Remove explosion networking jank (#12733)

Content.Client/Explosion/ExplosionOverlay.cs

@@ -1,3 +1,4 @@
+using Content.Shared.Explosion;
 using JetBrains.Annotations;
 using Robust.Client.Graphics;
 using Robust.Shared.Enums;
@@ -10,26 +11,10 @@ namespace Content.Client.Explosion;
 [UsedImplicitly]
 public sealed class ExplosionOverlay : Overlay
 {
-    /// <summary>
-    ///     The explosion that needs to be drawn. This explosion is currently being processed by the server and
-    ///     expanding outwards.
-    /// </summary>
-    internal Explosion? ActiveExplosion;
-
-    /// <summary>
-    ///     This index specifies what parts of the currently expanding explosion should be drawn.
-    /// </summary>
-    public int Index;
-
-    /// <summary>
-    ///     These explosions have finished expanding, but we will draw for a few more frames. This is important for
-    ///     small explosions, as otherwise they disappear far too quickly.
-    /// </summary>
-    internal List<Explosion> CompletedExplosions = new ();
-
     [Dependency] private readonly IRobustRandom _robustRandom = default!;
     [Dependency] private readonly IMapManager _mapManager = default!;
     [Dependency] private readonly IEntityManager _entMan = default!;
+    [Dependency] private readonly IPrototypeManager _proto = default!;
 
     public override OverlaySpace Space => OverlaySpace.WorldSpaceBelowFOV;
 
@@ -38,7 +23,7 @@ public sealed class ExplosionOverlay : Overlay
     public ExplosionOverlay()
     {
         IoCManager.InjectDependencies(this);
-        _shader = IoCManager.Resolve<IPrototypeManager>().Index<ShaderPrototype>("unshaded").Instance();
+        _shader = _proto.Index<ShaderPrototype>("unshaded").Instance();
     }
 
     protected override void Draw(in OverlayDrawArgs args)
@@ -48,22 +33,20 @@ public sealed class ExplosionOverlay : Overlay
 
         var xforms = _entMan.GetEntityQuery<TransformComponent>();
 
-        if (ActiveExplosion != null && ActiveExplosion.Map == args.Viewport.Eye?.Position.MapId)
+        foreach (var (comp, appearance) in _entMan.EntityQuery<ExplosionVisualsComponent, AppearanceComponent>(true))
         {
-            DrawExplosion(drawHandle, args.WorldBounds, ActiveExplosion, Index, xforms);
+            if (!appearance.TryGetData(ExplosionAppearanceData.Progress, out int index))
-        }
+                continue;
 
-        foreach (var exp in CompletedExplosions)
+            index = Math.Min(index, comp.Intensity.Count - 1);
-        {
+            DrawExplosion(drawHandle, args.WorldBounds, comp, index, xforms);
-            if (exp.Map == args.Viewport.Eye?.Position.MapId)
-                DrawExplosion(drawHandle, args.WorldBounds, exp, exp.Intensity.Count, xforms);
         }
 
         drawHandle.SetTransform(Matrix3.Identity);
         drawHandle.UseShader(null);
     }
 
-    private void DrawExplosion(DrawingHandleWorld drawHandle, Box2Rotated worldBounds, Explosion exp, int index, EntityQuery<TransformComponent> xforms)
+    private void DrawExplosion(DrawingHandleWorld drawHandle, Box2Rotated worldBounds, ExplosionVisualsComponent exp, int index, EntityQuery<TransformComponent> xforms)
     {
         Box2 gridBounds;
         foreach (var (gridId, tiles) in exp.Tiles)
@@ -94,10 +77,10 @@ public sealed class ExplosionOverlay : Overlay
         Box2 gridBounds,
         int index,
         Dictionary<int, List<Vector2i>> tileSets,
-        Explosion exp,
+        ExplosionVisualsComponent exp,
         ushort tileSize)
     {
-        for (var j = 0; j < index; j++)
+        for (var j = 0; j <= index; j++)
         {
             if (!tileSets.TryGetValue(j, out var tiles))
                 continue;

Content.Client/Explosion/ExplosionOverlaySystem.cs

@@ -1,11 +1,8 @@
-using Content.Shared.CCVar;
 using Content.Shared.Explosion;
-using Content.Shared.GameTicking;
 using Robust.Client.GameObjects;
 using Robust.Client.Graphics;
 using Robust.Client.ResourceManagement;
-using Robust.Shared.Configuration;
+using Robust.Shared.GameStates;
-using Robust.Shared.Map;
 using Robust.Shared.Prototypes;
 
 namespace Content.Client.Explosion;
@@ -16,12 +13,9 @@ namespace Content.Client.Explosion;
 /// </summary>
 public sealed class ExplosionOverlaySystem : EntitySystem
 {
-    private ExplosionOverlay _overlay = default!;
-
     [Dependency] private readonly IPrototypeManager _protoMan = default!;
-    [Dependency] private readonly IMapManager _mapMan = default!;
     [Dependency] private readonly IResourceCache _resCache = default!;
-    [Dependency] private readonly IConfigurationManager _cfg = default!;
+    [Dependency] private readonly IOverlayManager _overlayMan = default!;
 
     /// <summary>
     ///     For how many seconds should an explosion stay on-screen once it has finished expanding?
@@ -32,209 +26,57 @@ public sealed class ExplosionOverlaySystem : EntitySystem
     {
         base.Initialize();
 
-        SubscribeNetworkEvent<ExplosionEvent>(OnExplosion);
+        SubscribeLocalEvent<ExplosionVisualsComponent, ComponentInit>(OnExplosionInit);
-        SubscribeNetworkEvent<ExplosionOverlayUpdateEvent>(HandleExplosionUpdate);
+        SubscribeLocalEvent<ExplosionVisualsComponent, ComponentRemove>(OnCompRemove);
-        SubscribeLocalEvent<MapChangedEvent>(OnMapChanged);
+        SubscribeLocalEvent<ExplosionVisualsComponent, ComponentHandleState>(OnExplosionHandleState);
-        SubscribeAllEvent<RoundRestartCleanupEvent>(OnReset);
+        _overlayMan.AddOverlay(new ExplosionOverlay());
-
-        _cfg.OnValueChanged(CCVars.ExplosionPersistence, SetExplosionPersistence, true);
-
-        var overlayManager = IoCManager.Resolve<IOverlayManager>();
-        _overlay = new ExplosionOverlay();
-        if (!overlayManager.HasOverlay<ExplosionOverlay>())
-            overlayManager.AddOverlay(_overlay);
     }
 
-    private void OnReset(RoundRestartCleanupEvent ev)
+    private void OnExplosionHandleState(EntityUid uid, ExplosionVisualsComponent component, ref ComponentHandleState args)
     {
-        // Not sure if round restart cleans up client-side entities, but better safe than sorry.
+        if (args.Current is not ExplosionVisualsState state)
-        foreach (var exp in _overlay.CompletedExplosions)
+            return;
-        {
+
-            QueueDel(exp.LightEntity);
+        component.Epicenter = state.Epicenter;
-        }
+        component.SpaceTiles = state.SpaceTiles;
-        if (_overlay.ActiveExplosion != null)
+        component.Tiles = state.Tiles;
-            QueueDel(_overlay.ActiveExplosion.LightEntity);
+        component.Intensity = state.Intensity;
-        
+        component.ExplosionType = state.ExplosionType;
-        _overlay.CompletedExplosions.Clear();
+        component.SpaceMatrix = state.SpaceMatrix;
-        _overlay.ActiveExplosion = null;
+        component.SpaceTileSize = state.SpaceTileSize;
-        _overlay.Index = 0;
     }
 
-    private void OnMapChanged(MapChangedEvent ev)
+    private void OnCompRemove(EntityUid uid, ExplosionVisualsComponent component, ComponentRemove args)
     {
-        if (ev.Created)
+        QueueDel(component.LightEntity);
-            return;
-
-        if (_overlay.ActiveExplosion?.Map == ev.Map)
-            _overlay.ActiveExplosion = null;
-
-        _overlay.CompletedExplosions.RemoveAll(exp => exp.Map == ev.Map);
     }
 
-    private void SetExplosionPersistence(float value) => ExplosionPersistence = value;
+    private void OnExplosionInit(EntityUid uid, ExplosionVisualsComponent component, ComponentInit args)
-
-    public override void FrameUpdate(float frameTime)
     {
-        base.FrameUpdate(frameTime);
+        if (!_protoMan.TryIndex(component.ExplosionType, out ExplosionPrototype? type))
-
-        // increment the lifetime of completed explosions, and remove them if they have been ons screen for more
-        // than ExplosionPersistence seconds
-        for (int i = _overlay.CompletedExplosions.Count - 1; i>= 0; i--) 
-        {
-            var explosion = _overlay.CompletedExplosions[i];
-
-            if (_mapMan.IsMapPaused(explosion.Map))
-                continue;
-
-            explosion.Lifetime += frameTime;
-
-            if (explosion.Lifetime >= ExplosionPersistence)
-            {
-                EntityManager.QueueDeleteEntity(explosion.LightEntity);
-
-                // Remove-swap
-                _overlay.CompletedExplosions[i] = _overlay.CompletedExplosions[^1];
-                _overlay.CompletedExplosions.RemoveAt(_overlay.CompletedExplosions.Count - 1);
-            }
-        }
-    }
-
-    /// <summary>
-    ///     The server has processed some explosion. This updates the client-side overlay so that the area covered
-    ///     by the fire-visual matches up with the area that the explosion has affected.
-    /// </summary>
-    private void HandleExplosionUpdate(ExplosionOverlayUpdateEvent args)
-    {
-        if (args.ExplosionId != _overlay.ActiveExplosion?.Explosionid && !IsNewer(args.ExplosionId))
-        {
-            // out of order events. Ignore.
-            return;
-        }
-
-        _overlay.Index = args.Index;
-
-        if (_overlay.ActiveExplosion == null)
-        {
-            // no active explosion... events out of order?
-            return;
-        }
-
-        if (args.Index != int.MaxValue)
             return;
 
-        // the explosion has finished expanding
+        // spawn in a client-side light source at the epicenter
-        _overlay.Index = 0;
+        var lightEntity = Spawn("ExplosionLight", component.Epicenter);
-        _overlay.CompletedExplosions.Add(_overlay.ActiveExplosion);
-        _overlay.ActiveExplosion = null;
-    }
-
-    /// <summary>
-    ///     A new explosion occurred. This prepares the client-side light entity and stores the
-    ///     explosion/fire-effect overlay data.
-    /// </summary>
-    private void OnExplosion(ExplosionEvent args)
-    {
-        if (!_protoMan.TryIndex(args.TypeID, out ExplosionPrototype? type))
-            return;
-
-        // spawn in a light source at the epicenter
-        var lightEntity = Spawn("ExplosionLight", args.Epicenter);
         var light = EnsureComp<PointLightComponent>(lightEntity);
-        light.Energy = light.Radius = args.Intensity.Count;
+        light.Energy = light.Radius = component.Intensity.Count;
         light.Color = type.LightColor;
+        component.LightEntity = lightEntity;
+        component.FireColor = type.FireColor;
+        component.IntensityPerState = type.IntensityPerState;
 
-        if (_overlay.ActiveExplosion == null)
+        var fireRsi = _resCache.GetResource<RSIResource>(type.TexturePath).RSI;
+        foreach (var state in fireRsi)
         {
-            _overlay.ActiveExplosion = new(args, type, lightEntity, _resCache);
+            component.FireFrames.Add(state.GetFrames(RSI.State.Direction.South));
-            return;
+            if (component.FireFrames.Count == type.FireStates)
+                break;
         }
-
-        // we have a currently active explosion. Can happen when events are received out of order. either multiple
-        // explosions are happening in one tick, or a new explosion was received before the event telling us the old one
-        // finished got through.
-
-        if (IsNewer(args.ExplosionId))
-        {
-            // This is a newer explosion. Add the old-currently-active explosions to the completed list
-            _overlay.CompletedExplosions.Add(_overlay.ActiveExplosion);
-            _overlay.ActiveExplosion = new(args, type, lightEntity, _resCache);
-        }
-        else
-        {
-            // explosions were out of order. keep the active one, and directly add the received one to the completed
-            // list.
-            _overlay.CompletedExplosions.Add(new(args, type, lightEntity, _resCache));
-            return;
-        }
-    }
-
-    public bool IsNewer(int explosionId)
-    {
-        if (_overlay.ActiveExplosion == null)
-            return true;
-
-        // If we ever get servers stable enough to live this long, the explosion Id int might overflow.
-        return _overlay.ActiveExplosion.Explosionid < explosionId
-            || _overlay.ActiveExplosion.Explosionid > int.MaxValue/2 && explosionId < int.MinValue/2;
     }
 
     public override void Shutdown()
     {
         base.Shutdown();
-
+        _overlayMan.RemoveOverlay<ExplosionOverlay>();
-        _cfg.UnsubValueChanged(CCVars.ExplosionPersistence, SetExplosionPersistence);
-
-        var overlayManager = IoCManager.Resolve<IOverlayManager>();
-        if (overlayManager.HasOverlay<ExplosionOverlay>())
-            overlayManager.RemoveOverlay<ExplosionOverlay>();
-    }
-}
-
-internal sealed class Explosion
-{
-    public readonly Dictionary<int, List<Vector2i>>? SpaceTiles;
-    public readonly Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> Tiles;
-    public readonly List<float> Intensity;
-    public readonly EntityUid LightEntity;
-    public readonly MapId Map;
-    public readonly int Explosionid;
-    public readonly ushort SpaceTileSize;
-    public readonly float IntensityPerState;
-
-    public readonly Matrix3 SpaceMatrix;
-
-    /// <summary>
-    ///     How long have we been drawing this explosion, starting from the time the explosion was fully drawn.
-    /// </summary>
-    public float Lifetime;
-
-    /// <summary>
-    ///     The textures used for the explosion fire effect. Each fire-state is associated with an explosion
-    ///     intensity range, and each stat itself has several textures.
-    /// </summary>
-    public readonly List<Texture[]> FireFrames = new();
-
-    public readonly Color? FireColor;
-
-    internal Explosion(ExplosionEvent args, ExplosionPrototype type, EntityUid lightEntity, IResourceCache resCache)
-    {
-        Map = args.Epicenter.MapId;
-        SpaceTiles = args.SpaceTiles;
-        Tiles = args.Tiles;
-        Intensity = args.Intensity;
-        SpaceMatrix = args.SpaceMatrix;
-        Explosionid = args.ExplosionId;
-        FireColor = type.FireColor;
-        LightEntity = lightEntity;
-        SpaceTileSize = args.SpaceTileSize;
-        IntensityPerState = type.IntensityPerState;
-
-        var fireRsi = resCache.GetResource<RSIResource>(type.TexturePath).RSI;
-        foreach (var state in fireRsi)
-        {
-            FireFrames.Add(state.GetFrames(RSI.State.Direction.South));
-            if (FireFrames.Count == type.FireStates)
-                break;
-        }
     }
 }

Content.Client/Explosion/ExplosionVisualsComponent.cs

@@ -0,0 +1,25 @@
+using Content.Shared.Explosion;
+using Robust.Client.Graphics;
+
+namespace Content.Client.Explosion;
+
+[RegisterComponent]
+[ComponentReference(typeof(SharedExplosionVisualsComponent))]
+public sealed class ExplosionVisualsComponent : SharedExplosionVisualsComponent
+{
+    public EntityUid LightEntity;
+    /// <summary>
+    ///     How long have we been drawing this explosion, starting from the time the explosion was fully drawn.
+    /// </summary>
+    public float Lifetime;
+
+    public float IntensityPerState;
+
+    /// <summary>
+    ///     The textures used for the explosion fire effect. Each fire-state is associated with an explosion
+    ///     intensity range, and each stat itself has several textures.
+    /// </summary>
+    public List<Texture[]> FireFrames = new();
+
+    public Color? FireColor;
+}

Content.Server/Explosion/Components/ExplosionVisualsComponent.cs

@@ -0,0 +1,9 @@
+using Content.Shared.Explosion;
+
+namespace Content.Server.Explosion;
+
+[RegisterComponent]
+[ComponentReference(typeof(SharedExplosionVisualsComponent))]
+public sealed class ExplosionVisualsComponent : SharedExplosionVisualsComponent
+{
+}

Content.Server/Explosion/EntitySystems/ExplosionSystem.Processing.cs

@@ -1,8 +1,10 @@
 using System.Linq;
+using Content.Shared.CCVar;
 using Content.Shared.Damage;
 using Content.Shared.Explosion;
 using Content.Shared.Maps;
 using Content.Shared.Physics;
+using Content.Shared.Spawners.Components;
 using Robust.Shared.Map;
 using Robust.Shared.Map.Components;
 using Robust.Shared.Physics;
@@ -15,16 +17,6 @@ namespace Content.Server.Explosion.EntitySystems;
 
 public sealed partial class ExplosionSystem : EntitySystem
 {
-    /// <summary>
-    ///     Used to identify explosions when communicating with the client. Might be needed if more than one explosion is spawned in a single tick.
-    /// </summary>
-    /// <remarks>
-    ///     Overflowing back to 0 should cause no issue, as long as you don't have more than 256 explosions happening in a single tick.
-    /// </remarks>
-    private int _explosionCounter = 0;
-    // maybe should just use a UID/explosion-entity and a state to convey information?
-    // but then need to ignore PVS? Eeehh this works well enough for now.
-
     /// <summary>
     ///     Used to limit explosion processing time. See <see cref="MaxProcessingTime"/>.
     /// </summary>
@@ -63,6 +55,7 @@ public sealed partial class ExplosionSystem : EntitySystem
         if (_activeExplosion?.Epicenter.MapId != ev.Map)
             return;
 
+        QueueDel(_activeExplosion.VisualEnt);
         _activeExplosion = null;
         _nodeGroupSystem.PauseUpdating = false;
         _pathfindingSystem.PauseUpdating = false;
@@ -103,7 +96,6 @@ public sealed partial class ExplosionSystem : EntitySystem
                 if (_activeExplosion == null)
                     continue;
 
-                _explosionCounter++;
                 _previousTileIteration = 0;
 
                 // just a lil nap
@@ -131,14 +123,20 @@ public sealed partial class ExplosionSystem : EntitySystem
 
                 // has the explosion finished processing?
                 if (_activeExplosion.FinishedProcessing)
-                    _activeExplosion = null;
+            {
+                var comp = EnsureComp<TimedDespawnComponent>(_activeExplosion.VisualEnt);
+                comp.Lifetime = _cfg.GetCVar(CCVars.ExplosionPersistence);
+                _appearance.SetData(_activeExplosion.VisualEnt, ExplosionAppearanceData.Progress, int.MaxValue);
+                _activeExplosion = null;
+            }
 #if EXCEPTION_TOLERANCE
             }
             catch (Exception e)
             {
                 // Ensure the system does not get stuck in an error-loop.
+                if (_activeExplosion != null)
+                    QueueDel(_activeExplosion.VisualEnt);
                 _activeExplosion = null;
-                RaiseNetworkEvent(new ExplosionOverlayUpdateEvent(_explosionCounter, int.MaxValue));
                 _nodeGroupSystem.PauseUpdating = false;
                 _pathfindingSystem.PauseUpdating = false;
                 throw;
@@ -151,21 +149,13 @@ public sealed partial class ExplosionSystem : EntitySystem
         // we have finished processing our tiles. Is there still an ongoing explosion?
         if (_activeExplosion != null)
         {
-            // update the client explosion overlays. This ensures that the fire-effects sync up with the entities currently being damaged.
+            _appearance.SetData(_activeExplosion.VisualEnt, ExplosionAppearanceData.Progress, _activeExplosion.CurrentIteration + 1);
-            if (_previousTileIteration == _activeExplosion.CurrentIteration)
-                return;
-
-            _previousTileIteration = _activeExplosion.CurrentIteration;
-            RaiseNetworkEvent(new ExplosionOverlayUpdateEvent(_explosionCounter, _previousTileIteration + 1));
             return;
         }
 
         if (_explosionQueue.Count > 0)
             return;
 
-        // We have finished processing all explosions. Clear client explosion overlays
-        RaiseNetworkEvent(new ExplosionOverlayUpdateEvent(_explosionCounter, int.MaxValue));
-
         //wakey wakey
         _nodeGroupSystem.PauseUpdating = false;
         _pathfindingSystem.PauseUpdating = false;
@@ -586,6 +576,8 @@ sealed class Explosion
     private readonly IEntityManager _entMan;
     private readonly ExplosionSystem _system;
 
+    public readonly EntityUid VisualEnt;
+
     /// <summary>
     ///     Initialize a new instance for processing
     /// </summary>
@@ -601,8 +593,10 @@ sealed class Explosion
         int maxTileBreak,
         bool canCreateVacuum,
         IEntityManager entMan,
-        IMapManager mapMan)
+        IMapManager mapMan,
+        EntityUid visualEnt)
     {
+        VisualEnt = visualEnt;
         _system = system;
         ExplosionType = explosionType;
         _tileSetIntensity = tileSetIntensity;

Content.Server/Explosion/EntitySystems/ExplosionSystem.TileFill.cs

@@ -313,7 +313,7 @@ public sealed partial class ExplosionSystem : EntitySystem
         return (grids, referenceGrid, radius);
     }
 
-    public ExplosionEvent? GenerateExplosionPreview(SpawnExplosionEuiMsg.PreviewRequest request)
+    public ExplosionVisualsState? GenerateExplosionPreview(SpawnExplosionEuiMsg.PreviewRequest request)
     {
         var stopwatch = new Stopwatch();
         stopwatch.Start();
@@ -332,7 +332,19 @@ public sealed partial class ExplosionSystem : EntitySystem
 
         Logger.Info($"Generated explosion preview with {area} tiles in {stopwatch.Elapsed.TotalMilliseconds}ms");
 
-        // the explosion event that **would** be sent to all clients, if it were a real explosion.
+        Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> tileLists = new();
-        return GetExplosionEvent(request.Epicenter, request.TypeId, spaceMatrix, spaceData, gridData.Values, iterationIntensity);
+        foreach (var (grid, data) in gridData)
+        {
+            tileLists.Add(grid, data.TileLists);
+        }
+
+        return new ExplosionVisualsState(
+            request.Epicenter,
+            request.TypeId,
+            iterationIntensity,
+            spaceData?.TileLists,
+            tileLists, spaceMatrix,
+            spaceData?.TileSize ?? DefaultTileSize
+            );
     }
 }

Content.Server/Explosion/EntitySystems/ExplosionSystem.Visuals.cs

@@ -0,0 +1,58 @@
+using Content.Shared.Explosion;
+using Robust.Server.GameObjects;
+using Robust.Shared.GameStates;
+using Robust.Shared.Map;
+
+namespace Content.Server.Explosion.EntitySystems;
+
+// This part of the system handled send visual / overlay data to clients.
+public sealed partial class ExplosionSystem : EntitySystem
+{
+    public void InitVisuals()
+    {
+        SubscribeLocalEvent<ExplosionVisualsComponent, ComponentGetState>(OnGetState);
+    }
+
+    private void OnGetState(EntityUid uid, ExplosionVisualsComponent component, ref ComponentGetState args)
+    {
+        args.State = new ExplosionVisualsState(
+            component.Epicenter,
+            component.ExplosionType,
+            component.Intensity,
+            component.SpaceTiles,
+            component.Tiles,
+            component.SpaceMatrix,
+            component.SpaceTileSize);
+    }
+
+    /// <summary>
+    ///     Constructor for the shared <see cref="ExplosionEvent"/> using the server-exclusive explosion classes.
+    /// </summary>
+    private EntityUid CreateExplosionVisualEntity(MapCoordinates epicenter, string prototype, Matrix3 spaceMatrix, ExplosionSpaceTileFlood? spaceData, IEnumerable<ExplosionGridTileFlood> gridData, List<float> iterationIntensity)
+    {
+        var explosionEntity = Spawn(null, MapCoordinates.Nullspace);
+        var comp = AddComp<ExplosionVisualsComponent>(explosionEntity);
+
+        foreach (var grid in gridData)
+        {
+            comp.Tiles.Add(grid.Grid.Owner, grid.TileLists);
+        }
+
+        comp.SpaceTiles = spaceData?.TileLists;
+        comp.Epicenter = epicenter;
+        comp.ExplosionType = prototype;
+        comp.Intensity = iterationIntensity;
+        comp.SpaceMatrix = spaceMatrix;
+        comp.SpaceTileSize = spaceData?.TileSize ?? DefaultTileSize;
+        Dirty(comp);
+
+        // Light, sound & visuals may extend well beyond normal PVS range. In principle, this should probably still be
+        // restricted to something like the same map, but whatever.
+        _pvsSys.AddGlobalOverride(explosionEntity);
+
+        var appearance = AddComp<ServerAppearanceComponent>(explosionEntity);
+        _appearance.SetData(explosionEntity, ExplosionAppearanceData.Progress, 1, appearance);
+
+        return explosionEntity;
+    }
+}

Content.Server/Explosion/EntitySystems/ExplosionSystem.cs

@@ -11,6 +11,7 @@ using Content.Shared.Explosion;
 using Content.Shared.GameTicking;
 using Content.Shared.Inventory;
 using Content.Shared.Throwing;
+using Robust.Server.GameStates;
 using Robust.Server.Player;
 using Robust.Shared.Audio;
 using Robust.Shared.Configuration;
@@ -31,12 +32,14 @@ public sealed partial class ExplosionSystem : EntitySystem
     [Dependency] private readonly IConfigurationManager _cfg = default!;
     [Dependency] private readonly IPlayerManager _playerManager = default!;
 
+    [Dependency] private readonly SharedAppearanceSystem _appearance = default!;
     [Dependency] private readonly DamageableSystem _damageableSystem = default!;
     [Dependency] private readonly NodeGroupSystem _nodeGroupSystem = default!;
     [Dependency] private readonly PathfindingSystem _pathfindingSystem = default!;
     [Dependency] private readonly SharedCameraRecoilSystem _recoilSystem = default!;
     [Dependency] private readonly IAdminLogManager _adminLogger = default!;
     [Dependency] private readonly ThrowingSystem _throwingSystem = default!;
+    [Dependency] private readonly PVSOverrideSystem _pvsSys = default!;
     [Dependency] private readonly SharedTransformSystem _transformSystem = default!;
 
     /// <summary>
@@ -81,11 +84,14 @@ public sealed partial class ExplosionSystem : EntitySystem
         SubscribeLocalEvent<AirtightComponent, DamageChangedEvent>(OnAirtightDamaged);
         SubscribeCvars();
         InitAirtightMap();
+        InitVisuals();
     }
 
     private void OnReset(RoundRestartCleanupEvent ev)
     {
         _explosionQueue.Clear();
+        if (_activeExplosion !=null)
+            QueueDel(_activeExplosion.VisualEnt);
         _activeExplosion = null;
         _nodeGroupSystem.PauseUpdating = false;
         _pathfindingSystem.PauseUpdating = false;
@@ -281,7 +287,7 @@ public sealed partial class ExplosionSystem : EntitySystem
 
         var (area, iterationIntensity, spaceData, gridData, spaceMatrix) = results.Value;
 
-        RaiseNetworkEvent(GetExplosionEvent(epicenter, type.ID, spaceMatrix, spaceData, gridData.Values, iterationIntensity));
+        var visualEnt = CreateExplosionVisualEntity(epicenter, type.ID, spaceMatrix, spaceData, gridData.Values, iterationIntensity);
 
         // camera shake
         CameraShake(iterationIntensity.Count * 2.5f, epicenter, totalIntensity);
@@ -306,23 +312,8 @@ public sealed partial class ExplosionSystem : EntitySystem
             maxTileBreak,
             canCreateVacuum,
             EntityManager,
-            _mapManager);
+            _mapManager,
-    }
+            visualEnt);
-
-    /// <summary>
-    ///     Constructor for the shared <see cref="ExplosionEvent"/> using the server-exclusive explosion classes.
-    /// </summary>
-    internal ExplosionEvent GetExplosionEvent(MapCoordinates epicenter, string id, Matrix3 spaceMatrix, ExplosionSpaceTileFlood? spaceData, IEnumerable<ExplosionGridTileFlood> gridData, List<float> iterationIntensity)
-    {
-        var spaceTiles = spaceData?.TileLists;
-
-        Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> tileLists = new();
-        foreach (var grid in gridData)
-        {
-            tileLists.Add(grid.Grid.Owner, grid.TileLists);
-        }
-
-        return new ExplosionEvent(_explosionCounter, epicenter, id, iterationIntensity, spaceTiles, tileLists, spaceMatrix, spaceData?.TileSize ?? DefaultTileSize);
     }
 
     private void CameraShake(float range, MapCoordinates epicenter, float totalIntensity)

Content.Shared/Administration/SpawnExplosionEuiMsg.cs

@@ -40,9 +40,9 @@ public static class SpawnExplosionEuiMsg
     {
         public readonly float Slope;
         public readonly float TotalIntensity;
-        public readonly ExplosionEvent Explosion;
+        public readonly ExplosionVisualsState Explosion;
 
-        public PreviewData(ExplosionEvent explosion, float slope, float totalIntensity)
+        public PreviewData(ExplosionVisualsState explosion, float slope, float totalIntensity)
         {
             Slope = slope;
             TotalIntensity = totalIntensity;

Content.Shared/CCVar/CCVars.cs

@@ -630,11 +630,10 @@ namespace Content.Shared.CCVar
             CVarDef.Create("explosion.incremental_tile", false, CVar.SERVERONLY);
 
         /// <summary>
-        ///     Client-side explosion visuals: for how many seconds should an explosion stay on-screen once it has
+        ///     This determines for how many seconds an explosion should stay visible once it has finished expanding.
-        ///     finished expanding?
         /// </summary>
         public static readonly CVarDef<float> ExplosionPersistence =
-            CVarDef.Create("explosion.persistence", 0.3f, CVar.REPLICATED);
+            CVarDef.Create("explosion.persistence", 0.3f, CVar.SERVERONLY);
 
         /// <summary>
         ///     If an explosion covers a larger area than this number, the damaging/processing will always start during

Content.Shared/Explosion/ExplosionEvents.cs

@@ -24,61 +24,3 @@ public sealed class GetExplosionResistanceEvent : EntityEventArgs, IInventoryRel
         ExplotionPrototype = id;
     }
 }
-
-/// <summary>
-///     An explosion event. Used for client side rendering.
-/// </summary>
-[Serializable, NetSerializable]
-public sealed class ExplosionEvent : EntityEventArgs
-{
-    public MapCoordinates Epicenter;
-
-    public Dictionary<int, List<Vector2i>>? SpaceTiles;
-    public Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> Tiles;
-
-    public List<float> Intensity;
-
-    public string TypeID;
-
-    public Matrix3 SpaceMatrix;
-
-    public int ExplosionId;
-
-    public ushort SpaceTileSize;
-
-    public ExplosionEvent(
-        int explosionId,
-        MapCoordinates epicenter,
-        string typeID,
-        List<float> intensity,
-        Dictionary<int, List<Vector2i>>? spaceTiles,
-        Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> tiles,
-        Matrix3 spaceMatrix,
-        ushort spaceTileSize)
-    {
-        Epicenter = epicenter;
-        SpaceTiles = spaceTiles;
-        Tiles = tiles;
-        Intensity = intensity;
-        TypeID = typeID;
-        SpaceMatrix = spaceMatrix;
-        ExplosionId = explosionId;
-        SpaceTileSize = spaceTileSize;
-    }
-}
-
-/// <summary>
-///     Update visual rendering of the explosion to correspond to the servers processing of it.
-/// </summary>
-[Serializable, NetSerializable]
-public sealed class ExplosionOverlayUpdateEvent : EntityEventArgs
-{
-    public int Index;
-    public int ExplosionId;
-
-    public ExplosionOverlayUpdateEvent(int explosionId, int index)
-    {
-        Index = index;
-        ExplosionId = explosionId;
-    }
-}

Content.Shared/Explosion/SharedExplosionVisualsComponent.cs

@@ -0,0 +1,56 @@
+using Robust.Shared.GameStates;
+using Robust.Shared.Map;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.Explosion;
+
+/// <summary>
+///     Component that is used to send explosion overlay/visual data to an abstract explosion entity.
+/// </summary>
+[NetworkedComponent]
+public abstract class SharedExplosionVisualsComponent : Component
+{
+    public MapCoordinates Epicenter;
+    public Dictionary<int, List<Vector2i>>? SpaceTiles;
+    public Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> Tiles = new();
+    public List<float> Intensity = new();
+    public string ExplosionType = string.Empty;
+    public Matrix3 SpaceMatrix;
+    public ushort SpaceTileSize;
+}
+
+[Serializable, NetSerializable]
+public sealed class ExplosionVisualsState : ComponentState
+{
+    public MapCoordinates Epicenter;
+    public Dictionary<int, List<Vector2i>>? SpaceTiles;
+    public Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> Tiles;
+    public List<float> Intensity;
+    public string ExplosionType = string.Empty;
+    public Matrix3 SpaceMatrix;
+    public ushort SpaceTileSize;
+
+    public ExplosionVisualsState(
+        MapCoordinates epicenter,
+        string typeID,
+        List<float> intensity,
+        Dictionary<int, List<Vector2i>>? spaceTiles,
+        Dictionary<EntityUid, Dictionary<int, List<Vector2i>>> tiles,
+        Matrix3 spaceMatrix,
+        ushort spaceTileSize)
+    {
+        Epicenter = epicenter;
+        SpaceTiles = spaceTiles;
+        Tiles = tiles;
+        Intensity = intensity;
+        ExplosionType = typeID;
+        SpaceMatrix = spaceMatrix;
+        SpaceTileSize = spaceTileSize;
+    }
+}
+
+[Serializable, NetSerializable]
+public enum ExplosionAppearanceData
+{
+    Progress, // iteration index tracker for explosions that are still expanding outwards, 
+}