From a2c7bf7d06405428f54fa79885adc1df98321c6d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20L=C3=BCbe=C3=9F?= <simon.luebess@gmail.com>
Date: Sun, 17 Mar 2024 20:25:38 +0100
Subject: [PATCH] Ensure generating unique Entity IDs

---
 GlitchyEngine/src/World/Components/Components.bf |  3 +--
 GlitchyEngine/src/World/Scene.bf                 | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/GlitchyEngine/src/World/Components/Components.bf b/GlitchyEngine/src/World/Components/Components.bf
index 2faa3c3..41d0c70 100644
--- a/GlitchyEngine/src/World/Components/Components.bf
+++ b/GlitchyEngine/src/World/Components/Components.bf
@@ -24,10 +24,9 @@ namespace GlitchyEngine.World
 	{
 		public readonly UUID ID;
 
-		/// Create a new IDComponent with a random UUID.
 		public this()
 		{
-			ID = UUID.Create();
+			ID = .Zero;
 		}
 
 		public this(UUID id)
diff --git a/GlitchyEngine/src/World/Scene.bf b/GlitchyEngine/src/World/Scene.bf
index 20971f0..167de44 100644
--- a/GlitchyEngine/src/World/Scene.bf
+++ b/GlitchyEngine/src/World/Scene.bf
@@ -834,7 +834,7 @@ namespace GlitchyEngine.World
 		}
 
 		/// Creates a new Entity with the given name.
-		public Entity CreateEntity(StringView name = "", UUID id = default)
+		public Entity CreateEntity(StringView name = "", UUID id = .Zero)
 		{
 			Entity entity = Entity(_ecsWorld.NewEntity(), this);
 			entity.AddComponent<TransformComponent>();
@@ -848,7 +848,7 @@ namespace GlitchyEngine.World
 #endif
 			
 			// If no id is given generate a random one.
-			IDComponent idComponent = (id == default) ? IDComponent() : IDComponent(id);
+			IDComponent idComponent = (id == .Zero) ? IDComponent(CreateEntityId()) : IDComponent(id);
 
 			entity.AddComponent<IDComponent>(idComponent);
 
@@ -857,6 +857,18 @@ namespace GlitchyEngine.World
 			return entity;
 		}
 
+		/// Creates a new entity Id that is unique within this scene.
+		public UUID CreateEntityId()
+		{
+			while (true)
+			{
+				UUID entityId = UUID.Create();
+
+				if (!_idToEntity.ContainsKey(entityId))
+					return entityId;
+			}
+		}
+
 		/** Deletes the given entity.
 		 * @param entity The entity to delete.
 		 * @param destroyChildren If set to true all children of entity will be destroyed.