implement Filter

src/Rev2/Archetype.cs

@@ -13,13 +13,12 @@ namespace MoonTools.ECS.Rev2
 			new Dictionary<ComponentId, int>();
 		public SortedDictionary<ComponentId, ArchetypeEdge> Edges = new SortedDictionary<ComponentId, ArchetypeEdge>();
 
-		public int Count;
+		public int Count => RowToEntity.Count;
 
 		public Archetype(ArchetypeId id, ArchetypeSignature signature)
 		{
 			Id = id;
 			Signature = signature;
-			Count = 0;
 		}
 	}
 }

src/Rev2/Filter.cs

@@ -1,36 +1,161 @@
 using System;
-using System.Runtime.InteropServices;
+using System.Collections.Generic;
 
 namespace MoonTools.ECS.Rev2
 {
 	// TODO: do we want to get fancy with queries beyond Include and Exclude?
-	// TODO: need an edge iterator as part of this nested horseshit
 	public class Filter
 	{
-		private Archetype Start;
+		private Archetype EmptyArchetype;
+		private HashSet<ComponentId> Included;
+		private HashSet<ComponentId> Excluded;
 
-		public EntityEnumerator Entities => new EntityEnumerator(Start);
+		public EntityEnumerator Entities => new EntityEnumerator(this);
+		internal ArchetypeEnumerator Archetypes => new ArchetypeEnumerator(this);
+		public RandomEntityEnumerator EntitiesInRandomOrder => new RandomEntityEnumerator(this);
 
-		private ref struct FilterEnumerator
+		public bool Empty
+		{
+			get
+			{
+				var empty = true;
+
+				foreach (var archetype in Archetypes)
+				{
+					if (archetype.Count > 0)
+					{
+						return false;
+					}
+				}
+
+				return empty;
+			}
+		}
+
+		public int Count
+		{
+			get
+			{
+				var count = 0;
+
+				foreach (var archetype in Archetypes)
+				{
+					count += archetype.Count;
+				}
+
+				return count;
+			}
+		}
+
+		// WARNING: this WILL crash if the index is out of range!
+		public EntityId NthEntity(int index)
+		{
+			var count = 0;
+
+			foreach (var archetype in Archetypes)
+			{
+				count += archetype.Count;
+				if (index < count)
+				{
+					return archetype.RowToEntity[index];
+				}
+
+				index -= count;
+			}
+
+			throw new InvalidOperationException("Filter index out of range!");
+		}
+
+		public EntityId RandomEntity
+		{
+			get
+			{
+				var randomIndex = RandomManager.Next(Count);
+				return NthEntity(randomIndex);
+			}
+		}
+
+		public Filter(Archetype emptyArchetype, HashSet<ComponentId> included, HashSet<ComponentId> excluded)
+		{
+			EmptyArchetype = emptyArchetype;
+			Included = included;
+			Excluded = excluded;
+		}
+
+		internal ref struct ArchetypeEnumerator
 		{
 			private Archetype CurrentArchetype;
 			private bool Active;
 
-			public FilterEnumerator(Archetype start)
+			// TODO: pool these
+			private Queue<Archetype> ArchetypeQueue = new Queue<Archetype>();
+			private Queue<Archetype> ArchetypeSearchQueue = new Queue<Archetype>();
+			private HashSet<Archetype> Explored = new HashSet<Archetype>();
+
+			public ArchetypeEnumerator GetEnumerator() => this;
+
+			public ArchetypeEnumerator(Filter filter)
 			{
-				CurrentArchetype = start;
 				Active = false;
+
+				var empty = filter.EmptyArchetype;
+				ArchetypeSearchQueue.Enqueue(empty);
+
+				while (ArchetypeSearchQueue.TryDequeue(out var current))
+				{
+					// exclude the empty archetype
+					var satisfiesFilter = filter.Included.Count != 0;
+
+					foreach (var componentId in filter.Included)
+					{
+						if (!current.ComponentToColumnIndex.ContainsKey(componentId))
+						{
+							satisfiesFilter = false;
+						}
+					}
+
+					foreach (var componentId in filter.Excluded)
+					{
+						if (current.ComponentToColumnIndex.ContainsKey(componentId))
+						{
+							satisfiesFilter = false;
+						}
+					}
+
+					if (satisfiesFilter)
+					{
+						ArchetypeQueue.Enqueue(current);
+					}
+
+					// if the current archetype satisfies the filter, we need to add all edges that
+					// do not have an excluded component
+					// if the current archetype does not satisfy the filter, we need to add all edges that
+					// include an included component
+					foreach (var (componentId, edge) in current.Edges)
+					{
+						if (satisfiesFilter)
+						{
+							if (!filter.Excluded.Contains(componentId) && !Explored.Contains(edge.Add))
+							{
+								Explored.Add(edge.Add);
+								ArchetypeSearchQueue.Enqueue(edge.Add);
+							}
+						}
+						else
+						{
+							if (filter.Included.Contains(componentId) && !Explored.Contains(edge.Add))
+							{
+								Explored.Add(edge.Add);
+								ArchetypeSearchQueue.Enqueue(edge.Add);
+							}
+						}
+					}
+				}
 			}
 
 			public bool MoveNext()
 			{
-				if (!Active)
+				return ArchetypeQueue.TryDequeue(out CurrentArchetype!);
-				{
-					Active = true;
-					return true;
-				}
-
-				// TODO: go to next available edge
 			}
 
 			public Archetype Current => CurrentArchetype;
@@ -38,39 +163,50 @@ namespace MoonTools.ECS.Rev2
 
 		public ref struct EntityEnumerator
 		{
-			private FilterEnumerator FilterEnumerator;
+			private EntityId CurrentEntity;
-			private ReverseSpanEnumerator<EntityId> EntityListEnumerator;
-			private bool EntityListEnumeratorActive;
 
 			public EntityEnumerator GetEnumerator() => this;
 
-			public EntityEnumerator(Archetype start)
+			// TODO: pool this
+			Queue<EntityId> EntityQueue = new Queue<EntityId>();
+
+			internal EntityEnumerator(Filter filter)
 			{
-				FilterEnumerator = new FilterEnumerator(start);
+				var archetypeEnumerator = new ArchetypeEnumerator(filter);
+
+				foreach (var archetype in archetypeEnumerator)
+				{
+					foreach (var entity in archetype.RowToEntity)
+					{
+						EntityQueue.Enqueue(entity);
+					}
+				}
 			}
 
 			public bool MoveNext()
 			{
-				if (!EntityListEnumeratorActive || !EntityListEnumerator.MoveNext())
+				return EntityQueue.TryDequeue(out CurrentEntity);
+			}
+
+			public EntityId Current => CurrentEntity;
+		}
+
+		public ref struct RandomEntityEnumerator
 		{
-					if (!FilterEnumerator.MoveNext())
+			private Filter Filter;
+			private LinearCongruentialEnumerator LinearCongruentialEnumerator;
+
+			public RandomEntityEnumerator GetEnumerator() => this;
+
+			internal RandomEntityEnumerator(Filter filter)
 			{
-						return false;
+				Filter = filter;
+				LinearCongruentialEnumerator =
+					RandomManager.LinearCongruentialSequence(filter.Count);
 			}
 
-					if (FilterEnumerator.Current.RowToEntity.Count != 0)
+			public bool MoveNext() => LinearCongruentialEnumerator.MoveNext();
-					{
+			public EntityId Current => Filter.NthEntity(LinearCongruentialEnumerator.Current);
-						EntityListEnumerator = new ReverseSpanEnumerator<EntityId>(CollectionsMarshal.AsSpan(FilterEnumerator.Current.RowToEntity));
-						EntityListEnumeratorActive = true;
-					}
-
-					return MoveNext();
-				}
-
-				return true;
-			}
-
-			public EntityId Current => EntityListEnumerator.Current;
 		}
 	}
 }

src/Rev2/World.cs

@@ -27,6 +27,8 @@ namespace MoonTools.ECS.Rev2
 		IdAssigner<EntityId> EntityIdAssigner = new IdAssigner<EntityId>();
 		IdAssigner<ComponentId> ComponentIdAssigner = new IdAssigner<ComponentId>();
 
+		public readonly Archetype EmptyArchetype;
+
 		private bool IsDisposed;
 
 		public delegate void RefAction<T1, T2>(ref T1 arg1, ref T2 arg2);
@@ -34,7 +36,7 @@ namespace MoonTools.ECS.Rev2
 		public World()
 		{
 			// Create the Empty Archetype
-			CreateArchetype(ArchetypeSignature.Empty);
+			EmptyArchetype = CreateArchetype(ArchetypeSignature.Empty);
 		}
 
 		private Archetype CreateArchetype(ArchetypeSignature signature)
@@ -62,7 +64,7 @@ namespace MoonTools.ECS.Rev2
 		{
 			var entityId = EntityIdAssigner.Assign();
 			var emptyArchetype = ArchetypeIndex[ArchetypeSignature.Empty];
-			EntityIndex.Add(entityId, new Record(emptyArchetype, 0));
+			EntityIndex.Add(entityId, new Record(emptyArchetype, emptyArchetype.Count));
 			emptyArchetype.RowToEntity.Add(entityId);
 			return entityId;
 		}
@@ -210,14 +212,15 @@ namespace MoonTools.ECS.Rev2
 				archetype.Components[i].Delete(row);
 			}
 
-			if (archetype.Count > 1)
+			if (row != archetype.Count - 1)
 			{
-				// update row to entity lookup on archetype
+				// move last row entity to open spot
-				archetype.RowToEntity[row] = archetype.RowToEntity[archetype.Count - 1];
+				var lastRowEntity = archetype.RowToEntity[archetype.Count - 1];
-				archetype.RowToEntity.RemoveAt(archetype.Count - 1);
+				archetype.RowToEntity[row] = lastRowEntity;
+				EntityIndex[lastRowEntity] = new Record(archetype, row);
 			}
 
-			archetype.Count -= 1;
+			archetype.RowToEntity.RemoveAt(archetype.Count - 1);
 			EntityIndex.Remove(entityId);
 			EntityIdAssigner.Unassign(entityId);
 		}
@@ -236,20 +239,19 @@ namespace MoonTools.ECS.Rev2
 				from.Components[i].Delete(row);
 			}
 
-			if (from.Count > 1)
+			if (row != from.Count - 1)
 			{
-				// update row to entity lookup on from archetype
+				// move last row entity to open spot
-				from.RowToEntity[row] = from.RowToEntity[from.Count - 1];
+				var lastRowEntity = from.RowToEntity[from.Count - 1];
-				from.RowToEntity.RemoveAt(from.Count - 1);
+				from.RowToEntity[row] = lastRowEntity;
-				EntityIndex[from.RowToEntity[row]] = new Record(from, row);
+				EntityIndex[lastRowEntity] = new Record(from, row);
 			}
 
+			from.RowToEntity.RemoveAt(from.Count - 1);
+
 			// update row to entity lookup on to archetype
 			EntityIndex[entityId] = new Record(to, to.Count);
 			to.RowToEntity.Add(entityId);
-
-			to.Count += 1;
-			from.Count -= 1;
 		}
 
 		private void MoveEntityToLowerArchetype(EntityId entityId, int row, Archetype from, Archetype to, ComponentId removed)
@@ -269,32 +271,31 @@ namespace MoonTools.ECS.Rev2
 				}
 			}
 
-			if (from.Count > 1)
+			if (row != from.Count - 1)
 			{
 				// update row to entity lookup on from archetype
-				from.RowToEntity[row] = from.RowToEntity[from.Count - 1];
+				var lastRowEntity = from.RowToEntity[from.Count - 1];
-				from.RowToEntity.RemoveAt(from.Count - 1);
+				from.RowToEntity[row] = lastRowEntity;
-				EntityIndex[from.RowToEntity[row]] = new Record(from, row);
+				EntityIndex[lastRowEntity] = new Record(from, row);
 			}
 
+			from.RowToEntity.RemoveAt(from.Count - 1);
+
 			// update row to entity lookup on to archetype
 			EntityIndex[entityId] = new Record(to, to.Count);
 			to.RowToEntity.Add(entityId);
-
-			to.Count += 1;
-			from.Count -= 1;
 		}
 
-		public unsafe void ForEachEntity<T, T1, T2>(ArchetypeSignature signature,
+		public unsafe void ForEachEntity<T, T1, T2>(Filter filter,
 			T rowForEachContainer) where T : IForEach<T1, T2> where T1 : unmanaged where T2 : unmanaged
 		{
-			var archetype = ArchetypeIndex[signature];
+			foreach (var archetype in filter.Archetypes)
-
+			{
-			var componentIdOne = signature[0];
+				var componentIdOne = archetype.Signature[0];
 				var columnIndexOne = archetype.ComponentToColumnIndex[componentIdOne];
 				var columnOneElements = archetype.Components[columnIndexOne].Elements;
 
-			var componentIdTwo = signature[1];
+				var componentIdTwo = archetype.Signature[1];
 				var columnIndexTwo = archetype.ComponentToColumnIndex[componentIdTwo];
 				var columnTwoElements = archetype.Components[columnIndexTwo].Elements;
 
@@ -302,25 +303,18 @@ namespace MoonTools.ECS.Rev2
 				{
 					rowForEachContainer.Update(ref ((T1*) columnOneElements)[i], ref ((T2*) columnTwoElements)[i]);
 				}
-
-			foreach (var edge in archetype.Edges.Values)
-			{
-				if (edge.Add != archetype)
-				{
-					ForEachEntity<T, T1, T2>(edge.Add.Signature, rowForEachContainer);
-				}
 			}
 		}
 
-		public unsafe void ForEachEntity<T1, T2>(ArchetypeSignature signature, RefAction<T1, T2> rowAction) where T1 : unmanaged where T2 : unmanaged
+		public unsafe void ForEachEntity<T1, T2>(Filter filter, RefAction<T1, T2> rowAction) where T1 : unmanaged where T2 : unmanaged
 		{
-			var archetype = ArchetypeIndex[signature];
+			foreach (var archetype in filter.Archetypes)
-
+			{
-			var componentIdOne = signature[0];
+				var componentIdOne = archetype.Signature[0];
 				var columnIndexOne = archetype.ComponentToColumnIndex[componentIdOne];
 				var columnOneElements = archetype.Components[columnIndexOne].Elements;
 
-			var componentIdTwo = signature[1];
+				var componentIdTwo = archetype.Signature[1];
 				var columnIndexTwo = archetype.ComponentToColumnIndex[componentIdTwo];
 				var columnTwoElements = archetype.Components[columnIndexTwo].Elements;
 
@@ -328,41 +322,8 @@ namespace MoonTools.ECS.Rev2
 				{
 					rowAction(ref ((T1*) columnOneElements)[i], ref ((T2*) columnTwoElements)[i]);
 				}
-
-			foreach (var edge in archetype.Edges.Values)
-			{
-				if (edge.Add != archetype)
-				{
-					ForEachEntity(edge.Add.Signature, rowAction);
 			}
 		}
-		}
-
-		public void ForEachEntity(ArchetypeSignature signature, Action<EntityId> rowAction)
-		{
-			var archetype = ArchetypeIndex[signature];
-
-			for (int i = 0; i < archetype.Count; i += 1)
-			{
-				rowAction(archetype.RowToEntity[i]);
-			}
-
-			// recursion might get too hairy here
-			foreach (var edge in archetype.Edges.Values)
-			{
-				if (edge.Add != archetype)
-				{
-					ForEachEntity(edge.Add.Signature, rowAction);
-				}
-			}
-		}
-
-		public ReverseSpanEnumerator<EntityId> Entities(ArchetypeSignature signature)
-		{
-			var archetype = ArchetypeIndex[signature];
-			return new ReverseSpanEnumerator<EntityId>(
-				CollectionsMarshal.AsSpan(archetype.RowToEntity));
-		}
 
 		protected virtual void Dispose(bool disposing)
 		{