From f2af90bcb079a4180bc9e07d0e68536d5a0f2b8e Mon Sep 17 00:00:00 2001
From: Daniel <danwip@hotmail.com>
Date: Sat, 8 Nov 2025 14:33:01 +0100
Subject: [PATCH] ensured only one component per type can be present on a
 single entity

---
 src/EngineSharp.Core/EngineSharp.Core/ECS/Scene.cs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/EngineSharp.Core/EngineSharp.Core/ECS/Scene.cs b/src/EngineSharp.Core/EngineSharp.Core/ECS/Scene.cs
index a777a32..8fcd6b4 100644
--- a/src/EngineSharp.Core/EngineSharp.Core/ECS/Scene.cs
+++ b/src/EngineSharp.Core/EngineSharp.Core/ECS/Scene.cs
@@ -5,6 +5,7 @@ namespace EngineSharp.Core.ECS;
 
 public class Scene
 {
+     // TODO: Maybe instead of a List, use a HashSet instead. Maybe implement a equality comparer to ensure, only one element per type can be present
      private readonly Dictionary<long, List<LogicComponent>> _logicComponents = new();
      private readonly Dictionary<long, List<DataComponent>> _dataComponents = new();
      private readonly Dictionary<long, List<RenderComponent>> _renderComponents = new();
@@ -40,6 +41,9 @@ public class Scene
           }
      }
 
+     /// <summary>
+     /// If the component already exists on the entity, it will not be added
+     /// </summary>
      internal void AddComponent<T>(Entity entity, T component)
           where T : class, IComponent
      {
@@ -81,11 +85,14 @@ public class Scene
           return null;
      }
 
+     /// <summary>
+     /// If the component already exists on the entity, it will not be added
+     /// </summary>
      private static void AddComponent<TComponent, TArchetype>(long id, TComponent component, Dictionary<long, List<TArchetype>> componentStore)
           where TArchetype : class, IComponent
           where TComponent : TArchetype
      {
-          if (componentStore.TryGetValue(id, out var components))
+          if (componentStore.TryGetValue(id, out var components) && !components.OfType<TComponent>().Any())
           {
                components.Add(component);
           }