DragonECS/src/Builtin/Systems.cs

using System.Collections.Generic;
using DCFApixels.DragonECS.Internal;

namespace DCFApixels.DragonECS
{
    namespace Internal
    {
        [DebugHide, DebugColor(DebugColor.Black)]
        public class SystemsLayerMarkerSystem : IEcsSystem
        {
            public readonly string name;
            public SystemsLayerMarkerSystem(string name) => this.name = name;
        }
        [DebugHide, DebugColor(DebugColor.Grey)]
        public class DeleteEmptyEntitesSystem : IEcsRunProcess, IEcsPreInject
        {
            private List<EcsWorld> _worlds = new List<EcsWorld>();
            public void PreInject(object obj)
            {
                if (obj is EcsWorld world)
                    _worlds.Add(world);
            }
            public void Run(EcsPipeline pipeline)
            {
                foreach (var world in _worlds)
                    world.DeleteEmptyEntites();
            }
        }
        [DebugHide, DebugColor(DebugColor.Grey)]
        public class DeleteOneFrameComponentSystem<TWorld, TComponent> : IEcsRunProcess, IEcsInject<TWorld>
            where TWorld : EcsWorld<TWorld>
            where TComponent : struct, IEcsComponent
        {
            private sealed class Subject : EcsSubject
            {
                public EcsPool<TComponent> pool;
                public Subject(Builder b) => pool = b.Include<TComponent>();
            }
            private TWorld _world;
            public void Inject(TWorld obj) => _world = obj;
            public void Run(EcsPipeline pipeline)
            {
                foreach (var e in _world.Where(out Subject s))
                    s.pool.Del(e);
            }
        }
    }
    public static class DeleteOneFrameComponentSystemExtensions
    {
        private const string AUTO_DEL_LAYER = nameof(AUTO_DEL_LAYER);
        public static EcsPipeline.Builder AutoDel<TWorld, TComponent>(this EcsPipeline.Builder b)
            where TWorld : EcsWorld<TWorld>
            where TComponent : struct, IEcsComponent
        {
            b.Layers.Insert(EcsConsts.POST_END_LAYER, AUTO_DEL_LAYER);
            b.AddUnique(new DeleteOneFrameComponentSystem<TWorld, TComponent>(), AUTO_DEL_LAYER);
            return b;
        }
        /// <summary>for EcsDefaultWorld</summary>
        public static EcsPipeline.Builder AutoDel<TComponent>(this EcsPipeline.Builder b)
            where TComponent : struct, IEcsComponent
        {
            b.Layers.Insert(EcsConsts.POST_END_LAYER, AUTO_DEL_LAYER);
            b.AddUnique(new DeleteOneFrameComponentSystem<EcsDefaultWorld, TComponent>(), AUTO_DEL_LAYER);
            return b;
        }
    }
}