finalised crude ECS. Should now be able to create custom logic that gets executed each frame without touching the Engine project

src/EngineSharp.Core/EngineSharp.Core/ECS/Entity.cs

@@ -9,9 +9,10 @@ namespace EngineSharp.Core.ECS;
 public struct Entity
 {
     public readonly long Id;
-    
     private Scene _scene;
-
+    
+    public string Name { get; set; }
+    
     internal Entity(long id, Scene scene)
     {
         this.Id = id;

src/EngineSharp.Core/EngineSharp.Core/ECS/Scene.cs

@@ -1,4 +1,4 @@
-using System.ComponentModel;
+using System.Linq;
 
 namespace EngineSharp.Core.ECS;
 
@@ -7,6 +7,29 @@ public class Scene
      private Dictionary<long, LogicComponent> _logicComponents = new();
      private Dictionary<long, DataComponent> _dataComponents = new();
 
+     private long _nextSceneId; // ugly solution but it works
+
+     public Entity CreateEntity(string name)
+     {
+          return new Entity(_nextSceneId++, this);
+     }
+
+     internal void StartComponents()
+     {
+          foreach (var component in _logicComponents.Values)
+          {
+               component.Start();
+          }
+     }
+
+     internal void UpdateComponents(double deltaTime)
+     {
+          foreach (var component in _logicComponents.Values)
+          {
+               component.OnUpdate(deltaTime);
+          }
+     }
+     
      internal void AddComponent(Entity entity, IComponent component)
      {
           switch (component)

src/EngineSharp.Core/EngineSharp.Core/IEngine.cs

@@ -1,4 +1,5 @@
-using Silk.NET.Windowing;
+using EngineSharp.Core.ECS;
+using Silk.NET.Windowing;
 
 namespace EngineSharp.Core;
 
@@ -6,6 +7,8 @@ public interface IEngine
 {
     void Start();
     void Stop();
+    
+    Scene CreateScene();
 }
 
 public enum GraphicsAPI

src/EngineSharp.Core/EngineSharp.Core/OpenGLEngine.cs

@@ -1,4 +1,5 @@
 using System.Drawing;
+using EngineSharp.Core.ECS;
 using Silk.NET.Input;
 using Silk.NET.Maths;
 using Silk.NET.OpenGL;
@@ -9,9 +10,11 @@ namespace EngineSharp.Core;
 internal class OpenGLEngine : IEngine
 {
     private readonly IWindow _window;
+    private readonly List<Scene> _scenes;    
     private GL _gl = null!; // because between constructing the engine and OnLoad being called nothing should be able to call these fields. Therefore, we do this to get rid of warnings
     private Input _input = null!;
     private PerspectiveCamera _camera = null!;
+    private Scene? _currentScene;
     
     public OpenGLEngine(WindowOptions windowOptions)
     {
@@ -20,6 +23,8 @@ internal class OpenGLEngine : IEngine
         _window.Update += OnUpdate;
         _window.Render += OnRender;
         _window.Resize += OnResize;
+
+        _scenes = new();
     }
     
     public void Start()
@@ -32,6 +37,19 @@ internal class OpenGLEngine : IEngine
         _window.Close();
     }
 
+    public Scene CreateScene()
+    {
+        var scene = new Scene();
+        _scenes.Add(scene);
+        return scene;
+    }
+
+    public void SetCurrentScene(Scene scene)
+    {
+        _currentScene = scene;
+        _currentScene.StartComponents();
+    }
+
     private void OnLoad()
     {
         _gl = _window.CreateOpenGL();
@@ -49,7 +67,11 @@ internal class OpenGLEngine : IEngine
         {
             _window.Close();
         }
-        // TODO: here call custom code / game logic
+
+        if (_currentScene is not null)
+        {
+            _currentScene.UpdateComponents(deltaTime);
+        }
     }
 
     private void OnRender(double deltaTime)