improved ECS and added new render component

src/EngineSharp.Core/EngineSharp.Core/ECS/RenderComponent.cs

@@ -0,0 +1,8 @@
+using Silk.NET.OpenGL;
+
+namespace EngineSharp.Core.ECS;
+
+public abstract class RenderComponent : IComponent
+{
+    internal abstract void Render(GL gl);
+}

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

@@ -1,13 +1,15 @@
 using System.Linq;
+using Silk.NET.OpenGL;
 
 namespace EngineSharp.Core.ECS;
 
 public class Scene
 {
-     private Dictionary<long, LogicComponent> _logicComponents = new();
-     private Dictionary<long, DataComponent> _dataComponents = new();
+     private readonly Dictionary<long, List<LogicComponent>> _logicComponents = new();
+     private readonly Dictionary<long, List<DataComponent>> _dataComponents = new();
+     private readonly Dictionary<long, List<RenderComponent>> _renderComponents = new();
 
-     private long _nextSceneId; // ugly solution but it works
+     private long _nextSceneId; // not the prettiest solution but it works
 
      public Entity CreateEntity(string name)
      {
@@ -16,63 +18,80 @@ public class Scene
 
      internal void StartComponents()
      {
-          foreach (var component in _logicComponents.Values)
+          foreach (var components in _logicComponents.Values)
           {
-               component.Start();
+               components.ForEach(c => c.Start());
           }
      }
 
      internal void UpdateComponents(double deltaTime)
      {
-          foreach (var component in _logicComponents.Values)
+          foreach (var components in _logicComponents.Values)
           {
-               component.OnUpdate(deltaTime);
+               components.ForEach(c => c.OnUpdate(deltaTime));
           }
      }
 
-     internal void AddComponent(Entity entity, IComponent component)
+     internal void RenderComponents(GL gl)
+     {
+          foreach (var components in _renderComponents.Values)
+          {
+               components.ForEach(c => c.Render(gl));
+          }
+     }
+
+     internal void AddComponent<T>(Entity entity, T component)
+          where T : class, IComponent
      {
           switch (component)
           {
                case LogicComponent logic:
-                    _logicComponents.TryAdd(entity.Id, logic);
+                    AddComponent(entity.Id, logic, _logicComponents);
                     break;
                case DataComponent data:
-                    _dataComponents.TryAdd(entity.Id, data);
+                    AddComponent(entity.Id, data, _dataComponents);
+                    break;
+               case RenderComponent render:
+                    AddComponent(entity.Id, render, _renderComponents);
                     break;
           }
      }
 
-     internal IComponent? GetComponent(Entity entity, IComponent component)
+     internal T? GetComponent<T>(Entity entity, T component) 
+          where T : class, IComponent
      {
-          switch (component)
+          return component switch
           {
-               case LogicComponent logic:
-                    return GetComponent(entity.Id, logic);
-               case DataComponent data:
-                    return GetComponent(entity.Id, data);
-               default:
-                    return null;
-          }
+               LogicComponent => GetComponent<T, LogicComponent>(entity.Id, _logicComponents),
+               DataComponent => GetComponent<T, DataComponent>(entity.Id, _dataComponents),
+               RenderComponent => GetComponent<T, RenderComponent>(entity.Id, _renderComponents),
+               _ => null
+          };
      }
 
-     private LogicComponent? GetComponent(long id, LogicComponent component)
+     private static TComponent? GetComponent<TComponent, TArchetype>(long id, Dictionary<long, List<TArchetype>> componentStore) 
+          where TComponent : class, IComponent
      {
-          if (_logicComponents.TryGetValue(id, out var logic))
+          // ReSharper disable once ConvertIfStatementToReturnStatement
+          if (componentStore.TryGetValue(id, out var components))
           {
-               return logic;
+               return components.OfType<TComponent>().SingleOrDefault();
           }
 
           return null;
      }
 
-     private DataComponent? GetComponent(long id, DataComponent component)
+     private static void AddComponent<TComponent, TArchetype>(long id, TComponent component, Dictionary<long, List<TArchetype>> componentStore)
+          where TArchetype : class, IComponent
+          where TComponent : TArchetype
      {
-          if (_dataComponents.TryGetValue(id, out var data))
+          if (componentStore.TryGetValue(id, out var components))
           {
-               return data;
+               components.Add(component);
+          }
+          else
+          {
+               componentStore.Add(id, [component]);
           }
-
-          return null;
      }
 }

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

@@ -80,8 +80,12 @@ internal class OpenGLEngine : IEngine
         var viewMatrix = _camera.ViewMatrix;
         
         // TODO: Here render all meshes etc.
-        // On constructing a MeshRenderer, register it somewhere so it can be rendered here (MeshRenderer would then be a component while Mesh would be a normal C# object in the context of an ECS)
         // MeshRenderer contains a mesh; Mesh contains a material; Material contains a shader and the values for all uniforms of the shader (apart from the matrices; I am not sure how to best handle the model matrix with this approach)
+
+        if (_currentScene is not null)
+        {
+            _currentScene.RenderComponents(_gl);
+        }
     }
     
     private void OnResize(Vector2D<int> newDimensions)

src/EngineSharp.Core/EngineSharp.Core/Rendering/MeshRenderer.cs

@@ -1,14 +1,15 @@
-using Silk.NET.OpenGL;
+using EngineSharp.Core.ECS;
+using Silk.NET.OpenGL;
 
 namespace EngineSharp.Core.Rendering;
 
-public class MeshRenderer
+public class MeshRenderer : RenderComponent
 {
     public Mesh Mesh { get; set; }
 
     private uint vao, vbo, ebo;
 
-    internal void Render(GL gl)
+    internal override void Render(GL gl)
     {
         GenerateRenderableMesh(gl);
         gl.BindVertexArray(vao);