Decal state handling (#12624)

Content.Shared/Decals/DecalGridComponent.cs

@@ -1,16 +1,110 @@
+using Robust.Shared.GameStates;
+using Robust.Shared.Serialization;
+using Robust.Shared.Timing;
+using Robust.Shared.Utility;
+using static Content.Shared.Decals.DecalGridComponent;
+
 namespace Content.Shared.Decals
 {
     [RegisterComponent]
     [Access(typeof(SharedDecalSystem))]
+    [NetworkedComponent]
     public sealed class DecalGridComponent : Component
     {
         [DataField("chunkCollection", serverOnly: true)]
         public DecalGridChunkCollection ChunkCollection = new(new ());
 
-        [DataRecord]
-        public record DecalGridChunkCollection(Dictionary<Vector2i, Dictionary<uint, Decal>> ChunkCollection)
+        /// <summary>
+        ///     Tick at which PVS was last toggled. Ensures that all players receive a full update when toggling PVS.
+        /// </summary>
+        public GameTick ForceTick { get; set; }
+
+        [DataDefinition]
+        [Serializable, NetSerializable]
+        public sealed class DecalChunk
+        {
+            [DataField("decals")]
+            public Dictionary<uint, Decal> Decals;
+
+            [NonSerialized]
+            public GameTick LastModified;
+
+            public DecalChunk()
+            {
+                Decals = new();
+            }
+
+            public DecalChunk(Dictionary<uint, Decal> decals)
+            {
+                Decals = decals;
+            }
+
+            public DecalChunk(DecalChunk chunk)
+            {
+                // decals are readonly, so this should be fine.
+                Decals = chunk.Decals.ShallowClone();
+                LastModified = chunk.LastModified;
+            }
+        }
+
+        [DataRecord, Serializable, NetSerializable]
+        public record DecalGridChunkCollection(Dictionary<Vector2i, DecalChunk> ChunkCollection)
         {
             public uint NextUid;
         }
     }
+
+    [Serializable, NetSerializable]
+    public sealed class DecalGridState : ComponentState, IComponentDeltaState
+    {
+        public Dictionary<Vector2i, DecalChunk> Chunks;
+        public bool FullState => AllChunks == null;
+
+        // required to infer deleted/missing chunks for delta states
+        public HashSet<Vector2i>? AllChunks;
+
+        public DecalGridState(Dictionary<Vector2i, DecalChunk> chunks)
+        {
+            Chunks = chunks;
+        }
+
+        public void ApplyToFullState(ComponentState fullState)
+        {
+            DebugTools.Assert(!FullState);
+            var state = (DecalGridState) fullState;
+            DebugTools.Assert(state.FullState);
+
+            foreach (var key in state.Chunks.Keys)
+            {
+                if (!AllChunks!.Contains(key))
+                    state.Chunks.Remove(key);
+            }
+
+            foreach (var (chunk, data) in Chunks)
+            {
+                state.Chunks[chunk] = new(data);
+            }
+        }
+
+        public ComponentState CreateNewFullState(ComponentState fullState)
+        {
+            DebugTools.Assert(!FullState);
+            var state = (DecalGridState) fullState;
+            DebugTools.Assert(state.FullState);
+
+            var chunks = new Dictionary<Vector2i, DecalChunk>(state.Chunks.Count);
+
+            foreach (var (chunk, data) in Chunks)
+            {
+                chunks[chunk] = new(data);
+            }
+
+            foreach (var (chunk, data) in state.Chunks)
+            {
+                if (AllChunks!.Contains(chunk))
+                    chunks.TryAdd(chunk, new(data));
+            }
+            return new DecalGridState(chunks);
+        }
+    }
 }