force the use of explicit groups

Svelto.ECS/EnginesRoot.GenericEntityFactory.cs

@@ -1,6 +1,4 @@
-using Svelto.ECS.Internal;
-
-#if ENGINE_PROFILER_ENABLED && UNITY_EDITOR
+#if ENGINE_PROFILER_ENABLED && UNITY_EDITOR
 using Svelto.ECS.Profiler;
 #endif
 
@@ -22,9 +20,9 @@ namespace Svelto.ECS
                 return _weakEngine.Target.BuildEntity<T>(new EGID(entityID), implementors);
             }
 
-            public EntityStructInitializer BuildEntity<T>(int entityID, int groupID, object[] implementors) where T : IEntityDescriptor, new()
+            public EntityStructInitializer BuildEntity<T>(int entityID, ExclusiveGroups groupID, object[] implementors) where T : IEntityDescriptor, new()
             {
-                return _weakEngine.Target.BuildEntity<T>(new EGID(entityID, groupID), implementors);
+                return _weakEngine.Target.BuildEntity<T>(new EGID(entityID, (int)groupID), implementors);
             }
 
             public EntityStructInitializer BuildEntity<T>(EGID egid, object[] implementors) where T : IEntityDescriptor, new()
@@ -42,9 +40,9 @@ namespace Svelto.ECS
                 return _weakEngine.Target.BuildEntity(egid, entityToBuild, implementors);
             }
 
-            public EntityStructInitializer BuildEntity(int entityID, int groupID, IEntityBuilder[] entityToBuild, object[] implementors)
+            public EntityStructInitializer BuildEntity(int entityID, ExclusiveGroups groupID, IEntityBuilder[] entityToBuild, object[] implementors)
             {
-                return _weakEngine.Target.BuildEntity(new EGID(entityID, groupID), entityToBuild, implementors);
+                return _weakEngine.Target.BuildEntity(new EGID(entityID, (int)groupID), entityToBuild, implementors);
             }
             
             public void PreallocateEntitySpace<T>(int size) where T : IEntityDescriptor, new()
@@ -52,9 +50,9 @@ namespace Svelto.ECS
                 _weakEngine.Target.Preallocate<T>(ExclusiveGroups.StandardEntity, size);
             }
             
-            public void PreallocateEntitySpace<T>(int groupID, int size) where T : IEntityDescriptor, new()
+            public void PreallocateEntitySpace<T>(ExclusiveGroups groupID, int size) where T : IEntityDescriptor, new()
             {
-                _weakEngine.Target.Preallocate<T>(groupID, size);
+                _weakEngine.Target.Preallocate<T>((int)groupID, size);
             }
         }
     }

Svelto.ECS/ExclusiveGroups.cs

@@ -1,7 +1,20 @@
-namespace Svelto.ECS.Internal
+namespace Svelto.ECS
 {
-    static class ExclusiveGroups
+    public class ExclusiveGroups
     {
         internal const int StandardEntity = int.MaxValue;
+
+        public ExclusiveGroups()
+        {
+            _id = _globalId++;
+        }
+        
+        public static explicit operator int(ExclusiveGroups group) // explicit byte to digit conversion operator
+        {
+            return group._id;
+        }
+
+        readonly int _id;
+        static int _globalId;
     }
 }

Svelto.ECS/IEntityFactory.cs

@@ -6,18 +6,24 @@ namespace Svelto.ECS
     /// an EnginesRoot reference cannot be held by anything else than the Composition Root
     /// where it has been created. IEntityFactory and IEntityFunctions allow a weakreference
     /// of the EnginesRoot to be passed around.
+    ///
+    /// ExclusiveGroups must be used in your game like:
+    /// static class GameExclusiveGroup
+    ///{
+    ///   public static readonly ExclusiveGroups PlayerEntitiesGroup = new ExclusiveGroups();
+    ///}
+    /// 
     /// </summary>
     public interface IEntityFactory
     {
-
-        /// <summary>
+    /// <summary>
         ///where performance is critical, you may wish to pre allocate the space needed
         ///to store the entities
         /// </summary>
         /// <typeparam name="T"></typeparam>
         /// <param name="size"></param>
         void PreallocateEntitySpace<T>(int size) where T : IEntityDescriptor, new();
-        void PreallocateEntitySpace<T>(int groupID, int size) where T : IEntityDescriptor, new();
+        void PreallocateEntitySpace<T>(ExclusiveGroups groupID, int size) where T : IEntityDescriptor, new();
         
         /// <summary>
         ///     The EntityDescriptor doesn't need to be ever instantiated. It just describes the Entity
@@ -41,7 +47,7 @@ namespace Svelto.ECS
         /// <param name="groupID"></param>
         /// <param name="ed"></param>
         /// <param name="implementors"></param>
-        EntityStructInitializer BuildEntity<T>(int entityID, int groupID, object[] implementors) where T:IEntityDescriptor, new();
+        EntityStructInitializer BuildEntity<T>(int entityID, ExclusiveGroups groupID, object[] implementors) where T:IEntityDescriptor, new();
         EntityStructInitializer BuildEntity<T>(EGID egid, object[] implementors) where T:IEntityDescriptor, new();
         
 
@@ -53,7 +59,7 @@ namespace Svelto.ECS
         /// <param name="entityDescriptor"></param>
         /// <param name="implementors"></param>
         /// 
-        EntityStructInitializer BuildEntity(int entityID, int groupID, IEntityBuilder[] entityToBuild, object[] implementors);
+        EntityStructInitializer BuildEntity(int entityID, ExclusiveGroups groupID, IEntityBuilder[] entityToBuild, object[] implementors);
         EntityStructInitializer BuildEntity(int entityID, IEntityBuilder[] entityToBuild, object[] implementors);
         EntityStructInitializer BuildEntity(EGID egid, IEntityBuilder[] entityToBuild, object[] implementors);
     }