lol microsoft

encompass-cs.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.30717.126
+# Visual Studio 15
+VisualStudioVersion = 15.0.26124.0
 MinimumVisualStudioVersion = 15.0.26124.0
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "encompass-cs", "encompass-cs\encompass-cs.csproj", "{B862FC25-0740-4CEA-BC53-3C5F43DCD985}"
 EndProject
@@ -9,28 +9,38 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "test", "test\test.csproj",
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
 		Debug|x64 = Debug|x64
 		Debug|x86 = Debug|x86
+		Release|Any CPU = Release|Any CPU
 		Release|x64 = Release|x64
 		Release|x86 = Release|x86
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x64.ActiveCfg = Debug|x64
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x64.Build.0 = Debug|x64
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x86.ActiveCfg = Debug|x86
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x86.Build.0 = Debug|x86
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x64.ActiveCfg = Release|x64
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x64.Build.0 = Release|x64
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x86.ActiveCfg = Release|x86
-		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x86.Build.0 = Release|x86
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x64.ActiveCfg = Debug|x64
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x64.Build.0 = Debug|x64
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x86.ActiveCfg = Debug|x86
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x86.Build.0 = Debug|x86
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x64.ActiveCfg = Release|x64
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x64.Build.0 = Release|x64
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x86.ActiveCfg = Release|x86
-		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x86.Build.0 = Release|x86
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x64.Build.0 = Debug|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Debug|x86.Build.0 = Debug|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x64.ActiveCfg = Release|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x64.Build.0 = Release|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x86.ActiveCfg = Release|Any CPU
+		{B862FC25-0740-4CEA-BC53-3C5F43DCD985}.Release|x86.Build.0 = Release|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x64.Build.0 = Debug|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Debug|x86.Build.0 = Debug|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|Any CPU.Build.0 = Release|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x64.ActiveCfg = Release|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x64.Build.0 = Release|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x86.ActiveCfg = Release|Any CPU
+		{23D6C29C-A310-4D3E-8455-8D0B8CA1FC06}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

encompass-cs/Attributes/Adds.cs

@@ -1,16 +0,0 @@
-using System;
-using System.Collections.Generic;
-
-namespace Encompass
-{
-    [AttributeUsage(AttributeTargets.Class)]
-    public class Adds : Attribute
-    {
-        public readonly HashSet<Type> addTypes;
-
-        public Adds(params Type[] addTypes)
-        {
-            this.addTypes = new HashSet<Type>(addTypes);
-        }
-    }
-}

encompass-cs/Attributes/Receives.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
+using Encompass.Exceptions;
 
 namespace Encompass
 {
@@ -10,6 +12,15 @@ namespace Encompass
 
         public Receives(params Type[] receiveTypes)
         {
+            foreach (var receiveType in receiveTypes)
+            {
+                var isMessage = receiveType.GetInterfaces().Contains(typeof(IMessage));
+                if (!isMessage)
+                {
+                    throw new IllegalSendTypeException("{0} must be a Message", receiveType.Name);
+                }
+            }
+
             ReceiveTypes = new HashSet<Type>(receiveTypes);
         }
     }

encompass-cs/Attributes/Sends.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
+using Encompass.Exceptions;
 
 namespace Encompass
 {
@@ -10,6 +12,15 @@ namespace Encompass
 
         public Sends(params Type[] sendTypes)
         {
+            foreach (var sendType in sendTypes)
+            {
+                var isMessage = sendType.GetInterfaces().Contains(typeof(IMessage));
+                if (!isMessage)
+                {
+                    throw new IllegalSendTypeException("{0} must be a Message", sendType.Name);
+                }
+            }
+
             this.SendTypes = new HashSet<Type>(sendTypes);
         }
     }

encompass-cs/Collections/MessageStore.cs

@@ -8,60 +8,60 @@ namespace Encompass
     {
         private readonly Dictionary<Type, TypedMessageStore> _stores = new Dictionary<Type, TypedMessageStore>(512);
 
-        private void RegisterMessageType<TMessage>() where TMessage : struct
+        private void RegisterMessageType<TMessage>() where TMessage : struct, IMessage
         {
             _stores.Add(typeof(TMessage), new TypedMessageStore<TMessage>());
         }
 
-        private TypedMessageStore<TMessage> Lookup<TMessage>() where TMessage : struct
+        private TypedMessageStore<TMessage> Lookup<TMessage>() where TMessage : struct, IMessage
         {
             if (!_stores.ContainsKey(typeof(TMessage))) { RegisterMessageType<TMessage>(); }
             return _stores[typeof(TMessage)] as TypedMessageStore<TMessage>;
         }
 
-        public void AddMessage<TMessage>(in TMessage message) where TMessage : struct
+        public void AddMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             Lookup<TMessage>().Add(message);
         }
 
-        public void AddMessage<TMessage>(in TMessage message, double time) where TMessage : struct
+        public void AddMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             Lookup<TMessage>().Add(message, time);
         }
 
-        public void AddMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct
+        public void AddMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             Lookup<TMessage>().AddIgnoringTimeDilation(message, time);
         }
 
-        public ref readonly TMessage First<TMessage>() where TMessage : struct
+        public ref readonly TMessage First<TMessage>() where TMessage : struct, IMessage
         {
             if (!Any<TMessage>()) { throw new NoMessageOfTypeException("No Message of type {0} exists", typeof(TMessage).Name); }
 
             return ref Lookup<TMessage>().First();
         }
 
-        public ReadOnlySpan<TMessage> All<TMessage>() where TMessage : struct
+        public ReadOnlySpan<TMessage> All<TMessage>() where TMessage : struct, IMessage
         {
             return Lookup<TMessage>().All();
         }
 
-        public bool Any<TMessage>() where TMessage : struct
+        public bool Any<TMessage>() where TMessage : struct, IMessage
         {
             return Lookup<TMessage>().Any();
         }
 
-        public IEnumerable<TMessage> WithEntity<TMessage>(int entityID) where TMessage : struct, IHasEntity
+        public IEnumerable<TMessage> WithEntity<TMessage>(int entityID) where TMessage : struct, IMessage, IHasEntity
         {
             return Lookup<TMessage>().WithEntity(entityID);
         }
 
-        public ref readonly TMessage FirstWithEntity<TMessage>(int entityID) where TMessage : struct
+        public ref readonly TMessage FirstWithEntity<TMessage>(int entityID) where TMessage : struct, IMessage
         {
             return ref Lookup<TMessage>().FirstWithEntity(entityID);
         }
 
-        public bool SomeWithEntity<TMessage>(int entityID) where TMessage : struct, IHasEntity
+        public bool SomeWithEntity<TMessage>(int entityID) where TMessage : struct, IMessage, IHasEntity
         {
             return Lookup<TMessage>().SomeWithEntity(entityID);
         }

encompass-cs/Collections/TypedComponentStore.cs

@@ -78,8 +78,8 @@ namespace Encompass
         {
             if (!_priorities.ContainsKey(entityID) || priority <= _priorities[entityID]) // if priorities are equal that means it's the same engine
             {
-                ForceRemove(entityID);
                 _priorities[entityID] = priority;
+                ForceRemove(entityID);
                 return true;
             }
 
@@ -92,6 +92,7 @@ namespace Encompass
             {
                 var storageIndex = _entityIDToStorageIndex[entityID];
                 _entityIDToStorageIndex.Remove(entityID);
+                _priorities.Remove(entityID);
 
                 // move a component into the hole to maintain contiguous memory
                 if (_nextID > 1 && storageIndex != _nextID - 1)

encompass-cs/Collections/TypedMessageStore.cs

@@ -9,7 +9,7 @@ namespace Encompass
         public abstract void Clear();
     }
 
-    internal class TypedMessageStore<TMessage> : TypedMessageStore where TMessage : struct
+    internal class TypedMessageStore<TMessage> : TypedMessageStore where TMessage : struct, IMessage
     {
         // messages are placed in a contiguous region
         // so we can return the collection as a Span

encompass-cs/ComponentManager.cs

@@ -5,6 +5,8 @@ namespace Encompass
 {
     internal class ComponentManager
     {
+        private readonly DrawLayerManager _drawLayerManager;
+
         private readonly ComponentStore _existingComponentStore;
         private readonly ComponentStore _immediateComponentStore;
         private readonly ComponentDeltaStore _replayStore;
@@ -17,8 +19,9 @@ namespace Encompass
         internal ComponentBitSet ImmediateBits { get { return _immediateComponentStore.ComponentBitSet; } }
         internal ComponentBitSet ExistingBits { get { return _existingComponentStore.ComponentBitSet; } }
 
-        public ComponentManager(Dictionary<Type, int> typeToIndex)
+        public ComponentManager(DrawLayerManager drawLayerManager, Dictionary<Type, int> typeToIndex)
         {
+            this._drawLayerManager = drawLayerManager;
             _existingComponentStore = new ComponentStore(typeToIndex);
             _immediateComponentStore = new ComponentStore(typeToIndex);
             _replayStore = new ComponentDeltaStore(typeToIndex);
@@ -44,6 +47,11 @@ namespace Encompass
             _upToDateComponentStore.SwapWith(componentStore);
         }
 
+        internal void RegisterDrawableComponent<TComponent>(int entityID, int layer) where TComponent : struct
+        {
+            _drawLayerManager.RegisterComponentWithLayer<TComponent>(entityID, layer);
+        }
+
         internal void WriteComponents()
         {
             _existingComponentStore.UpdateUsing(_replayStore);
@@ -256,6 +264,7 @@ namespace Encompass
                 _immediateComponentStore.Remove(entityID);
                 _replayStore.Remove(entityID);
                 _upToDateComponentStore.Remove(entityID);
+                _drawLayerManager.UnRegisterEntityWithLayer(entityID);
             }
 
             _entitiesMarkedForRemoval.Clear();
@@ -267,6 +276,7 @@ namespace Encompass
             {
                 _replayStore.Remove<TComponent>(entityID, priority);
                 _upToDateComponentStore.Remove<TComponent>(entityID, priority);
+                _drawLayerManager.UnRegisterComponentWithLayer<TComponent>(entityID);
                 return true;
             }
             return false;
@@ -277,6 +287,7 @@ namespace Encompass
             if (_upToDateComponentStore.Remove<TComponent>(entityID, priority))
             {
                 _replayStore.Remove<TComponent>(entityID, priority);
+                _drawLayerManager.UnRegisterComponentWithLayer<TComponent>(entityID);
             }
         }
 

encompass-cs/DrawLayerManager.cs

@@ -0,0 +1,132 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Encompass.Exceptions;
+
+namespace Encompass
+{
+    internal class DrawLayerManager
+    {
+        private readonly SortedList<int, int> _layerOrder = new SortedList<int, int>();
+
+        private readonly Dictionary<int, Dictionary<Type, HashSet<int>>> _layerIndexToTypeToID = new Dictionary<int, Dictionary<Type, HashSet<int>>>();
+        private readonly Dictionary<int, HashSet<GeneralRenderer>> _layerIndexToGeneralRenderers = new Dictionary<int, HashSet<GeneralRenderer>>(512);
+
+        private readonly Dictionary<Type, Dictionary<int, int>> _typeToEntityToLayer = new Dictionary<Type, Dictionary<int, int>>(512);
+        public IEnumerable<int> LayerOrder { get { return _layerOrder.Values; } }
+
+        public DrawLayerManager()
+        {
+            RegisterDrawLayer(0);
+        }
+
+        public void RegisterDrawLayer(int layer)
+        {
+            if (!_layerIndexToTypeToID.ContainsKey(layer))
+            {
+                _layerOrder.Add(layer, layer);
+                _layerIndexToGeneralRenderers.Add(layer, new HashSet<GeneralRenderer>());
+                _layerIndexToTypeToID.Add(layer, new Dictionary<Type, HashSet<int>>());
+            }
+        }
+
+        public void RegisterOrderedDrawable<TComponent>() where TComponent : struct
+        {
+            if (!_typeToEntityToLayer.ContainsKey(typeof(TComponent)))
+            {
+                _typeToEntityToLayer.Add(typeof(TComponent), new Dictionary<int, int>(128));
+            }
+
+            foreach (var pair in _layerIndexToTypeToID)
+            {
+                if (!pair.Value.ContainsKey(typeof(TComponent)))
+                {
+                    pair.Value.Add(typeof(TComponent), new HashSet<int>());
+                }
+            }
+        }
+
+        public void RegisterGeneralRendererWithLayer(GeneralRenderer renderer, int layer)
+        {
+            RegisterDrawLayer(layer);
+            var set = _layerIndexToGeneralRenderers[layer];
+            set.Add(renderer);
+        }
+
+        public void RegisterComponentWithLayer<TComponent>(int entityID, int layer) where TComponent : struct
+        {
+            if (!_layerIndexToTypeToID.ContainsKey(layer))
+            {
+                throw new UndefinedLayerException("Layer {0} is not defined. Use WorldBuilder.RegisterDrawLayer to register the layer.", layer);
+            }
+
+            if (_typeToEntityToLayer[typeof(TComponent)].ContainsKey(entityID))
+            {
+                if (_typeToEntityToLayer[typeof(TComponent)][entityID] != layer)
+                {
+                    UnRegisterComponentWithLayer<TComponent>(entityID);
+
+                    var set = _layerIndexToTypeToID[layer][typeof(TComponent)];
+                    set.Add(entityID);
+
+                    _typeToEntityToLayer[typeof(TComponent)].Add(entityID, layer);
+                }
+            }
+            else
+            {
+                var set = _layerIndexToTypeToID[layer][typeof(TComponent)];
+                set.Add(entityID);
+
+                _typeToEntityToLayer[typeof(TComponent)].Add(entityID, layer);
+            }
+        }
+
+        public void UnRegisterComponentWithLayer<TComponent>(int entityID) where TComponent : struct
+        {
+            if (!_typeToEntityToLayer.ContainsKey(typeof(TComponent))) { return; }
+
+            if (_typeToEntityToLayer[typeof(TComponent)].ContainsKey(entityID))
+            {
+                var layer = _typeToEntityToLayer[typeof(TComponent)][entityID];
+                _layerIndexToTypeToID[layer][typeof(TComponent)].Remove(entityID);
+            }
+            _typeToEntityToLayer[typeof(TComponent)].Remove(entityID);
+        }
+
+        public void UnRegisterEntityWithLayer(int entityID)
+        {
+            foreach (var store in _layerIndexToTypeToID.Values)
+            {
+                foreach (var typeToSet in store)
+                {
+                    var type = typeToSet.Key;
+                    var set = typeToSet.Value;
+
+                    if (set.Contains(entityID))
+                    {
+                        _typeToEntityToLayer[type].Remove(entityID);
+                        set.Remove(entityID);
+                    }
+                }
+            }
+        }
+
+        public IEnumerable<GeneralRenderer> GeneralRenderersByLayer(int layer)
+        {
+            return _layerIndexToGeneralRenderers.ContainsKey(layer) ?
+                _layerIndexToGeneralRenderers[layer] :
+                Enumerable.Empty<GeneralRenderer>();
+        }
+
+        public IEnumerable<(int, Type)> AllInLayer(int layer)
+        {
+            foreach (var kvp in _layerIndexToTypeToID[layer])
+            {
+                foreach (var id in kvp.Value)
+                {
+                    yield return (id, kvp.Key);
+                }
+            }
+        }
+    }
+}

encompass-cs/Engine.cs

@@ -23,7 +23,6 @@ namespace Encompass
         internal readonly HashSet<Type> WriteImmediateTypes = new HashSet<Type>();
         internal readonly HashSet<Type> QueryWithTypes = new HashSet<Type>();
         internal readonly HashSet<Type> QueryWithoutTypes = new HashSet<Type>();
-        internal readonly HashSet<Type> AddTypes = new HashSet<Type>();
         internal readonly Dictionary<Type, int> WritePriorities = new Dictionary<Type, int>();
         internal readonly int DefaultWritePriority = 0;
 
@@ -59,12 +58,6 @@ namespace Encompass
         {
             _id = Guid.NewGuid();
 
-            var addsAttribute = GetType().GetCustomAttribute<Adds>(false);
-            if (addsAttribute != null)
-            {
-                AddTypes = addsAttribute.addTypes;
-            }
-
             var sendsAttribute = GetType().GetCustomAttribute<Sends>(false);
             if (sendsAttribute != null)
             {
@@ -176,7 +169,7 @@ namespace Encompass
             _trackingManager = trackingManager;
         }
 
-        internal void CheckMessageRead<TMessage>() where TMessage : struct
+        internal void CheckMessageRead<TMessage>() where TMessage : struct, IMessage
         {
             if (!ReceiveTypes.Contains(typeof(TMessage)))
             {
@@ -229,7 +222,7 @@ namespace Encompass
         /// <summary>
         /// Returns all Entities containing the specified Component type.
         /// </summary>
-        protected ReadOnlySpan<Entity> ReadEntities<TComponent>() where TComponent : struct
+        protected ReadOnlySpan<Entity> ReadEntities<TComponent>() where TComponent : struct, IComponent
         {
             var immediateRead = ReadImmediateTypes.Contains(typeof(TComponent));
             var existingRead = ReadTypes.Contains(typeof(TComponent));
@@ -254,7 +247,7 @@ namespace Encompass
         /// <summary>
         /// Returns an Entity containing the specified Component type.
         /// </summary>
-        protected ref readonly Entity ReadEntity<TComponent>() where TComponent : struct
+        protected ref readonly Entity ReadEntity<TComponent>() where TComponent : struct, IComponent
         {
             var immediateRead = ReadImmediateTypes.Contains(typeof(TComponent));
             var existingRead = ReadTypes.Contains(typeof(TComponent));
@@ -279,7 +272,7 @@ namespace Encompass
         /// <summary>
         /// Returns all of the Components with the specified Component Type.
         /// </summary>
-        protected ReadOnlySpan<TComponent> ReadComponents<TComponent>() where TComponent : struct
+        protected ReadOnlySpan<TComponent> ReadComponents<TComponent>() where TComponent : struct, IComponent
         {
             var immediateRead = ReadImmediateTypes.Contains(typeof(TComponent));
             var existingRead = ReadTypes.Contains(typeof(TComponent));
@@ -304,7 +297,7 @@ namespace Encompass
         /// <summary>
         /// Returns a Component with the specified Component Type. If multiples exist, an arbitrary Component is returned.
         /// </summary>
-        protected ref readonly TComponent ReadComponent<TComponent>() where TComponent : struct
+        protected ref readonly TComponent ReadComponent<TComponent>() where TComponent : struct, IComponent
         {
             var immediateRead = ReadImmediateTypes.Contains(typeof(TComponent));
             var existingRead = ReadTypes.Contains(typeof(TComponent));
@@ -329,7 +322,7 @@ namespace Encompass
         /// <summary>
         /// Returns true if any Component with the specified Component Type exists.
         /// </summary>
-        protected bool SomeComponent<TComponent>() where TComponent : struct
+        protected bool SomeComponent<TComponent>() where TComponent : struct, IComponent
         {
             var immediateRead = ReadImmediateTypes.Contains(typeof(TComponent));
             var existingRead = ReadTypes.Contains(typeof(TComponent));
@@ -351,7 +344,7 @@ namespace Encompass
             }
         }
 
-        private ref TComponent GetComponentHelper<TComponent>(int entityID) where TComponent : struct
+        private ref TComponent GetComponentHelper<TComponent>(int entityID) where TComponent : struct, IComponent
         {
             var immediateRead = ReadImmediateTypes.Contains(typeof(TComponent));
             var existingRead = ReadTypes.Contains(typeof(TComponent));
@@ -382,7 +375,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalReadException">
         /// Thrown when the Engine does not declare that it reads the given Component Type.
         /// </exception>
-        protected ref readonly TComponent GetComponent<TComponent>(in Entity entity) where TComponent : struct
+        protected ref readonly TComponent GetComponent<TComponent>(in Entity entity) where TComponent : struct, IComponent
         {
             return ref GetComponentHelper<TComponent>(entity.ID);
         }
@@ -393,7 +386,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalReadException">
         /// Thrown when the Engine does not declare that is Reads the given Component Type.
         /// </exception>
-        protected bool HasComponent<TComponent>(in Entity entity) where TComponent : struct
+        protected bool HasComponent<TComponent>(in Entity entity) where TComponent : struct, IComponent
         {
             var immediateRead = ReadImmediateTypes.Contains(typeof(TComponent));
             var existingRead = ReadTypes.Contains(typeof(TComponent));
@@ -451,7 +444,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalWriteException">
         /// Thrown when the Engine does not declare that it Writes the given Component Type.
         /// </exception>
-        protected void SetComponent<TComponent>(in Entity entity, in TComponent component) where TComponent : struct
+        protected void SetComponent<TComponent>(in Entity entity, in TComponent component) where TComponent : struct, IComponent
         {
             var priority = WritePriorities.ContainsKey(typeof(TComponent)) ? WritePriorities[typeof(TComponent)] : DefaultWritePriority;
 
@@ -478,6 +471,11 @@ namespace Encompass
             {
                 _trackingManager.RegisterAddition(entity.ID, typeof(TComponent));
             }
+
+            if (written && component is IDrawableComponent drawableComponent)
+            {
+                _componentManager.RegisterDrawableComponent<TComponent>(entity.ID, drawableComponent.Layer);
+            }
         }
 
         /// <summary>
@@ -486,13 +484,8 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalWriteException">
         /// Thrown when the Engine does not declare that it Writes the given Component Type.
         /// </exception>
-        protected void AddComponent<TComponent>(in Entity entity, in TComponent component) where TComponent : struct
+        protected void AddComponent<TComponent>(in Entity entity, in TComponent component) where TComponent : struct, IComponent
         {
-            if (!AddTypes.Contains(typeof(TComponent)))
-            {
-                throw new IllegalWriteException("Engine {0} tried to add undeclared Component {1}", GetType().Name, typeof(TComponent).Name);
-            }
-
             if (!EntityCreatedThisFrame(entity.ID))
             {
                 throw new IllegalWriteException("AddComponent used on Entity that was not created in this context. Use SetComponent instead.");
@@ -509,6 +502,11 @@ namespace Encompass
             }
 
             _trackingManager.RegisterAddition(entity.ID, typeof(TComponent));
+
+            if (component is IDrawableComponent drawableComponent)
+            {
+                _componentManager.RegisterDrawableComponent<TComponent>(entity.ID, drawableComponent.Layer);
+            }
         }
 
         /// <summary>
@@ -517,7 +515,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalSendException">
         /// Thrown when the Engine does not declare that it Sends the Message Type.
         /// </exception>
-        protected void SendMessage<TMessage>(in TMessage message) where TMessage : struct
+        protected void SendMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             if (!SendTypes.Contains(typeof(TMessage)))
             {
@@ -531,7 +529,7 @@ namespace Encompass
         /// Sends a message after the specified number of seconds, respecting time dilation.
         /// </summary>
         /// <param name="time">The time in seconds that will elapse before the message is sent.</param>
-        protected void SendMessage<TMessage>(in TMessage message, double time) where TMessage : struct
+        protected void SendMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageManager.AddMessage(message, time);
         }
@@ -540,7 +538,7 @@ namespace Encompass
         /// Sends a message after the specified number of seconds, ignoring time dilation.
         /// </summary>
         /// <param name="time">The time in seconds that will elapse before the message is sent.</param>
-        protected void SendMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct
+        protected void SendMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageManager.AddMessageIgnoringTimeDilation(message, time);
         }
@@ -551,7 +549,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalReadException">
         /// Thrown when the Engine does not declare that it Receives the specified Message Type.
         /// </exception>
-        protected ReadOnlySpan<TMessage> ReadMessages<TMessage>() where TMessage : struct
+        protected ReadOnlySpan<TMessage> ReadMessages<TMessage>() where TMessage : struct, IMessage
         {
             CheckMessageRead<TMessage>();
             return _messageManager.GetMessagesByType<TMessage>();
@@ -563,7 +561,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalReadException">
         /// Thrown when the Engine does not declare that it Receives the specified Message Type.
         /// </exception>
-        protected ref readonly TMessage ReadMessage<TMessage>() where TMessage : struct
+        protected ref readonly TMessage ReadMessage<TMessage>() where TMessage : struct, IMessage
         {
             CheckMessageRead<TMessage>();
             return ref _messageManager.First<TMessage>();
@@ -575,7 +573,7 @@ namespace Encompass
         /// <exception cref="Encompass.Exceptions.IllegalReadException">
         /// Thrown when the Engine does not declare that it Receives the specified Message Type.
         /// </exception>
-        protected bool SomeMessage<TMessage>() where TMessage : struct
+        protected bool SomeMessage<TMessage>() where TMessage : struct, IMessage
         {
             CheckMessageRead<TMessage>();
             return _messageManager.Any<TMessage>();
@@ -594,7 +592,7 @@ namespace Encompass
         /// Destroys an arbitrary Entity containing a Component of the specified Type.
         /// Entity destruction takes place after all the Engines have been processed by World Update.
         /// </summary>
-        protected void DestroyWith<TComponent>() where TComponent : struct
+        protected void DestroyWith<TComponent>() where TComponent : struct, IComponent
         {
             Destroy(ReadEntity<TComponent>());
         }
@@ -603,7 +601,7 @@ namespace Encompass
         /// Destroys all Entities containing a Component of the specified Type.
         /// Entity destruction takes place after all the Engines have been processed by World Update.
         /// </summary>
-        protected void DestroyAllWith<TComponent>() where TComponent : struct
+        protected void DestroyAllWith<TComponent>() where TComponent : struct, IComponent
         {
             foreach (var entity in ReadEntities<TComponent>())
             {
@@ -616,7 +614,7 @@ namespace Encompass
         /// Note that the Engine must Read the Component type that is being removed.
         /// If a Component with the specified type does not exist on the Entity, returns false and does not mutate the Entity.
         /// </summary>
-        protected void RemoveComponent<TComponent>(in Entity entity) where TComponent : struct
+        protected void RemoveComponent<TComponent>(in Entity entity) where TComponent : struct, IComponent
         {
             var priority = WritePriorities.ContainsKey(typeof(TComponent)) ? WritePriorities[typeof(TComponent)] : DefaultWritePriority;
 
@@ -709,7 +707,7 @@ namespace Encompass
         /// <typeparam name="TMessage">The Message subtype.</typeparam>
         /// <param name="entity">The entity that all messages in the IEnumerable refer to.</param>
         /// <returns></returns>
-        protected IEnumerable<TMessage> ReadMessagesWithEntity<TMessage>(in Entity entity) where TMessage : struct, IHasEntity
+        protected IEnumerable<TMessage> ReadMessagesWithEntity<TMessage>(in Entity entity) where TMessage : struct, IMessage, IHasEntity
         {
             CheckMessageRead<TMessage>();
             return _messageManager.WithEntity<TMessage>(entity.ID);
@@ -719,7 +717,7 @@ namespace Encompass
         /// Efficiently reads a single Message of a given type that references a given Entity.
         /// It is recommended to use this method in conjunction with SomeMessageWithEntity to prevent errors.
         /// </summary>
-        protected ref readonly TMessage ReadMessageWithEntity<TMessage>(in Entity entity) where TMessage : struct, IHasEntity
+        protected ref readonly TMessage ReadMessageWithEntity<TMessage>(in Entity entity) where TMessage : struct, IMessage, IHasEntity
         {
             CheckMessageRead<TMessage>();
             return ref _messageManager.WithEntitySingular<TMessage>(entity.ID);
@@ -728,7 +726,7 @@ namespace Encompass
         /// <summary>
         /// Efficiently checks if any Message of a given type referencing a given Entity exists.
         /// </summary>
-        protected bool SomeMessageWithEntity<TMessage>(in Entity entity) where TMessage : struct, IHasEntity
+        protected bool SomeMessageWithEntity<TMessage>(in Entity entity) where TMessage : struct, IMessage, IHasEntity
         {
             CheckMessageRead<TMessage>();
             return _messageManager.SomeWithEntity<TMessage>(entity.ID);

encompass-cs/Engines/Spawner.cs

@@ -6,7 +6,7 @@ namespace Encompass
     /// A Spawner is a special type of Engine that runs a Spawn method in response to each Message it receives.
     /// Spawners are useful for organizing the building of new Entities in your game.
     /// </summary>
-    public abstract class Spawner<TMessage> : Engine where TMessage : struct
+    public abstract class Spawner<TMessage> : Engine where TMessage : struct, IMessage
     {
         protected Spawner() : base()
         {

encompass-cs/Exceptions/IllegalSendTypeException.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace Encompass.Exceptions
+{
+    public class IllegalSendTypeException : Exception
+    {
+        public IllegalSendTypeException(
+            string format,
+            params object[] args
+        ) : base(string.Format(format, args)) { }
+    }
+}

encompass-cs/IMessage.cs

@@ -0,0 +1,7 @@
+namespace Encompass
+{
+    /// <summary>
+    /// Structs that implement IMessage are considered to be Messages.
+    /// </summary>
+    public interface IMessage { }
+}

encompass-cs/Interfaces/IComponent.cs

@@ -0,0 +1,4 @@
+namespace Encompass
+{
+    public interface IComponent { }
+}

encompass-cs/Interfaces/IDrawableComponent.cs

@@ -0,0 +1,7 @@
+namespace Encompass
+{
+    public interface IDrawableComponent
+    {
+        int Layer { get; }
+    }
+}

encompass-cs/MessageManager.cs

@@ -13,17 +13,17 @@ namespace Encompass
             _timeManager = timeManager;
         }
 
-        internal void AddMessage<TMessage>(in TMessage message) where TMessage : struct
+        internal void AddMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             _messageStore.AddMessage(message);
         }
 
-        internal void AddMessage<TMessage>(in TMessage message, double time) where TMessage : struct
+        internal void AddMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageStore.AddMessage(message, time);
         }
 
-        internal void AddMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct
+        internal void AddMessageIgnoringTimeDilation<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageStore.AddMessageIgnoringTimeDilation(message, time);
         }
@@ -38,32 +38,32 @@ namespace Encompass
             _messageStore.ProcessDelayedMessages(dt * _timeManager.TimeDilationFactor, dt);
         }
 
-        internal ReadOnlySpan<TMessage> GetMessagesByType<TMessage>() where TMessage : struct
+        internal ReadOnlySpan<TMessage> GetMessagesByType<TMessage>() where TMessage : struct, IMessage
         {
             return _messageStore.All<TMessage>();
         }
 
-        internal bool Any<TMessage>() where TMessage : struct
+        internal bool Any<TMessage>() where TMessage : struct, IMessage
         {
             return _messageStore.Any<TMessage>();
         }
 
-        internal ref readonly TMessage First<TMessage>() where TMessage : struct
+        internal ref readonly TMessage First<TMessage>() where TMessage : struct, IMessage
         {
             return ref _messageStore.First<TMessage>();
         }
 
-        internal IEnumerable<TMessage> WithEntity<TMessage>(int entityID) where TMessage : struct, IHasEntity
+        internal IEnumerable<TMessage> WithEntity<TMessage>(int entityID) where TMessage : struct, IMessage, IHasEntity
         {
             return _messageStore.WithEntity<TMessage>(entityID);
         }
 
-        internal ref readonly TMessage WithEntitySingular<TMessage>(int entityID) where TMessage : struct, IHasEntity
+        internal ref readonly TMessage WithEntitySingular<TMessage>(int entityID) where TMessage : struct, IMessage, IHasEntity
         {
             return ref _messageStore.FirstWithEntity<TMessage>(entityID);
         }
 
-        internal bool SomeWithEntity<TMessage>(int entityID) where TMessage : struct, IHasEntity
+        internal bool SomeWithEntity<TMessage>(int entityID) where TMessage : struct, IMessage, IHasEntity
         {
             return _messageStore.SomeWithEntity<TMessage>(entityID);
         }

encompass-cs/RenderManager.cs

@@ -1,27 +1,51 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 
 namespace Encompass
 {
     internal class RenderManager
     {
         private readonly EntityManager _entityManager;
-        private readonly List<Renderer> renderers = new List<Renderer>();
+        private readonly DrawLayerManager _drawLayerManager;
 
-        public RenderManager(EntityManager entityManager)
+        private readonly Dictionary<Type, Action<Entity>> _drawComponentTypeToOrderedRenderer = new Dictionary<Type, Action<Entity>>(256);
+
+        public RenderManager(EntityManager entityManager, DrawLayerManager drawLayerManager)
         {
             _entityManager = entityManager;
+            _drawLayerManager = drawLayerManager;
         }
 
-        public void AddRenderer(Renderer renderer)
+        public void RegisterOrderedRenderer<TComponent>(Action<Entity> renderAction) where TComponent : struct
         {
-            renderers.Add(renderer);
+            _drawComponentTypeToOrderedRenderer.Add(typeof(TComponent), renderAction);
+            _drawLayerManager.RegisterOrderedDrawable<TComponent>();
         }
 
-        public void Draw(double dt, double alpha)
+        public void RegisterGeneralRendererWithLayer(GeneralRenderer renderer, int layer)
         {
-            foreach (var renderer in renderers)
+            _drawLayerManager.RegisterGeneralRendererWithLayer(renderer, layer);
+        }
+
+        public void Draw()
+        {
+            foreach (var layer in _drawLayerManager.LayerOrder)
             {
-                renderer.Render(dt, alpha);
+                var generalRendererSet = _drawLayerManager.GeneralRenderersByLayer(layer);
+
+                foreach (var (entityID, componentType) in _drawLayerManager.AllInLayer(layer))
+                {
+                    if (_drawComponentTypeToOrderedRenderer.ContainsKey(componentType))
+                    {
+                        var internalRenderAction = _drawComponentTypeToOrderedRenderer[componentType];
+                        internalRenderAction(_entityManager.GetEntity(entityID));
+                    }
+                }
+
+                foreach (var generalRenderer in generalRendererSet)
+                {
+                    generalRenderer.Render();
+                }
             }
         }
     }

encompass-cs/Renderer.cs

@@ -18,49 +18,47 @@ namespace Encompass
             _componentManager = componentManager;
         }
 
-        public abstract void Render(double dt, double alpha);
-
-        protected ReadOnlySpan<Entity> ReadEntities<TComponent>() where TComponent : struct
+        protected ReadOnlySpan<Entity> ReadEntities<TComponent>() where TComponent : struct, IComponent
         {
             return _componentManager.GetExistingEntities<TComponent>();
         }
 
-        protected IEnumerable<Entity> ReadEntitiesAsEnumerable<TComponent>() where TComponent : struct
+        protected IEnumerable<Entity> ReadEntitiesAsEnumerable<TComponent>() where TComponent : struct, IComponent
         {
             return _componentManager.GetExistingEntitiesAsEnumerable<TComponent>();
         }
 
-        protected ref readonly Entity ReadEntity<TComponent>() where TComponent : struct
+        protected ref readonly Entity ReadEntity<TComponent>() where TComponent : struct, IComponent
         {
             return ref _componentManager.ExistingSingularEntity<TComponent>();
         }
 
-        protected ReadOnlySpan<TComponent> ReadComponents<TComponent>() where TComponent : struct
+        protected ReadOnlySpan<TComponent> ReadComponents<TComponent>() where TComponent : struct, IComponent
         {
             return _componentManager.GetComponentsByType<TComponent>();
         }
 
-        protected IEnumerable<TComponent> ReadComponentsAsEnumerable<TComponent>() where TComponent : struct
+        protected IEnumerable<TComponent> ReadComponentsAsEnumerable<TComponent>() where TComponent : struct, IComponent
         {
             return _componentManager.GetComponentsByTypeEnumerable<TComponent>();
         }
 
-        protected ref readonly TComponent ReadComponent<TComponent>() where TComponent : struct
+        protected ref readonly TComponent ReadComponent<TComponent>() where TComponent : struct, IComponent
         {
             return ref _componentManager.ExistingSingular<TComponent>();
         }
 
-        protected ref readonly TComponent GetComponent<TComponent>(Entity entity) where TComponent : struct
+        protected ref readonly TComponent GetComponent<TComponent>(Entity entity) where TComponent : struct, IComponent
         {
             return ref _componentManager.GetComponentByEntityAndType<TComponent>(entity.ID);
         }
 
-        protected bool HasComponent<TComponent>(Entity entity) where TComponent : struct
+        protected bool HasComponent<TComponent>(Entity entity) where TComponent : struct, IComponent
         {
             return _componentManager.EntityHasComponentOfType<TComponent>(entity.ID);
         }
 
-        protected bool SomeComponent<TComponent>() where TComponent : struct
+        protected bool SomeComponent<TComponent>() where TComponent : struct, IComponent
         {
             return _componentManager.SomeExistingComponent<TComponent>();
         }

encompass-cs/Renderers/GeneralRenderer.cs

@@ -0,0 +1,11 @@
+namespace Encompass
+{
+    /// <summary>
+    /// GeneralRenderer is a Renderer which generically reads the game state in order to draw elements to the screen.
+    /// GeneralRenderers have a layer specified when they are added to the World.
+    /// </summary>
+    public abstract class GeneralRenderer : Renderer
+    {
+        public abstract void Render();
+    }
+}

encompass-cs/Renderers/OrderedRenderer.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace Encompass
+{
+    /// <summary>
+    /// OrdereredRenderer provides a structure for the common pattern of wishing to draw a specific DrawComponent at a specific layer.
+    /// </summary>
+    public abstract class OrderedRenderer<TComponent> : Renderer where TComponent : struct, IComponent, IDrawableComponent
+    {
+        public abstract void Render(Entity entity, in TComponent drawComponent);
+
+        internal void InternalRender(Entity entity)
+        {
+            ref readonly var component = ref GetComponent<TComponent>(entity);
+            Render(entity, component);
+        }
+    }
+}

encompass-cs/UberEngine.cs

@@ -14,7 +14,6 @@ namespace Encompass
         {
             _componentTypes = componentTypes;
             _messageTypes = messageTypes;
-            AddTypes.UnionWith(componentTypes);
             ReadTypes.UnionWith(componentTypes);
             WriteTypes.UnionWith(componentTypes);
             SendTypes.UnionWith(messageTypes);
@@ -55,7 +54,7 @@ namespace Encompass
 
         // we can't reflect invoke on byref returns or Span returns right now... so we have non-return wrapper methods
 
-        protected void CallAllComponentMethods<TComponent>() where TComponent : struct
+        protected void CallAllComponentMethods<TComponent>() where TComponent : struct, IComponent
         {
             ReadComponent<TComponent>();
             ReadComponents<TComponent>();
@@ -70,7 +69,7 @@ namespace Encompass
             AddComponent<TComponent>(Entity, default);
         }
 
-        protected void CallAllMessageMethods<TMessage>() where TMessage : struct
+        protected void CallAllMessageMethods<TMessage>() where TMessage : struct, IMessage
         {
             SendMessageIgnoringTimeDilation<TMessage>(default, 0.1);
             SendMessage<TMessage>(default);
@@ -80,7 +79,7 @@ namespace Encompass
             SomeMessage<TMessage>();
         }
 
-        protected void CallAllEntityMessageMethods<TMessage>() where TMessage : struct, IHasEntity
+        protected void CallAllEntityMessageMethods<TMessage>() where TMessage : struct, IMessage, IHasEntity
         {
             ReadMessagesWithEntity<TMessage>(Entity);
             ReadMessageWithEntity<TMessage>(Entity);

encompass-cs/UberRenderer.cs

@@ -20,7 +20,7 @@ namespace Encompass
         }
 
         // can't reflect invoke on Span returns...
-        public override void Render(double dt, double alpha)
+        public void Render()
         {
             foreach (var type in _componentTypes)
             {
@@ -28,7 +28,7 @@ namespace Encompass
             }
         }
 
-        protected void CallAllComponentMethods<TComponent>() where TComponent : struct
+        protected void CallAllComponentMethods<TComponent>() where TComponent : struct, IComponent
         {
             ReadEntity<TComponent>();
             ReadEntities<TComponent>();

encompass-cs/World.cs

@@ -69,9 +69,9 @@ namespace Encompass
         /// <summary>
         /// Causes the Renderers to draw.
         /// </summary>
-        public void Draw(double dt, double alpha)
+        public void Draw()
         {
-            _renderManager.Draw(dt, alpha);
+            _renderManager.Draw();
         }
     }
 }

encompass-cs/WorldBuilder.cs

@@ -26,6 +26,7 @@ namespace Encompass
         private readonly EntityManager _entityManager;
         private readonly MessageManager _messageManager;
         private readonly TimeManager _timeManager;
+        private readonly DrawLayerManager _drawLayerManager;
         private readonly RenderManager _renderManager;
         private readonly TrackingManager _trackingManager;
 
@@ -35,15 +36,18 @@ namespace Encompass
         private readonly HashSet<Type> _messageTypes = new HashSet<Type>();
         private readonly Dictionary<Type, int> _typeToIndex = new Dictionary<Type, int>();
 
+        private bool _rendererRegistered = false;
+
         public WorldBuilder(int entityCapacity = 32768)
         {
             _entityCapacity = entityCapacity;
+            _drawLayerManager = new DrawLayerManager();
             _timeManager = new TimeManager();
             _trackingManager = new TrackingManager();
-            _componentManager = new ComponentManager(_typeToIndex);
+            _componentManager = new ComponentManager(_drawLayerManager, _typeToIndex);
             _messageManager = new MessageManager(_timeManager);
             _entityManager = new EntityManager(_componentManager, entityCapacity);
-            _renderManager = new RenderManager(_entityManager);
+            _renderManager = new RenderManager(_entityManager, _drawLayerManager);
 
             _startingExistingComponentStore = new ComponentStore(_typeToIndex);
             _startingUpToDateComponentStore = new ComponentStore(_typeToIndex);
@@ -60,7 +64,7 @@ namespace Encompass
         /// <summary>
         /// Specifies that the given Message should be sent immediately on the first World Update.
         /// </summary>
-        public void SendMessage<TMessage>(in TMessage message) where TMessage : struct
+        public void SendMessage<TMessage>(in TMessage message) where TMessage : struct, IMessage
         {
             _messageManager.AddMessage(message);
         }
@@ -68,7 +72,7 @@ namespace Encompass
         /// <summary>
         /// Specifies that the given Message should be sent after the specified number of seconds after the first World Update.
         /// </summary>
-        public void SendMessage<TMessage>(in TMessage message, double time) where TMessage : struct
+        public void SendMessage<TMessage>(in TMessage message, double time) where TMessage : struct, IMessage
         {
             _messageManager.AddMessage<TMessage>(message, time);
         }
@@ -76,21 +80,20 @@ namespace Encompass
         /// <summary>
         /// Sets Component data for the specified Component Type on the specified Entity.
         /// </summary>
-        public void SetComponent<TComponent>(Entity entity, in TComponent component) where TComponent : struct
+        public void SetComponent<TComponent>(Entity entity, in TComponent component) where TComponent : struct, IComponent
         {
             RegisterComponentType<TComponent>();
             _startingExistingComponentStore.Set(entity.ID, component);
             _startingUpToDateComponentStore.Set(entity.ID, component);
+
+            if (component is IDrawableComponent drawableComponent)
+            {
+                _componentManager.RegisterDrawableComponent<TComponent>(entity.ID, drawableComponent.Layer);
+                _drawLayerManager.RegisterOrderedDrawable<TComponent>();
+            }
         }
 
-        internal void RegisterComponentTypeNonGeneric(Type type)
-        {
-            var method = GetType().GetMethod("RegisterComponentType", BindingFlags.NonPublic | BindingFlags.Instance);
-            var generic = method.MakeGenericMethod(type);
-            generic.Invoke(this, null);
-        }
-
-        internal void RegisterComponentType<TComponent>() where TComponent : struct
+        internal void RegisterComponentType<TComponent>() where TComponent : struct, IComponent
         {
             if (!_typeToIndex.ContainsKey(typeof(TComponent)))
             {
@@ -155,26 +158,6 @@ namespace Encompass
                 _senders.Add(engine);
             }
 
-            foreach (var componentType in engine.ReadTypes)
-            {
-                RegisterComponentTypeNonGeneric(componentType);
-            }
-
-            foreach (var componentType in engine.AddTypes)
-            {
-                RegisterComponentTypeNonGeneric(componentType);
-            }
-
-            foreach (var componentType in engine.WriteTypes)
-            {
-                RegisterComponentTypeNonGeneric(componentType);
-            }
-
-            foreach (var componentType in engine.WriteImmediateTypes)
-            {
-                RegisterComponentTypeNonGeneric(componentType);
-            }
-
             foreach (var componentType in engine.QueryWithTypes)
             {
                 _trackingManager.RegisterComponentTypeToEngine(componentType, engine);
@@ -217,13 +200,44 @@ namespace Encompass
         }
 
         /// <summary>
-        /// Adds the specified Renderer to the World.
+        /// Registers a draw layer. This must be done before any Renderers are registered.
         /// </summary>
-        public void AddRenderer(Renderer renderer)
+        /// <param name="layer">The draw layer to register.</param>
+        public void RegisterDrawLayer(int layer)
         {
-            renderer.AssignComponentManager(_componentManager);
+            if (_rendererRegistered)
+            {
+                throw new IllegalDrawLayerException("Cannot register a draw layer after a Renderer has been registered.");
+            }
+            _drawLayerManager.RegisterDrawLayer(layer);
+        }
+
+        /// <summary>
+        /// Adds the specified OrderedRenderer to the World.
+        /// </summary>
+        public OrderedRenderer<TComponent> AddOrderedRenderer<TComponent>(OrderedRenderer<TComponent> renderer) where TComponent : struct, IComponent, IDrawableComponent
+        {
+            RegisterComponentType<TComponent>();
             renderer.AssignEntityManager(_entityManager);
-            _renderManager.AddRenderer(renderer);
+            renderer.AssignComponentManager(_componentManager);
+            _renderManager.RegisterOrderedRenderer<TComponent>(renderer.InternalRender);
+            _rendererRegistered = true;
+            return renderer;
+        }
+
+        /// <summary>
+        /// Adds the specified GeneralRenderer to the World at the specified layer.
+        /// Higher layer numbers draw on top of lower layer numbers.
+        /// </summary>
+        /// <param name="renderer">An instance of a GeneralRenderer.</param>
+        /// <param name="layer">The layer at which the GeneralRenderer should render. Higher numbers draw over lower numbers.</param>
+        public TRenderer AddGeneralRenderer<TRenderer>(TRenderer renderer, int layer) where TRenderer : GeneralRenderer
+        {
+            renderer.AssignEntityManager(_entityManager);
+            renderer.AssignComponentManager(_componentManager);
+            _renderManager.RegisterGeneralRendererWithLayer(renderer, layer);
+            _rendererRegistered = true;
+            return renderer;
         }
 
         private void BuildEngineGraph()
@@ -427,20 +441,44 @@ namespace Encompass
         {
             var dummyTimeManager = new TimeManager();
             var dummyMessageManager = new MessageManager(dummyTimeManager);
+            var dummyDrawLayerManager = new DrawLayerManager();
             var dummyTrackingManager = new TrackingManager();
-            var dummyComponentManager = new ComponentManager(_typeToIndex);
+            var dummyComponentManager = new ComponentManager(dummyDrawLayerManager, _typeToIndex);
             var dummyEntityManager = new EntityManager(dummyComponentManager, _entityCapacity);
-            var dummyRenderManager = new RenderManager(dummyEntityManager);
+            var dummyRenderManager = new RenderManager(dummyEntityManager, dummyDrawLayerManager);
+
+            // doing reflection to grab all component types, because not all writes need to be declared
+            foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies())
+            {
+                foreach (var componentType in assembly.GetTypes())
+                {
+                    if (typeof(IComponent).IsAssignableFrom(componentType) && componentType.IsValueType && !componentType.IsEnum && !componentType.IsPrimitive)
+                    {
+                        var method = typeof(WorldBuilder).GetMethod("RegisterComponentType", BindingFlags.NonPublic | BindingFlags.Instance);
+                        var generic = method.MakeGenericMethod(componentType);
+                        generic.Invoke(this, null);
+
+                        var dummyRegisterMethod = typeof(ComponentManager).GetMethod("RegisterComponentType", BindingFlags.Public | BindingFlags.Instance);
+                        var dummyGeneric = dummyRegisterMethod.MakeGenericMethod(componentType);
+                        dummyGeneric.Invoke(dummyComponentManager, null);
+                    }
+
+                    if (componentType.GetInterface("IDrawableComponent") != null)
+                    {
+                        // register draw layer using property value
+                        var instance = Activator.CreateInstance(componentType);
+                        var layerPropertyInfo = componentType.GetProperty("Layer");
+                        dummyDrawLayerManager.RegisterDrawLayer((int)layerPropertyInfo.GetValue(instance));
+
+                        var drawLayerManagerRegisterMethod = typeof(DrawLayerManager).GetMethod("RegisterOrderedDrawable");
+                        var drawLayerManagerRegisterGenericMethod = drawLayerManagerRegisterMethod.MakeGenericMethod(componentType);
+                        drawLayerManagerRegisterGenericMethod.Invoke(dummyDrawLayerManager, null);
+                    }
+                }
+            }
 
             var prepEngineOrder = new List<Engine>();
 
-            foreach (var componentType in _componentTypesToPreload)
-            {
-                var dummyRegisterMethod = typeof(ComponentManager).GetMethod("RegisterComponentType", BindingFlags.Public | BindingFlags.Instance);
-                var dummyGeneric = dummyRegisterMethod.MakeGenericMethod(componentType);
-                dummyGeneric.Invoke(dummyComponentManager, null);
-            }
-
             var uberEngine = new UberEngine(_componentTypesToPreload, messageTypes);
 
             uberEngine.AssignEntityManager(dummyEntityManager);
@@ -474,7 +512,7 @@ namespace Encompass
             dummyComponentManager.WriteComponents();
 
             uberRenderer.SetEntity(uberEngine.Entity);
-            uberRenderer.Render(1, 0);
+            uberRenderer.Render();
         }
     }
 }

encompass-cs/encompass-cs.csproj

@@ -17,7 +17,6 @@
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <AssemblyName>EncompassECS.Framework</AssemblyName>
     <PackageLicenseFile>LICENSE</PackageLicenseFile>
-    <Platforms>x64;x86</Platforms>
   </PropertyGroup>
   <ItemGroup>
     <None Include="..\LICENSE">

test/ComponentTest.cs

@@ -8,12 +8,12 @@ namespace Tests
 {
     public class ComponentTests
     {
-        struct MockComponent
+        struct MockComponent : IComponent
         {
             public int myInt;
         }
 
-        struct EntityMessage
+        struct EntityMessage : IMessage
         {
             public Entity entity;
         }
@@ -33,7 +33,7 @@ namespace Tests
             }
         }
 
-        struct AddComponentTestMessage
+        struct AddComponentTestMessage : IMessage
         {
             public Entity entity;
             public MockComponent mockComponent;
@@ -62,6 +62,8 @@ namespace Tests
 
             var entity = worldBuilder.CreateEntity();
 
+            const string MyString = "hello";
+
             MockComponent mockComponent;
             mockComponent.myInt = 3;
 
@@ -172,7 +174,7 @@ namespace Tests
             Assert.DoesNotThrow(() => world.Update(0.01));
         }
 
-        struct AddMockComponentMessage
+        struct AddMockComponentMessage : IMessage
         {
             public Entity entity;
             public MockComponent mockComponent;
@@ -269,7 +271,7 @@ namespace Tests
 
             Assert.AreEqual(mockComponent, gottenMockComponent);
         }
-        struct HasComponentTestMessage
+        struct HasComponentTestMessage : IMessage
         {
             public Entity entity;
         }
@@ -367,7 +369,7 @@ namespace Tests
             Assert.IsFalse(hasComponentRuntimeTypeResult);
         }
 
-        struct RemoveComponentTestMessage
+        struct RemoveComponentTestMessage : IMessage
         {
             public Entity entity;
         }
@@ -461,7 +463,7 @@ namespace Tests
             hasComponentResult.Should().BeFalse();
         }
 
-        struct CheckHasMockComponentMessage
+        struct CheckHasMockComponentMessage : IMessage
         {
             public Entity entity;
             public bool shouldHaveComponent;

test/EngineTest.cs

@@ -10,7 +10,7 @@ using Encompass.Exceptions;
 
 namespace Tests
 {
-    struct MockComponent
+    struct MockComponent : IComponent
     {
         public int myInt;
     }
@@ -271,7 +271,7 @@ namespace Tests
             Assert.That(ex.Message, Is.EqualTo("Engine UndeclaredUpdateComponentTestEngine tried to update undeclared Component MockComponent"));
         }
 
-        struct MockMessage
+        struct MockMessage : IMessage
         {
             public string myString;
         }
@@ -435,7 +435,7 @@ namespace Tests
             Assert.Throws<IllegalReadException>(() => world.Update(0.01f));
         }
 
-        struct EntityMessage : IHasEntity
+        struct EntityMessage : IMessage, IHasEntity
         {
             public EntityMessage(Entity entity, int myInt)
             {
@@ -650,7 +650,7 @@ namespace Tests
             world.Update(0.01f);
         }
 
-        struct DestroyerComponent { }
+        struct DestroyerComponent : IComponent { }
 
         [Reads(typeof(DestroyerComponent))]
         class DestroyerEngine : Engine
@@ -955,7 +955,7 @@ namespace Tests
             resultComponents.Should().BeEmpty();
         }
 
-        struct DestroyComponentMessage { public Entity entity; }
+        struct DestroyComponentMessage : IMessage { public Entity entity; }
 
         [Reads(typeof(MockComponent))]
         [Writes(typeof(MockComponent))]
@@ -1007,7 +1007,7 @@ namespace Tests
             Assert.Throws<NoComponentOfTypeException>(() => world.Update(0.01), "No component of type MockComponent exists");
         }
 
-        struct MockComponentB
+        struct MockComponentB : IComponent
         {
             private int value;
 
@@ -1324,7 +1324,6 @@ namespace Tests
             undilatedDeltaTime.Should().Be(0.5);
         }
 
-        [Adds(typeof(MockComponent))]
         class AddComponentWithoutPriorityEngine : Engine
         {
             public override void Update(double dt)
@@ -1381,7 +1380,6 @@ namespace Tests
             Assert.Throws<IllegalWriteException>(() => world.Update(0.01));
         }
 
-        [Adds(typeof(MockComponentB))]
         [WritesImmediate(typeof(MockComponentB))]
         class AddImmediateComponentEngine : Engine
         {
@@ -1452,9 +1450,9 @@ namespace Tests
 
         public class QueryTests
         {
-            struct MockComponentB { }
-            struct MockComponentC { }
-            struct MockComponentD { }
+            struct MockComponentB : IComponent { }
+            struct MockComponentC : IComponent { }
+            struct MockComponentD : IComponent { }
 
             [Writes(typeof(MockComponentB))]
             [QueryWith(typeof(MockComponent), typeof(MockComponentB))]
@@ -1904,7 +1902,7 @@ namespace Tests
                 _components.Should().NotBeEmpty();
             }
 
-            struct MockTimerComponent
+            struct MockTimerComponent : IComponent
             {
                 public double Timer { get; }
 

test/GeneralRendererTest.cs

@@ -5,15 +5,15 @@ namespace Tests
 {
     public static class GeneralRendererTest
     {
-        struct AComponent { }
+        struct AComponent : IComponent { }
 
         public class SingletonRead
         {
             static (AComponent, Entity) result;
 
-            class TestRenderer : Renderer
+            class TestRenderer : GeneralRenderer
             {
-                public override void Render(double dt, double alpha)
+                public override void Render()
                 {
                     ref readonly var entity = ref ReadEntity<AComponent>();
                     result = (GetComponent<AComponent>(entity), entity);
@@ -24,7 +24,7 @@ namespace Tests
             public void SingletonComponent()
             {
                 var worldBuilder = new WorldBuilder();
-                worldBuilder.AddRenderer(new TestRenderer());
+                worldBuilder.AddGeneralRenderer(new TestRenderer(), 1);
 
                 AComponent aComponent;
 
@@ -34,10 +34,10 @@ namespace Tests
                 var world = worldBuilder.Build();
 
                 world.Update(0.01f);
-                world.Draw(0.01f, 0);
+                world.Draw();
 
                 world.Update(0.01);
-                world.Draw(0.01f, 0);
+                world.Draw();
 
                 Assert.That(result, Is.EqualTo((aComponent, entity)));
             }
@@ -46,7 +46,7 @@ namespace Tests
             public void MultipleComponents()
             {
                 var worldBuilder = new WorldBuilder();
-                worldBuilder.AddRenderer(new TestRenderer());
+                worldBuilder.AddGeneralRenderer(new TestRenderer(), 1);
 
                 AComponent aComponent;
                 AComponent aComponentTwo;
@@ -59,10 +59,10 @@ namespace Tests
                 var world = worldBuilder.Build();
 
                 world.Update(0.01f);
-                world.Draw(0.01f, 0);
+                world.Draw();
 
                 world.Update(0.01f);
-                world.Draw(0.01f, 0);
+                world.Draw();
 
                 Assert.That(result, Is.EqualTo((aComponent, entity)).Or.EqualTo((aComponentTwo, entityB)));
             }

test/OrderedRendererTest.cs

@@ -0,0 +1,109 @@
+using System;
+
+using NUnit.Framework;
+using FluentAssertions;
+using Encompass;
+using System.Collections.Generic;
+
+namespace Tests
+{
+    public class OrderedRendererTest
+    {
+        struct AComponent : IComponent { }
+        struct BComponent : IComponent { }
+        struct CComponent : IComponent { }
+
+        struct TestDrawComponent : IComponent, IDrawableComponent
+        {
+            public int Layer { get; set; }
+        }
+
+        class TestRenderer : OrderedRenderer<TestDrawComponent>
+        {
+            public override void Render(Entity entity, in TestDrawComponent testDrawComponent) { }
+        }
+
+        static bool called = false;
+        class DeactivatedRenderer : TestRenderer
+        {
+            public override void Render(Entity entity, in TestDrawComponent testDrawComponent)
+            {
+                called = true;
+            }
+        }
+
+        static bool calledOnDraw = false;
+        static (TestDrawComponent, Entity) resultComponent;
+
+        class CalledRenderer : OrderedRenderer<TestDrawComponent>
+        {
+            public override void Render(Entity entity, in TestDrawComponent testDrawComponent)
+            {
+                resultComponent = (testDrawComponent, entity);
+                calledOnDraw = true;
+            }
+        }
+
+        [Test]
+        public void RenderMethodCalledOnWorldDraw()
+        {
+            var worldBuilder = new WorldBuilder();
+            worldBuilder.RegisterDrawLayer(2);
+
+            var renderer = worldBuilder.AddOrderedRenderer(new CalledRenderer());
+
+            AComponent aComponent;
+            CComponent cComponent;
+
+            var testDrawComponent = new TestDrawComponent { Layer = 2 };
+
+            var entity = worldBuilder.CreateEntity();
+            worldBuilder.SetComponent(entity, aComponent);
+            worldBuilder.SetComponent(entity, cComponent);
+            worldBuilder.SetComponent(entity, testDrawComponent);
+
+            var world = worldBuilder.Build();
+
+            world.Update(0.01f);
+            world.Draw();
+
+            Assert.IsTrue(calledOnDraw);
+            resultComponent.Should().BeEquivalentTo((testDrawComponent, entity));
+        }
+
+        [Reads(typeof(TestDrawComponent))]
+        class DestroyerEngine : Engine
+        {
+            public override void Update(double dt)
+            {
+                foreach (var entity in ReadEntities<TestDrawComponent>())
+                {
+                    Destroy(entity);
+                }
+            }
+        }
+        [Test]
+        public void RenderMethodNotCalledAfterDestroy()
+        {
+            calledOnDraw = false;
+
+            var worldBuilder = new WorldBuilder();
+            worldBuilder.RegisterDrawLayer(1);
+
+            worldBuilder.AddEngine(new DestroyerEngine());
+            var renderer = worldBuilder.AddOrderedRenderer(new CalledRenderer());
+
+            TestDrawComponent testDrawComponent = new TestDrawComponent { Layer = 1 };
+
+            var entity = worldBuilder.CreateEntity();
+            worldBuilder.SetComponent(entity, testDrawComponent);
+
+            var world = worldBuilder.Build();
+
+            world.Update(0.01);
+            world.Draw();
+
+            Assert.IsFalse(calledOnDraw);
+        }
+    }
+}

test/SpawnerTest.cs

@@ -5,8 +5,8 @@ namespace Tests
 {
     public class SpawnerTest
     {
-        struct TestComponent { }
-        struct SpawnMessageA { }
+        struct TestComponent : IComponent { }
+        struct SpawnMessageA : IMessage { }
 
         static Entity resultEntity;
 

test/WorldBuilderTest.cs

@@ -13,8 +13,8 @@ namespace Tests
     {
         public class EngineCycleSimple
         {
-            struct AMessage { }
-            struct BMessage { }
+            struct AMessage : IMessage { }
+            struct BMessage : IMessage { }
 
             [Receives(typeof(AMessage))]
             [Sends(typeof(BMessage))]
@@ -51,10 +51,10 @@ namespace Tests
 
         public class EngineCycleComplex
         {
-            struct AMessage { }
-            struct BMessage { }
-            struct CMessage { }
-            struct DMessage { }
+            struct AMessage : IMessage { }
+            struct BMessage : IMessage { }
+            struct CMessage : IMessage { }
+            struct DMessage : IMessage { }
 
             [Receives(typeof(AMessage))]
             [Sends(typeof(BMessage))]
@@ -142,12 +142,12 @@ namespace Tests
 
         public class MultipleEngineWriteWithPriority
         {
-            struct SetMessage
+            struct SetMessage : IMessage
             {
                 public Entity entity;
             }
 
-            struct AComponent
+            struct AComponent : IComponent
             {
                 public int myInt;
             }
@@ -211,12 +211,12 @@ namespace Tests
 
         public class DefaultWritePriority
         {
-            struct SetMessage
+            struct SetMessage : IMessage
             {
                 public Entity entity;
             }
 
-            struct AComponent
+            struct AComponent : IComponent
             {
                 public int myInt;
             }
@@ -298,7 +298,7 @@ namespace Tests
 
         public class EngineMessageSelfCycle
         {
-            struct AMessage { }
+            struct AMessage : IMessage { }
 
             [Receives(typeof(AMessage))]
             [Sends(typeof(AMessage))]
@@ -319,6 +319,28 @@ namespace Tests
             }
         }
 
+        public class IllegalWriteType
+        {
+            struct ANonMessage { }
+
+            [Sends(typeof(ANonMessage))]
+            class MyEngine : Engine
+            {
+                public override void Update(double dt)
+                {
+
+                }
+            }
+
+            [Test]
+            public void ThrowsError()
+            {
+                var worldBuilder = new WorldBuilder();
+
+                Assert.Throws<IllegalSendTypeException>(() => worldBuilder.AddEngine(new MyEngine()), "ANonMessage must be a Message or Component");
+            }
+        }
+
         public class PriorityConflict
         {
             [Writes(typeof(MockComponent), 2)]
@@ -385,13 +407,13 @@ namespace Tests
         {
             static List<Engine> order = new List<Engine>();
 
-            struct AComponent { }
-            struct BComponent { }
+            struct AComponent : IComponent { }
+            struct BComponent : IComponent { }
 
-            struct AMessage { }
-            struct BMessage { }
-            struct CMessage { }
-            struct DMessage { }
+            struct AMessage : IMessage { }
+            struct BMessage : IMessage { }
+            struct CMessage : IMessage { }
+            struct DMessage : IMessage { }
 
             [Sends(typeof(AMessage))]
             class AEngine : Engine
@@ -498,8 +520,8 @@ namespace Tests
         {
             static List<Engine> order = new List<Engine>();
 
-            struct AMessage { }
-            struct BMessage { }
+            struct AMessage : IMessage { }
+            struct BMessage : IMessage { }
 
             [Sends(typeof(AMessage), typeof(BMessage))]
             class AEngine : Engine
@@ -536,5 +558,57 @@ namespace Tests
                 Assert.That(order.IndexOf(engineA), Is.LessThan(order.IndexOf(engineB)));
             }
         }
+
+        public class DrawLayerRegister
+        {
+            struct AComponent : IComponent, IDrawableComponent
+            {
+                public int Layer { get; }
+            }
+
+            struct BComponent : IComponent, IDrawableComponent
+            {
+                public int Layer { get => 3; }
+            }
+
+            class ARenderer : OrderedRenderer<AComponent>
+            {
+                public override void Render(Entity entity, in AComponent drawComponent) { }
+            }
+
+            class BRenderer : OrderedRenderer<BComponent>
+            {
+                public override void Render(Entity entity, in BComponent drawComponent) { }
+            }
+
+            [Test]
+            public void DrawLayerRegisterAfterOrderedRendererRegisterThrows()
+            {
+                var worldBuilder = new WorldBuilder();
+
+                var rendererA = worldBuilder.AddOrderedRenderer(new ARenderer());
+
+                Assert.Throws<IllegalDrawLayerException>(() => worldBuilder.RegisterDrawLayer(1));
+            }
+
+            [Test]
+            public void DrawLayerRegisterBeforeOrderedRendererDoesNotThrow()
+            {
+                var worldBuilder = new WorldBuilder();
+
+                Assert.DoesNotThrow(() => worldBuilder.RegisterDrawLayer(1));
+                Assert.DoesNotThrow(() => worldBuilder.AddOrderedRenderer(new ARenderer()));
+            }
+
+            [Test]
+            public void DrawLayerWithProperty()
+            {
+                var worldBuilder = new WorldBuilder();
+
+                var rendererB = worldBuilder.AddOrderedRenderer(new BRenderer());
+
+                Assert.DoesNotThrow(() => worldBuilder.Build());
+            }
+        }
     }
 }

test/WorldTest.cs

@@ -0,0 +1,81 @@
+using NUnit.Framework;
+using FluentAssertions;
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+using Encompass;
+
+namespace Tests
+{
+    public class WorldTest
+    {
+        struct TestComponent : IComponent { }
+        struct TestDrawComponent : IComponent, IDrawableComponent
+        {
+            public int Layer { get; set; }
+        }
+
+        static List<object> drawOrder = new List<object>();
+
+        class TestEntityRenderer : OrderedRenderer<TestDrawComponent>
+        {
+            public override void Render(Entity entity, in TestDrawComponent testDrawComponent)
+            {
+                drawOrder.Add(entity);
+            }
+        }
+
+        class TestGeneralRenderer : GeneralRenderer
+        {
+            public override void Render()
+            {
+                drawOrder.Add(this);
+            }
+        }
+
+        [Test]
+        public void DrawOrder()
+        {
+            var worldBuilder = new WorldBuilder();
+            worldBuilder.RegisterDrawLayer(1);
+            worldBuilder.RegisterDrawLayer(2);
+            worldBuilder.RegisterDrawLayer(3);
+            worldBuilder.RegisterDrawLayer(4);
+            worldBuilder.RegisterDrawLayer(7);
+
+            worldBuilder.AddOrderedRenderer(new TestEntityRenderer());
+            var testGeneralRenderer = worldBuilder.AddGeneralRenderer(new TestGeneralRenderer(), 7);
+
+            TestComponent testComponent;
+            TestDrawComponent drawComponentThree = new TestDrawComponent { Layer = 3 };
+            var drawComponentTwo = new TestDrawComponent { Layer = 2 };
+            var drawComponentOne = new TestDrawComponent { Layer = 1 };
+            var drawComponentFour = new TestDrawComponent { Layer = 4 };
+
+            var entity = worldBuilder.CreateEntity();
+            worldBuilder.SetComponent(entity, testComponent);
+            worldBuilder.SetComponent(entity, drawComponentThree);
+
+            var entityTwo = worldBuilder.CreateEntity();
+            worldBuilder.SetComponent(entityTwo, testComponent);
+            worldBuilder.SetComponent(entityTwo, drawComponentTwo);
+
+            var entityThree = worldBuilder.CreateEntity();
+            worldBuilder.SetComponent(entityThree, testComponent);
+            worldBuilder.SetComponent(entityThree, drawComponentThree);
+
+            var entityFour = worldBuilder.CreateEntity();
+            worldBuilder.SetComponent(entityFour, testComponent);
+            worldBuilder.SetComponent(entityFour, drawComponentFour);
+
+            var world = worldBuilder.Build();
+
+            world.Update(0.01f);
+            world.Draw();
+
+            drawOrder.Should().BeEquivalentTo(entityFour, entityTwo, entity, entityThree, testGeneralRenderer);
+        }
+    }
+}

test/test.csproj

@@ -6,7 +6,6 @@
     <RootNamespace>Tests</RootNamespace>
     <AssemblyName>EncompassECS.Framework.Tests</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <Platforms>x64;x86</Platforms>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="FluentAssertions" Version="5.7.0" />