .00001f / 2;
-            var aabb = new Box2(position, position).Enlarged(range);
-
-            if (mapId == MapId.Nullspace)
-            {
-                return Enumerable.Empty<IEntity>();
-            }
+            if (mapId == MapId.Nullspace) return Enumerable.Empty<IEntity>();
 
+            var aabb = new Box2(position, position).Enlarged(PointEnlargeRange);
             var list = new List<IEntity>();
             var state = (list, position);
 
-            _entityTreesPerMap[mapId].QueryAabb(ref state, (ref (List<IEntity> list, Vector2 position) state, in IEntity ent) =>
+            foreach (var lookup in GetLookupsIntersecting(mapId, aabb))
             {
-                if (Intersecting(ent, state.position))
+                var offsetBox = aabb.Translated(-lookup.Owner.Transform.WorldPosition);
+
+                lookup.Tree.QueryAabb(ref state, (ref (List<IEntity> list, Vector2 position) state, in IEntity ent) =>
                 {
-                    state.list.Add(ent);
-                }
-                return true;
-            }, aabb, approximate);
+                    if (Intersecting(ent, state.position))
+                    {
+                        state.list.Add(ent);
+                    }
+                    return true;
+                }, offsetBox, approximate);
+            }
 
             return list;
         }
@@ -365,34 +434,44 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public IEnumerable<IEntity> GetEntitiesInMap(MapId mapId)
         {
-            if (!_entityTreesPerMap.TryGetValue(mapId, out var trees))
-                yield break;
-
-            foreach (var entity in trees)
+            foreach (EntityLookupComponent comp in _compManager.EntityQuery<EntityLookupComponent>(true))
             {
-                if (!entity.Deleted)
+                foreach (var entity in comp.Tree)
+                {
+                    if (entity.Deleted) continue;
+
                     yield return entity;
+                }
             }
         }
 
         /// <inheritdoc />
         public IEnumerable<IEntity> GetEntitiesAt(MapId mapId, Vector2 position, bool approximate = false)
         {
+            if (mapId == MapId.Nullspace) return Enumerable.Empty<IEntity>();
+
             var list = new List<IEntity>();
 
             var state = (list, position);
 
-            _entityTreesPerMap[mapId].QueryPoint(ref state, (ref (List<IEntity> list, Vector2 position) state, in IEntity ent) =>
-            {
-                var transform = ent.Transform;
-                if (MathHelper.CloseTo(transform.Coordinates.X, state.position.X) &&
-                    MathHelper.CloseTo(transform.Coordinates.Y, state.position.Y))
-                {
-                    state.list.Add(ent);
-                }
+            var aabb = new Box2(position, position).Enlarged(PointEnlargeRange);
 
-                return true;
-            }, position, approximate);
+            foreach (var lookup in GetLookupsIntersecting(mapId, aabb))
+            {
+                var offsetPos = position -lookup.Owner.Transform.WorldPosition;
+
+                lookup.Tree.QueryPoint(ref state, (ref (List<IEntity> list, Vector2 position) state, in IEntity ent) =>
+                {
+                    var transform = ent.Transform;
+                    if (MathHelper.CloseTo(transform.Coordinates.X, state.position.X) &&
+                        MathHelper.CloseTo(transform.Coordinates.Y, state.position.Y))
+                    {
+                        state.list.Add(ent);
+                    }
+
+                    return true;
+                }, offsetPos, approximate);
+            }
 
             return list;
         }
@@ -400,88 +479,119 @@ namespace Robust.Shared.GameObjects
         #endregion
 
         #region Entity DynamicTree
+
+        private static EntityLookupComponent? GetLookup(IEntity entity)
+        {
+            if (entity.Transform.MapID == MapId.Nullspace)
+            {
+                return null;
+            }
+
+            // if it's map return null. Grids should return the map's broadphase.
+            if (entity.HasComponent<EntityLookupComponent>() &&
+                entity.Transform.Parent == null)
+            {
+                return null;
+            }
+
+            var parent = entity.Transform.Parent?.Owner;
+
+            while (true)
+            {
+                if (parent == null) break;
+
+                if (parent.TryGetComponent(out EntityLookupComponent? comp)) return comp;
+                parent = parent.Transform.Parent?.Owner;
+            }
+
+            return null;
+        }
+
         /// <inheritdoc />
         public virtual bool UpdateEntityTree(IEntity entity, Box2? worldAABB = null)
         {
+            // look there's JANK everywhere but I'm just bandaiding it for now for shuttles and we'll fix it later when
+            // PVS is more stable and entity anchoring has been battle-tested.
             if (entity.Deleted)
             {
                 RemoveFromEntityTrees(entity);
                 return true;
             }
 
-            if (!entity.Initialized || !_entityManager.EntityExists(entity.Uid))
+            if (!entity.Initialized)
             {
                 return false;
             }
 
-            var transform = entity.Transform;
+            var lookup = GetLookup(entity);
 
+            if (lookup == null)
+            {
+                RemoveFromEntityTrees(entity);
+                return true;
+            }
+
+            // Temp PVS guard for when we clear dynamictree for now.
+            worldAABB ??= GetWorldAabbFromEntity(entity);
+            var center = worldAABB.Value.Center;
+
+            if (float.IsNaN(center.X) || float.IsNaN(center.Y))
+            {
+                RemoveFromEntityTrees(entity);
+                return true;
+            }
+
+            var transform = entity.Transform;
             DebugTools.Assert(transform.Initialized);
 
-            var mapId = transform.MapID;
-
-            if (!_entityTreesPerMap.TryGetValue(mapId, out var entTree))
-            {
-                entTree = new DynamicTree<IEntity>(
-                    GetWorldAabbFromEntity,
-                    capacity: 16,
-                    growthFunc: x => x == 16 ? 3840 : x + 256
-                );
-                _entityTreesPerMap.Add(mapId, entTree);
-            }
+            var aabb = worldAABB.Value.Translated(-lookup.Owner.Transform.WorldPosition);
 
             // for debugging
             var necessary = 0;
 
-            if (entTree.AddOrUpdate(entity, worldAABB))
+            if (lookup.Tree.AddOrUpdate(entity, aabb))
             {
                 ++necessary;
             }
 
-            foreach (var childTx in entity.Transform.ChildEntityUids)
+            if (!entity.HasComponent<EntityLookupComponent>())
             {
-                if (UpdateEntityTree(_entityManager.GetEntity(childTx)))
+                foreach (var childTx in entity.Transform.ChildEntityUids)
                 {
-                    ++necessary;
+                    if (!_handledThisTick.Add(childTx)) continue;
+
+                    if (UpdateEntityTree(_entityManager.GetEntity(childTx)))
+                    {
+                        ++necessary;
+                    }
                 }
             }
 
             return necessary > 0;
         }
 
-        public bool RemoveFromEntityTree(IEntity entity, MapId mapId)
-        {
-            if (_entityTreesPerMap.TryGetValue(mapId, out var tree))
-            {
-                return tree.Remove(entity);
-            }
-
-            return false;
-        }
-
         /// <inheritdoc />
         public void RemoveFromEntityTrees(IEntity entity)
         {
-            foreach (var mapId in _mapManager.GetAllMapIds())
+            foreach (var lookup in _compManager.EntityQuery<EntityLookupComponent>(true))
             {
-                if (_entityTreesPerMap.TryGetValue(mapId, out var entTree))
-                {
-                    entTree.Remove(entity);
-                }
+                lookup.Tree.Remove(entity);
             }
         }
 
         public Box2 GetWorldAabbFromEntity(in IEntity ent)
         {
-            if (ent.Deleted)
-                return new Box2(0, 0, 0, 0);
+            return GetWorldAABB(ent);
+        }
 
+        private static Box2 GetWorldAABB(in IEntity ent)
+        {
             var pos = ent.Transform.WorldPosition;
 
-            if (ent.TryGetComponent(out IPhysBody? collider))
-                return collider.GetWorldAABB(pos);
+            if (ent.Deleted || !ent.TryGetComponent(out PhysicsComponent? physics))
+                return new Box2(pos, pos);
 
-            return new Box2(pos, pos);
+            return physics.GetWorldAABB(pos);
         }
 
         #endregion

Robust.Shared/GameObjects/Systems/SharedPhysicsSystem.cs

@@ -100,19 +100,59 @@ namespace Robust.Shared.GameObjects
             _mapManager.MapCreated += HandleMapCreated;
             _mapManager.MapDestroyed += HandleMapDestroyed;
 
+            SubscribeLocalEvent<GridInitializeEvent>(HandleGridInit);
             SubscribeLocalEvent<PhysicsUpdateMessage>(HandlePhysicsUpdateMessage);
             SubscribeLocalEvent<PhysicsWakeMessage>(HandleWakeMessage);
             SubscribeLocalEvent<PhysicsSleepMessage>(HandleSleepMessage);
             SubscribeLocalEvent<EntMapIdChangedMessage>(HandleMapChange);
-
             SubscribeLocalEvent<EntInsertedIntoContainerMessage>(HandleContainerInserted);
             SubscribeLocalEvent<EntRemovedFromContainerMessage>(HandleContainerRemoved);
+            SubscribeLocalEvent<EntParentChangedMessage>(HandleParentChange);
+
             BuildControllers();
             Logger.DebugS("physics", $"Found {_controllers.Count} physics controllers.");
 
             IoCManager.Resolve<IIslandManager>().Initialize();
         }
 
+        private void HandleParentChange(EntParentChangedMessage args)
+        {
+            var entity = args.Entity;
+
+            if (!entity.Initialized ||
+                !entity.TryGetComponent(out PhysicsComponent? body) ||
+                entity.IsInContainer()) return;
+
+            var oldParent = args.OldParent;
+            var linearVelocityDiff = Vector2.Zero;
+            var angularVelocityDiff = 0f;
+
+            if (oldParent != null && oldParent.TryGetComponent(out PhysicsComponent? oldBody))
+            {
+                var (linear, angular) = oldBody.MapVelocities;
+
+                linearVelocityDiff += linear;
+                angularVelocityDiff += angular;
+            }
+
+            if (entity.Transform.Parent!.Owner.TryGetComponent(out PhysicsComponent? newBody))
+            {
+                var (linear, angular) = newBody.MapVelocities;
+
+                linearVelocityDiff -= linear;
+                angularVelocityDiff -= angular;
+            }
+
+            body.LinearVelocity += linearVelocityDiff;
+            body.AngularVelocity += angularVelocityDiff;
+        }
+        
+        private void HandleGridInit(GridInitializeEvent ev)
+        {
+            if (!EntityManager.TryGetEntity(ev.EntityUid, out var gridEntity)) return;
+            var collideComp = gridEntity.EnsureComponent<PhysicsComponent>();
+            collideComp.BodyType = BodyType.Static;
+        }
 
         private void BuildControllers()
         {

Robust.Shared/GameStates/NetworkedComponentAttribute.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace Robust.Shared.GameStates
+{
+    /// <summary>
+    /// This attribute marks a component as networked, so that it is replicated to clients.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class)]
+    public class NetworkedComponentAttribute : Attribute { }
+}

Robust.Shared/Map/GridChunkPartition.cs

@@ -8,10 +8,8 @@ namespace Robust.Shared.Map
     /// </summary>
     internal static class GridChunkPartition
     {
-        public static void PartitionChunk(IMapChunk chunk, ref IList<Box2> rectangles, out Box2i bounds)
+        public static void PartitionChunk(IMapChunk chunk, out Box2i bounds)
         {
-            rectangles.Clear();
-
             var size = chunk.ChunkSize;
 
             // copy 2d img
@@ -37,8 +35,6 @@ namespace Robust.Shared.Map
                 var bottom = block.x1;
                 var top = block.x2 + 1;
 
-                rectangles.Add(new Box2(left, bottom, right, top));
-
                 if(bounds.Size.Equals(Vector2i.Zero))
                     bounds = new Box2i(left, bottom, right, top);
                 else

Robust.Shared/Map/IMapChunkInternal.cs

@@ -15,10 +15,5 @@ namespace Robust.Shared.Map
         /// The last game simulation tick that this chunk was modified.
         /// </summary>
         GameTick LastModifiedTick { get; }
-
-        /// <summary>
-        /// The physical collision boxes of this chunk.
-        /// </summary>
-        IEnumerable<Box2> CollisionBoxes { get; }
     }
 }

Robust.Shared/Map/IMapGridInternal.cs

@@ -24,7 +24,7 @@ namespace Robust.Shared.Map
         ///     This wouldn't even be separate if not for the whole "ability to suppress automatic collision regeneration" thing.
         ///     As it is, YamlGridSerializer performs manual collision regeneration and that wasn't properly getting propagated to the grid. Thus, this needs to exist.
         /// </summary>
-        void NotifyChunkCollisionRegenerated();
+        void NotifyChunkCollisionRegenerated(MapChunk chunk);
 
         /// <summary>
         ///     Returns the chunk at the given indices. If the chunk does not exist,

Robust.Shared/Map/ITileDefinition.cs

@@ -25,6 +25,11 @@
         /// </summary>
         string SpriteName { get; }
 
+        /// <summary>
+        ///     Path to the folder where the tile sprite is contained.
+        /// </summary>
+        string Path { get; }
+
         /// <summary>
         ///     Physics objects that are interacting on this tile are slowed down by this float.
         /// </summary>

Robust.Shared/Map/MapChunk.cs

@@ -2,7 +2,9 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
 using Robust.Shared.Maths;
+using Robust.Shared.Physics.Dynamics;
 using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 
@@ -16,6 +18,8 @@ namespace Robust.Shared.Map
         /// </summary>
         private const int SnapCellStartingCapacity = 1;
 
+        public GridId GridId => _grid.Index;
+
         private readonly IMapGridInternal _grid;
         private readonly Vector2i _gridIndices;
 
@@ -23,13 +27,12 @@ namespace Robust.Shared.Map
         private readonly SnapGridCell[,] _snapGrid;
 
         private Box2i _cachedBounds;
-        private IList<Box2> _colBoxes;
+
+        public Fixture? Fixture { get; set; }
 
         /// <inheritdoc />
         public GameTick LastModifiedTick { get; private set; }
 
-        public IEnumerable<Box2> CollisionBoxes => _colBoxes;
-
         /// <summary>
         ///     Constructs an instance of a MapGrid chunk.
         /// </summary>
@@ -46,7 +49,6 @@ namespace Robust.Shared.Map
 
             _tiles = new Tile[ChunkSize, ChunkSize];
             _snapGrid = new SnapGridCell[ChunkSize, ChunkSize];
-            _colBoxes = new List<Box2>(0);
         }
 
         /// <inheritdoc />
@@ -233,8 +235,8 @@ namespace Robust.Shared.Map
         public void RegenerateCollision()
         {
             // generate collision rects
-            GridChunkPartition.PartitionChunk(this, ref _colBoxes, out _cachedBounds);
-            _grid.NotifyChunkCollisionRegenerated();
+            GridChunkPartition.PartitionChunk(this, out _cachedBounds);
+            _grid.NotifyChunkCollisionRegenerated(this);
         }
 
         /// <inheritdoc />
@@ -264,12 +266,6 @@ namespace Robust.Shared.Map
             return _tiles[localIndices.X, localIndices.Y].TypeId != Tile.Empty.TypeId;
         }
 
-        /// <inheritdoc />
-        public bool CollidesWithChunk(Box2 pos)
-        {
-            throw new NotImplementedException();
-        }
-
         /// <inheritdoc />
         public override string ToString()
         {
@@ -281,4 +277,14 @@ namespace Robust.Shared.Map
             public List<EntityUid>? Center;
         }
     }
+
+    internal sealed class RegenerateChunkCollisionEvent : EntityEventArgs
+    {
+        public MapChunk Chunk { get; }
+
+        public RegenerateChunkCollisionEvent(MapChunk chunk)
+        {
+            Chunk = chunk;
+        }
+    }
 }

Robust.Shared/Map/MapGrid.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
 using Robust.Shared.Maths;
 using Robust.Shared.Timing;
 using Robust.Shared.Utility;
@@ -40,7 +41,7 @@ namespace Robust.Shared.Map
         private readonly Dictionary<Vector2i, IMapChunkInternal> _chunks = new();
 
         private readonly IMapManagerInternal _mapManager;
-        private readonly IEntityManager _entityManager;     
+        private readonly IEntityManager _entityManager;
 
         /// <summary>
         ///     Initializes a new instance of the <see cref="MapGrid"/> class.
@@ -146,8 +147,18 @@ namespace Robust.Shared.Map
         }
 
         /// <inheritdoc />
-        public void NotifyChunkCollisionRegenerated()
+        public void NotifyChunkCollisionRegenerated(MapChunk chunk)
         {
+            // TODO: Ideally we wouldn't have LocalBounds on the grid and we could just treat it like a physics object
+            // (eventually, well into the future).
+            // For now we'll just attach a fixture to each chunk.
+
+            // Not raising directed because the grid's EntityUid isn't set yet.
+            IoCManager
+                .Resolve<IEntityManager>()
+                .EventBus
+                .RaiseEvent(EventSource.Local, new RegenerateChunkCollisionEvent(chunk));
+
             UpdateAABB();
         }