Version: 267.2.2

83ad6042a7 & b267cd6fb4

Does not include test code to avoid risking merge conflicts.

(cherry picked from commit 415585a30d74fcae61f581808220a7aaeca3eaf5)

Directory.Packages.props

@@ -59,6 +59,7 @@
     <PackageVersion Include="SixLabors.ImageSharp" Version="3.1.11" />
     <PackageVersion Include="SpaceWizards.HttpListener" Version="0.1.1" />
     <PackageVersion Include="SpaceWizards.NFluidsynth" Version="0.2.2" />
+    <PackageVersion Include="SpaceWizards.Sdl" Version="1.0.0" />
     <PackageVersion Include="SpaceWizards.SharpFont" Version="1.1.0" />
     <PackageVersion Include="SpaceWizards.Sodium" Version="0.2.1" />
     <PackageVersion Include="libsodium" Version="1.0.20.1" />

MSBuild/Robust.Engine.Version.props

@@ -1,4 +1,4 @@
 <Project>
 
-    <!-- This file automatically reset by Tools/version.py -->
+    <!-- This file automatically reset by Tools/version.py -->
 

RELEASE-NOTES.md

@@ -54,12 +54,134 @@ END TEMPLATE-->
 *None yet*
 
 
-## 267.0.2
+## 267.2.2
 
 
-## 267.0.1
+## 267.2.1
 
 
+## 267.2.0
+
+### New features
+
+* Sprites and Sprite layers have a new `Loop` data field that can be set to false to automatically pause animations once they have finished.
+
+### Bugfixes
+
+* Fixed `CollectionExtensions.TryGetValue` throwing an exception when given a negative list index.
+* Fixed `EntityManager.PredictedQueueDeleteEntity()` not deferring changes for networked entities until the end of the tick. 
+* Fixed `EntityManager.IsQueuedForDeletion` not returning true foe entities getting deleted via `PredictedQueueDeleteEntity()`
+
+### Other
+
+* `IResourceManager.GetContentRoots()` has been obsoleted and returns no more results.
+
+### Internal
+
+* `IResourceManager.GetContentRoots()` has been replaced with a similar method on `IResourceManagerInternal`. This new method returns `string`s instead of `ResPath`s, and usage code has been updated to use these paths correctly.
+
+
+## 267.1.0
+
+### New features
+
+* Animation:
+  * `AnimationTrackProperty.KeyFrame` can now have easings functions applied.
+* Graphics:
+  * `PointLightComponent` now has two fields, `falloff` and `curveFactor`, for controlling light falloff and the shape of the light attenuation curve.
+  * `IClydeViewport` now has an `Id` and `ClearCachedResources` event. Together, these allow you to properly cache rendering resources per viewport.
+* Miscellaneous:
+  * Added `display.max_fps` CVar.
+  * Added `IGameTiming.FrameStartTime`.
+* Sandbox:
+  * Added `System.WeakReference<T>`.
+  * Added `SpaceWizards.Sodium.CryptoGenericHashBlake2B.Hash()`.
+  * Added `System.Globalization.UnicodeCategory`.
+* Serialization:
+  * Added a new entity yaml deserialization option (`SerializationOptions.EntityExceptionBehaviour`) that can optionally make deserialization more exception tolerant.
+* Tooling:
+  * `devwindow` now has a tab listing active `IRenderTarget`s, allowing insight into resource consumption.
+  * `loadgrid` now creates a map if passed an invalid map ID.
+  * Added game version information to F3 overlay.
+  * Added completions to more map commands.
+* UI system:
+  * `Control.OrderedChildCollection` (gotten from `.Children`) now implements `IReadOnlyList<Control>`, allowing it to be indexed directly.
+    * Added `WrapContainer` control. This lays out multiple elements along an axis, wrapping them if there's not enough space. It comes with many options and can handle multiple axes.
+  * Popups/modals now work in secondary windows. This entails putting roots for these on each UI root.
+  * If you are not using `OSWindow` and are instead creating secondary windows manually, you need to call `WindowRoot.CreateRootControls()` manually for this to work.
+  * Added `Axis` enum, `IAxisImplementation` interface and axis implementations. These allow writing general-purpose UI layout code that can work on multiple axis at once.
+* WebView:
+  * Added `web.remote_debug_port` CVar to change Chromium's remote debug port.
+
+### Bugfixes
+
+* Audio:
+  * Fix audio occlusion & velocity being calculated with the audio entity instead of the source entity.
+* Bound UI:
+  * Try to fix an assert related to `UserInterfaceComponent` delta states.
+* Configuration:
+  * The client no longer tries to send `CLIENT | REPLICATED` CVars when not connected to a server. This could cause test failures.
+* Math:
+  * Fixed `Matrix3Helpers.TransformBounds()` returning an incorrect result. Now it effectively behaves like `Matrix3Helpers.TransformBox()` and has been marked as obsolete.
+* Physics:
+  * Work around an undiagnosed crash processing entities without parents.
+* Serialization:
+  * Fix `[DataRecord]`s with computed get-only properties.
+* Resources:
+  * Fix some edge case broken path joining in `DirLoader` and `WritableDirProvider`.
+* Tests:
+  * Fix `PlacementManager.CurrentMousePosition` in integration tests.
+* UI system:
+  * Animations for the debug console and scrolling are no longer framerate dependent.
+  * Fix `OutputPanel.SetMessage` triggering a scrolling animation when editing messages other than the last one.
+  * Fix word wrapping with two-`char` runes in `RichTextLabel` and `OutputPanel`.
+* WebView:
+  * Multiple clients with WebView can now run at the same time, thanks to better CEF cache management.
+
+### Other
+
+* Audio:
+  * Improved error logging for invalid file names in `SharedAudioSystem`.
+* Configuration:
+  * Fix crash if more than 255 `REPLICATED` CVars exist. Also increased the max size of the CVar replication message.
+* Entities:
+  * Transform:
+    * `AnchorEntity` logs instead of using an assert for invalid arguments.
+  * Containers:
+    * `SharedContainerSystem.CleanContainer` now uses `PredictedDel()` instead.
+* Networking:
+  * The client now logs an error when attempting to send a network message without server connection. Previously, it would be silently dropped.
+  * `net.interp` and `net.buffer_size` CVars are now `REPLICATED`.
+* Graphics:
+  * The function used for pointlight attenuation has been modified to be c1 continuous as opposed to simply c0 continuous, resulting in smoother boundary behavior.
+  * RSI validator no longer allows empty (`""`) state names.
+* Packaging:
+  * Server packaging now excludes all files in the `Audio/` directory.
+  * Server packaging now excludes engine resources `EngineFonts/` and `Midi/`.
+  * ACZ explicitly specifies manifest charset as UTF-8.
+* Serialization:
+  * `CurTime`-relative `TimeSpan` values that are `MaxValue` now deserialize without overflow.
+  * `SpriteSpecifier.Texture` will now fail to validate if the path is inside a `.rsi`. Use RSI sprite specifiers instead.
+* Resources:
+  * `IWritableDirProvider.RootDir` is now null on clients.
+* WebView:
+  * CEF cache is no longer in the content-accessible user data directory.
+
+### Internal
+
+* Added some debug commands for debugging viewport resource management: `vp_clear_all_cached` & `vp_test_finalize`
+* `uitest` command now supports command argument for tab selection, like `uitest2`.
+* Rewrote `BoxContainer` implementation to make use of new axis system.
+* Moved `uitest2` and `devwindow` to use the `OSWindow` control.
+* SDL3 binding has been moved to `SpaceWizards.Sdl` NuGet package.
+* `dmetamem` command has been moved from `DEBUG` to `TOOLS`.
+* Consolidate `AttachToGridOrMap` with `TryGetMapOrGridCoordinates`.
+* Secondary window render targets have clear names specified.
+* Updated `SpaceWizards.NFluidsynth` to `0.2.2`.
+* `Robust.Client.WebView.Cef.Program` is now internal.
+* `download_manifest_file.py` script in repo now always decodes as UTF-8 correctly.
+* Added a new debug assert to game state processing.
+
 ## 267.0.0
 
 ### Breaking changes

Resources/Locale/en-US/_generic.ftl

@@ -0,0 +1,3 @@
+generic-map = map
+generic-grid = grid
+generic-mapid = map Id

Resources/Locale/en-US/commands.ftl

@@ -577,3 +577,5 @@ cmd-localization_set_culture-desc = Set DefaultCulture for the client Localizati
 cmd-localization_set_culture-help = Usage: localization_set_culture <cultureName>
 cmd-localization_set_culture-culture-name = <cultureName>
 cmd-localization_set_culture-changed = Localization changed to { $code } ({ $nativeName } / { $englishName })
+
+cmd-addmap-hint-2 = runMapInit [true / false]

Resources/Locale/en-US/dev-window.ftl

@@ -8,3 +8,18 @@ dev-window-tab-textures-info = Width: { $width } Height: { $height }
     PixelType: { $pixelType } sRGB: { $srgb }
     Name: { $name }
     Est. memory usage: { $bytes }
+
+## "Render Targets" dev window tab
+dev-window-tab-render-targets-title = Render Targets
+dev-window-tab-render-targets-reload = Reload
+dev-window-tab-render-targets-filter = Filter
+dev-window-tab-render-targets-column-id = ID
+dev-window-tab-render-targets-column-name = Name
+dev-window-tab-render-targets-column-size = Size
+dev-window-tab-render-targets-column-type = Type
+dev-window-tab-render-targets-column-vram = VRAM
+dev-window-tab-render-targets-column-thumbnail = Thumbnail
+
+dev-window-tab-render-targets-value-null = null
+dev-window-tab-render-targets-value-not-available = Not available
+dev-window-tab-render-targets-summary = Total VRAM: { $vram }

Resources/Shaders/Internal/light_shared.swsl

@@ -14,6 +14,8 @@ uniform highp vec2 lightCenter;
 uniform highp float lightRange;
 uniform highp float lightPower;
 uniform highp float lightSoftness;
+uniform highp float lightFalloff;
+uniform highp float lightCurveFactor;
 uniform highp float lightIndex;
 uniform sampler2D shadowMap;
 
@@ -47,8 +49,15 @@ void fragment()
         discard;
     }
 
-    highp float dist = dot(diff, diff) + LIGHTING_HEIGHT;
-    highp float val = clamp((1.0 - clamp(sqrt(dist) / lightRange, 0.0, 1.0)) * (1.0 / (sqrt(dist + 1.0))), 0.0, 1.0);
+    // this implementation of light attenuation primarily adapted from
+    // https://lisyarus.github.io/blog/posts/point-light-attenuation.html
+    highp float sqr_dist = dot(diff, diff) + LIGHTING_HEIGHT;
+
+    highp float s = clamp(sqrt(sqr_dist) / lightRange, 0.0, 1.0);
+    highp float s2 = s * s;
+    // controls curve by lerping between two variants (inverse-shape and inversequadratic-shape)
+    highp float curveFactor = mix(s, s2, clamp(lightCurveFactor, 0.0, 1.0));
+    highp float val = clamp(((1.0 - s2) * (1.0 - s2)) / (1.0 + lightFalloff * curveFactor), 0.0, 1.0);
 
     val *= lightPower;
     val *= mask;

Robust.Client.WebView/Cef/WebViewManagerCef.Lock.cs

@@ -0,0 +1,51 @@
+using System;
+using System.IO;
+using Robust.Client.Utility;
+
+namespace Robust.Client.WebView.Cef;
+
+internal sealed partial class WebViewManagerCef
+{
+    private const string BaseCacheName = "cef_cache";
+    private const string LockFileName = "robust.lock";
+    private FileStream? _lockFileStream;
+    private const int MaxAttempts = 15; // This probably shouldn't be a cvar because the only reason you'd need it change for legit just botting the game.
+
+    private string FindAndLockCacheDirectory()
+    {
+        var rootDir = Path.Combine(UserDataDir.GetRootUserDataDir(_gameController), BaseCacheName);
+
+        for (var i = 0; i < MaxAttempts; i++)
+        {
+            var cacheDirPath = Path.Combine(rootDir, i.ToString());
+
+            if (TryLockCacheDir(i, cacheDirPath))
+                return cacheDirPath;
+        }
+
+        throw new Exception("Unable to locate available CEF cache directory!");
+    }
+
+    private bool TryLockCacheDir(int attempt, string path)
+    {
+        _sawmill.Verbose($"Trying to lock cache directory {attempt}");
+
+        // Does not fail if directory already exists.
+        Directory.CreateDirectory(path);
+
+        var lockFilePath = Path.Combine(path, LockFileName);
+
+        try
+        {
+            var file = File.Open(lockFilePath, FileMode.Create, FileAccess.ReadWrite, FileShare.None);
+            _lockFileStream = file;
+            _sawmill.Debug($"Successfully locked CEF cache directory {attempt}");
+            return true;
+        }
+        catch (IOException ex)
+        {
+            _sawmill.Error($"Failed to lock cache directory {attempt}: {ex}");
+            return false;
+        }
+    }
+}

Robust.Client.WebView/Cef/WebViewManagerCef.cs

@@ -61,12 +61,9 @@ namespace Robust.Client.WebView.Cef
             if (cefResourcesPath == null)
                 throw new InvalidOperationException("Unable to locate cef_resources directory!");
 
-            var cachePath = "";
-            if (_resourceManager.UserData is WritableDirProvider userData)
-            {
-                var rootDir = UserDataDir.GetRootUserDataDir(_gameController);
-                cachePath = Path.Combine(rootDir, "cef_cache", "0");
-            }
+            var remoteDebugPort = _cfg.GetCVar(WCVars.WebRemoteDebugPort);
+
+            var cachePath = FindAndLockCacheDirectory();
 
             var settings = new CefSettings()
             {
@@ -76,7 +73,7 @@ namespace Robust.Client.WebView.Cef
                 BrowserSubprocessPath = subProcessPath,
                 LocalesDirPath = Path.Combine(cefResourcesPath, "locales"),
                 ResourcesDirPath = cefResourcesPath,
-                RemoteDebuggingPort = 9222,
+                RemoteDebuggingPort = remoteDebugPort,
                 CookieableSchemesList = "usr,res",
                 CachePath = cachePath,
             };

Robust.Client.WebView/WCVars.cs

@@ -26,4 +26,16 @@ public static class WCVars
     /// </summary>
     public static readonly CVarDef<bool> WebHeadless =
         CVarDef.Create("web.headless", false, CVar.CLIENTONLY);
+
+#if TOOLS
+    private const int DefaultRemoteDebugPort = 9222;
+#else
+    private const int DefaultRemoteDebugPort = 0;
+#endif
+
+    /// <summary>
+    /// If not 0, the port number used for Chromium's remote debugging.
+    /// </summary>
+    public static readonly CVarDef<int> WebRemoteDebugPort =
+        CVarDef.Create("web.remote_debug_port", DefaultRemoteDebugPort, CVar.CLIENTONLY);
 }

Robust.Client/Animations/AnimationTrackProperty.cs

@@ -54,8 +54,14 @@ namespace Robust.Client.Animations
             }
             else
             {
+                var next = KeyFrames[nextKeyFrame];
+
                 // Get us a scale 0 -> 1 here.
-                var t = playingTime / KeyFrames[nextKeyFrame].KeyTime;
+                var t = playingTime / next.KeyTime;
+
+                // Apply easing to time parameter, if one was specified
+                if (next.Easing != null)
+                    t = next.Easing(t);
 
                 switch (InterpolationMode)
                 {
@@ -147,10 +153,20 @@ namespace Robust.Client.Animations
             /// </summary>
             public readonly float KeyTime;
 
-            public KeyFrame(object value, float keyTime)
+            /// <summary>
+            ///     An easing function to apply when interpolating to this keyframe's value.
+            ///     Modifies the time parameter (0..1) of the interpolation between the previous keyframe and this one.
+            /// </summary>
+            /// <remarks>
+            ///     See <see cref="Easings"/> for examples of easing functions, or provide your own.
+            /// </remarks>
+            public readonly Func<float, float>? Easing;
+
+            public KeyFrame(object value, float keyTime, Func<float, float>? easing = null)
             {
                 Value = value;
                 KeyTime = keyTime;
+                Easing = easing;
             }
         }
     }

Robust.Client/Audio/AudioSystem.cs

@@ -372,13 +372,13 @@ public sealed partial class AudioSystem : SharedAudioSystem
             return;
         }
 
+        var parentUid = xform.ParentUid;
         Vector2 worldPos;
         component.Volume = component.Params.Volume;
 
         // Handle grid audio differently by using grid position.
         if ((component.Flags & AudioFlags.GridAudio) != 0x0)
         {
-            var parentUid = xform.ParentUid;
             worldPos = _maps.GetGridPosition(parentUid);
         }
         else
@@ -412,7 +412,7 @@ public sealed partial class AudioSystem : SharedAudioSystem
         }
         else
         {
-            var occlusion = GetOcclusion(listener, delta, distance, entity);
+            var occlusion = GetOcclusion(listener, delta, distance, parentUid);
             component.Occlusion = occlusion;
         }
 
@@ -420,11 +420,11 @@ public sealed partial class AudioSystem : SharedAudioSystem
         component.Position = worldPos;
 
         // Make race cars go NYYEEOOOOOMMMMM
-        if (_physicsQuery.TryGetComponent(entity, out var physicsComp))
+        if (_physicsQuery.TryGetComponent(parentUid, out var physicsComp))
         {
             // This actually gets the tracked entity's xform & iterates up though the parents for the second time. Bit
             // inefficient.
-            var velocity = _physics.GetMapLinearVelocity(entity, physicsComp, xform);
+            var velocity = _physics.GetMapLinearVelocity(parentUid, physicsComp);
             component.Velocity = velocity;
         }
     }
@@ -589,6 +589,11 @@ public sealed partial class AudioSystem : SharedAudioSystem
         var playing = CreateAndStartPlayingStream(audioParams, specifier, stream);
         _xformSys.SetCoordinates(playing.Entity, new EntityCoordinates(entity, Vector2.Zero));
 
+        // Since we're playing the sound immediately in the middle of a tick, we need to force ProcessStream -now-
+        // to set occlusion/position/velocity etc
+        // otherwise predicted positional sounds will sound very incorrect in several possible ways (e#5802, e#6175) until the next tick
+        ProcessStream(playing.Entity, playing.Component, Transform(playing.Entity), GetListenerCoordinates());
+
         return playing;
     }
 
@@ -632,6 +637,10 @@ public sealed partial class AudioSystem : SharedAudioSystem
 
         var playing = CreateAndStartPlayingStream(audioParams, specifier, stream);
         _xformSys.SetCoordinates(playing.Entity, coordinates);
+
+        // see PlayEntity for why this is necessary
+        ProcessStream(playing.Entity, playing.Component, Transform(playing.Entity), GetListenerCoordinates());
+
         return playing;
     }
 
@@ -714,8 +723,6 @@ public sealed partial class AudioSystem : SharedAudioSystem
         offset = Math.Clamp(offset, 0f, maxOffset);
         source.PlaybackPosition = offset;
 
-        // For server we will rely on the adjusted one but locally we will have to adjust it ourselves.
-        ApplyAudioParams(comp.Params, comp);
         source.StartPlaying();
         return (entity, comp);
     }

Robust.Client/Configuration/ClientNetConfigurationManager.cs

@@ -71,7 +71,7 @@ internal sealed class ClientNetConfigurationManager : NetConfigurationManager, I
         // Actually set the CVar
         base.SetCVar(name, value, force);
 
-        if ((flags & CVar.REPLICATED) == 0)
+        if ((flags & CVar.REPLICATED) == 0 || !NetManager.IsConnected)
             return;
 
         var msg = new MsgConVars();

Robust.Client/Console/Commands/DumpMetadataMembersCommand.cs

@@ -4,7 +4,7 @@ using Robust.Shared.ContentPack;
 
 namespace Robust.Client.Console.Commands
 {
-#if DEBUG
+#if TOOLS
     internal sealed class DumpMetadataMembersCommand : LocalizedCommands
     {
         public override string Command => "dmetamem";

Robust.Client/Console/Commands/UITestCommand.TabWrapContainer.cs

@@ -0,0 +1,124 @@
+using System;
+using Robust.Client.Graphics;
+using Robust.Client.UserInterface;
+using Robust.Client.UserInterface.Controls;
+using Robust.Shared.Maths;
+using ItemJustification = Robust.Client.UserInterface.Controls.WrapContainer.ItemJustification;
+
+namespace Robust.Client.Console.Commands;
+
+internal sealed partial class UITestControl
+{
+    private sealed class TabWrapContainer : Control
+    {
+        private readonly CheckBox _equalSizeBox;
+        private readonly CheckBox _reverseBox;
+        private readonly OptionButton _axisButton;
+        private readonly OptionButton _justifyButton;
+        private readonly LineEdit _separationEdit;
+        private readonly LineEdit _crossSeparationEdit;
+
+        public TabWrapContainer()
+        {
+            var container = new WrapContainer
+            {
+                MouseFilter = MouseFilterMode.Stop,
+                VerticalExpand = true,
+            };
+
+            var random = new Random(3005);
+
+            for (var i = 0; i < 35; i++)
+            {
+                var val = random.Next(1, 16);
+
+                var text = string.Create(val, 0, (span, _) => span.Fill('O'));
+                container.AddChild(new Button { Text = text });
+            }
+
+            AddChild(new BoxContainer
+            {
+                Orientation = BoxContainer.LayoutOrientation.Vertical,
+                Children =
+                {
+                    new BoxContainer
+                    {
+                        Orientation = BoxContainer.LayoutOrientation.Horizontal,
+                        SeparationOverride = 4,
+                        Children =
+                        {
+                            (_equalSizeBox = new CheckBox
+                            {
+                                Text = nameof(WrapContainer.EqualSize)
+                            }),
+                            (_reverseBox = new CheckBox
+                            {
+                                Text = nameof(WrapContainer.Reverse)
+                            }),
+                            (_axisButton = new OptionButton()),
+                            (_justifyButton = new OptionButton()),
+                            (_separationEdit = new LineEdit
+                            {
+                                PlaceHolder = "Separation",
+                                SetWidth = 100,
+                            }),
+                            (_crossSeparationEdit = new LineEdit
+                            {
+                                PlaceHolder = "Cross Separation",
+                                SetWidth = 100,
+                            })
+                        }
+                    },
+                    new PanelContainer
+                    {
+                        PanelOverride = new StyleBoxFlat { BackgroundColor = Color.Black },
+                        Children =
+                        {
+                            container
+                        }
+                    }
+                },
+            });
+
+            _axisButton.AddItem(nameof(Axis.Horizontal), (int)Axis.Horizontal);
+            _axisButton.AddItem(nameof(Axis.HorizontalReverse), (int)Axis.HorizontalReverse);
+            _axisButton.AddItem(nameof(Axis.Vertical), (int)Axis.Vertical);
+            _axisButton.AddItem(nameof(Axis.VerticalReverse), (int)Axis.VerticalReverse);
+
+            _axisButton.OnItemSelected += args =>
+            {
+                _axisButton.SelectId(args.Id);
+                container.LayoutAxis = (Axis)args.Id;
+            };
+
+            _justifyButton.AddItem(nameof(ItemJustification.Begin), (int)ItemJustification.Begin);
+            _justifyButton.AddItem(nameof(ItemJustification.Center), (int)ItemJustification.Center);
+            _justifyButton.AddItem(nameof(ItemJustification.End), (int)ItemJustification.End);
+
+            _justifyButton.OnItemSelected += args =>
+            {
+                _justifyButton.SelectId(args.Id);
+                container.Justification = (ItemJustification)args.Id;
+            };
+
+            _equalSizeBox.OnPressed += _ => container.EqualSize = _equalSizeBox.Pressed;
+            _reverseBox.OnPressed += _ => container.Reverse = _reverseBox.Pressed;
+
+            _separationEdit.OnTextChanged += args =>
+            {
+                if (!int.TryParse(args.Text, out var sep))
+                    sep = 0;
+
+                container.SeparationOverride = sep;
+            };
+
+            _crossSeparationEdit.OnTextChanged += args =>
+            {
+                if (!int.TryParse(args.Text, out var sep))
+                    sep = 0;
+
+                container.CrossSeparationOverride = sep;
+            };
+        }
+    }
+}

Robust.Client/Console/Commands/UITestCommand.cs

@@ -4,8 +4,6 @@ using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Shared.Console;
-using Robust.Shared.IoC;
-using Robust.Shared.Localization;
 using Robust.Shared.Maths;
 using Robust.Shared.Utility;
 
@@ -44,7 +42,10 @@ Suspendisse hendrerit blandit urna ut laoreet. Suspendisse ac elit at erat males
         var progressBar = new ProgressBar { MaxValue = 10, Value = 5 };
         vBox.AddChild(progressBar);
 
-        var optionButton = new OptionButton();
+        var optionButton = new OptionButton
+        {
+            ToolTip = "This button has a tooltip. Spooky!"
+        };
         optionButton.AddItem("Honk");
         optionButton.AddItem("Foo");
         optionButton.AddItem("Bar");
@@ -155,6 +156,7 @@ Suspendisse hendrerit blandit urna ut laoreet. Suspendisse ac elit at erat males
         _sprite = new TabSpriteView();
         _tabContainer.AddChild(_sprite);
         _tabContainer.AddChild(TabCursorShapes());
+        _tabContainer.AddChild(new TabWrapContainer { Name = nameof(Tab.WrapContainer) });
     }
 
     public void OnClosed()
@@ -275,32 +277,13 @@ Suspendisse hendrerit blandit urna ut laoreet. Suspendisse ac elit at erat males
         RichText = 7,
         SpriteView = 8,
         TabCursorShapes = 9,
+        WrapContainer = 10,
     }
 }
 
-internal sealed class UITestCommand : LocalizedCommands
+internal abstract class BaseUITestCommand : LocalizedCommands
 {
-    public override string Command => "uitest";
-
-    public override void Execute(IConsoleShell shell, string argStr, string[] args)
-    {
-        var window = new DefaultWindow { MinSize = new(800, 600) };
-        var control = new UITestControl();
-        window.OnClose += control.OnClosed;
-        window.Contents.AddChild(control);
-
-        window.OpenCentered();
-    }
-}
-
-internal sealed class UITest2Command : LocalizedCommands
-{
-    [Dependency] private readonly IClyde _clyde = default!;
-    [Dependency] private readonly IUserInterfaceManager _uiMgr = default!;
-
-    public override string Command => "uitest2";
-
-    public override void Execute(IConsoleShell shell, string argStr, string[] args)
+    public sealed override void Execute(IConsoleShell shell, string argStr, string[] args)
     {
         if (args.Length > 1)
         {
@@ -321,18 +304,10 @@ internal sealed class UITest2Command : LocalizedCommands
             control.SelectTab(tab);
         }
 
-        var window = _clyde.CreateWindow(new WindowCreateParameters
-        {
-            Title = Loc.GetString("cmd-uitest2-title"),
-        });
-
-        var root = _uiMgr.CreateWindowRoot(window);
-        window.DisposeOnClose = true;
-        window.RequestClosed += _ => control.OnClosed();
-        root.AddChild(control);
+        CreateWindow(control);
     }
 
-    public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
+    public sealed override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
     {
         if (args.Length == 1)
         {
@@ -343,4 +318,35 @@ internal sealed class UITest2Command : LocalizedCommands
 
         return CompletionResult.Empty;
     }
+
+    protected abstract void CreateWindow(UITestControl control);
+}
+
+internal sealed class UITestCommand : BaseUITestCommand
+{
+    public override string Command => "uitest";
+
+    protected override void CreateWindow(UITestControl control)
+    {
+        var window = new DefaultWindow { MinSize = new(800, 600) };
+        window.OnClose += control.OnClosed;
+        window.Contents.AddChild(control);
+        window.OpenCentered();
+    }
+}
+
+internal sealed class UITest2Command : BaseUITestCommand
+{
+    public override string Command => "uitest2";
+
+    protected override void CreateWindow(UITestControl control)
+    {
+        var window = new OSWindow
+        {
+            Title = Loc.GetString("cmd-uitest2-title"),
+        };
+        window.AddChild(control);
+        window.Closed += control.OnClosed;
+        window.Show();
+    }
 }

Robust.Client/Console/Commands/ViewportDebugCommands.cs

@@ -0,0 +1,44 @@
+#if TOOLS
+
+using Robust.Client.Graphics;
+using Robust.Shared.Console;
+using Robust.Shared.IoC;
+using Robust.Shared.Maths;
+
+namespace Robust.Client.Console.Commands;
+
+internal sealed class ViewportClearAllCachedCommand : IConsoleCommand
+{
+    [Dependency] private readonly IClydeInternal _clyde = default!;
+
+    public string Command => "vp_clear_all_cached";
+    public string Description => "Fires IClydeViewport.ClearCachedResources on all viewports";
+    public string Help => "";
+
+    public void Execute(IConsoleShell shell, string argStr, string[] args)
+    {
+        _clyde.ViewportsClearAllCached();
+    }
+}
+
+internal sealed class ViewportTestFinalizeCommand : IConsoleCommand
+{
+    [Dependency] private readonly IClyde _clyde = default!;
+    [Dependency] private readonly IEyeManager _eyeManager = default!;
+
+    public string Command => "vp_test_finalize";
+    public string Description => "Creates a viewport, renders it once, then leaks it (finalizes it).";
+    public string Help => "";
+
+    public void Execute(IConsoleShell shell, string argStr, string[] args)
+    {
+        var vp = _clyde.CreateViewport(new Vector2i(1920, 1080), nameof(ViewportTestFinalizeCommand));
+        vp.Eye = _eyeManager.CurrentEye;
+
+        vp.Render();
+
+        // Leak it.
+    }
+}
+
+#endif // TOOLS

Robust.Client/GameController/GameController.Standalone.cs

@@ -8,6 +8,7 @@ using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Timing;
 using Robust.Shared.Utility;
+using SDL3;
 
 namespace Robust.Client
 {
@@ -93,6 +94,8 @@ namespace Robust.Client
 
         public void Run(DisplayMode mode, GameControllerOptions options, Func<ILogHandler>? logHandlerFactory = null)
         {
+            _displayMode = mode;
+
             if (!StartupSystemSplash(options, logHandlerFactory))
             {
                 _logger.Fatal("Failed to start game controller!");

Robust.Client/GameController/GameController.cs

@@ -110,6 +110,8 @@ namespace Robust.Client
 
         private ResourceManifestData? _resourceManifest;
 
+        private DisplayMode _displayMode;
+
         public void SetCommandLineArgs(CommandLineArgs args)
         {
             _commandLineArgs = args;
@@ -273,6 +275,9 @@ namespace Robust.Client
                 }
             };
 
+            _configurationManager.OnValueChanged(CVars.DisplayMaxFPS, _ => UpdateVsyncConfig());
+            _configurationManager.OnValueChanged(CVars.DisplayVSync, _ => UpdateVsyncConfig(), invokeImmediately: true);
+
             _clyde.Ready();
 
             if (_resourceManifest!.AutoConnect &&
@@ -709,6 +714,30 @@ namespace Robust.Client
         }
 
 
+        private void UpdateVsyncConfig()
+        {
+            if (_displayMode == DisplayMode.Headless)
+                return;
+
+            var vsync = _configurationManager.GetCVar(CVars.DisplayVSync);
+            var maxFps = Math.Clamp(_configurationManager.GetCVar(CVars.DisplayMaxFPS), 0, 10_000);
+
+            _clyde.VsyncEnabled = vsync;
+
+            if (_mainLoop == null)
+                return;
+
+            if (vsync || maxFps == 0)
+            {
+                _mainLoop.SleepMode = SleepMode.None;
+            }
+            else
+            {
+                _mainLoop.SleepMode = SleepMode.Limit;
+                _mainLoop.LimitMinFrameTime = TimeSpan.FromSeconds(1.0 / maxFps);
+            }
+        }
+
         internal enum DisplayMode : byte
         {
             Headless,

Robust.Client/GameObjects/ClientEntityManager.cs

@@ -29,6 +29,9 @@ namespace Robust.Client.GameObjects
         internal event Action? AfterStartup;
         internal event Action? AfterShutdown;
 
+        private readonly Queue<EntityUid> _queuedPredictedDeletions = new();
+        private readonly HashSet<EntityUid> _queuedPredictedDeletionsSet = new();
+
         public override void Initialize()
         {
             SetupNetworking();
@@ -213,6 +216,34 @@ namespace Robust.Client.GameObjects
                 }
             }
 
+            using (histogram?.WithLabels("PredictedQueueDel").NewTimer())
+            {
+                while (_queuedPredictedDeletions.TryDequeue(out var uid))
+                {
+                    if (!MetaQuery.TryGetComponentInternal(uid, out var meta))
+                        continue;
+
+                    if (meta.EntityLifeStage >= EntityLifeStage.Terminating)
+                        continue;
+
+                    var xform = TransformQuery.GetComponentInternal(uid);
+                    if (meta.NetEntity.IsClientSide())
+                    {
+                        DeleteEntity(uid, meta, xform);
+                    }
+                    else
+                    {
+                        _xforms.DetachEntity(uid, xform, meta, null);
+                        // base call bypasses IGameTiming.InPrediction check
+                        // This is pretty janky and there should be a way for the client to dirty an entity outside of prediction
+                        // TODO PREDICTION
+                        base.Dirty(uid, xform, meta);
+                    }
+                }
+
+                _queuedPredictedDeletionsSet.Clear();
+            }
+
             base.TickUpdate(frameTime, noPredictions, histogram);
         }
 
@@ -317,18 +348,23 @@ namespace Robust.Client.GameObjects
             }
         }
 
-        /// <inheritdoc />
-        public override void PredictedQueueDeleteEntity(Entity<MetaDataComponent?, TransformComponent?> ent)
-        {
-            if (IsQueuedForDeletion(ent.Owner)
-                || !MetaQuery.Resolve(ent.Owner, ref ent.Comp1)
-                || ent.Comp1.EntityLifeStage >= EntityLifeStage.Terminating
-                || !TransformQuery.Resolve(ent.Owner, ref ent.Comp2))
-            {
-                return;
-            }
+        public override bool IsQueuedForDeletion(EntityUid uid)
+            => QueuedDeletionsSet.Contains(uid) || _queuedPredictedDeletions.Contains(uid);
 
-            if (ent.Comp1.NetEntity.IsClientSide())
+        /// <inheritdoc />
+        public override void PredictedQueueDeleteEntity(Entity<MetaDataComponent?> ent)
+        {
+            // Some UIs get disposed after entity-manager has shut down and already deleted all entities.
+            if (!Started)
+                return;
+
+            if (IsQueuedForDeletion(ent.Owner))
+                return;
+
+            if (!MetaQuery.Resolve(ent.Owner, ref ent.Comp, false))
+                return;
+
+            if (ent.Comp.NetEntity.IsClientSide())
             {
                 // client-side QueueDeleteEntity re-fetches MetadataComp and checks IsClientSide().
                 // base call to skip that.
@@ -337,7 +373,10 @@ namespace Robust.Client.GameObjects
             }
             else
             {
-                _xforms.DetachEntity(ent.Owner, ent.Comp2);
+                if (!_queuedPredictedDeletionsSet.Add(ent.Owner))
+                    return;
+
+                _queuedPredictedDeletions.Enqueue(ent.Owner);
             }
         }
     }

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

@@ -294,6 +294,16 @@ namespace Robust.Client.GameObjects
             LocalMatrix = Matrix3Helpers.CreateTransform(in offset, in rotation, in scale);
         }
 
+        /// <summary>
+        /// If false, this will prevent any of this sprite's animated layers from looping their animation.
+        /// This will set <see cref="Layer.AutoAnimated"/> whenever any layer's animation finishes.
+        /// </summary>
+        /// <remarks>
+        /// If this is false, this effectively overrides each layer's own <see cref="Layer.Loop"/>.
+        /// </remarks>
+        [DataField]
+        public bool Loop = true;
+
         /// <summary>
         /// Update this sprite component to visibly match the current state of other at the time
         /// this is called. Does not keep them perpetually in sync.
@@ -601,6 +611,7 @@ namespace Robust.Client.GameObjects
 
             layer.RenderingStrategy = layerDatum.RenderingStrategy ?? layer.RenderingStrategy;
             layer.Cycle = layerDatum.Cycle;
+            layer.Loop = layerDatum.Loop;
 
             layer.Color = layerDatum.Color ?? layer.Color;
             layer._rotation = layerDatum.Rotation ?? layer._rotation;
@@ -1157,6 +1168,15 @@ namespace Robust.Client.GameObjects
             /// </remarks>
             [ViewVariables] public bool Cycle;
 
+            /// <summary>
+            /// If false, this will prevent the layer's animation from looping.
+            /// This will set <see cref="AutoAnimated"/> to false once the animation finishes.
+            /// </summary>
+            /// <remarks>
+            /// This may be overriden by the parent's loop property.
+            /// </remarks>
+            [ViewVariables] public bool Loop = true;
+
             // TODO SPRITE ACCESS
             internal RSI.State? _actualState;
             [ViewVariables] public RSI.State? ActualState => _actualState;
@@ -1336,6 +1356,8 @@ namespace Robust.Client.GameObjects
                 DirOffset = toClone.DirOffset;
                 _autoAnimated = toClone._autoAnimated;
                 RenderingStrategy = toClone.RenderingStrategy;
+                Cycle = toClone.Cycle;
+                Loop = toClone.Loop;
                 if (toClone.CopyToShaderParameters is { } copyToShaderParameters)
                     CopyToShaderParameters = new CopyToShaderParameters(copyToShaderParameters);
             }
@@ -1663,17 +1685,25 @@ namespace Robust.Client.GameObjects
 
             internal void AdvanceFrameAnimation(RSI.State state)
             {
-                // Can't advance frames without more than 1 delay which is already checked above.
                 var delayCount = state.DelayCount;
+
                 while (AnimationTimeLeft < 0)
                 {
                     if (Reversed)
                     {
                         AnimationFrame -= 1;
 
-                        // Animation finished, do we cycle back to positive or reset.
                         if (AnimationFrame < 0)
                         {
+                            if (!Loop || !_parent.Loop)
+                            {
+                                // stop at first frame
+                                AnimationFrame = 0;
+                                AnimationTimeLeft = 0;
+                                AutoAnimated = false;
+                                return;
+                            }
+
                             if (Cycle)
                             {
                                 AnimationFrame = 1;
@@ -1691,9 +1721,17 @@ namespace Robust.Client.GameObjects
                     {
                         AnimationFrame += 1;
 
-                        // Animation finished, do we reverse or reset.
                         if (AnimationFrame >= delayCount)
                         {
+                            if (!Loop || !_parent.Loop)
+                            {
+                                // stop at last frame
+                                AnimationFrame = delayCount - 1;
+                                AnimationTimeLeft = 0;
+                                AutoAnimated = false;
+                                return;
+                            }
+
                             if (Cycle)
                             {
                                 AnimationFrame = delayCount - 2;
@@ -1711,6 +1749,7 @@ namespace Robust.Client.GameObjects
                     AnimationTimeLeft += state.GetDelay(AnimationFrame);
                 }
             }
+
         }
 
         /// <summary>

Robust.Client/GameObjects/EntitySystems/MapSystem.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics.Contracts;
 using Robust.Client.Graphics;
 using Robust.Client.Map;
 using Robust.Client.ResourceManagement;
@@ -9,13 +10,14 @@ namespace Robust.Client.GameObjects;
 
 public sealed class MapSystem : SharedMapSystem
 {
-    protected override MapId GetNextMapId()
+    [Pure]
+    internal override MapId GetNextMapId()
     {
         // Client-side map entities use negative map Ids to avoid conflict with server-side maps.
-        var id = new MapId(--LastMapId);
+        var id = new MapId(LastMapId - 1);
         while (MapExists(id) || UsedIds.Contains(id))
         {
-            id = new MapId(--LastMapId);
+            id = new MapId(id.Value - 1);
         }
         return id;
     }

Robust.Client/GameObjects/EntitySystems/PointLightSystem.cs

@@ -29,6 +29,8 @@ namespace Robust.Client.GameObjects
             component.Enabled = state.Enabled;
             component.Offset = state.Offset;
             component.Softness = state.Softness;
+            component.Falloff = state.Falloff;
+            component.CurveFactor = state.CurveFactor;
             component.CastShadows = state.CastShadows;
             component.Energy = state.Energy;
             component.Radius = state.Radius;

Robust.Client/GameObjects/EntitySystems/SpriteSystem.Component.cs

@@ -88,6 +88,7 @@ public sealed partial class SpriteSystem
 
         target.Comp.RenderOrder = source.Comp.RenderOrder;
         target.Comp.GranularLayersRendering = source.Comp.GranularLayersRendering;
+        target.Comp.Loop = source.Comp.Loop;
 
         DirtyBounds(target!);
         _tree.QueueTreeUpdate(target!);

Robust.Client/GameStates/GameStateProcessor.cs

@@ -220,24 +220,34 @@ Had full state: {LastFullState != null}"
                 {
                     var compState = change.State;
 
-                    if (compState is IComponentDeltaState delta
-                        && compData.TryGetValue(change.NetID, out var old)) // May fail if relying on implicit data
+                    if (compState is not IComponentDeltaState delta)
                     {
-                        DebugTools.Assert(old is not IComponentDeltaState, "last state is not a full state");
-
-                        if (cloneDelta)
-                        {
-                            compState = delta.CreateNewFullState(old!);
-                        }
-                        else
-                        {
-                            delta.ApplyToFullState(old!);
-                            compState = old;
-                        }
-                        DebugTools.Assert(compState is not IComponentDeltaState, "newly constructed state is not a full state");
+                        compData[change.NetID] = compState;
+                        continue;
                     }
 
-                    compData[change.NetID] = compState;
+                    if (!compData.TryGetValue(change.NetID, out var old))
+                    {
+                        // Either the server needs to ensure that the initial state it sends to a client is a full
+                        // state, or the client needs to be able to construct an implicit full state (i.e., get-state
+                        // code needs to be in shared code).
+                        //
+                        // Without this, the client won't be able to reset predicted changes made to this component.
+                        DebugTools.Assert("Received delta state without having received or constructed an implicit full state");
+                        continue;
+                    }
+
+                    DebugTools.Assert(old is not IComponentDeltaState, "last state is not a full state");
+
+                    if (!cloneDelta)
+                    {
+                        delta.ApplyToFullState(old!);
+                        continue;
+                    }
+
+                    var newFull = delta.CreateNewFullState(old!);
+                    compData[change.NetID] = newFull;
+                    DebugTools.Assert(newFull is not IComponentDeltaState, "constructed state is not a full state");
                 }
 
                 if (entityState.NetComponents == null)

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

@@ -121,6 +121,19 @@ namespace Robust.Client.Graphics.Clyde
             }
         }
 
+        public void RenderNow(IRenderTarget renderTarget, Action<IRenderHandle> callback)
+        {
+            ClearRenderState();
+
+            _renderHandle.RenderInRenderTarget(
+                renderTarget,
+                () =>
+                {
+                    callback(_renderHandle);
+                },
+                null);
+        }
+
         private void RenderSingleWorldOverlay(Overlay overlay, Viewport vp, OverlaySpace space, in Box2 worldBox, in Box2Rotated worldBounds)
         {
             // Check that entity manager has started.

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

@@ -451,6 +451,8 @@ namespace Robust.Client.Graphics.Clyde
             var lastPower = float.NaN;
             var lastColor = new Color(float.NaN, float.NaN, float.NaN, float.NaN);
             var lastSoftness = float.NaN;
+            var lastFalloff = float.NaN;
+            var lastCurveFactor = float.NaN;
             Texture? lastMask = null;
 
             using (_prof.Group("Draw Lights"))
@@ -504,6 +506,18 @@ namespace Robust.Client.Graphics.Clyde
                         lightShader.SetUniformMaybe("lightSoftness", lastSoftness);
                     }
 
+                    if (!MathHelper.CloseToPercent(lastFalloff, component.Falloff))
+                    {
+                        lastFalloff = component.Falloff;
+                        lightShader.SetUniformMaybe("lightFalloff", lastFalloff);
+                    }
+
+                    if (!MathHelper.CloseToPercent(lastCurveFactor, component.CurveFactor))
+                    {
+                        lastCurveFactor = component.CurveFactor;
+                        lightShader.SetUniformMaybe("lightCurveFactor", lastCurveFactor);
+                    }
+
                     lightShader.SetUniformMaybe("lightCenter", lightPos);
                     lightShader.SetUniformMaybe("lightIndex",
                         component.CastShadows ? (i + 0.5f) / ShadowTexture.Height : -1);

Robust.Client/Graphics/Clyde/Clyde.RenderTargets.cs

@@ -209,6 +209,7 @@ namespace Robust.Client.Graphics.Clyde
             var pressure = estPixSize * size.X * size.Y;
 
             var handle = AllocRid();
+            var renderTarget = new RenderTexture(size, textureObject, this, handle);
             var data = new LoadedRenderTarget
             {
                 IsWindow = false,
@@ -220,10 +221,11 @@ namespace Robust.Client.Graphics.Clyde
                 MemoryPressure = pressure,
                 ColorFormat = format.ColorFormat,
                 SampleParameters = sampleParameters,
+                Instance = new WeakReference<RenderTargetBase>(renderTarget),
+                Name = name,
             };
 
             //GC.AddMemoryPressure(pressure);
-            var renderTarget = new RenderTexture(size, textureObject, this, handle);
             _renderTargets.Add(handle, data);
             return renderTarget;
         }
@@ -301,10 +303,22 @@ namespace Robust.Client.Graphics.Clyde
             }
         }
 
-        private sealed class LoadedRenderTarget
+        public IEnumerable<(RenderTargetBase, LoadedRenderTarget)> GetLoadedRenderTextures()
+        {
+            foreach (var loaded in _renderTargets.Values)
+            {
+                if (!loaded.Instance.TryGetTarget(out var instance))
+                    continue;
+
+                yield return (instance, loaded);
+            }
+        }
+
+        internal sealed class LoadedRenderTarget
         {
             public bool IsWindow;
             public WindowId WindowId;
+            public string? Name;
 
             public Vector2i Size;
             public bool IsSrgb;
@@ -325,9 +339,11 @@ namespace Robust.Client.Graphics.Clyde
             public long MemoryPressure;
 
             public TextureSampleParameters? SampleParameters;
+
+            public required WeakReference<RenderTargetBase> Instance;
         }
 
-        private abstract class RenderTargetBase : IRenderTarget
+        internal abstract class RenderTargetBase : IRenderTarget
         {
             protected readonly Clyde Clyde;
             private bool _disposed;
@@ -389,7 +405,7 @@ namespace Robust.Client.Graphics.Clyde
             }
         }
 
-        private sealed class RenderTexture : RenderTargetBase, IRenderTexture
+        internal sealed class RenderTexture : RenderTargetBase, IRenderTexture
         {
             public RenderTexture(Vector2i size, ClydeTexture texture, Clyde clyde, ClydeHandle handle)
                 : base(clyde, handle)

Robust.Client/Graphics/Clyde/Clyde.Viewport.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Numerics;
 using Robust.Client.UserInterface.CustomControls;
@@ -15,10 +16,14 @@ namespace Robust.Client.Graphics.Clyde
         private readonly Dictionary<ClydeHandle, WeakReference<Viewport>> _viewports =
             new();
 
+        private long _nextViewportId = 1;
+
+        private readonly ConcurrentQueue<ViewportDisposeData> _viewportDisposeQueue = new();
+
         private Viewport CreateViewport(Vector2i size, TextureSampleParameters? sampleParameters = default, string? name = null)
         {
             var handle = AllocRid();
-            var viewport = new Viewport(handle, name, this)
+            var viewport = new Viewport(_nextViewportId++, handle, name, this)
             {
                 Size = size,
                 RenderTarget = CreateRenderTarget(size,
@@ -59,28 +64,43 @@ namespace Robust.Client.Graphics.Clyde
 
         private void FlushViewportDispose()
         {
-            // Free of allocations unless a dead viewport is found.
-            List<ClydeHandle>? toRemove = null;
-            foreach (var (handle, viewportRef) in _viewports)
+            while (_viewportDisposeQueue.TryDequeue(out var data))
             {
-                if (!viewportRef.TryGetTarget(out _))
-                {
-                    toRemove ??= new List<ClydeHandle>();
-                    toRemove.Add(handle);
-                }
-            }
-
-            if (toRemove == null)
-            {
-                return;
-            }
-
-            foreach (var remove in toRemove)
-            {
-                _viewports.Remove(remove);
+                DisposeViewport(data);
             }
         }
 
+        private void DisposeViewport(ViewportDisposeData disposeData)
+        {
+            _clydeSawmill.Warning($"Viewport {disposeData.Id} got leaked");
+
+            _viewports.Remove(disposeData.Handle);
+            if (disposeData.ClearEvent is not { } clearEvent)
+                return;
+
+            try
+            {
+                clearEvent(disposeData.ClearEventData);
+            }
+            catch (Exception ex)
+            {
+                _clydeSawmill.Error($"Caught exception while disposing viewport: {ex}");
+            }
+        }
+
+#if TOOLS
+        public void ViewportsClearAllCached()
+        {
+            foreach (var vpRef in _viewports.Values)
+            {
+                if (!vpRef.TryGetTarget(out var vp))
+                    continue;
+
+                vp.FireClear();
+            }
+        }
+#endif // TOOLS
+
         private sealed class Viewport : IClydeViewport
         {
             private readonly ClydeHandle _handle;
@@ -106,17 +126,20 @@ namespace Robust.Client.Graphics.Clyde
 
             public string? Name { get; }
 
-            public Viewport(ClydeHandle handle, string? name, Clyde clyde)
+            public Viewport(long id, ClydeHandle handle, string? name, Clyde clyde)
             {
                 Name = name;
                 _handle = handle;
                 _clyde = clyde;
+                Id = id;
             }
 
             public Vector2i Size { get; set; }
+            public event Action<ClearCachedViewportResourcesEvent>? ClearCachedResources;
             public Color? ClearColor { get; set; } = Color.Black;
             public Vector2 RenderScale { get; set; } = Vector2.One;
             public bool AutomaticRender { get; set; }
+            public long Id { get; }
 
             void IClydeViewport.Render()
             {
@@ -186,20 +209,56 @@ namespace Robust.Client.Graphics.Clyde
                 _clyde.RenderOverlaysDirect(this, control, handle, OverlaySpace.ScreenSpace, viewportBounds);
             }
 
+            ~Viewport()
+            {
+                _clyde._viewportDisposeQueue.Enqueue(DisposeData(referenceSelf: false));
+            }
+
             public void Dispose()
             {
+                GC.SuppressFinalize(this);
+
                 RenderTarget.Dispose();
                 LightRenderTarget.Dispose();
                 WallMaskRenderTarget.Dispose();
                 WallBleedIntermediateRenderTarget1.Dispose();
                 WallBleedIntermediateRenderTarget2.Dispose();
 
-                _clyde._viewports.Remove(_handle);
+                _clyde.DisposeViewport(DisposeData(referenceSelf: false));
+            }
+
+            private ViewportDisposeData DisposeData(bool referenceSelf)
+            {
+                return new ViewportDisposeData
+                {
+                    Handle = _handle,
+                    Id = Id,
+                    ClearEvent = ClearCachedResources,
+                    ClearEventData = MakeClearEvent(referenceSelf)
+                };
+            }
+
+            private ClearCachedViewportResourcesEvent MakeClearEvent(bool referenceSelf)
+            {
+                return new ClearCachedViewportResourcesEvent(Id, referenceSelf ? this : null);
+            }
+
+            public void FireClear()
+            {
+                ClearCachedResources?.Invoke(MakeClearEvent(referenceSelf: true));
             }
 
             IRenderTexture IClydeViewport.RenderTarget => RenderTarget;
             IRenderTexture IClydeViewport.LightRenderTarget => LightRenderTarget;
             public IEye? Eye { get; set; }
         }
+
+        private sealed class ViewportDisposeData
+        {
+            public ClydeHandle Handle;
+            public long Id;
+            public Action<ClearCachedViewportResourcesEvent>? ClearEvent;
+            public ClearCachedViewportResourcesEvent ClearEventData;
+        }
     }
 }

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

@@ -354,15 +354,17 @@ namespace Robust.Client.Graphics.Clyde
                 _windowHandles.Add(reg.Handle);
 
                 var rtId = AllocRid();
+                var renderTarget = new RenderWindow(this, rtId);
                 _renderTargets.Add(rtId, new LoadedRenderTarget
                 {
                     Size = reg.FramebufferSize,
                     IsWindow = true,
                     WindowId = reg.Id,
-                    IsSrgb = true
+                    IsSrgb = true,
+                    Instance = new WeakReference<RenderTargetBase>(renderTarget),
                 });
 
-                reg.RenderTarget = new RenderWindow(this, rtId);
+                reg.RenderTarget = renderTarget;
 
                 _glContext!.WindowCreated(glSpec, reg);
             }
@@ -405,10 +407,17 @@ namespace Robust.Client.Graphics.Clyde
             _glContext?.SwapAllBuffers();
         }
 
-        private void VSyncChanged(bool newValue)
+        public bool VsyncEnabled
         {
-            _vSync = newValue;
-            _glContext?.UpdateVSync();
+            get => _vSync;
+            set
+            {
+                if (_vSync == value)
+                    return;
+
+                _vSync = value;
+                _glContext?.UpdateVSync();
+            }
         }
 
         private void WindowModeChanged(int mode)

Robust.Client/Graphics/Clyde/Clyde.cs

@@ -114,7 +114,6 @@ namespace Robust.Client.Graphics.Clyde
             _proto.PrototypesReloaded += OnProtoReload;
 
             _cfg.OnValueChanged(CVars.DisplayOGLCheckErrors, b => _checkGLErrors = b, true);
-            _cfg.OnValueChanged(CVars.DisplayVSync, VSyncChanged, true);
             _cfg.OnValueChanged(CVars.DisplayWindowMode, WindowModeChanged, true);
             _cfg.OnValueChanged(CVars.LightResolutionScale, LightResolutionScaleChanged, true);
             _cfg.OnValueChanged(CVars.MaxShadowcastingLights, MaxShadowcastingLightsChanged, true);

Robust.Client/Graphics/Clyde/ClydeHeadless.cs

@@ -34,6 +34,7 @@ namespace Robust.Client.Graphics.Clyde
         public bool IsFocused => true;
         private readonly List<IClydeWindow> _windows = new();
         private int _nextWindowId = 2;
+        private long _nextViewportId = 1;
 
         public ShaderInstance InstanceShader(ShaderSourceResource handle, bool? light = null, ShaderBlendMode? blend = null)
         {
@@ -75,6 +76,11 @@ namespace Robust.Client.Graphics.Clyde
             return [];
         }
 
+        public IEnumerable<(Clyde.RenderTargetBase, Clyde.LoadedRenderTarget)> GetLoadedRenderTextures()
+        {
+            return [];
+        }
+
         public ClydeDebugLayers DebugLayers { get; set; }
 
         public string GetKeyName(Keyboard.Key key) => string.Empty;
@@ -240,7 +246,7 @@ namespace Robust.Client.Graphics.Clyde
         public IClydeViewport CreateViewport(Vector2i size, TextureSampleParameters? sampleParameters,
             string? name = null)
         {
-            return new Viewport(size);
+            return new Viewport(_nextViewportId++, size);
         }
 
         public IEnumerable<IClydeMonitor> EnumerateMonitors()
@@ -307,6 +313,19 @@ namespace Robust.Client.Graphics.Clyde
 
         public IFileDialogManagerImplementation? FileDialogImpl => null;
 
+        public bool VsyncEnabled { get; set; }
+
+#if TOOLS
+        public void ViewportsClearAllCached()
+        {
+            throw new NotImplementedException();
+        }
+#endif // TOOLS
+
+        public void RenderNow(IRenderTarget renderTarget, Action<IRenderHandle> callback)
+        {
+        }
+
         private sealed class DummyCursor : ICursor
         {
             public void Dispose()
@@ -482,15 +501,19 @@ namespace Robust.Client.Graphics.Clyde
 
         private sealed class Viewport : IClydeViewport
         {
-            public Viewport(Vector2i size)
+            public Viewport(long id, Vector2i size)
             {
                 Size = size;
+                Id = id;
             }
 
             public void Dispose()
             {
+                ClearCachedResources?.Invoke(new ClearCachedViewportResourcesEvent(Id, null));
             }
 
+            public long Id { get; }
+
             public IRenderTexture RenderTarget { get; } =
                 new DummyRenderTexture(Vector2i.One, new DummyTexture(Vector2i.One));
 
@@ -499,6 +522,7 @@ namespace Robust.Client.Graphics.Clyde
 
             public IEye? Eye { get; set; }
             public Vector2i Size { get; }
+            public event Action<ClearCachedViewportResourcesEvent>? ClearCachedResources;
             public Color? ClearColor { get; set; } = Color.Black;
             public Vector2 RenderScale { get; set; }
             public bool AutomaticRender { get; set; }

Robust.Client/Graphics/Clyde/GLContext/GLContextWindow.cs

@@ -328,11 +328,14 @@ namespace Robust.Client.Graphics.Clyde
             {
                 reg.RenderTexture?.Dispose();
 
-                reg.RenderTexture = Clyde.CreateRenderTarget(reg.Reg.FramebufferSize, new RenderTargetFormatParameters
-                {
-                    ColorFormat = RenderTargetColorFormat.Rgba8Srgb,
-                    HasDepthStencil = true
-                });
+                reg.RenderTexture = Clyde.CreateRenderTarget(
+                    reg.Reg.FramebufferSize,
+                    new RenderTargetFormatParameters
+                    {
+                        ColorFormat = RenderTargetColorFormat.Rgba8Srgb,
+                        HasDepthStencil = true
+                    },
+                    name: $"{reg.Reg.Id}-RenderTexture");
                 // Necessary to correctly sync multi-context blitting.
                 reg.RenderTexture.MakeGLFence = true;
             }

Robust.Client/Graphics/Clyde/Windowing/SDL3-CS/LICENSE

@@ -1,25 +0,0 @@
-/* SDL3-CS - C# Bindings for SDL3
- *
- * Copyright (c) 2024 Colin Jackson
- *
- * This software is provided 'as-is', without any express or implied warranty.
- * In no event will the authors be held liable for any damages arising from
- * the use of this software.
- *
- * Permission is granted to anyone to use this software for any purpose,
- * including commercial applications, and to alter it and redistribute it
- * freely, subject to the following restrictions:
- *
- * 1. The origin of this software must not be misrepresented; you must not
- * claim that you wrote the original software. If you use this software in a
- * product, an acknowledgment in the product documentation would be
- * appreciated but is not required.
- *
- * 2. Altered source versions must be plainly marked as such, and must not be
- * misrepresented as being the original software.
- *
- * 3. This notice may not be removed or altered from any source distribution.
- *
- * Colin "cryy22" Jackson <c@cryy22.art>
- *
- */

Robust.Client/Graphics/Clyde/Windowing/SDL3-CS/SDL3.Core.Ext.cs

@@ -1,57 +0,0 @@
-using System;
-using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
-
-namespace SDL3;
-
-public static partial class SDL
-{
-    // Extensions to SDL3-CS that aren't part of the main library.
-
-    [LibraryImport(nativeLibName)]
-    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static unsafe partial void SDL_SetLogOutputFunction(delegate* unmanaged[Cdecl] <void*, int, SDL_LogPriority, byte*, void> callback, void* userdata);
-
-    [LibraryImport(nativeLibName)]
-    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static unsafe partial SDLBool SDL_AddEventWatch(delegate* unmanaged[Cdecl] <void*, SDL_Event*, byte> filter, void* userdata);
-
-    [LibraryImport(nativeLibName)]
-    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static unsafe partial void SDL_RemoveEventWatch(delegate* unmanaged[Cdecl] <void*, SDL_Event*, byte> filter, void* userdata);
-
-    [LibraryImport(nativeLibName, StringMarshalling = StringMarshalling.Utf8)]
-    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static unsafe partial void SDL_ShowFileDialogWithProperties(int type, delegate* unmanaged[Cdecl]<void*, byte**, int, void> callback, void* userdata, uint properties);
-
-    [LibraryImport(nativeLibName, EntryPoint = "SDL_WaitEvent")]
-    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static partial SDLBool SDL_WaitEventRef(ref SDL_Event @event);
-
-    public const byte SDL_BUTTON_LEFT = 1;
-    public const byte SDL_BUTTON_MIDDLE = 2;
-    public const byte SDL_BUTTON_RIGHT = 3;
-    public const byte SDL_BUTTON_X1 = 4;
-    public const byte SDL_BUTTON_X2 = 5;
-
-    public const int SDL_GL_CONTEXT_PROFILE_CORE = 0x0001;
-    public const int SDL_GL_CONTEXT_PROFILE_COMPATIBILITY = 0x0002;
-    public const int SDL_GL_CONTEXT_PROFILE_ES = 0x0004;
-
-    public const int SDL_GL_CONTEXT_DEBUG_FLAG = 0x0001;
-    public const int SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG = 0x0002;
-    public const int SDL_GL_CONTEXT_ROBUST_ACCESS_FLAG = 0x0004;
-    public const int SDL_GL_CONTEXT_RESET_ISOLATION_FLAG = 0x0008;
-
-    public const int SDL_FILEDIALOG_OPENFILE = 0;
-    public const int SDL_FILEDIALOG_SAVEFILE = 1;
-    public const int SDL_FILEDIALOG_OPENFOLDER = 2;
-
-    public const string SDL_PROP_FILE_DIALOG_NFILTERS_NUMBER = "SDL.filedialog.nfilters";
-    public const string SDL_PROP_FILE_DIALOG_FILTERS_POINTER = "SDL.filedialog.filters";
-    public const string SDL_PROP_FILE_DIALOG_WINDOW_POINTER = "SDL.filedialog.window";
-
-    public static int SDL_VERSIONNUM_MAJOR(int version) => version / 1000000;
-    public static int SDL_VERSIONNUM_MINOR(int version) => version / 1000 % 1000;
-    public static int SDL_VERSIONNUM_MICRO(int version) => version % 1000;
-}

Robust.Client/Graphics/IClydeInternal.cs

@@ -55,6 +55,7 @@ namespace Robust.Client.Graphics
 
         Texture GetStockTexture(ClydeStockTexture stockTexture);
         IEnumerable<(Clyde.Clyde.ClydeTexture, Clyde.Clyde.LoadedTexture)> GetLoadedTextures();
+        IEnumerable<(Clyde.Clyde.RenderTargetBase, Clyde.Clyde.LoadedRenderTarget)> GetLoadedRenderTextures();
 
         ClydeDebugLayers DebugLayers { get; set; }
 
@@ -72,5 +73,20 @@ namespace Robust.Client.Graphics
         void RunOnWindowThread(Action action);
 
         IFileDialogManagerImplementation? FileDialogImpl { get; }
+
+        bool VsyncEnabled { get; set; }
+
+        // Viewports
+
+#if TOOLS
+
+        /// <summary>
+        /// Fires <see cref="IClydeViewport.ClearCachedResources"/> on all viewports. For debugging.
+        /// </summary>
+        void ViewportsClearAllCached();
+
+#endif // TOOLS
+
+        void RenderNow(IRenderTarget renderTarget, Action<IRenderHandle> callback);
     }
 }

Robust.Client/Graphics/IClydeViewport.cs

@@ -13,6 +13,11 @@ namespace Robust.Client.Graphics
     /// </summary>
     public interface IClydeViewport : IDisposable
     {
+        /// <summary>
+        /// A unique ID for this viewport. No other viewport with this ID can ever exist in the app lifetime.
+        /// </summary>
+        long Id { get; }
+
         /// <summary>
         ///     The render target that is rendered to when rendering this viewport.
         /// </summary>
@@ -22,6 +27,16 @@ namespace Robust.Client.Graphics
         IEye? Eye { get; set; }
         Vector2i Size { get; }
 
+        /// <summary>
+        /// Raised when the viewport indicates that any cached rendering resources (e.g. render targets)
+        /// should be purged.
+        /// </summary>
+        /// <remarks>
+        /// This event is raised if the viewport is disposed (manually or via finalization).
+        /// However, code should expect this event to be raised at any time, even if the viewport is not disposed fully.
+        /// </remarks>
+        event Action<ClearCachedViewportResourcesEvent> ClearCachedResources;
+
         /// <summary>
         /// Color to clear the render target to before rendering. If null, no clearing will happen.
         /// </summary>
@@ -85,4 +100,23 @@ namespace Robust.Client.Graphics
             IViewportControl control,
             in UIBox2i viewportBounds);
     }
+
+    public struct ClearCachedViewportResourcesEvent
+    {
+        /// <summary>
+        /// The <see cref="IClydeViewport.Id"/> of the viewport.
+        /// </summary>
+        public readonly long ViewportId;
+
+        /// <summary>
+        /// The viewport itself. This is not available if the viewport was disposed.
+        /// </summary>
+        public readonly IClydeViewport? Viewport;
+
+        internal ClearCachedViewportResourcesEvent(long viewportId, IClydeViewport? viewport)
+        {
+            ViewportId = viewportId;
+            Viewport = viewport;
+        }
+    }
 }

Robust.Client/Placement/PlacementManager.cs

@@ -562,7 +562,7 @@ namespace Robust.Client.Placement
             }
 
             coordinates = InputManager.MouseScreenPosition;
-            return true;
+            return coordinates.IsValid;
         }
 
         private bool CurrentEraserMouseCoordinates(out EntityCoordinates coordinates)

Robust.Client/Replays/Commands/ReplayCommand.cs

@@ -11,7 +11,6 @@ namespace Robust.Client.Replays.Commands;
 public abstract class BaseReplayCommand : LocalizedCommands
 {
     [Dependency] protected readonly IReplayPlaybackManager PlaybackManager = default!;
-    protected ILocalizationManager Loc => LocalizationManager;
 
     public override string Description => Loc.GetString($"cmd-{Command.Replace('_','-')}-desc");
 

Robust.Client/Robust.Client.csproj

@@ -20,6 +20,7 @@
     <PackageReference Include="OpenToolkit.Graphics" PrivateAssets="compile" />
     <PackageReference Include="OpenTK.Audio.OpenAL" PrivateAssets="compile" />
     <PackageReference Include="SpaceWizards.SharpFont" PrivateAssets="compile" />
+    <PackageReference Include="SpaceWizards.Sdl" PrivateAssets="compile" />
     <PackageReference Include="Robust.Natives" />
     <PackageReference Include="TerraFX.Interop.Windows" PrivateAssets="compile" />
     <PackageReference Condition="'$(RobustToolsBuild)' == 'True'" Include="JetBrains.Profiler.Api" PrivateAssets="compile" />
@@ -63,6 +64,7 @@
     <RobustLinkAssemblies Include="TerraFX.Interop.Windows" />
     <RobustLinkAssemblies Include="TerraFX.Interop.Xlib" />
     <RobustLinkAssemblies Include="OpenToolkit.Graphics" />
+    <RobustLinkAssemblies Include="SpaceWizards.Sdl" />
     <RobustLinkAssemblies Include="SpaceWizards.SharpFont" />
   </ItemGroup>
 

Robust.Client/UserInterface/Axis.cs

@@ -0,0 +1,192 @@
+using System.Numerics;
+using Robust.Shared.Maths;
+
+namespace Robust.Client.UserInterface;
+
+/// <summary>
+/// Defines an axis that certain controls can be laid out along.
+/// </summary>
+/// <seealso cref="IAxisImplementation"/>
+public enum Axis : byte
+{
+    /// <summary>
+    /// Items are laid out left to right.
+    /// </summary>
+    Horizontal,
+
+    /// <summary>
+    /// Items are laid out right to left.
+    /// </summary>
+    HorizontalReverse,
+
+    /// <summary>
+    /// Items are laid out top to bottom.
+    /// </summary>
+    Vertical,
+
+    /// <summary>
+    /// Items are laid out bottom to top.
+    /// </summary>
+    VerticalReverse,
+}
+
+/// <summary>
+/// Interface that implements the rules of an <see cref="Axis"/>.
+/// </summary>
+/// <remarks>
+/// <para>
+/// To make it easier to write code that supports all 4 layout axis, layout code is advised to use generics over this
+/// type and its implementors.
+/// </para>
+/// <para>
+/// An axis has a "main" and a "cross" axis. For example,
+/// <see cref="HorizontalAxis"/> has the main axis go left to right, and the cross axis go top to bottom.
+/// </para>
+/// <para>
+/// The functions in this interface primarily allow converting between "UI space" (the normal UI coordinate system) and
+/// "axis space" (same as UI space for <see cref="HorizontalAxis"/>). This allows you to write all code as if you're
+/// doing only horizontal layout, but automatically have it work on all axis.
+/// </para>
+/// </remarks>
+/// <seealso cref="HorizontalAxis"/>
+/// <seealso cref="HorizontalReverseAxis"/>
+/// <seealso cref="VerticalAxis"/>
+/// <seealso cref="VerticalReverseAxis"/>
+public interface IAxisImplementation
+{
+    //
+    // To/from axis space conversions
+    //
+
+    /// <summary>
+    /// Convert a size value (e.g. from <see cref="Control.DesiredSize"/>) from UI space to axis space.
+    /// </summary>
+    static abstract Vector2 SizeToAxis(Vector2 size);
+
+    /// <summary>
+    /// Convert a size value (e.g. for <see cref="Control.Measure"/>) from axis space to UI space.
+    /// </summary>
+    static abstract Vector2 SizeFromAxis(Vector2 size);
+
+    /// <summary>
+    /// Convert a box (e.g. for <see cref="Control.Arrange"/>) from axis space to UI space.
+    /// </summary>
+    /// <param name="box">The box to convert, in axis space.</param>
+    /// <param name="spaceSize">The amount of space, in UI space, that the layout is happening relative to.</param>
+    static abstract UIBox2 BoxFromAxis(UIBox2 box, Vector2 spaceSize);
+
+    //
+    // Control
+    //
+
+    /// <summary>
+    /// Gets the "expand flag" (<see cref="Control.HorizontalExpand"/> or <see cref="Control.VerticalExpand"/>) for a
+    /// control that is appropriate for the main axis.
+    /// </summary>
+    static abstract bool GetMainExpandFlag(Control control);
+}
+
+/// <summary>
+/// Axis implementation for <see cref="Axis.Horizontal"/>.
+/// </summary>
+public struct HorizontalAxis : IAxisImplementation
+{
+    public static Vector2 SizeToAxis(Vector2 size)
+    {
+        return size;
+    }
+
+    public static Vector2 SizeFromAxis(Vector2 size)
+    {
+        return size;
+    }
+
+    public static UIBox2 BoxFromAxis(UIBox2 box, Vector2 spaceSize)
+    {
+        return box;
+    }
+
+    public static bool GetMainExpandFlag(Control control)
+    {
+        return control.HorizontalExpand;
+    }
+}
+
+/// <summary>
+/// Axis implementation for <see cref="Axis.HorizontalReverse"/>.
+/// </summary>
+public struct HorizontalReverseAxis : IAxisImplementation
+{
+    public static Vector2 SizeToAxis(Vector2 size)
+    {
+        return size;
+    }
+
+    public static Vector2 SizeFromAxis(Vector2 size)
+    {
+        return size;
+    }
+
+    public static UIBox2 BoxFromAxis(UIBox2 box, Vector2 spaceSize)
+    {
+        return new UIBox2(spaceSize.X - box.Right, box.Top, spaceSize.X - box.Left, box.Bottom);
+    }
+
+    public static bool GetMainExpandFlag(Control control)
+    {
+        return control.HorizontalExpand;
+    }
+}
+
+/// <summary>
+/// Axis implementation for <see cref="Axis.Vertical"/>.
+/// </summary>
+public struct VerticalAxis : IAxisImplementation
+{
+    public static Vector2 SizeToAxis(Vector2 size)
+    {
+        return new Vector2(size.Y, size.X);
+    }
+
+    public static Vector2 SizeFromAxis(Vector2 size)
+    {
+        return new Vector2(size.Y, size.X);
+    }
+
+    public static UIBox2 BoxFromAxis(UIBox2 box, Vector2 spaceSize)
+    {
+        return new UIBox2(box.Top, box.Left, box.Bottom, box.Right);
+    }
+
+    public static bool GetMainExpandFlag(Control control)
+    {
+        return control.VerticalExpand;
+    }
+}
+
+/// <summary>
+/// Axis implementation for <see cref="Axis.VerticalReverse"/>.
+/// </summary>
+public struct VerticalReverseAxis : IAxisImplementation
+{
+    public static Vector2 SizeToAxis(Vector2 size)
+    {
+        return new Vector2(size.Y, size.X);
+    }
+
+    public static Vector2 SizeFromAxis(Vector2 size)
+    {
+        return new Vector2(size.Y, size.X);
+    }
+
+    public static UIBox2 BoxFromAxis(UIBox2 box, Vector2 spaceSize)
+    {
+        return new UIBox2(box.Top, spaceSize.Y - box.Right, box.Bottom, spaceSize.Y - box.Left);
+    }
+
+    public static bool GetMainExpandFlag(Control control)
+    {
+        return control.VerticalExpand;
+    }
+}
+

Robust.Client/UserInterface/Control.cs

@@ -1049,7 +1049,7 @@ namespace Robust.Client.UserInterface
             Ignore = 2,
         }
 
-        public sealed class OrderedChildCollection : ICollection<Control>, IReadOnlyCollection<Control>
+        public sealed class OrderedChildCollection : ICollection<Control>, IReadOnlyList<Control>
         {
             private readonly Control Owner;
 
@@ -1101,6 +1101,7 @@ namespace Robust.Client.UserInterface
 
             int ICollection<Control>.Count => Owner.ChildCount;
             int IReadOnlyCollection<Control>.Count => Owner.ChildCount;
+            public Control this[int index] => Owner._orderedChildren[index];
 
             public bool IsReadOnly => false;
 

Robust.Client/UserInterface/Controls/BoxContainer.cs

@@ -27,8 +27,6 @@ namespace Robust.Client.UserInterface.Controls
         /// </remarks>
         public AlignMode Align { get; set; }
 
-        private bool Vertical => Orientation == LayoutOrientation.Vertical;
-
         public LayoutOrientation Orientation
         {
             get => _orientation;
@@ -56,19 +54,24 @@ namespace Robust.Client.UserInterface.Controls
 
         protected override Vector2 MeasureOverride(Vector2 availableSize)
         {
-            // Account for separation.
-            var separation = ActualSeparation * (Children.Where(c => c.Visible).Count() - 1);
-            var desiredSize = Vector2.Zero;
-            if (Vertical)
+            if (Orientation == LayoutOrientation.Vertical)
             {
-                desiredSize.Y += separation;
-                availableSize.Y = Math.Max(0, availableSize.Y - separation);
+                return MeasureItems<VerticalAxis>(availableSize);
             }
             else
             {
-                desiredSize.X += separation;
-                availableSize.X = Math.Max(0, availableSize.X - separation);
+                return MeasureItems<HorizontalAxis>(availableSize);
             }
+        }
+
+        private Vector2 MeasureItems<TAxis>(Vector2 availableSize) where TAxis : IAxisImplementation
+        {
+            availableSize = TAxis.SizeToAxis(availableSize);
+
+            // Account for separation.
+            var separation = ActualSeparation * (Children.Where(c => c.Visible).Count() - 1);
+            var desiredSize = new Vector2(separation, 0);
+            availableSize.X = Math.Max(0, availableSize.X) - separation;
 
             // First, we measure non-stretching children.
             foreach (var child in Children)
@@ -76,46 +79,74 @@ namespace Robust.Client.UserInterface.Controls
                 if (!child.Visible)
                     continue;
 
-                child.Measure(availableSize);
+                child.Measure(TAxis.SizeFromAxis(availableSize));
+                var childDesired = TAxis.SizeToAxis(child.DesiredSize);
 
-                if (Vertical)
-                {
-                    desiredSize.Y += child.DesiredSize.Y;
-                    desiredSize.X = Math.Max(desiredSize.X, child.DesiredSize.X);
-                    availableSize.Y = Math.Max(0, availableSize.Y - child.DesiredSize.Y);
-                }
-                else
-                {
-                    desiredSize.X += child.DesiredSize.X;
-                    desiredSize.Y = Math.Max(desiredSize.Y, child.DesiredSize.Y);
-                    availableSize.X = Math.Max(0, availableSize.X - child.DesiredSize.X);
-                }
+                desiredSize.X += childDesired.X;
+                desiredSize.Y = Math.Max(desiredSize.Y, childDesired.Y);
+
+                availableSize.X = Math.Max(0, availableSize.X - childDesired.X);
             }
 
-            return desiredSize;
+            return TAxis.SizeFromAxis(desiredSize);
         }
 
         protected override Vector2 ArrangeOverride(Vector2 finalSize)
         {
             var separation = ActualSeparation;
-            var visibleChildCount = Children.Where(c => c.Visible).Count();
 
-            var stretchAvail = Vertical ? finalSize.Y : finalSize.X;
+            if (Orientation == LayoutOrientation.Vertical)
+            {
+                LayOutItems<VerticalAxis>(default, finalSize, Align, Children, 0, ChildCount, separation);
+            }
+            else
+            {
+                LayOutItems<HorizontalAxis>(default, finalSize, Align, Children, 0, ChildCount, separation);
+            }
+
+            return finalSize;
+        }
+
+        internal static void LayOutItems<TAxis>(
+            Vector2 baseOffset,
+            Vector2 finalSize,
+            AlignMode align,
+            OrderedChildCollection children,
+            int start,
+            int end,
+            float separation,
+            Vector2? fixedSize = null)
+            where TAxis : IAxisImplementation
+        {
+            var realFinalSize = finalSize;
+            finalSize = TAxis.SizeToAxis(finalSize);
+            fixedSize = fixedSize == null ? null : TAxis.SizeToAxis(fixedSize.Value);
+
+            var visibleChildCount = 0;
+            for (var i = start; i < end; i++)
+            {
+                if (children[i].Visible)
+                    visibleChildCount += 1;
+            }
+
+            var stretchAvail = finalSize.X;
             stretchAvail -= separation * (visibleChildCount - 1);
             stretchAvail = Math.Max(0, stretchAvail);
 
             // Step one: figure out the sizes of all our children and whether they want to stretch.
             var sizeList = new List<(Control control, float size, bool stretch)>(visibleChildCount);
             var totalStretchRatio = 0f;
-            foreach (var child in Children)
+            for (var i = start; i < end; i++)
             {
+                var child = children[i];
                 if (!child.Visible)
                     continue;
 
-                bool stretch = Vertical ? child.VerticalExpand : child.HorizontalExpand;
+                bool stretch = TAxis.GetMainExpandFlag(child);
                 if (!stretch)
                 {
-                    var size = Vertical ? child.DesiredSize.Y : child.DesiredSize.X;
+                    var measuredSize = fixedSize ?? TAxis.SizeToAxis(child.DesiredSize);
+                    var size = measuredSize.X;
                     size = Math.Clamp(size, 0, stretchAvail);
                     stretchAvail -= size;
                     sizeList.Add((child, size, false));
@@ -146,7 +177,8 @@ namespace Robust.Client.UserInterface.Controls
                             continue;
 
                         var share = stretchAvail * control.SizeFlagsStretchRatio / totalStretchRatio;
-                        var desired = Vertical ? control.DesiredSize.Y : control.DesiredSize.X;
+                        var measuredSize = fixedSize ?? TAxis.SizeToAxis(control.DesiredSize);
+                        var desired = measuredSize.X;
                         if (share >= desired)
                         {
                             sizeList[i] = (control, share, true);
@@ -164,7 +196,7 @@ namespace Robust.Client.UserInterface.Controls
             else
             {
                 // No stretching children -> offset the children based on the alignment.
-                switch (Align)
+                switch (align)
                 {
                     case AlignMode.Begin:
                         break;
@@ -190,22 +222,14 @@ namespace Robust.Client.UserInterface.Controls
 
                 first = false;
 
-                UIBox2 targetBox;
-                if (Vertical)
-                {
-                    targetBox = new UIBox2(0, offset, finalSize.X, offset + size);
-                }
-                else
-                {
-                    targetBox = new UIBox2(offset, 0, offset + size, finalSize.Y);
-                }
+                var targetBox = TAxis.BoxFromAxis(new UIBox2(offset, 0, offset + size, finalSize.Y), realFinalSize);
+
+                targetBox = targetBox.Translated(baseOffset);
 
                 control.Arrange(targetBox);
 
                 offset += size;
             }
-
-            return finalSize;
         }
 
         public enum AlignMode : byte

Robust.Client/UserInterface/Controls/MultiselectOptionButton.cs

@@ -121,11 +121,14 @@ namespace Robust.Client.UserInterface.Controls
         {
             if (show)
             {
+                if (Root == null)
+                    throw new InvalidOperationException("No UI root! We can't pop up!");
+
                 var globalPos = GlobalPosition;
                 _popupVBox.Measure(Vector2Helpers.Infinity);
                 var (minX, minY) = _popupVBox.DesiredSize;
                 var box = UIBox2.FromDimensions(globalPos, new Vector2(Math.Max(minX, Width), minY));
-                UserInterfaceManager.ModalRoot.AddChild(_popup);
+                Root.ModalRoot.AddChild(_popup);
                 _popup.Open(box);
             }
             else
@@ -136,7 +139,7 @@ namespace Robust.Client.UserInterface.Controls
 
         private void OnPopupHide()
         {
-            UserInterfaceManager.ModalRoot.RemoveChild(_popup);
+            _popup.Orphan();
         }
 
 

Robust.Client/UserInterface/Controls/OSWindow.cs

@@ -135,7 +135,13 @@ namespace Robust.Client.UserInterface.Controls
             ClydeWindow.Resized += OnWindowResized;
 
             _root = UserInterfaceManager.CreateWindowRoot(ClydeWindow);
+            _root.CreateRootControls();
+
+            // Add ourselves *after* creating the root.
+            // This way root controls are valid in EnteredTree().
+            // We have to re-organize the controls after, of course.
             _root.AddChild(this);
+            SetPositionFirst();
 
             // Resize the window by our UIScale
             ClydeWindow.Size = new((int)(ClydeWindow.Size.X * UIScale), (int)(ClydeWindow.Size.Y * UIScale));

Robust.Client/UserInterface/Controls/OptionButton.cs

@@ -153,13 +153,16 @@ namespace Robust.Client.UserInterface.Controls
         {
             if (show)
             {
+                if (Root == null)
+                    throw new InvalidOperationException("No UI root! We can't pop up!");
+
                 var globalPos = GlobalPosition;
                 globalPos.Y += Size.Y + 1; // Place it below us, with a safety margin.
                 globalPos.Y -= Margin.SumVertical;
                 OptionsScroll.Measure(Window?.Size ?? Vector2Helpers.Infinity);
                 var (minX, minY) = OptionsScroll.DesiredSize;
                 var box = UIBox2.FromDimensions(globalPos, new Vector2(Math.Max(minX, Width), minY));
-                UserInterfaceManager.ModalRoot.AddChild(_popup);
+                Root.ModalRoot.AddChild(_popup);
                 _popup.Open(box);
             }
             else
@@ -170,7 +173,7 @@ namespace Robust.Client.UserInterface.Controls
 
         private void OnPopupHide()
         {
-            UserInterfaceManager.ModalRoot.RemoveChild(_popup);
+            _popup.Orphan();
         }
 
         private void ButtonOnPressed(ButtonEventArgs obj)

Robust.Client/UserInterface/Controls/OutputPanel.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.Contracts;
 using System.Numerics;
 using Robust.Client.Graphics;
 using Robust.Client.UserInterface.RichText;
@@ -154,6 +155,7 @@ namespace Robust.Client.UserInterface.Controls
 
         public void SetMessage(Index index, FormattedMessage message, Type[]? tagsAllowed = null, Color? defaultColor = null)
         {
+            var atBottom = !_scrollDownButton.Visible;
             var oldEntry = _entries[index];
             var font = _getFont();
             _totalContentHeight -= oldEntry.Height + font.GetLineSeparation(UIScale);
@@ -164,6 +166,10 @@ namespace Robust.Client.UserInterface.Controls
             _entries[index] = entry;
 
             AddNewItemHeight(font, in entry);
+
+            _scrollBar.MaxValue = Math.Max(_scrollBar.Page, _totalContentHeight);
+            if (atBottom)
+                _scrollBar.Value = _scrollBar.MaxValue;
         }
 
         private void AddNewItemHeight(Font font, in RichTextEntry entry)
@@ -278,7 +284,7 @@ namespace Robust.Client.UserInterface.Controls
             }
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private Font _getFont()
         {
             if (TryGetStyleProperty<Font>("font", out var font))
@@ -289,7 +295,7 @@ namespace Robust.Client.UserInterface.Controls
             return UserInterfaceManager.ThemeDefaults.DefaultFont;
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private StyleBox? _getStyleBox()
         {
             if (StyleBoxOverride != null)
@@ -301,14 +307,14 @@ namespace Robust.Client.UserInterface.Controls
             return box;
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private float _getScrollSpeed()
         {
             // The scroll speed depends on the UI scale because the scroll bar is working with physical pixels.
             return GetScrollSpeed(_getFont(), UIScale);
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private UIBox2 _getContentBox()
         {
             var style = _getStyleBox();

Robust.Client/UserInterface/Controls/Popup.cs

@@ -30,7 +30,7 @@ namespace Robust.Client.UserInterface.Controls
 
         public bool CloseOnEscape { get; set; } = true;
 
-        public virtual void Open(UIBox2? box = null, Vector2? altPos = null)
+        public virtual void Open(UIBox2? box = null, Vector2? altPos = null, Vector2? altPosUp = null)
         {
             if (Visible)
             {
@@ -44,10 +44,12 @@ namespace Robust.Client.UserInterface.Controls
             if (box != null &&
                 (_desiredSize != box.Value.Size ||
                  PopupContainer.GetPopupOrigin(this) != box.Value.TopLeft ||
-                 PopupContainer.GetAltOrigin(this) != altPos))
+                 PopupContainer.GetAltOrigin(this) != altPos ||
+                 PopupContainer.GetAltOriginUp(this) != altPosUp))
             {
                 PopupContainer.SetPopupOrigin(this, box.Value.TopLeft);
                 PopupContainer.SetAltOrigin(this, altPos);
+                PopupContainer.SetAltOriginUp(this, altPosUp);
 
                 _desiredSize = box.Value.Size;
                 InvalidateMeasure();

Robust.Client/UserInterface/Controls/PopupContainer.cs

@@ -27,6 +27,13 @@ namespace Robust.Client.UserInterface.Controls
         public static readonly AttachedProperty AltOriginProperty = AttachedProperty.Create("AltOrigin",
             typeof(PopupContainer), typeof(Vector2?), changed: PopupOriginChangedCallback);
 
+        /// <summary>
+        ///     Alternative position to bottom-left-align the popup if <see cref="PopupOriginProperty"/>
+        ///     would put it off-screen vertically.
+        /// </summary>
+        public static readonly AttachedProperty AltOriginUpProperty = AttachedProperty.Create("AltOriginUp",
+            typeof(PopupContainer), typeof(Vector2?), changed: PopupOriginChangedCallback);
+
         public PopupContainer()
         {
             RectClipContent = true;
@@ -47,11 +54,21 @@ namespace Robust.Client.UserInterface.Controls
             return control.GetValue<Vector2?>(AltOriginProperty);
         }
 
+        public static Vector2? GetAltOriginUp(Control control)
+        {
+            return control.GetValue<Vector2?>(AltOriginUpProperty);
+        }
+
         public static void SetAltOrigin(Control control, Vector2? origin)
         {
             control.SetValue(AltOriginProperty, origin);
         }
 
+        public static void SetAltOriginUp(Control control, Vector2? origin)
+        {
+            control.SetValue(AltOriginUpProperty, origin);
+        }
+
         private static void PopupOriginChangedCallback(Control owner, AttachedPropertyChangedEventArgs eventArgs)
         {
             if (owner.Parent is PopupContainer container)
@@ -67,47 +84,58 @@ namespace Robust.Client.UserInterface.Controls
                 var size = child.DesiredSize;
                 var offset = child.GetValue<Vector2>(PopupOriginProperty);
                 var altPos = child.GetValue<Vector2?>(AltOriginProperty);
+                var altPosUp = child.GetValue<Vector2?>(AltOriginUpProperty);
 
-                var (r, b) = size + offset; // bottom right corner.
+                var box = UIBox2.FromDimensions(offset, size);
 
                 var isAltPos = false;
+                var isAltPosUp = false;
 
                 // Clamp the right edge.
-                if (r > Width)
+                if (box.Right > Width)
                 {
                     // Try to position at alt pos.
                     if (altPos != null && altPos.Value.X - size.X > 0)
                     {
                         // There is horizontal room at the alt pos so there we go.
                         isAltPos = true;
-                        offset = new Vector2(altPos.Value.X - size.X, altPos.Value.Y);
-                        (_, b) = size + offset;
+                        box = UIBox2.FromDimensions(new Vector2(altPos.Value.X - size.X, altPos.Value.Y), size);
                     }
                     else
                     {
-                        offset -= new Vector2(r - Width, 0);
+                        box = box.Translated(new Vector2(-(box.Right - Width), 0));
                     }
                 }
 
                 // Clamp the bottom edge.
-                if (b > Height)
+                if (box.Bottom > Height)
                 {
-                    offset -= new Vector2(0, b - Height);
+                    // Try to position at alt pos.
+                    if (altPosUp != null && altPosUp.Value.Y - size.Y > 0)
+                    {
+                        // There is vertical room at the alt pos so there we go.
+                        isAltPosUp = true;
+                        box = UIBox2.FromDimensions(new Vector2(altPosUp.Value.X, altPosUp.Value.Y - size.Y), size);
+                    }
+                    else
+                    {
+                        box = box.Translated(new Vector2(0, -(box.Bottom - Height)));
+                    }
                 }
 
                 // Try to clamp the left edge.
-                if (offset.X < 0 && !isAltPos)
+                if (box.Left < 0 && !isAltPos)
                 {
-                    offset -= new Vector2(offset.X, 0);
+                    box = box.Translated(new Vector2(-offset.X, 0));
                 }
 
                 // Try to clamp the top edge.
-                if (offset.Y < 0)
+                if (box.Top < 0 && !isAltPosUp)
                 {
-                    offset -= new Vector2(0, offset.Y);
+                    box = box.Translated(new Vector2(0, -offset.Y));
                 }
 
-                child.Arrange(UIBox2.FromDimensions(offset, size));
+                child.Arrange(box);
             }
 
             return finalSize;

Robust.Client/UserInterface/Controls/ScrollBar.cs

@@ -74,7 +74,7 @@ namespace Robust.Client.UserInterface.Controls
             else
             {
                 _updating = true;
-                Value = MathHelper.Lerp(Value, ValueTarget, Math.Min(args.DeltaSeconds * 15, 1));
+                Value = UIAnimations.LerpAnimate(Value, ValueTarget, args.DeltaSeconds, 15);
                 _updating = false;
             }
         }

Robust.Client/UserInterface/Controls/TableContainer.cs

@@ -0,0 +1,270 @@
+using System;
+using System.Numerics;
+using Robust.Shared.Maths;
+
+namespace Robust.Client.UserInterface.Controls;
+
+internal sealed class TableContainer : Container
+{
+    private int _columns = 1;
+
+    /// <summary>
+    /// The absolute minimum width a column can be forced to.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// If a column *asks* for less width than this (small contents), it can still be smaller.
+    /// But if it asks for more it cannot go below this width.
+    /// </para>
+    /// </remarks>
+    public float MinForcedColumnWidth { get; set; } = 50;
+
+    // Scratch space used while calculating layout, cached to avoid regular allocations during layout pass.
+    private ColumnData[] _columnDataCache = [];
+    private RowData[] _rowDataCache = [];
+
+    /// <summary>
+    /// How many columns should be displayed.
+    /// </summary>
+    public int Columns
+    {
+        get => _columns;
+        set
+        {
+            ArgumentOutOfRangeException.ThrowIfLessThan(value, 1, nameof(value));
+
+            _columns = value;
+        }
+    }
+
+    protected override Vector2 MeasureOverride(Vector2 availableSize)
+    {
+        ResetCachedArrays();
+
+        // Do a first pass measuring all child controls as if they're given infinite space.
+        // This gives us a maximum width the columns want, which we use to proportion them later.
+        var columnIdx = 0;
+        foreach (var child in Children)
+        {
+            ref var column = ref _columnDataCache[columnIdx];
+
+            child.Measure(new Vector2(float.PositiveInfinity, float.PositiveInfinity));
+            column.MaxWidth = Math.Max(column.MaxWidth, child.DesiredSize.X);
+
+            columnIdx += 1;
+            if (columnIdx == _columns)
+                columnIdx = 0;
+        }
+
+        // Calculate Slack and MinWidth for all columns. Also calculate sums for all columns.
+        var totalMinWidth = 0f;
+        var totalMaxWidth = 0f;
+        var totalSlack = 0f;
+
+        for (var c = 0; c < _columns; c++)
+        {
+            ref var column = ref _columnDataCache[c];
+            column.MinWidth = Math.Min(column.MaxWidth, MinForcedColumnWidth);
+            column.Slack = column.MaxWidth - column.MinWidth;
+
+            totalMinWidth += column.MinWidth;
+            totalMaxWidth += column.MaxWidth;
+            totalSlack += column.Slack;
+        }
+
+        if (totalMaxWidth <= availableSize.X)
+        {
+            // We want less horizontal space than we're given. Huh, that's convenient.
+            // Just set assigned width to be however much they asked for.
+            // We could probably skip the second measure pass in this scenario,
+            // but that's just an optimization, so I don't care right now.
+            //
+            // There's probably a very clever way to make this behavior work with the else block of logic,
+            // just by fiddling with the math.
+            // I'm dumb, it's 4:30 AM. Yeah, I *started* at 2 AM.
+            for (var c = 0; c < _columns; c++)
+            {
+                ref var column = ref _columnDataCache[c];
+
+                column.AssignedWidth = column.MaxWidth;
+            }
+        }
+        else
+        {
+            // We don't have enough horizontal space,
+            // at least without causing *some* sort of word wrapping (assuming text contents).
+            //
+            // Assign horizontal space proportional to the wanted maximum size of the columns.
+            var assignableWidth =  Math.Max(0, availableSize.X - totalMinWidth);
+            for (var c = 0; c < _columns; c++)
+            {
+                ref var column = ref _columnDataCache[c];
+
+                var slackRatio = column.Slack / totalSlack;
+                column.AssignedWidth = column.MinWidth + slackRatio * assignableWidth;
+            }
+        }
+
+        // Go over controls for a second measuring pass, this time giving them their assigned measure width.
+        // This will give us a height to slot into per-row data.
+        // We still measure assuming infinite vertical space.
+        // This control can't properly handle being constrained on the Y axis.
+        columnIdx = 0;
+        var rowIdx = 0;
+        foreach (var child in Children)
+        {
+            ref var column = ref _columnDataCache[columnIdx];
+            ref var row = ref _rowDataCache[rowIdx];
+
+            child.Measure(new Vector2(column.AssignedWidth, float.PositiveInfinity));
+            row.MeasuredHeight = Math.Max(row.MeasuredHeight, child.DesiredSize.Y);
+
+            columnIdx += 1;
+            if (columnIdx == _columns)
+            {
+                columnIdx = 0;
+                rowIdx += 1;
+            }
+        }
+
+        // Sum up height of all rows to get final measured table height.
+        var totalHeight = 0f;
+        for (var r = 0; r < _rowDataCache.Length; r++)
+        {
+            ref var row = ref _rowDataCache[r];
+            totalHeight += row.MeasuredHeight;
+        }
+
+        return new Vector2(Math.Min(availableSize.X, totalMaxWidth), totalHeight);
+    }
+
+    protected override Vector2 ArrangeOverride(Vector2 finalSize)
+    {
+        // TODO: Expand to fit given vertical space.
+
+        // Calculate MinWidth and Slack sums again from column data.
+        // We could've cached these from measure but whatever.
+        var totalMinWidth = 0f;
+        var totalSlack = 0f;
+
+        for (var c = 0; c < _columns; c++)
+        {
+            ref var column = ref _columnDataCache[c];
+            totalMinWidth += column.MinWidth;
+            totalSlack += column.Slack;
+        }
+
+        // Calculate new width based on final given size, also assign horizontal positions of all columns.
+        var assignableWidth = Math.Max(0, finalSize.X - totalMinWidth);
+        var xPos = 0f;
+        for (var c = 0; c < _columns; c++)
+        {
+            ref var column = ref _columnDataCache[c];
+
+            var slackRatio = column.Slack / totalSlack;
+            column.ArrangedWidth = column.MinWidth + slackRatio * assignableWidth;
+            column.ArrangedX = xPos;
+
+            xPos += column.ArrangedWidth;
+        }
+
+        // Do actual arrangement row-by-row.
+        var arrangeY = 0f;
+        for (var r = 0; r < _rowDataCache.Length; r++)
+        {
+            ref var row = ref _rowDataCache[r];
+
+            for (var c = 0; c < _columns; c++)
+            {
+                ref var column = ref _columnDataCache[c];
+                var index = c + r * _columns;
+
+                if (index >= ChildCount) // Quit early if we don't actually fill out the row.
+                    break;
+                var child = GetChild(c + r * _columns);
+
+                child.Arrange(UIBox2.FromDimensions(column.ArrangedX, arrangeY, column.ArrangedWidth, row.MeasuredHeight));
+            }
+
+            arrangeY += row.MeasuredHeight;
+        }
+
+        return finalSize with { Y = arrangeY };
+    }
+
+    /// <summary>
+    /// Ensure cached array space is allocated to correct size and is reset to a clean slate.
+    /// </summary>
+    private void ResetCachedArrays()
+    {
+        // 1-argument Array.Clear() is not currently available in sandbox (added in .NET 6).
+
+        if (_columnDataCache.Length != _columns)
+            _columnDataCache = new ColumnData[_columns];
+
+        Array.Clear(_columnDataCache, 0, _columnDataCache.Length);
+
+        var rowCount = ChildCount / _columns;
+        if (ChildCount % _columns != 0)
+            rowCount += 1;
+
+        if (rowCount != _rowDataCache.Length)
+            _rowDataCache = new RowData[rowCount];
+
+        Array.Clear(_rowDataCache, 0, _rowDataCache.Length);
+    }
+
+    /// <summary>
+    /// Per-column data used during layout.
+    /// </summary>
+    private struct ColumnData
+    {
+        // Measure data.
+
+        /// <summary>
+        /// The maximum width any control in this column wants, if given infinite space.
+        /// Maximum of all controls on the column.
+        /// </summary>
+        public float MaxWidth;
+
+        /// <summary>
+        /// The minimum width this column may be given.
+        /// This is either <see cref="MaxWidth"/> or <see cref="TableContainer.MinForcedColumnWidth"/>.
+        /// </summary>
+        public float MinWidth;
+
+        /// <summary>
+        /// Difference between max and min width; how much this column can expand from its minimum.
+        /// </summary>
+        public float Slack;
+
+        /// <summary>
+        /// How much horizontal space this column was assigned at measure time.
+        /// </summary>
+        public float AssignedWidth;
+
+        // Arrange data.
+
+        /// <summary>
+        /// How much horizontal space this column was assigned at arrange time.
+        /// </summary>
+        public float ArrangedWidth;
+
+        /// <summary>
+        /// The horizontal position this column was assigned at arrange time.
+        /// </summary>
+        public float ArrangedX;
+    }
+
+    private struct RowData
+    {
+        // Measure data.
+
+        /// <summary>
+        /// How much height the tallest control on this row was measured at,
+        /// measuring for infinite vertical space but assigned column width.
+        /// </summary>
+        public float MeasuredHeight;
+    }
+}
+

Robust.Client/UserInterface/Controls/UIRoot.cs

@@ -18,6 +18,9 @@ namespace Robust.Client.UserInterface.Controls
 
         public Color? BackgroundColor { get; set; }
 
+        public virtual LayoutContainer PopupRoot => throw new NotSupportedException();
+        public virtual PopupContainer ModalRoot  => throw new NotSupportedException();
+
         private Color _styleBgColor;
 
         internal Color ActualBgColor => BackgroundColor ?? _styleBgColor;

Robust.Client/UserInterface/Controls/WindowRoot.cs

@@ -1,12 +1,14 @@
-using Robust.Client.Graphics;
+using System;
+using Robust.Client.Graphics;
 using Robust.Shared;
-using Robust.Shared.Maths;
-using Robust.Shared.ViewVariables;
 
 namespace Robust.Client.UserInterface.Controls
 {
     public sealed class WindowRoot : UIRoot
     {
+        private PopupContainer? _modalRoot;
+        private LayoutContainer? _popupRoot;
+
         internal WindowRoot(IClydeWindow window)
         {
             Window = window;
@@ -32,5 +34,39 @@ namespace Robust.Client.UserInterface.Controls
         /// </remarks>
         /// <seealso cref="CVars.ResAutoScaleEnabled"/>
         public bool DisableAutoScaling { get; set; } = true;
+
+        public override PopupContainer ModalRoot => _modalRoot ?? throw new InvalidOperationException(
+            $"Tried to access root controls without calling {nameof(CreateRootControls)}!");
+
+        public override LayoutContainer PopupRoot => _popupRoot ?? throw new InvalidOperationException(
+            $"Tried to access root controls without calling {nameof(CreateRootControls)}!");
+
+        /// <summary>
+        /// Creates root controls (e.g. <see cref="UIRoot.ModalRoot"/>) that are necessary for the UI system to
+        /// fully function.
+        /// </summary>
+        /// <remarks>
+        /// This should be called *after* inserting the main content into this instance,
+        /// so that the created root controls (e.g. popups) correctly stay on top.
+        /// </remarks>
+        public void CreateRootControls()
+        {
+            if (_modalRoot != null)
+                throw new InvalidOperationException("We've already created root controls!");
+
+            _modalRoot = new PopupContainer
+            {
+                Name = nameof(ModalRoot),
+                MouseFilter = MouseFilterMode.Ignore,
+            };
+            AddChild(_modalRoot);
+
+            _popupRoot = new LayoutContainer
+            {
+                Name = nameof(PopupRoot),
+                MouseFilter = MouseFilterMode.Ignore
+            };
+            AddChild(_popupRoot);
+        }
     }
 }

Robust.Client/UserInterface/Controls/WrapContainer.cs

@@ -0,0 +1,330 @@
+using System;
+using System.Numerics;
+using Robust.Shared.Collections;
+using Robust.Shared.Maths;
+
+namespace Robust.Client.UserInterface.Controls;
+
+/// <summary>
+/// Lays of children sequentially, "wrapping" them onto another row/column if necessary.
+/// </summary>
+public sealed class WrapContainer : Container
+{
+    /// <summary>
+    /// Specifies the amount of space between two children, on the main axis.
+    /// </summary>
+    public const string StylePropertySeparation = "separation";
+
+    /// <summary>
+    /// Specifies the amount of space between two children, on the cross axis.
+    /// </summary>
+    public const string StylePropertyCrossSeparation = "cross-separation";
+
+    // Parameters.
+    private Axis _layoutAxis;
+    private ItemJustification _justification;
+    private bool _equalSize;
+    private bool _reverse;
+    private int? _separationOverride;
+    private int? _crossSeparationOverride;
+
+    // Cached layout data.
+    private ValueList<(int endIndex, float cross)> _rowIndices;
+    private float _lastMeasureCross;
+
+    /// <summary>
+    /// Specifies the amount of space between two children, on the main axis.
+    /// </summary>
+    /// <remarks>
+    /// This property overrides <see cref="StylePropertySeparation"/>, if set.
+    /// </remarks>
+    public int? SeparationOverride
+    {
+        get => _separationOverride;
+        set
+        {
+            _separationOverride = value;
+            InvalidateMeasure();
+        }
+    }
+
+    /// <summary>
+    /// Specifies the amount of space between two children, on the cross axis.
+    /// </summary>
+    /// <remarks>
+    /// This property overrides <see cref="StylePropertyCrossSeparation"/>, if set.
+    /// </remarks>
+    public int? CrossSeparationOverride
+    {
+        get => _crossSeparationOverride;
+        set
+        {
+            _crossSeparationOverride = value;
+            InvalidateMeasure();
+        }
+    }
+
+    /// <summary>
+    /// The <see cref="Axis"/> along which to lay out children.
+    /// </summary>
+    public Axis LayoutAxis
+    {
+        get => _layoutAxis;
+        set
+        {
+            _layoutAxis = value;
+            InvalidateMeasure();
+        }
+    }
+
+    /// <summary>
+    /// If true, all children will be laid out with the size of the largest child.
+    /// </summary>
+    public bool EqualSize
+    {
+        get => _equalSize;
+        set
+        {
+            _equalSize = value;
+            InvalidateMeasure();
+        }
+    }
+
+    /// <summary>
+    /// Determines where items will be laid out on an individual row/column.
+    /// </summary>
+    public ItemJustification Justification
+    {
+        get => _justification;
+        set
+        {
+            _justification = value;
+            InvalidateArrange();
+        }
+    }
+
+    /// <summary>
+    /// If true, reverses the order on which wrapping rows/columns are laid out.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// On horizontal axis, the first children are on the top row, and new rows are added <i>downwards</i>.
+    /// With <see cref="Reverse"/> set to true,
+    /// the first children are instead on the bottom row, with new rows growing upwards.
+    /// </para>
+    /// </remarks>
+    public bool Reverse
+    {
+        get => _reverse;
+        set
+        {
+            _reverse = value;
+            InvalidateArrange();
+        }
+    }
+
+    private int ActualSeparation
+    {
+        get
+        {
+            if (TryGetStyleProperty(StylePropertySeparation, out int separation))
+            {
+                return separation;
+            }
+
+            return SeparationOverride ?? 0;
+        }
+    }
+
+    private int ActualCrossSeparation
+    {
+        get
+        {
+            if (TryGetStyleProperty(StylePropertyCrossSeparation, out int separation))
+            {
+                return separation;
+            }
+
+            return CrossSeparationOverride ?? 0;
+        }
+    }
+
+    protected override Vector2 MeasureOverride(Vector2 availableSize)
+    {
+        var axis = LayoutAxis;
+
+        return axis switch
+        {
+            Axis.Horizontal => MeasureImplementation<HorizontalAxis>(availableSize),
+            Axis.HorizontalReverse => MeasureImplementation<HorizontalReverseAxis>(availableSize),
+            Axis.Vertical => MeasureImplementation<VerticalAxis>(availableSize),
+            Axis.VerticalReverse => MeasureImplementation<VerticalReverseAxis>(availableSize),
+            _ => throw new ArgumentOutOfRangeException()
+        };
+    }
+
+    private Vector2 MeasureImplementation<TAxis>(Vector2 availableSize) where TAxis : IAxisImplementation
+    {
+        _rowIndices.Clear();
+
+        var realAvailableSize = availableSize;
+        availableSize = TAxis.SizeToAxis(availableSize);
+
+        // TODO: Round to pixels properly.
+        var separation = ActualSeparation;
+        var crossSeparation = ActualCrossSeparation;
+        var curMainSize = 0f;
+        var curCrossSize = 0f;
+        var totalCrossSize = 0f;
+        var maxMainSize = 0f;
+        var firstOnRow = true;
+
+        var equalDesiredSize = _equalSize ? TAxis.SizeToAxis(GetMaxMeasure(realAvailableSize)) : default;
+        var countLaidOut = 0;
+
+        foreach (var control in Children)
+        {
+            Vector2 controlDesiredSize;
+            if (_equalSize)
+            {
+                controlDesiredSize = equalDesiredSize;
+            }
+            else
+            {
+                control.Measure(realAvailableSize);
+                controlDesiredSize = TAxis.SizeToAxis(control.DesiredSize);
+            }
+
+            var controlMainSize = controlDesiredSize.X;
+            var spaceTaken = controlMainSize + (firstOnRow ? 0 : separation);
+            if (curMainSize + spaceTaken > availableSize.X)
+            {
+                // We've wrapped.
+                RowEnd(lastRow: false);
+                curMainSize = controlMainSize;
+            }
+            else
+            {
+                curMainSize += spaceTaken;
+            }
+            curCrossSize = Math.Max(curCrossSize, controlDesiredSize.Y);
+            firstOnRow = false;
+            countLaidOut += 1;
+        }
+
+        RowEnd(lastRow: true);
+
+        _lastMeasureCross = totalCrossSize;
+
+        return TAxis.SizeFromAxis(new Vector2(maxMainSize, totalCrossSize));
+
+        void RowEnd(bool lastRow)
+        {
+            maxMainSize = Math.Max(maxMainSize, curMainSize);
+            totalCrossSize += curCrossSize;
+            if (!lastRow)
+                totalCrossSize += crossSeparation;
+            _rowIndices.Add((countLaidOut, curCrossSize));
+            curCrossSize = 0;
+        }
+    }
+
+    private Vector2 GetMaxDesired()
+    {
+        var vec = Vector2.Zero;
+
+        foreach (var child in Children)
+        {
+            vec = Vector2.Max(vec, child.DesiredSize);
+        }
+
+        return vec;
+    }
+
+    private Vector2 GetMaxMeasure(Vector2 availableSize)
+    {
+        var vec = Vector2.Zero;
+
+        foreach (var child in Children)
+        {
+            child.Measure(availableSize);
+            vec = Vector2.Max(vec, child.DesiredSize);
+        }
+
+        return vec;
+    }
+
+    protected override Vector2 ArrangeOverride(Vector2 finalSize)
+    {
+        var axis = LayoutAxis;
+
+        return axis switch
+        {
+            Axis.Horizontal => ArrangeImplementation<HorizontalAxis>(finalSize),
+            Axis.HorizontalReverse => ArrangeImplementation<HorizontalReverseAxis>(finalSize),
+            Axis.Vertical => ArrangeImplementation<VerticalAxis>(finalSize),
+            Axis.VerticalReverse => ArrangeImplementation<VerticalReverseAxis>(finalSize),
+            _ => throw new ArgumentOutOfRangeException()
+        };
+    }
+
+    private Vector2 ArrangeImplementation<TAxis>(Vector2 finalSize) where TAxis : IAxisImplementation
+    {
+        var realFinalSize = finalSize;
+        finalSize = TAxis.SizeToAxis(finalSize);
+
+        var separation = ActualSeparation;
+        var crossSeparation = ActualCrossSeparation;
+
+        var baseOffset = Reverse ? new Vector2(0, _lastMeasureCross) : Vector2.Zero;
+
+        var fixedSize = _equalSize ? (Vector2?)GetMaxDesired() : null;
+
+        var start = 0;
+        for (var i = 0; i < _rowIndices.Count; i++)
+        {
+            var (endIndex, cross) = _rowIndices[i];
+
+            if (Reverse)
+            {
+                baseOffset.Y -= cross;
+            }
+
+            var box = TAxis.BoxFromAxis(UIBox2.FromDimensions(baseOffset, finalSize with { Y = cross }), realFinalSize);
+
+            BoxContainer.LayOutItems<TAxis>(
+                box.TopLeft,
+                box.Size,
+                (BoxContainer.AlignMode)_justification,
+                Children,
+                start,
+                endIndex,
+                separation,
+                fixedSize);
+
+            start = endIndex;
+
+            if (Reverse)
+            {
+                baseOffset.Y -= crossSeparation;
+            }
+            else
+            {
+                baseOffset.Y = baseOffset.Y + cross + crossSeparation;
+            }
+        }
+
+        return realFinalSize;
+    }
+
+    /// <summary>
+    /// Justification values for <see cref="WrapContainer.Justification"/>.
+    /// </summary>
+    public enum ItemJustification : byte
+    {
+        // These MUST match the values in BoxContainer.
+        Begin = BoxContainer.AlignMode.Begin,
+        Center = BoxContainer.AlignMode.Center,
+        End = BoxContainer.AlignMode.End
+    }
+}

Robust.Client/UserInterface/CustomControls/DebugConsole.xaml.Completions.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Numerics;
 using System.Threading;
 using Robust.Client.UserInterface.Controls;
 using Robust.Shared;
@@ -224,10 +225,13 @@ public sealed partial class DebugConsole
 
         if (_compPopup.Contents.ChildCount != 0)
         {
-            _compPopup.Open(
-                UIBox2.FromDimensions(
-                    offset - _compPopup.Contents.Margin.Left, CommandBar.GlobalPosition.Y + CommandBar.Height + 2,
-                    5, 5));
+            var box = UIBox2.FromDimensions(
+                offset - _compPopup.Contents.Margin.Left,
+                CommandBar.GlobalPosition.Y + CommandBar.Height + 2,
+                5,
+                5);
+            var altPosUp = new Vector2(offset - _compPopup.Contents.Margin.Left, CommandBar.GlobalPosition.Y);
+            _compPopup.Open(box, altPosUp: altPosUp);
         }
     }
 

Robust.Client/UserInterface/CustomControls/DebugConsole.xaml.cs

@@ -83,7 +83,7 @@ namespace Robust.Client.UserInterface.CustomControls
             _consoleHost.ClearText += OnClearText;
             _cfg.OnValueChanged(CVars.ConMaxEntries, MaxEntriesChanged, true);
 
-            UserInterfaceManager.ModalRoot.AddChild(_compPopup);
+            Root!.ModalRoot.AddChild(_compPopup);
         }
 
         protected override void ExitedTree()
@@ -95,7 +95,7 @@ namespace Robust.Client.UserInterface.CustomControls
             _consoleHost.ClearText -= OnClearText;
             _cfg.UnsubValueChanged(CVars.ConMaxEntries, MaxEntriesChanged);
 
-            UserInterfaceManager.ModalRoot.RemoveChild(_compPopup);
+            _compPopup.Orphan();
         }
 
         private void MaxEntriesChanged(int value)

Robust.Client/UserInterface/CustomControls/DebugMonitorControls/DebugMonitors.cs

@@ -1,42 +1,39 @@
 using System;
 using Robust.Client.GameStates;
-using Robust.Client.Graphics;
-using Robust.Client.Input;
-using Robust.Client.Player;
 using Robust.Client.Profiling;
-using Robust.Client.State;
 using Robust.Client.Timing;
 using Robust.Client.UserInterface.Controls;
 using Robust.Shared.Configuration;
 using Robust.Shared.IoC;
-using Robust.Shared.Map;
 using Robust.Shared.Network;
 
 namespace Robust.Client.UserInterface.CustomControls.DebugMonitorControls
 {
     internal sealed class DebugMonitors : BoxContainer, IDebugMonitors
     {
+        [Dependency] private readonly IClientGameTiming _timing = default!;
+        [Dependency] private readonly IClientGameStateManager _state = default!;
+        [Dependency] private readonly IConfigurationManager _cfg = default!;
+        [Dependency] private readonly IClientNetManager _net = default!;
+
         private readonly Control[] _monitors = new Control[Enum.GetNames<DebugMonitor>().Length];
 
-        //TODO: Think about a factory for this
-        public DebugMonitors(IClientGameTiming gameTiming, IPlayerManager playerManager, IEyeManager eyeManager,
-            IInputManager inputManager, IStateManager stateManager, IClyde displayManager, IClientNetManager netManager,
-            IMapManager mapManager)
+        public void Init()
         {
             Visible = false;
-
             SeparationOverride = 2;
             Orientation = LayoutOrientation.Vertical;
 
-            Add(DebugMonitor.Fps, new FpsCounter(gameTiming));
+            Add(DebugMonitor.Fps, new FpsCounter(_timing));
             Add(DebugMonitor.Coords, new DebugCoordsPanel());
-            Add(DebugMonitor.Net, new DebugNetPanel(netManager, gameTiming));
-            Add(DebugMonitor.Bandwidth, new DebugNetBandwidthPanel(netManager, gameTiming));
-            Add(DebugMonitor.Time, new DebugTimePanel(gameTiming, IoCManager.Resolve<IClientGameStateManager>()));
-            Add(DebugMonitor.Frames, new FrameGraph(gameTiming, IoCManager.Resolve<IConfigurationManager>()));
+            Add(DebugMonitor.Net, new DebugNetPanel(_net, _timing));
+            Add(DebugMonitor.Bandwidth, new DebugNetBandwidthPanel(_net, _timing));
+            Add(DebugMonitor.Time, new DebugTimePanel(_timing, _state));
+            Add(DebugMonitor.Frames, new FrameGraph(_timing, _cfg));
             Add(DebugMonitor.Memory, new DebugMemoryPanel());
             Add(DebugMonitor.Clyde, new DebugClydePanel { HorizontalAlignment = HAlignment.Left });
             Add(DebugMonitor.System, new DebugSystemPanel { HorizontalAlignment = HAlignment.Left });
+            Add(DebugMonitor.Version, new DebugVersionPanel(_cfg) {HorizontalAlignment = HAlignment.Left});
             Add(DebugMonitor.Input, new DebugInputPanel { HorizontalAlignment = HAlignment.Left });
             Add(DebugMonitor.Prof, new LiveProfileViewControl());
 

Robust.Client/UserInterface/CustomControls/DebugMonitorControls/DebugVersionPanel.cs

@@ -0,0 +1,39 @@
+using Robust.Client.Graphics;
+using Robust.Client.UserInterface.Controls;
+using Robust.Shared.Configuration;
+using Robust.Shared.Maths;
+using Robust.Shared.Utility;
+
+namespace Robust.Client.UserInterface.CustomControls.DebugMonitorControls
+{
+    internal sealed class DebugVersionPanel : PanelContainer
+    {
+        public DebugVersionPanel(IConfigurationManager cfg)
+        {
+            var contents = new Label
+            {
+                FontColorShadowOverride = Color.Black,
+            };
+            AddChild(contents);
+
+            PanelOverride = new StyleBoxFlat
+            {
+                BackgroundColor = new Color(35, 134, 37, 138),
+                ContentMarginLeftOverride = 5,
+                ContentMarginRightOverride = 5,
+                ContentMarginTopOverride = 5,
+                ContentMarginBottomOverride = 5,
+            };
+
+            MouseFilter = contents.MouseFilter = MouseFilterMode.Ignore;
+
+            // Set visible explicitly
+            Visible = true;
+            HorizontalAlignment = HAlignment.Left;
+            VerticalAlignment = VAlignment.Top;
+
+            var buildInfo = GameBuildInformation.GetBuildInfoFromConfig(cfg);
+            contents.Text = $"Fork ID: {buildInfo.ForkId}\nFork Version: {buildInfo.Version}";
+        }
+    }
+}

Robust.Client/UserInterface/CustomControls/DropDownDebugConsole.xaml.cs

@@ -71,7 +71,7 @@ namespace Robust.Client.UserInterface.CustomControls
             }
             else
             {
-                _curAnchorOffset = MathHelper.Lerp(_curAnchorOffset, targetOffset, args.DeltaSeconds * 20);
+                _curAnchorOffset = UIAnimations.LerpAnimate(_curAnchorOffset, targetOffset, args.DeltaSeconds, 20);
             }
 
             UpdateAnchorOffset();

Robust.Client/UserInterface/DevWindow/DevWindow.xaml

@@ -6,5 +6,6 @@
         <DevWindowTabUI Name="UI" />
         <DevWindowTabPerf Name="Perf" />
         <DevWindowTabTextures Name="Textures" />
+        <DevWindowTabRenderTargets Name="RenderTargets" />
     </TabContainer>
 </Control>

Robust.Client/UserInterface/DevWindow/DevWindow.xaml.cs

@@ -28,6 +28,7 @@ namespace Robust.Client.UserInterface
             TabContainer.SetTabTitle(UI, "User Interface");
             TabContainer.SetTabTitle(Perf, "Profiling");
             TabContainer.SetTabTitle(Textures, Loc.GetString("dev-window-tab-textures-title"));
+            TabContainer.SetTabTitle(RenderTargets, Loc.GetString("dev-window-tab-render-targets-title"));
 
             Stylesheet =
                 new DefaultStylesheet(IoCManager.Resolve<IResourceCache>(), IoCManager.Resolve<IUserInterfaceManager>()).Stylesheet;
@@ -41,26 +42,14 @@ namespace Robust.Client.UserInterface
 
         public override void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            var clyde = IoCManager.Resolve<IClyde>();
-            var monitor = clyde.EnumerateMonitors().First();
-            if (args.Length > 0)
+            var window = new OSWindow
             {
-                var id = int.Parse(args[0]);
-                monitor = clyde.EnumerateMonitors().Single(m => m.Id == id);
-            }
-
-            var window = clyde.CreateWindow(new WindowCreateParameters
-            {
-                //Maximized = true,
                 Title = "Robust Debug Window",
-                //Monitor = monitor,
-            });
-            var root = IoCManager.Resolve<IUserInterfaceManager>().CreateWindowRoot(window);
-            window.DisposeOnClose = true;
-
+            };
             var control = new DevWindow();
+            window.AddChild(control);
 
-            root.AddChild(control);
+            window.Show();
         }
     }
 }

Robust.Client/UserInterface/DevWindow/DevWindowTabRenderTargets.xaml

@@ -0,0 +1,26 @@
+<Control xmlns="https://spacestation14.io"
+         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+         x:Class="Robust.Client.UserInterface.DevWindowTabRenderTargets">
+    <BoxContainer Orientation="Vertical">
+        <BoxContainer Orientation="Horizontal">
+            <Button Text="{Loc 'dev-window-tab-render-targets-reload'}" Name="ReloadButton" />
+        </BoxContainer>
+        <LineEdit Name="FilterEdit" PlaceHolder="{Loc 'dev-window-tab-render-targets-filter'}" />
+        <ScrollContainer VerticalExpand="True" VScrollEnabled="True" HScrollEnabled="False">
+            <BoxContainer Orientation="Vertical">
+                <TableContainer Name="Table" Margin="2" Columns="6">
+                    <Label Margin="4" Text="{Loc 'dev-window-tab-render-targets-column-id'}" />
+                    <Label Margin="4" Text="{Loc 'dev-window-tab-render-targets-column-name'}" />
+                    <Label Margin="4" Text="{Loc 'dev-window-tab-render-targets-column-size'}" />
+                    <Label Margin="4" Text="{Loc 'dev-window-tab-render-targets-column-type'}" />
+                    <Label Margin="4" Text="{Loc 'dev-window-tab-render-targets-column-vram'}" />
+                    <Label Margin="4" Text="{Loc 'dev-window-tab-render-targets-column-thumbnail'}" />
+                </TableContainer>
+            </BoxContainer>
+        </ScrollContainer>
+        <BoxContainer Orientation="Horizontal">
+            <Label Name="TotalLabel" Margin="4" />
+        </BoxContainer>
+    </BoxContainer>
+
+</Control>

Robust.Client/UserInterface/DevWindow/DevWindowTabRenderTargets.xaml.cs

@@ -0,0 +1,242 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Numerics;
+using Robust.Client.AutoGenerated;
+using Robust.Client.Graphics;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.UserInterface.XAML;
+using Robust.Shared.Graphics;
+using Robust.Shared.IoC;
+using Robust.Shared.Localization;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Utility;
+using RTCF = Robust.Client.Graphics.RenderTargetColorFormat;
+
+namespace Robust.Client.UserInterface;
+
+[GenerateTypedNameReferences]
+internal sealed partial class DevWindowTabRenderTargets : Control
+{
+    [Dependency] private readonly IClydeInternal _clyde = default!;
+    [Dependency] private readonly ILocalizationManager _loc = default!;
+
+    private readonly Control[] _gridHeader;
+
+    private readonly StyleBoxFlat _styleAltRow = new() { BackgroundColor = Color.FromHex("#222") };
+
+#if TOOLS
+    private readonly HashSet<IRenderTarget> _copyTextures = new();
+#endif // TOOLS
+
+    public DevWindowTabRenderTargets()
+    {
+        RobustXamlLoader.Load(this);
+        IoCManager.InjectDependencies(this);
+
+        _gridHeader = Table.Children.ToArray();
+
+        ReloadButton.OnPressed += _ => Reload();
+        FilterEdit.OnTextChanged += _ => Reload();
+    }
+
+    protected override void VisibilityChanged(bool newVisible)
+    {
+        base.VisibilityChanged(newVisible);
+
+        if (newVisible)
+        {
+            Reload();
+        }
+        else
+        {
+            // Clear to release memory when tab not visible.
+            Clear();
+        }
+    }
+
+    protected override void ExitedTree()
+    {
+        base.ExitedTree();
+
+        Clear();
+    }
+
+    private void Clear()
+    {
+        Table.RemoveAllChildren();
+
+#if TOOLS
+        foreach (var copiedTexture in _copyTextures)
+        {
+            copiedTexture.Dispose();
+        }
+
+        _copyTextures.Clear();
+#endif
+    }
+
+    private void Reload()
+    {
+        Table.RemoveAllChildren();
+
+        foreach (var header in _gridHeader)
+        {
+            Table.AddChild(header);
+        }
+
+        var totalVram = 0L;
+
+        var even = true;
+
+        var rts = _clyde.GetLoadedRenderTextures().OrderBy(x => x.Item1.Handle.Value).ToArray();
+        foreach (var (instance, loaded) in rts)
+        {
+#if TOOLS
+            if (_copyTextures.Contains(instance))
+                continue;
+#endif // TOOLS
+
+            if (!string.IsNullOrWhiteSpace(FilterEdit.Text))
+            {
+                if (loaded.Name is not { } name)
+                    continue;
+
+                if (!name.Contains(FilterEdit.Text, StringComparison.CurrentCultureIgnoreCase))
+                    continue;
+            }
+
+
+            AddColumnText(instance.Handle.Value.ToString());
+
+            if (loaded.Name != null)
+                AddColumnText(loaded.Name);
+            else if (loaded.WindowId != WindowId.Invalid)
+                AddColumnText(loaded.WindowId.ToString());
+            else
+                AddColumnText(_loc.GetString("dev-window-tab-render-targets-value-null"));
+
+            AddColumnText(loaded.Size.ToString());
+            var type = loaded.ColorFormat.ToString();
+            if (loaded.DepthStencilHandle != default)
+                type += "+DS";
+            AddColumnText(type);
+            AddColumnText(ByteHelpers.FormatBytes(loaded.MemoryPressure));
+
+            // Disable texture thumbnails outside TOOLS.
+            // Avoid people cheating by using devwindow to see through walls. Barely.
+#if TOOLS
+            if (instance is IRenderTexture renderTexture)
+            {
+                var clone = CloneTexture(renderTexture.Texture, loaded.ColorFormat);
+
+                _copyTextures.Add(clone);
+
+                AddColumn(new TextureRect
+                {
+                    Texture = clone.Texture,
+                    Stretch = TextureRect.StretchMode.KeepAspect
+                });
+            }
+            else
+#endif // TOOLS
+            {
+                AddColumnText(_loc.GetString("dev-window-tab-render-targets-value-not-available"));
+            }
+
+            totalVram += loaded.MemoryPressure;
+
+            even = !even;
+        }
+
+        TotalLabel.Text = Loc.GetString(
+            "dev-window-tab-render-targets-summary",
+            ("vram", ByteHelpers.FormatBytes(totalVram)));
+
+        return;
+
+        void AddColumnText(string text)
+        {
+            var richTextLabel = new RichTextLabel { Margin = new Thickness(4) };
+            richTextLabel.SetMessage(text, defaultColor: Color.White);
+            AddColumn(richTextLabel);
+        }
+
+        void AddColumn(Control control)
+        {
+            control.VerticalAlignment = VAlignment.Center;
+
+            if (even)
+            {
+                control = new PanelContainer
+                {
+                    PanelOverride = _styleAltRow,
+                    Children = { control },
+                };
+            }
+            else
+            {
+                // Wrapping control so we can use SetHeight.
+                control = new Control
+                {
+                    Children = { control },
+                };
+            }
+
+            control.SetHeight = 50;
+
+            Table.AddChild(control);
+        }
+    }
+
+#if TOOLS
+    private IRenderTexture CloneTexture(Texture texture, RTCF colorFormat)
+    {
+        var thumbnailSize = GetThumbnailSize(texture.Size);
+
+        var rt = _clyde.CreateRenderTarget(
+            thumbnailSize,
+            new RenderTargetFormatParameters
+            {
+                ColorFormat = colorFormat,
+                HasDepthStencil = false,
+            },
+            new TextureSampleParameters
+            {
+                Filter = true,
+            },
+            name: $"{nameof(DevWindowTabRenderTargets)}-clone");
+
+        _clyde.RenderNow(rt,
+            handle =>
+            {
+                handle.DrawingHandleScreen.DrawTextureRect(texture, UIBox2.FromDimensions(Vector2.Zero, thumbnailSize));
+            });
+
+        return rt;
+    }
+
+    private static Vector2i GetThumbnailSize(Vector2i textureSize)
+    {
+        const int maxHeight = 50;
+        const int maxWidth = 100;
+
+        var (w, h) = (Vector2)textureSize;
+
+        if (h > maxHeight)
+        {
+            w /= h / maxHeight;
+            h = maxHeight;
+        }
+
+        if (w > maxWidth)
+        {
+            h /= w / maxWidth;
+            w = maxWidth;
+        }
+
+        return new Vector2i((int)w, (int)h);
+    }
+#endif // TOOLS
+}

Robust.Client/UserInterface/IDebugMonitors.cs

@@ -36,5 +36,6 @@ public enum DebugMonitor
     Input,
     Bandwidth,
     Prof,
-    System
+    System,
+    Version
 }

Robust.Client/UserInterface/Tooltips.cs

@@ -21,7 +21,7 @@ namespace Robust.Client.UserInterface
         /// <param name="tooltip">control to position (current size will be used to determine bounds)</param>
         public static void PositionTooltip(Control tooltip)
         {
-            PositionTooltip(tooltip.UserInterfaceManager.RootControl.Size,
+            PositionTooltip(tooltip.Root!.Size,
                 tooltip.UserInterfaceManager.MousePositionScaled.Position,
                 tooltip);
         }

Robust.Client/UserInterface/UIAnimations.cs

@@ -0,0 +1,13 @@
+using System;
+using Robust.Shared.Maths;
+
+namespace Robust.Client.UserInterface;
+
+internal static class UIAnimations
+{
+    // From https://blog.pkh.me/p/41-fixing-the-iterative-damping-interpolation-in-video-games.html
+    public static float LerpAnimate(float a, float b, float dt, float rate)
+    {
+        return MathHelper.Lerp(a, b, 1f - MathF.Exp(-dt * rate));
+    }
+}

Robust.Client/UserInterface/UserInterfaceManager.Input.cs

@@ -333,7 +333,7 @@ internal partial class UserInterfaceManager
 
         if (_suppliedTooltip != null)
         {
-            PopupRoot.RemoveChild(_suppliedTooltip);
+            _suppliedTooltip.Orphan();
             _suppliedTooltip = null;
         }
 
@@ -538,7 +538,7 @@ internal partial class UserInterfaceManager
         if (_showingTooltip) return;
         _showingTooltip = true;
         var hovered = CurrentlyHovered;
-        if (hovered == null)
+        if (hovered == null || hovered.Root == null)
         {
             return;
         }
@@ -563,7 +563,7 @@ internal partial class UserInterfaceManager
         if (_suppliedTooltip == null)
             return;
 
-        PopupRoot.AddChild(_suppliedTooltip);
+        hovered.Root.PopupRoot.AddChild(_suppliedTooltip);
         Tooltips.PositionTooltip(_suppliedTooltip);
         hovered.PerformShowTooltip();
     }

Robust.Client/UserInterface/UserInterfaceManager.cs

@@ -3,10 +3,8 @@ using System.Collections.Generic;
 using System.Numerics;
 using Robust.Client.Graphics;
 using Robust.Client.Input;
-using Robust.Client.Player;
 using Robust.Client.ResourceManagement;
 using Robust.Client.State;
-using Robust.Client.Timing;
 using Robust.Client.UserInterface.Controls;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.UserInterface.CustomControls.DebugMonitorControls;
@@ -20,9 +18,7 @@ using Robust.Shared.Input;
 using Robust.Shared.Input.Binding;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
-using Robust.Shared.Map;
 using Robust.Shared.Maths;
-using Robust.Shared.Network;
 using Robust.Shared.Profiling;
 using Robust.Shared.Prototypes;
 using Robust.Shared.Reflection;
@@ -37,13 +33,9 @@ namespace Robust.Client.UserInterface
         [Dependency] private readonly IInputManager _inputManager = default!;
         [Dependency] private readonly IFontManager _fontManager = default!;
         [Dependency] private readonly IClydeInternal _clyde = default!;
-        [Dependency] private readonly IClientGameTiming _gameTiming = default!;
         [Dependency] private readonly IResourceCache _resourceCache = default!;
-        [Dependency] private readonly IPlayerManager _playerManager = default!;
         [Dependency] private readonly IEyeManager _eyeManager = default!;
         [Dependency] private readonly IStateManager _stateManager = default!;
-        [Dependency] private readonly IClientNetManager _netManager = default!;
-        [Dependency] private readonly IMapManager _mapManager = default!;
         [Dependency] private readonly IPrototypeManager _protoManager = default!;
         [Dependency] private readonly IUserInterfaceManagerInternal _userInterfaceManager = default!;
         [Dependency] private readonly IDynamicTypeFactoryInternal _typeFactory = default!;
@@ -86,10 +78,10 @@ namespace Robust.Client.UserInterface
 
         [ViewVariables] public ViewportContainer MainViewport { get; private set; } = default!;
         [ViewVariables] public LayoutContainer StateRoot { get; private set; } = default!;
-        [ViewVariables] public PopupContainer ModalRoot { get; private set; } = default!;
+        [ViewVariables] public PopupContainer ModalRoot => RootControl.ModalRoot;
         [ViewVariables] public WindowRoot RootControl { get; private set; } = default!;
         [ViewVariables] public LayoutContainer WindowRoot { get; private set; } = default!;
-        [ViewVariables] public LayoutContainer PopupRoot { get; private set; } = default!;
+        [ViewVariables] public LayoutContainer PopupRoot => RootControl.PopupRoot;
         [ViewVariables] public DropDownDebugConsole DebugConsole { get; private set; } = default!;
         [ViewVariables] public IDebugMonitors DebugMonitors => _debugMonitors;
         private DebugMonitors _debugMonitors = default!;
@@ -117,10 +109,11 @@ namespace Robust.Client.UserInterface
 
             DebugConsole = new DropDownDebugConsole();
             RootControl.AddChild(DebugConsole);
-            DebugConsole.SetPositionInParent(ModalRoot.GetPositionInParent());
+            DebugConsole.SetPositionInParent(RootControl.ModalRoot.GetPositionInParent());
 
-            _debugMonitors = new DebugMonitors(_gameTiming, _playerManager, _eyeManager, _inputManager, _stateManager,
-                _clyde, _netManager, _mapManager);
+            _debugMonitors = new DebugMonitors();
+            _rootDependencies.InjectDependencies(_debugMonitors);
+            _debugMonitors.Init();
             DebugConsole.BelowConsole.AddChild(_debugMonitors);
 
             _inputManager.SetInputCommand(EngineKeyFunctions.ShowDebugConsole,
@@ -177,19 +170,7 @@ namespace Robust.Client.UserInterface
             };
             RootControl.AddChild(WindowRoot);
 
-            ModalRoot = new PopupContainer
-            {
-                Name = "ModalRoot",
-                MouseFilter = Control.MouseFilterMode.Ignore,
-            };
-            RootControl.AddChild(ModalRoot);
-
-            PopupRoot = new LayoutContainer
-            {
-                Name = "PopupRoot",
-                MouseFilter = Control.MouseFilterMode.Ignore
-            };
-            RootControl.AddChild(PopupRoot);
+            RootControl.CreateRootControls();
         }
 
         public void InitializeTesting()

Robust.Client/UserInterface/WordWrap.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Diagnostics.Contracts;
 using System.Text;
 using Robust.Client.Graphics;
@@ -36,10 +36,18 @@ internal struct WordWrap
         LastRune = new Rune('A');
     }
 
+    /// <summary>
+    /// Add <paramref name="rune" /> as the next glyph in the sequence and update internal line break state.
+    /// </summary>
+    /// <param name="breakLine">If non-null, indicates that a line break needs to be added at this rune
+    /// index within the string. This index will refer to the offset of a previously-entered rune</param>
+    /// <param name="breakNewLine">If non-null, indicates the rune index of an entered newline</param>
+    /// <param name="skip">If true, indicates that the rune should occupy zero space. Currently only used
+    /// for newlines.</param>
     public void NextRune(Rune rune, out int? breakLine, out int? breakNewLine, out bool skip)
     {
         BreakIndexCounter = NextBreakIndexCounter;
-        NextBreakIndexCounter += rune.Utf16SequenceLength;
+        NextBreakIndexCounter += 1;
 
         breakLine = null;
         breakNewLine = null;

Robust.Client/UserInterface/XAML/Proxy/XamlHotReloadManager.cs

@@ -22,7 +22,7 @@ internal sealed class XamlHotReloadManager : IXamlHotReloadManager
 {
     [Dependency] private readonly IConfigurationManager _cfg = null!;
     [Dependency] private readonly ILogManager _logManager = null!;
-    [Dependency] private readonly IResourceManager _resources = null!;
+    [Dependency] private readonly IResourceManagerInternal _resources = null!;
     [Dependency] private readonly ITaskManager _taskManager = null!;
     [Dependency] private readonly IXamlProxyManager _xamlProxyManager = null!;
 
@@ -120,9 +120,9 @@ internal sealed class XamlHotReloadManager : IXamlHotReloadManager
     private string? InferCodeLocation()
     {
         // ascend upwards from each content root until the solution file is found
-        foreach (var contentRoot in _resources.GetContentRoots())
+        foreach (var baseSystemPath in _resources.GetContentRoots())
         {
-            var systemPath = contentRoot.ToRelativeSystemPath();
+            var systemPath = baseSystemPath;
             while (true)
             {
                 var files = Array.Empty<string>();

Robust.Client/Utility/ClientDllMap.cs

@@ -30,15 +30,6 @@ namespace Robust.Client.Utility
 #endif
                 }
 
-                if (name == SDL.nativeLibName)
-                {
-#if LINUX || FREEBSD
-                    return NativeLibrary.Load("libSDL3.so.0", assembly, path);
-#elif MACOS
-                    return NativeLibrary.Load("libSDL3.0.dylib", assembly, path);
-#endif
-                }
-
                 return IntPtr.Zero;
             });
 

Robust.Client/Utility/ReloadManager.cs

@@ -19,7 +19,7 @@ internal sealed class ReloadManager : IReloadManager
     [Dependency] private readonly IClyde _clyde = default!;
     [Dependency] private readonly IConfigurationManager _cfg = default!;
     [Dependency] private readonly ILogManager _logMan = default!;
-    [Dependency] private readonly IResourceManager _res = default!;
+    [Dependency] private readonly IResourceManagerInternal _res = default!;
 #pragma warning disable CS0414
     [Dependency] private readonly ITaskManager _tasks = default!;
 #pragma warning restore CS0414
@@ -72,7 +72,7 @@ internal sealed class ReloadManager : IReloadManager
 
     public void Register(ResPath directory, string filter)
     {
-        Register(directory.ToString(), filter);
+        Register(directory.ToRelativeSystemPath(), filter);
     }
 
     public void Register(string directory, string filter)
@@ -83,7 +83,7 @@ internal sealed class ReloadManager : IReloadManager
 #if TOOLS
         foreach (var root in _res.GetContentRoots())
         {
-            var path = root + directory;
+            var path = Path.Join(root, directory);
 
             if (!Directory.Exists(path))
             {
@@ -128,17 +128,17 @@ internal sealed class ReloadManager : IReloadManager
 
             _tasks.RunOnMainThread(() =>
             {
-                var fullPath = args.FullPath.Replace(Path.DirectorySeparatorChar, '/');
-                var file = new ResPath(fullPath);
-
                 foreach (var rootIter in _res.GetContentRoots())
                 {
-                    if (!file.TryRelativeTo(rootIter, out var relative))
+                    var relPath = Path.GetRelativePath(rootIter, args.FullPath);
+                    if (relPath == args.FullPath)
                     {
+                        // Not relative.
                         continue;
                     }
 
-                    _reloadQueue.Add(relative.Value);
+                    var file = ResPath.FromRelativeSystemPath(relPath);
+                    _reloadQueue.Add(file);
                 }
             });
         }

Robust.Packaging/RobustServerAssetGraph.cs

@@ -24,8 +24,9 @@ namespace Robust.Packaging;
 ///     PresetPassesCore       --2--> Output
 ///     InputResources         -->    PresetPassesResources
 ///     PresetPassesResources  --1--> AudioMetadata
-///     PresetPassesResources  --2--> NormalizeTextResources
-///     PresetPassesResources  --3--> PrefixResources
+///     PresetPassesResources  --2--> DropAudioFiles
+///     PresetPassesResources  --3--> NormalizeTextResources
+///     PresetPassesResources  --4--> PrefixResources
 ///     AudioMetadata          -->    PrefixResources
 ///     NormalizeTextResources -->    PrefixResources
 ///     PrefixResources        -->    Output
@@ -59,6 +60,17 @@ public sealed class RobustServerAssetGraph
     public AssetPassPipe PresetPassesResources { get; }
     public AssetPassAudioMetadata AudioMetadata { get; }
 
+    /// <summary>
+    /// Used to drop all files in the <c>Audio/</c> directory.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// Most audio files are actually removed by <see cref="AudioMetadata"/>.
+    /// This pass cleans up stuff like attribution files and soundfonts in <c>Audio/MidiCustom</c>.
+    /// </para>
+    /// </remarks>
+    public AssetPassFilterDrop DropAudioFiles { get; }
+
     /// <summary>
     /// Normalizes text files in resources.
     /// </summary>
@@ -103,10 +115,12 @@ public sealed class RobustServerAssetGraph
         PresetPassesResources = new AssetPassPipe { Name = "RobustServerAssetGraphPresetPassesResources" };
         NormalizeTextResources = new AssetPassNormalizeText { Name = "RobustServerAssetGraphNormalizeTextResources" };
         AudioMetadata = new AssetPassAudioMetadata { Name = "RobustServerAssetGraphAudioMetadata" };
+        DropAudioFiles = new AssetPassFilterDrop(p => p.Path.StartsWith("Audio/")) { Name = "RobustServerAssetGraphDropAudioFiles" };
         PrefixResources = new AssetPassPrefix("Resources/") { Name = "RobustServerAssetGraphPrefixResources" };
 
         PresetPassesResources.AddDependency(InputResources);
-        AudioMetadata.AddDependency(PresetPassesResources).AddBefore(NormalizeTextResources);
+        AudioMetadata.AddDependency(PresetPassesResources).AddBefore(DropAudioFiles);
+        DropAudioFiles.AddDependency(PresetPassesResources).AddBefore(NormalizeTextResources);
         NormalizeTextResources.AddDependency(PresetPassesResources).AddBefore(PrefixResources);
         PrefixResources.AddDependency(PresetPassesResources);
         PrefixResources.AddDependency(AudioMetadata);
@@ -124,6 +138,7 @@ public sealed class RobustServerAssetGraph
             NormalizeTextResources,
             AudioMetadata,
             PrefixResources,
+            DropAudioFiles
         };
     }
 }

Robust.Packaging/RobustServerPackaging.cs

@@ -8,7 +8,9 @@ public sealed class RobustServerPackaging
     {
         "Textures",
         "Fonts",
+        "EngineFonts",
         "Shaders",
+        "Midi"
     };
 
     public static async Task WriteServerResources(

Robust.Server/Console/Commands/MapCommands.cs

@@ -102,8 +102,8 @@ namespace Robust.Server.Console.Commands
             var sys = _system.GetEntitySystem<SharedMapSystem>();
             if (!sys.MapExists(mapId))
             {
-                shell.WriteError("Target map does not exist.");
-                return;
+                shell.WriteError($"MapID {intMapId} did not exist, creating without map init");
+                sys.CreateMap(mapId, false); // doesnt runmapinit to be conservative.
             }
 
             Vector2 offset = default;

Robust.Server/GameObjects/EntitySystems/MapSystem.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics.Contracts;
 using System.Linq;
 using Robust.Server.GameStates;
 using Robust.Shared;
@@ -18,13 +19,15 @@ namespace Robust.Server.GameObjects
 
         private bool _deleteEmptyGrids;
 
-        protected override MapId GetNextMapId()
+        [Pure]
+        internal override MapId GetNextMapId()
         {
-            var id = new MapId(++LastMapId);
+            var id = new MapId(LastMapId + 1);
             while (MapExists(id) || UsedIds.Contains(id))
             {
-                id = new MapId(++LastMapId);
+                id = new MapId(id.Value + 1);
             }
+
             return id;
         }
 

Robust.Server/ServerStatus/StatusHost.Acz.cs

@@ -92,7 +92,7 @@ namespace Robust.Server.ServerStatus
             {
                 context.ResponseHeaders.Add("Content-Encoding", "zstd");
 
-                await context.RespondAsync(result.ManifestData, HttpStatusCode.OK);
+                await context.RespondAsync(result.ManifestData, HttpStatusCode.OK, "text/plain; charset=utf-8");
             }
             else
             {
@@ -110,7 +110,7 @@ namespace Robust.Server.ServerStatus
                 }
                 else
                 {
-                    await context.RespondAsync(result.ManifestData, HttpStatusCode.OK);
+                    await context.RespondAsync(result.ManifestData, HttpStatusCode.OK, "text/plain; charset=utf-8");
                 }
             }
 

Robust.Shared.Maths/Matrix3Helpers.cs

@@ -25,11 +25,11 @@ public static class Matrix3Helpers
         return a.EqualsApprox(b, (float) tolerance);
     }
 
-    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    [Obsolete("Use TransformBox")]
+    // This method was previously broken, and now just returns an bounding box pretending to be a Box2Rotated
     public static Box2Rotated TransformBounds(this Matrix3x2 refFromBox, Box2Rotated box)
     {
-        var matty = Matrix3x2.Multiply(refFromBox, box.Transform);
-        return new Box2Rotated(Vector2.Transform(box.BottomLeft, matty), Vector2.Transform(box.TopRight, matty));
+        return new Box2Rotated(TransformBox(refFromBox, box));
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]

Robust.Shared.Maths/Properties/AssemblyInfo.cs

@@ -6,4 +6,3 @@
 
 [assembly: InternalsVisibleTo("Robust.Client")]
 [assembly: InternalsVisibleTo("Robust.UnitTesting")]
-[assembly: InternalsVisibleTo("Content.Benchmarks")]

Robust.Shared/Audio/Systems/SharedAudioSystem.cs

@@ -437,7 +437,7 @@ public abstract partial class SharedAudioSystem : EntitySystem
     protected TimeSpan GetAudioLength(string filename)
     {
         if (!filename.StartsWith('/'))
-            throw new ArgumentException("Path must be rooted");
+            throw new ArgumentException($"Path must be rooted. Path: {filename}");
         return GetAudioLengthImpl(filename);
     }
 

Robust.Shared/CVars.cs

@@ -132,13 +132,13 @@ namespace Robust.Shared
         /// Whether to interpolate between server game states for render frames on the client.
         /// </summary>
         public static readonly CVarDef<bool> NetInterp =
-            CVarDef.Create("net.interp", true, CVar.ARCHIVE | CVar.CLIENTONLY);
+            CVarDef.Create("net.interp", true, CVar.ARCHIVE | CVar.CLIENT | CVar.REPLICATED);
 
         /// <summary>
         /// The target number of game states to keep buffered up to smooth out network inconsistency.
         /// </summary>
         public static readonly CVarDef<int> NetBufferSize =
-            CVarDef.Create("net.buffer_size", 2, CVar.ARCHIVE | CVar.CLIENTONLY);
+            CVarDef.Create("net.buffer_size", 2, CVar.ARCHIVE | CVar.CLIENT | CVar.REPLICATED);
 
         /// <summary>
         /// The maximum size of the game state buffer. If this is exceeded the client will request a full game state.
@@ -1002,6 +1002,15 @@ namespace Robust.Shared
         public static readonly CVarDef<bool> DisplayVSync =
             CVarDef.Create("display.vsync", true, CVar.ARCHIVE | CVar.CLIENTONLY);
 
+        /// <summary>
+        /// Maximum framerate the client should run at. Set to 0 to have no limit.
+        /// </summary>
+        /// <remarks>
+        /// This is ignored if <see cref="DisplayVSync"/> is enabled.
+        /// </remarks>
+        public static readonly CVarDef<int> DisplayMaxFPS =
+            CVarDef.Create("display.max_fps", 0, CVar.ARCHIVE | CVar.CLIENTONLY);
+
         /// <summary>
         /// Window mode for the main game window. 0 = windowed, 1 = fullscreen.
         /// </summary>

Robust.Shared/Console/Commands/MapCommands.cs

@@ -33,9 +33,23 @@ sealed class AddMapCommand : LocalizedEntityCommands
 
         shell.WriteError($"Map with ID {mapId} already exists!");
     }
+
+    public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
+    {
+        switch (args.Length)
+        {
+            case 1:
+                var mapId = _mapSystem.GetNextMapId();
+                return CompletionResult.FromHintOptions([ new CompletionOption($"{mapId}")], LocalizationManager.GetString("generic-mapid"));
+            case 2:
+                return CompletionResult.FromHint(LocalizationManager.GetString("cmd-addmap-hint-2"));
+            default:
+                return CompletionResult.Empty;
+        }
+    }
 }
 
-sealed class RemoveMapCommand : LocalizedCommands
+sealed class RemoveMapCommand : LocalizedEntityCommands
 {
     [Dependency] private readonly IEntitySystemManager _systems = default!;
 
@@ -62,6 +76,14 @@ sealed class RemoveMapCommand : LocalizedCommands
         mapSystem.DeleteMap(mapId);
         shell.WriteLine($"Map {mapId.Value} was removed.");
     }
+
+    public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
+    {
+        if (args.Length != 1)
+            return CompletionResult.Empty;
+
+        return CompletionResult.FromHintOptions(CompletionHelper.MapIds(args[0], entManager: EntityManager), LocalizationManager.GetString("generic-map"));
+    }
 }
 
 sealed class RemoveGridCommand : LocalizedEntityCommands
@@ -88,6 +110,14 @@ sealed class RemoveGridCommand : LocalizedEntityCommands
         EntityManager.DeleteEntity(gridId);
         shell.WriteLine($"Grid {gridId} was removed.");
     }
+
+    public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
+    {
+        if (args.Length != 1)
+            return CompletionResult.Empty;
+
+        return CompletionResult.FromHintOptions(CompletionHelper.Components<MapGridComponent>(args[0], entManager: EntityManager), LocalizationManager.GetString("generic-grid"));
+    }
 }
 
 internal sealed class RunMapInitCommand : LocalizedEntityCommands
@@ -153,7 +183,8 @@ internal sealed class ListMapsCommand : LocalizedEntityCommands
                 string.Join(",", _map.GetAllGrids(mapId).Select(grid => grid.Owner)));
         }
 
-        shell.WriteLine(msg.ToString());
+        // Trim the newline
+        shell.WriteLine(msg.ToString()[..^1]);
     }
 }
 
@@ -183,6 +214,6 @@ internal sealed class ListGridsCommand : LocalizedEntityCommands
                 uid, xform.MapID, uid, worldPos.X, worldPos.Y);
         }
 
-        shell.WriteLine(msg.ToString());
+        shell.WriteLine(msg.ToString()[..^1]);
     }
 }

Robust.Shared/Console/CompletionHelper.cs

@@ -208,11 +208,16 @@ public static class CompletionHelper
         return sorted ? playerOptions.OrderBy(o => o.Value) : playerOptions;
     }
 
+    public static IEnumerable<CompletionOption> MapIds(string text, IEntityManager entManager)
+    {
+        return GetComponents<MapComponent>(text, entManager: entManager).Select(o => new CompletionOption(o.Component.MapId.ToString(), o.EntityName));
+    }
+
     public static IEnumerable<CompletionOption> MapIds(IEntityManager? entManager = null)
     {
         IoCManager.Resolve(ref entManager);
 
-        return entManager.EntityQuery<MapComponent>(true).Select(o => new CompletionOption(o.MapId.ToString()));
+        return entManager.EntityQuery<MapComponent, MetaDataComponent>(true).Select(o => new CompletionOption(o.Item1.MapId.ToString(), o.Item2.EntityName));
     }
 
     public static IEnumerable<CompletionOption> MapUids(IEntityManager? entManager = null)
@@ -245,23 +250,29 @@ public static class CompletionHelper
         }
     }
 
-    public static IEnumerable<CompletionOption> Components<T>(string text, IEntityManager? entManager = null, int limit = 20) where T : IComponent
+    private static IEnumerable<(T Component, string NetString, string EntityName)> GetComponents<T>(string text, IEntityManager entManager, int limit = 20)
+        where T : IComponent
     {
         if (text != string.Empty && !NetEntity.TryParse(text, out _))
             yield break;
 
-        IoCManager.Resolve(ref entManager);
         var query = entManager.AllEntityQueryEnumerator<T, MetaDataComponent>();
 
         var i = 0;
-        while (i < limit && query.MoveNext(out _, out var metadata))
+        while (i < limit && query.MoveNext(out var comp, out var metadata))
         {
             var netString = metadata.NetEntity.ToString();
             if (!netString.StartsWith(text))
                 continue;
 
             i++;
-            yield return new CompletionOption(netString, metadata.EntityName);
+            yield return (comp, netString, metadata.EntityName);
         }
     }
+
+    public static IEnumerable<CompletionOption> Components<T>(string text, IEntityManager? entManager = null, int limit = 20) where T : IComponent
+    {
+        IoCManager.Resolve(ref entManager);
+        return GetComponents<T>(text, entManager, limit).Select(o => new CompletionOption(o.NetString, o.EntityName));
+    }
 }

Robust.Shared/Containers/SharedContainerSystem.cs

@@ -631,7 +631,7 @@ namespace Robust.Shared.Containers
                     continue;
 
                 Remove(ent, container, force: true);
-                Del(ent);
+                PredictedDel(ent);
             }
         }
 

Robust.Shared/ContentPack/AssemblyTypeChecker.Config.cs

@@ -88,6 +88,7 @@ namespace Robust.Shared.ContentPack
             public string SystemAssemblyName = default!;
             public HashSet<VerifierError> AllowedVerifierErrors = default!;
             public List<string> WhitelistedNamespaces = default!;
+            public List<string> AllowedAssemblyPrefixes = default!;
             public Dictionary<string, Dictionary<string, TypeConfig>> Types = default!;
         }
 

Robust.Shared/ContentPack/AssemblyTypeChecker.cs

@@ -131,6 +131,16 @@ namespace Robust.Shared.ContentPack
                 return false;
             }
 
+#pragma warning disable RA0004
+            var loadedConfig = _config.Result;
+#pragma warning restore RA0004
+
+            if (!loadedConfig.AllowedAssemblyPrefixes.Any(allowedNamePrefix => asmName.StartsWith(allowedNamePrefix)))
+            {
+                _sawmill.Error($"Assembly name '{asmName}' is not allowed for a content assembly");
+                return false;
+            }
+
             if (VerifyIL)
             {
                 if (!DoVerifyIL(asmName, resolver, peReader, reader))
@@ -179,10 +189,6 @@ namespace Robust.Shared.ContentPack
                 return true;
             }
 
-#pragma warning disable RA0004
-            var loadedConfig = _config.Result;
-#pragma warning restore RA0004
-
             var badRefs = new ConcurrentBag<EntityHandle>();
 
             // We still do explicit type reference scanning, even though the actual whitelists work with raw members.

Robust.Shared/ContentPack/IResourceManager.cs

@@ -139,6 +139,7 @@ namespace Robust.Shared.ContentPack
         ///     Returns a list of paths to all top-level content directories
         /// </summary>
         /// <returns></returns>
+        [Obsolete("This API is no longer content-accessible")]
         IEnumerable<ResPath> GetContentRoots();
 
         /// <summary>

Robust.Shared/ContentPack/IResourceManagerInternal.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using Robust.Shared.Utility;
@@ -69,5 +70,7 @@ namespace Robust.Shared.ContentPack
         /// </para>
         /// </remarks>
         bool TryGetDiskFilePath(ResPath path, [NotNullWhen(true)] out string? diskPath);
+
+        new IEnumerable<string> GetContentRoots();
     }
 }

Robust.Shared/ContentPack/ModLoader.cs

@@ -93,19 +93,23 @@ namespace Robust.Shared.ContentPack
         {
             var sw = Stopwatch.StartNew();
             Sawmill.Debug("LOADING modules");
-            var files = new Dictionary<string, (ResPath Path, string[] references)>();
+            var files = new Dictionary<string, (ResPath Path, MemoryStream data, string[] references)>();
 
             // Find all modules we want to load.
             foreach (var fullPath in paths)
             {
                 using var asmFile = _res.ContentFileRead(fullPath);
-                var refData = GetAssemblyReferenceData(asmFile);
+                var ms = new MemoryStream();
+                asmFile.CopyTo(ms);
+
+                ms.Position = 0;
+                var refData = GetAssemblyReferenceData(ms);
                 if (refData == null)
                     continue;
 
                 var (asmRefs, asmName) = refData.Value;
 
-                if (!files.TryAdd(asmName, (fullPath, asmRefs)))
+                if (!files.TryAdd(asmName, (fullPath, ms, asmRefs)))
                 {
                     Sawmill.Error("Found multiple modules with the same assembly name " +
                                   $"'{asmName}', A: {files[asmName].Path}, B: {fullPath}.");
@@ -122,10 +126,10 @@ namespace Robust.Shared.ContentPack
 
                 Parallel.ForEach(files, pair =>
                 {
-                    var (name, (path, _)) = pair;
+                    var (name, (_, data, _)) = pair;
 
-                    using var stream = _res.ContentFileRead(path);
-                    if (!typeChecker.CheckAssembly(stream, resolver))
+                    data.Position = 0;
+                    if (!typeChecker.CheckAssembly(data, resolver))
                     {
                         throw new TypeCheckFailedException($"Assembly {name} failed type checks.");
                     }
@@ -137,14 +141,15 @@ namespace Robust.Shared.ContentPack
             var nodes = TopologicalSort.FromBeforeAfter(
                 files,
                 kv => kv.Key,
-                kv => kv.Value.Path,
+                kv => kv.Value,
                 _ => Array.Empty<string>(),
                 kv => kv.Value.references,
                 allowMissing: true); // missing refs would be non-content assemblies so allow that.
 
             // Actually load them in the order they depend on each other.
-            foreach (var path in TopologicalSort.Sort(nodes))
+            foreach (var item in TopologicalSort.Sort(nodes))
             {
+                var (path, memory, _) = item;
                 Sawmill.Debug($"Loading module: '{path}'");
                 try
                 {
@@ -156,9 +161,9 @@ namespace Robust.Shared.ContentPack
                     }
                     else
                     {
-                        using var assemblyStream = _res.ContentFileRead(path);
+                        memory.Position = 0;
                         using var symbolsStream = _res.ContentFileReadOrNull(path.WithExtension("pdb"));
-                        LoadGameAssembly(assemblyStream, symbolsStream, skipVerify: true);
+                        LoadGameAssembly(memory, symbolsStream, skipVerify: true);
                     }
                 }
                 catch (Exception e)
@@ -174,7 +179,7 @@ namespace Robust.Shared.ContentPack
 
         private (string[] refs, string name)? GetAssemblyReferenceData(Stream stream)
         {
-            using var reader = ModLoader.MakePEReader(stream);
+            using var reader = ModLoader.MakePEReader(stream, leaveOpen: true);
             var metaReader = reader.GetMetadataReader();
 
             var name = metaReader.GetString(metaReader.GetAssemblyDefinition().Name);

Robust.Shared/ContentPack/ResourceManager.cs

@@ -371,20 +371,19 @@ namespace Robust.Shared.ContentPack
             AddRoot(ResPath.Root, loader);
         }
 
-        public IEnumerable<ResPath> GetContentRoots()
+        IEnumerable<ResPath> IResourceManager.GetContentRoots()
+        {
+            return [];
+        }
+
+        public IEnumerable<string> GetContentRoots()
         {
             foreach (var (_, root) in _contentRoots)
             {
-                if (root is DirLoader loader)
-                {
-                    var rootDir = loader.GetPath(new ResPath(@"/"));
+                if (root is not DirLoader loader)
+                    continue;
 
-                    // TODO: GET RID OF THIS.
-                    // This code shouldn't be passing OS disk paths through ResPath.
-                    rootDir = rootDir.Replace(Path.DirectorySeparatorChar, '/');
-
-                    yield return new ResPath(rootDir);
-                }
+                yield return loader.GetPath(ResPath.Root);
             }
         }
 

Robust.Shared/ContentPack/Sandbox.yml

@@ -17,6 +17,10 @@ WhitelistedNamespaces:
 - Content
 - OpenDreamShared
 
+AllowedAssemblyPrefixes:
+- OpenDream
+- Content
+
 # The type whitelist does NOT care about which assembly types come from.
 # This is because types switch assembly all the time.
 # Just look up stuff like StreamReader on https://apisof.net.
@@ -529,6 +533,7 @@ Types:
       - "string ToTitleCase(string)"
       - "string ToTitleCase(string)"
       - "string ToUpper(string)"
+    UnicodeCategory: { } # Enum
   System.IO.Compression:
     CompressionMode: { } # Enum
     CompressionLevel: { } # Enum
@@ -1559,6 +1564,11 @@ Types:
     ValueType: { All: True }
     Version: { All: True }
     Void: { All: True }
+    WeakReference`1:
+      Methods:
+      - "void .ctor(!0)"
+      - "bool TryGetTarget(ref !0)"
+      - "void SetTarget(!0)"
   YamlDotNet.Core.Events:
     MappingStyle: { } # Enum
     SequenceStyle: { } # Enum
@@ -1608,3 +1618,7 @@ Types:
     SourcePos: { }
   Pidgin.Configuration:
     IConfiguration`1: { All: True }
+  SpaceWizards.Sodium:
+    CryptoGenericHashBlake2B:
+      Methods:
+      - "byte[] Hash(int, System.ReadOnlySpan`1<byte>, System.ReadOnlySpan`1<byte>)"

Robust.Shared/EntitySerialization/EntityDeserializer.cs

@@ -685,38 +685,38 @@ public sealed class EntityDeserializer :
 
         foreach (var yamlId in MapYamlIds)
         {
-            var uid = UidMap[yamlId];
-            if (_mapQuery.TryComp(uid, out var map))
+            if (UidMap.TryGetValue(yamlId, out var uid) && _mapQuery.TryComp(uid, out var map))
             {
                 Result.Maps.Add((uid, map));
                 EntMan.EnsureComponent<LoadedMapComponent>(uid);
             }
             else
-                _log.Error($"Missing map entity: {EntMan.ToPrettyString(uid)}");
+                _log.Error($"Missing map entity: {EntMan.ToPrettyString(uid)}. YamlId: {yamlId}");
         }
 
         foreach (var yamlId in GridYamlIds)
         {
-            var uid = UidMap[yamlId];
-            if (_gridQuery.TryComp(uid, out var grid))
+            if (UidMap.TryGetValue(yamlId, out var uid) && _gridQuery.TryComp(uid, out var grid))
                 Result.Grids.Add((uid, grid));
             else
-                _log.Error($"Missing grid entity: {EntMan.ToPrettyString(uid)}");
+                _log.Error($"Missing grid entity: {EntMan.ToPrettyString(uid)}. YamlId: {yamlId}");
         }
 
         foreach (var yamlId in OrphanYamlIds)
         {
-            var uid = UidMap[yamlId];
-            if (_mapQuery.HasComponent(uid) || _xformQuery.Comp(uid).ParentUid.IsValid())
-                _log.Error($"Entity {EntMan.ToPrettyString(uid)} was incorrectly labelled as an orphan?");
+            if (!UidMap.TryGetValue(yamlId, out var uid))
+                _log.Error($"Missing orphan entity with YamlId: {yamlId}");
+            else if (_mapQuery.HasComponent(uid) || _xformQuery.Comp(uid).ParentUid.IsValid())
+                _log.Error($"Entity {EntMan.ToPrettyString(uid)} was incorrectly labelled as an orphan? YamlId: {yamlId}");
             else
                 Result.Orphans.Add(uid);
         }
 
         foreach (var yamlId in NullspaceYamlIds)
         {
-            var uid = UidMap[yamlId];
-            if (_mapQuery.HasComponent(uid) || _xformQuery.Comp(uid).ParentUid.IsValid())
+            if (!UidMap.TryGetValue(yamlId, out var uid))
+                _log.Error($"Missing nullspace entity with YamlId: {yamlId}");
+            else if (_mapQuery.HasComponent(uid) || _xformQuery.Comp(uid).ParentUid.IsValid())
                 _log.Error($"Entity {EntMan.ToPrettyString(uid)} was incorrectly labelled as a null-space entity?");
             else
                 Result.NullspaceEntities.Add(uid);
@@ -1152,6 +1152,7 @@ public sealed class EntityDeserializer :
         ISerializationContext? context,
         ISerializationManager.InstantiationDelegate<EntityUid>? _)
     {
+        string msg;
         if (node.Value == "invalid")
         {
             if (CurrentComponent == "Transform")
@@ -1160,7 +1161,7 @@ public sealed class EntityDeserializer :
             if (!Options.LogInvalidEntities)
                 return EntityUid.Invalid;
 
-            var msg = CurrentReadingEntity is not { } curr
+            msg = CurrentReadingEntity is not { } curr
                 ? $"Encountered invalid EntityUid reference"
                 : $"Encountered invalid EntityUid reference wile reading entity {curr.YamlId}, component: {CurrentComponent}";
             _log.Error(msg);
@@ -1170,7 +1171,10 @@ public sealed class EntityDeserializer :
         if (int.TryParse(node.Value, out var val) && UidMap.TryGetValue(val, out var entity))
             return entity;
 
-        _log.Error($"Invalid yaml entity id: '{val}'");
+        msg = CurrentReadingEntity is not { } ent
+            ? "Encountered unknown entity yaml uid"
+            : $"Encountered unknown entity yaml uid wile reading entity {ent.YamlId}, component: {CurrentComponent}";
+        _log.Error(msg);
         return EntityUid.Invalid;
     }
 

Robust.Shared/EntitySerialization/EntitySerializer.cs

@@ -110,6 +110,11 @@ public sealed class EntitySerializer : ISerializationContext,
     /// </summary>
     public readonly Dictionary<string, List<int>> Prototypes = new();
 
+    /// <summary>
+    /// Set of entities that have encountered issues during serialization and are now being ignored.
+    /// </summary>
+    public HashSet<EntityUid> ErroringEntities = new();
+
     /// <summary>
     /// Yaml ids of all serialized map entities.
     /// </summary>
@@ -412,7 +417,7 @@ public sealed class EntitySerializer : ISerializationContext,
 
         // It might be possible that something could cause an entity to be included twice.
         // E.g., if someone serializes a grid w/o its map, and then tries to separately include the map and all its children.
-        // In that case, the grid would already have been serialized as a orphan.
+        // In that case, the grid would already have been serialized as an orphan.
         // uhhh.... I guess its fine?
         if (EntityData.ContainsKey(saveId))
             return;
@@ -489,6 +494,95 @@ public sealed class EntitySerializer : ISerializationContext,
             xform._localRotation = 0;
         }
 
+        try
+        {
+            SerializeComponents(uid, cache, components);
+        }
+        catch(Exception e)
+        {
+            if (Options.EntityExceptionBehaviour == EntityExceptionBehaviour.Rethrow)
+            {
+                _log.Error($"Caught exception while serializing component {CurrentComponent} of entity {EntMan.ToPrettyString(uid)}");
+                throw;
+            }
+
+            _log.Error($"Caught exception while serializing component {CurrentComponent} of entity {EntMan.ToPrettyString(uid)}:\n{e}");
+            CurrentEntityYamlUid = 0;
+            CurrentEntity = null;
+            CurrentComponent = null;
+            RemoveErroringEntity(uid);
+            return;
+        }
+
+        CurrentComponent = null;
+        if (components.Count != 0)
+            entData.Add("components", components);
+
+        // TODO ENTITY SERIALIZATION
+        // Consider adding a Action<EntityUid, MappingDataNode>? OnEntitySerialized
+        // I.e., allow content to modify the per-entity data? I don't know if that would actually be useful, as content
+        // could just as easily append a separate entity dictionary to the output that has the extra per-entity data they
+        // want to serialize.
+
+        if (meta.EntityPrototype == null)
+        {
+            CurrentEntityYamlUid = 0;
+            CurrentEntity = null;
+            return;
+        }
+
+        // an entity may have fewer components than the original prototype, so we need to check if any are missing.
+        SequenceDataNode? missingComponents = null;
+        foreach (var (name, comp) in meta.EntityPrototype.Components)
+        {
+            // try comp instead of has-comp as it checks whether the component is supposed to have been
+            // deleted.
+            if (EntMan.TryGetComponent(uid, comp.Component.GetType(), out _))
+                continue;
+
+            missingComponents ??= new();
+            missingComponents.Add(new ValueDataNode(name));
+        }
+
+        if (missingComponents != null)
+            entData.Add("missingComponents", missingComponents);
+
+        CurrentEntityYamlUid = 0;
+        CurrentEntity = null;
+    }
+
+    /// <summary>
+    /// Remove an exception throwing entity (and possibly its children) from the serialized data.
+    /// </summary>
+    private void RemoveErroringEntity(EntityUid uid)
+    {
+        if (Options.EntityExceptionBehaviour == EntityExceptionBehaviour.IgnoreEntityAndChildren)
+        {
+            foreach (var child in _xformQuery.GetComponent(uid)._children)
+            {
+                RemoveErroringEntity(child);
+            }
+        }
+
+        ErroringEntities.Add(uid);
+        if (!YamlUidMap.TryGetValue(uid, out var yamlId))
+            return;
+
+        Nullspace.Remove(yamlId);
+        Orphans.Remove(yamlId);
+        Maps.Remove(yamlId);
+        Grids.Remove(yamlId);
+        EntityData.Remove(yamlId);
+        if (_metaQuery.TryGetComponent(uid, out var meta)
+            && meta.EntityPrototype != null
+            && Prototypes.TryGetValue(meta.EntityPrototype.ID, out var proto))
+        {
+            proto.Remove(yamlId);
+        }
+    }
+
+    private void SerializeComponents(EntityUid uid, Dictionary<string, MappingDataNode>? cache, SequenceDataNode components)
+    {
         foreach (var component in EntMan.GetComponentsInternal(uid))
         {
             var compType = component.GetType();
@@ -523,48 +617,12 @@ public sealed class EntitySerializer : ISerializationContext,
             // Don't need to write it if nothing was written! Note that if this entity has no associated
             // prototype, we ALWAYS want to write the component, because merely the fact that it exists is
             // information that needs to be written.
-            if (compMapping.Children.Count != 0 || protoMapping == null)
-            {
-                compMapping.InsertAt(0, "type", new ValueDataNode(reg.Name));
-                components.Add(compMapping);
-            }
-        }
-
-        CurrentComponent = null;
-        if (components.Count != 0)
-            entData.Add("components", components);
-
-        // TODO ENTITY SERIALIZATION
-        // Consider adding a Action<EntityUid, MappingDataNode>? OnEntitySerialized
-        // I.e., allow content to modify the per-entity data? I don't know if that would actually be useful, as content
-        // could just as easily append a separate entity dictionary to the output that has the extra per-entity data they
-        // want to serialize.
-
-        if (meta.EntityPrototype == null)
-        {
-            CurrentEntityYamlUid = 0;
-            CurrentEntity = null;
-            return;
-        }
-
-        // an entity may have less components than the original prototype, so we need to check if any are missing.
-        SequenceDataNode? missingComponents = null;
-        foreach (var (name, comp) in meta.EntityPrototype.Components)
-        {
-            // try comp instead of has-comp as it checks whether the component is supposed to have been
-            // deleted.
-            if (EntMan.TryGetComponent(uid, comp.Component.GetType(), out _))
+            if (compMapping.Children.Count == 0 && protoMapping != null)
                 continue;
 
-            missingComponents ??= new();
-            missingComponents.Add(new ValueDataNode(name));
+            compMapping.InsertAt(0, "type", new ValueDataNode(reg.Name));
+            components.Add(compMapping);
         }
-
-        if (missingComponents != null)
-            entData.Add("missingComponents", missingComponents);
-
-        CurrentEntityYamlUid = 0;
-        CurrentEntity = null;
     }
 
     private Dictionary<string, MappingDataNode>? GetProtoCache(EntityPrototype? proto)
@@ -656,7 +714,10 @@ public sealed class EntitySerializer : ISerializationContext,
 
     public SequenceDataNode WriteEntitySection()
     {
-        if (YamlIds.Count != YamlUidMap.Count || YamlIds.Count != EntityData.Count)
+        // Check that EntityData contains the expected number of entities.
+        if (Options.EntityExceptionBehaviour != EntityExceptionBehaviour.IgnoreEntity
+            && Options.EntityExceptionBehaviour != EntityExceptionBehaviour.IgnoreEntityAndChildren
+            && (YamlIds.Count != YamlUidMap.Count || YamlIds.Count != EntityData.Count))
         {
             // Maybe someone reserved a yaml id with ReserveYamlId() or implicitly with GetId() without actually
             // ever serializing the entity, This can lead to references to non-existent entities.
@@ -878,6 +939,7 @@ public sealed class EntitySerializer : ISerializationContext,
         if (YamlUidMap.TryGetValue(value, out var yamlId))
             return new ValueDataNode(yamlId.ToString(CultureInfo.InvariantCulture));
 
+
         if (CurrentComponent == _xformName)
         {
             if (value == EntityUid.Invalid)
@@ -886,12 +948,18 @@ public sealed class EntitySerializer : ISerializationContext,
             DebugTools.Assert(!Orphans.Contains(CurrentEntityYamlUid));
             Orphans.Add(CurrentEntityYamlUid);
 
-            if (Options.ErrorOnOrphan && CurrentEntity != null && value != Truncate)
+            if (Options.ErrorOnOrphan && CurrentEntity != null && value != Truncate && !ErroringEntities.Contains(value))
                 _log.Error($"Serializing entity {EntMan.ToPrettyString(CurrentEntity)} without including its parent {EntMan.ToPrettyString(value)}");
 
             return new ValueDataNode("invalid");
         }
 
+        if (ErroringEntities.Contains(value))
+        {
+            // Referenced entity already logged an error, so we just silently fail.
+            return new ValueDataNode("invalid");
+        }
+
         if (value == EntityUid.Invalid)
         {
             if (Options.MissingEntityBehaviour != MissingEntityBehaviour.Ignore)

Robust.Shared/EntitySerialization/Options.cs

@@ -1,5 +1,4 @@
 using System.Numerics;
-using JetBrains.Annotations;
 using Robust.Shared.EntitySerialization.Components;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Log;
@@ -21,7 +20,13 @@ public record struct SerializationOptions
     public MissingEntityBehaviour MissingEntityBehaviour = MissingEntityBehaviour.IncludeNullspace;
 
     /// <summary>
-    /// Whether or not to log an error when serializing an entity without its parent.
+    /// What to do when an exception is thrown while trying to serialize an entity. The default behaviour is to abort
+    /// the serialization.
+    /// </summary>
+    public EntityExceptionBehaviour EntityExceptionBehaviour = EntityExceptionBehaviour.Rethrow;
+
+    /// <summary>
+    /// Whether to log an error when serializing an entity without its parent.
     /// </summary>
     public bool ErrorOnOrphan = true;
 

Robust.Shared/EntitySerialization/SerializationEnums.cs

@@ -86,3 +86,33 @@ public enum MissingEntityBehaviour
     /// </summary>
     AutoInclude,
 }
+
+
+public enum EntityExceptionBehaviour
+{
+    /// <summary>
+    /// Re-throw the exception, interrupting the serialization.
+    /// </summary>
+    Rethrow,
+
+    /// <summary>
+    /// Continue serializing and simply skip/ignore this entity. May result in broken maps that log errors or simply
+    /// fail to load.
+    /// </summary>
+    IgnoreEntity,
+
+    /// <summary>
+    /// Continue serializing and simply skip/ignore this entity and all of its children.
+    /// May result in broken maps that log errors or simply fail to load.
+    /// </summary>
+    IgnoreEntityAndChildren,
+
+    // TODO SERIALIZATION
+    /*
+    /// <summary>
+    /// Continue the serialization while skipping over the component that caused the exception to be thrown. May result
+    /// in broken maps that log errors or simply fail to load.
+    /// </summary>
+    IgnoreComponent,
+    */
+}

Robust.Shared/EntitySerialization/Systems/MapLoaderSystem.Load.cs

@@ -110,7 +110,7 @@ public sealed partial class MapLoaderSystem
 
         // Using a local deserializer instead of a cached value, both to ensure that we don't accidentally carry over
         // data from a previous serializations, and because some entities cause other maps/grids to be loaded during
-        // during mapinit.
+        // mapinit.
         var deserializer = new EntityDeserializer(
             _dependency,
             data,
@@ -124,6 +124,17 @@ public sealed partial class MapLoaderSystem
             return false;
         }
 
+        // If the file isn't of the expected category, stop before we ever create any entities.
+        if (opts.ExpectedCategory is { } expected
+            && expected != deserializer.Result.Category
+            && deserializer.Result.Category != FileCategory.Unknown)
+        {
+            // Did someone try to load a map file as a grid or vice versa?
+            Log.Error($"Map {fileName} does not contain the expected data. Expected {expected} but got {deserializer.Result.Category}");
+            Delete(deserializer.Result);
+            return false;
+        }
+
         try
         {
             deserializer.CreateEntities();
@@ -135,6 +146,8 @@ public sealed partial class MapLoaderSystem
             throw;
         }
 
+        // If the map file was an older version, the category has to be inferred from the file's contents in CreateEntities()
+        // Hence the category is checked again here.
         if (opts.ExpectedCategory is { } exp && exp != deserializer.Result.Category)
         {
             // Did someone try to load a map file as a grid or vice versa?

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

@@ -14,6 +14,10 @@ public sealed class PointLightComponentState : ComponentState
 
     public float Softness;
 
+    public float Falloff;
+
+    public float CurveFactor;
+
     public bool CastShadows;
 
     public bool Enabled;

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

@@ -6,6 +6,7 @@ using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.ViewVariables;
 using System.Numerics;
 using Robust.Shared.IoC;
+using Robust.Shared.Serialization;
 
 namespace Robust.Shared.GameObjects
 {
@@ -33,6 +34,39 @@ namespace Robust.Shared.GameObjects
         [DataField("softness"), Animatable]
         public float Softness { get; set; } = 1f;
 
+        /// <summary>
+        ///     Controls how quickly the light falls off in power in its radius.
+        ///     A higher value means a stronger falloff.
+        /// </summary>
+        /// <remarks>
+        ///     The default value of 6.8 might seem suspect, but that's because this is a value which was introduced
+        ///     years after SS14 already standardized its light values using an older attenuation curve, and this was the value
+        ///     which, qualitatively, seemed about equivalent in brightness for the large majority of lights on the station
+        ///     compared to the old function.
+        ///
+        ///     See https://www.desmos.com/calculator/yjudaha0s6 for a demonstration of how this value affects the shape of the curve
+        ///     for different light radii and curve factors.
+        /// </remarks>
+        [DataField, Animatable]
+        public float Falloff { get; set; } = 6.8f;
+
+        /// <summary>
+        ///     Controls the shape of the curve used for point light attenuation.
+        ///     This value may vary between 0 and 1.
+        ///     A value of 0 gives a shape roughly equivalent to 1/1+distance (more or less realistic),
+        ///     while a value of 1 gives a shape roughly equivalent to 1+distance^2 (closer to a sphere-shaped light)
+        /// </summary>
+        /// <remarks>
+        ///     This does not directly control the exponent of the denominator, though it might seem that way.
+        ///     Rather, it just lerps between an inverse-shaped curve and an inverse-quadratic-shaped curve.
+        ///     Values below 0 or above 1 are nonsensical.
+        ///
+        ///     See https://www.desmos.com/calculator/yjudaha0s6 for a demonstration of how this value affects the shape of the curve
+        ///     for different light radii and falloff values.
+        /// </remarks>
+        [DataField, Animatable]
+        public float CurveFactor { get; set; } = 0.0f;
+
         /// <summary>
         ///     Whether this pointlight should cast shadows
         /// </summary>

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

@@ -49,6 +49,7 @@ public sealed partial class PrototypeLayerData
     [DataField] public PrototypeCopyToShaderParameters? CopyToShaderParameters;
 
     [DataField] public bool Cycle;
+    [DataField] public bool Loop = true;
 }
 
 /// <summary>