Better DynamicEntityDescriptorInfo, going to write how to use it properly on the Svelto.ECS wiki

fixed use of PlatformProfiler
I decided to support empty EntityViewStruct

Svelto.ECS/DynamicEntityDescriptorInfo.cs

@@ -5,18 +5,18 @@ namespace Svelto.ECS
 {
     public struct DynamicEntityDescriptorInfo<TType>:IEntityDescriptor where TType : IEntityDescriptor, new()
     {
-        public DynamicEntityDescriptorInfo(FasterList<IEntityBuilder> extraEntities) : this()
+        public DynamicEntityDescriptorInfo(IEntityBuilder[] extraEntities)
         {
-            DBC.ECS.Check.Require(extraEntities.Count > 0,
+            DBC.ECS.Check.Require(extraEntities.Length > 0,
                                   "don't use a DynamicEntityDescriptorInfo if you don't need to use extra EntityViews");
 
             var defaultEntities = EntityDescriptorTemplate<TType>.descriptor.entitiesToBuild;
             var length = defaultEntities.Length;
 
-            entitiesToBuild = new IEntityBuilder[length + extraEntities.Count + 1];
+            entitiesToBuild = new IEntityBuilder[length + extraEntities.Length + 1];
 
-            Array.Copy(defaultEntities,      0, entitiesToBuild, 0,      length);
-            Array.Copy(extraEntities.ToArrayFast(), 0, entitiesToBuild, length, extraEntities.Count);
+            Array.Copy(defaultEntities, 0, entitiesToBuild, 0, length);
+            Array.Copy(extraEntities, 0, entitiesToBuild, length, extraEntities.Length);
 
             var _builder = new EntityBuilder<EntityInfoView>
             {
@@ -25,7 +25,19 @@ namespace Svelto.ECS
             entitiesToBuild[entitiesToBuild.Length - 1] = _builder;
         }
 
-        public IEntityBuilder[] entitiesToBuild { get; private set; }
+        public IEntityBuilder[] entitiesToBuild { get; }
+    }
+
+    public class DynamicEntityDescriptorInfoRef<TType>:IEntityDescriptor where TType : IEntityDescriptor, new()
+    {
+        public DynamicEntityDescriptorInfoRef(IEntityBuilder[] extraEntities)
+        {
+            _dynamicDescriptor = new  DynamicEntityDescriptorInfo(extraEntities);
+        }
+
+        public IEntityBuilder[] entitiesToBuild { get { return _dynamicDescriptor.entitiesToBuild } }
+
+        DynamicEntityDescriptorInfo<T> _dynamicDescriptor;
     }
     
     public struct EntityInfoView : IEntityStruct

Svelto.ECS/EGID.cs

@@ -37,6 +37,11 @@ namespace Svelto.ECS
             return (long)groupId << 32 | ((long)(uint)entityId & 0xFFFFFFFF);
         }
 
+        public static implicit operator int(EGID id)
+        {
+            return id.entityID;
+        }
+
         public bool Equals(long other)
         {
             return _GID == other;

Svelto.ECS/EnginesRoot.Engines.cs

@@ -97,8 +97,6 @@ namespace Svelto.ECS
             throw new ArgumentException("Not Supported Engine " + engine.ToString());
         }
 
-        //The T parameter allows to pass datastructure sthat not necessarly are
-        //defined with IEngine, but must be defined with IEngine implementations
         static void AddEngine<T>(T engine, Type[] entityViewTypes,
                               Dictionary<Type, FasterList<T>> engines) where T:IEngine
         {

Svelto.ECS/EnginesRoot.GenericEntityFactory.cs

@@ -34,7 +34,7 @@ namespace Svelto.ECS
             {
                 return _weakEngine.Target.BuildEntity(new EGID(entityID, (int)groupStructId), descriptorEntity, implementors);
             }
-            
+
             public void PreallocateEntitySpace<T>(ExclusiveGroup.ExclusiveGroupStruct groupStructId, int size) where T : IEntityDescriptor, new()
             {
                 _weakEngine.Target.Preallocate<T>((int)groupStructId, size);

Svelto.ECS/EnginesRoot.Submission.cs

@@ -18,7 +18,7 @@ namespace Svelto.ECS
     {
         void SubmitEntityViews()
         {
-            using (new PlatformProfiler("Svelto.ECS submit"))
+            using (new PlatformProfiler("Svelto.ECS").Sample("Entities submit"))
             {
                 if (_entitiesOperations.Count > 0)
                 {

Svelto.ECS/EntitiesDB.cs

@@ -22,6 +22,16 @@ namespace Svelto.ECS.Internal
             return typeSafeDictionary.Values;
         }
 
+        public ReadOnlyCollectionStruct<T> QueryEntityViews<T>(ExclusiveGroup @group) where T : class, IEntityStruct
+        {
+            return QueryEntityViews<T>((int) group);
+        }
+
+        public T QueryEntityView<T>(int id, ExclusiveGroup @group) where T : class, IEntityStruct
+        {
+            return QueryEntityView<T>(new EGID(id, group));
+        }
+
         public T[] QueryEntities<T>(int @group, out int count) where T : IEntityStruct
         {
             TypeSafeDictionary<T> typeSafeDictionary;
@@ -115,6 +125,11 @@ namespace Svelto.ECS.Internal
             return TryQueryEntityViewInGroupInternal(entityegid, out entityView);
         }
         
+        public bool TryQueryEntityView<T>(int id, ExclusiveGroup @group, out T entityView) where T : class, IEntityStruct
+        {
+            return TryQueryEntityViewInGroupInternal(new EGID(id, group), out entityView);
+        }
+        
         bool TryQueryEntityViewInGroupInternal<T>(EGID entityGID, out T entityView) where T:class, IEntityStruct
         {
             entityView = null;
@@ -168,7 +183,9 @@ namespace Svelto.ECS.Internal
 
         static ReadOnlyCollectionStruct<T> RetrieveEmptyEntityViewList<T>()
         {
-            return ReadOnlyCollectionStruct<T>.DefaultList;
+            var arrayFast = FasterList<T>.DefaultList.ToArrayFast();
+            
+            return new ReadOnlyCollectionStruct<T>(arrayFast, 0);
         }
 
         static T[] RetrieveEmptyEntityViewArray<T>()

Svelto.ECS/EntityBuilder.cs

@@ -88,6 +88,8 @@ namespace Svelto.ECS
             if (needsReflection == true)
             {
                 DBC.ECS.Check.Require(implementors != null, "Implementors not found while building an EntityView");
+                DBC.ECS.Check.Require(castedDic.ContainsKey(entityID.entityID) == false,
+                                      "building an entity with already used entity id! id".FastConcat(entityID).FastConcat(" ", DESCRIPTOR_NAME));
 
                 T lentityView;
                 EntityView<T>.BuildEntityView(entityID, out lentityView);
@@ -96,7 +98,7 @@ namespace Svelto.ECS
                                   , entityViewBlazingFastReflection
                                   , implementors
                                   , DESCRIPTOR_NAME);
-
+                
                 castedDic.Add(entityID.entityID, ref lentityView);
             }
             else

Svelto.ECS/EntityDescriptorInfo.cs

@@ -0,0 +1,25 @@
+namespace Svelto.ECS
+{
+    public interface IEntityDescriptor
+    {
+        IEntityBuilder[] entitiesToBuild { get; }
+    }
+
+    public class EntityDescriptor : IEntityDescriptor
+    {
+        private EntityDescriptor()
+        {}
+        
+        protected EntityDescriptor(IEntityBuilder[] entityToBuild)
+        {
+            entitiesToBuild = entityToBuild;
+        }
+        
+        public IEntityBuilder[] entitiesToBuild { get; }
+    }
+
+    static class EntityDescriptorTemplate<TType> where TType : IEntityDescriptor, new()
+    {
+        public static readonly StaticEntityDescriptorInfo<TType> descriptor = new StaticEntityDescriptorInfo<TType>(new TType());
+    }
+}

Svelto.ECS/EntityViewUtility.cs

@@ -14,15 +14,11 @@ static class EntityViewUtility
     {
         int count;
 
-        //Very efficent way to collect the fields of every EntityViewType
+        //efficient way to collect the fields of every EntityViewType
         var setters =
             FasterList<KeyValuePair<Type, ActionCast<T>>>
                .NoVirt.ToArrayFast(entityViewBlazingFastReflection, out count);
-#if DEBUG && !PROFILER
-        if (count == 0) 
-            throw new Exception(NO_COMPONENTS_EXCEPTION.FastConcat("Type ", entityDescriptorName, " entityView ", 
-                                                                   entityBuilder.GetEntityType().ToString()));
-#endif
+
         for (var index = 0; index < implementors.Length; index++)
         {
             var implementor = implementors[index];
@@ -120,9 +116,7 @@ static class EntityViewUtility
     }
 #endif
     static readonly Dictionary<Type, Type[]> _cachedTypes = new Dictionary<Type, Type[]>();
-    const string NO_COMPONENTS_EXCEPTION =
-        "<color=orange>Svelto.ECS</color> An entity view without component interfaces has been found, if you are using an entity view struct or an entity struct, do not pass implementors";
-
+ 
     const string DUPLICATE_IMPLEMENTOR_ERROR =
         "<color=orange>Svelto.ECS</color> the same component is implemented with more than one implementor. This is considered an error and MUST be fixed. ";
 

Svelto.ECS/IEntitiesDB.cs

@@ -10,18 +10,21 @@ namespace Svelto.ECS
         /// over EntityView
         /// </summary>
         ReadOnlyCollectionStruct<T> QueryEntityViews<T>(int group) where T : class, IEntityStruct;
+        ReadOnlyCollectionStruct<T> QueryEntityViews<T>(ExclusiveGroup group) where T : class, IEntityStruct;
         /// <summary>
         /// All the EntityView related methods are left for back compatibility, but
         /// shouldn't be used anymore. Always pick EntityViewStruct or EntityStruct
         /// over EntityView
         /// </summary>
         bool TryQueryEntityView<T>(EGID egid, out T entityView) where T : class, IEntityStruct;
+        bool TryQueryEntityView<T>(int id, ExclusiveGroup group, out T entityView) where T : class, IEntityStruct;
         /// <summary>
         /// All the EntityView related methods are left for back compatibility, but
         /// shouldn't be used anymore. Always pick EntityViewStruct or EntityStruct
         /// over EntityView
         /// </summary>
         T QueryEntityView<T>(EGID egid) where T : class, IEntityStruct;
+        T QueryEntityView<T>(int id, ExclusiveGroup group) where T : class, IEntityStruct;
         /// <summary>
         /// Fast and raw (therefore not safe) return of entities buffer
         /// Modifying a buffer would compromise the integrity of the whole DB

Svelto.ECS/IEntityFactory.cs

@@ -22,7 +22,8 @@ namespace Svelto.ECS
         /// </summary>
         /// <typeparam name="T"></typeparam>
         /// <param name="size"></param>
-        void PreallocateEntitySpace<T>(ExclusiveGroup.ExclusiveGroupStruct groupStructId, int size) where T : IEntityDescriptor, new();
+        void PreallocateEntitySpace<T>(ExclusiveGroup.ExclusiveGroupStruct groupStructId,
+                                       int                                 size) where T : IEntityDescriptor, new();
         
         /// <summary>
         ///     The EntityDescriptor doesn't need to be ever instantiated. It just describes the Entity
@@ -30,7 +31,7 @@ namespace Svelto.ECS
         ///     references of the EntityViews components. Please read the articles on my blog
         ///     to understand better the terminologies
         ///     Using this function is like building a normal entity, but the entity views
-        ///     are grouped by groupID to be more efficently processed inside engines and
+        ///     are grouped by groupID to be more efficiently processed inside engines and
         ///     improve cache locality. Either class entityViews and struct entityViews can be
         ///     grouped.
         /// </summary>
@@ -38,7 +39,10 @@ namespace Svelto.ECS
         /// <param name="groupStructId"></param>
         /// <param name="ed"></param>
         /// <param name="implementors"></param>
-        EntityStructInitializer BuildEntity<T>(int entityID,  ExclusiveGroup.ExclusiveGroupStruct groupStructId, object[] implementors) where T:IEntityDescriptor, new();
+        EntityStructInitializer BuildEntity<T>(int                                 entityID,
+                                               ExclusiveGroup.ExclusiveGroupStruct groupStructId,
+                                               object[]                            implementors)
+            where T : IEntityDescriptor, new();
         EntityStructInitializer BuildEntity<T>(EGID egid, object[] implementors) where T:IEntityDescriptor, new();
         /// <summary>
         ///     When the type of the entity is not known (this is a special case!) an EntityDescriptorInfo
@@ -48,7 +52,11 @@ namespace Svelto.ECS
         /// <param name="entityDescriptor"></param>
         /// <param name="implementors"></param>
         /// 
-        EntityStructInitializer BuildEntity<T>(int entityID,  ExclusiveGroup.ExclusiveGroupStruct groupStructId, T descriptorEntity, object[] implementors)  where T:IEntityDescriptor;
+        EntityStructInitializer BuildEntity<T>(int                                 entityID,
+                                               ExclusiveGroup.ExclusiveGroupStruct groupStructId,
+                                               T                                   descriptorEntity,
+                                               object[]                            implementors)
+            where T : IEntityDescriptor;
         EntityStructInitializer BuildEntity<T>(EGID egid, T entityDescriptor, object[] implementors)  where T:IEntityDescriptor;
     }
 }

Svelto.ECS/StaticEntityDescriptorInfo.cs

@@ -1,25 +1,5 @@
 namespace Svelto.ECS
 {
-    public interface IEntityDescriptor
-    {
-        IEntityBuilder[] entitiesToBuild { get; }
-    }
-
-    public class EntityDescriptor : IEntityDescriptor
-    {
-        protected EntityDescriptor(IEntityBuilder[] entityToBuild)
-        {
-            this.entitiesToBuild = entityToBuild;
-        }
-
-        public IEntityBuilder[] entitiesToBuild { get; private set; }
-    }
-
-    public static class EntityDescriptorTemplate<TType> where TType : IEntityDescriptor, new()
-    {
-        public static readonly StaticEntityDescriptorInfo<TType> descriptor = new StaticEntityDescriptorInfo<TType>(new TType());
-    }
-
     public class StaticEntityDescriptorInfo<TType>: IEntityDescriptor where TType : IEntityDescriptor
     {
         internal StaticEntityDescriptorInfo(TType descriptor)
@@ -27,6 +7,7 @@ namespace Svelto.ECS
             entitiesToBuild = descriptor.entitiesToBuild;
         }
 
-        public IEntityBuilder[] entitiesToBuild { get; private set; }
+        public IEntityBuilder[] entitiesToBuild { get; }
     }
 }
+