Added Entity hierarchy and hierarchical transforms

GlitchyEngine/src/World/TransformSystem.bf

@@ -0,0 +1,57 @@
+namespace GlitchyEngine.World
+{
+	public static class TransformSystem
+	{
+		static uint _frame;
+
+		public static void Update(EcsWorld world)
+		{
+			_frame++;
+
+			for(var entity in world.Enumerate(typeof(TransformComponent)))
+			{
+				UpdateEntity(entity, world);
+			}
+		}
+
+		private static TransformComponent* UpdateEntity(Entity entity, EcsWorld world)
+		{
+			// Todo: this probably needs a rewrite as it may scale poorly with deep hierarchies!
+
+			var transform = world.GetComponent<TransformComponent>(entity);
+
+			// If tranform was updated this frame -> skip
+			if(transform.Frame == _frame)
+				return transform;
+
+			var parent = world.GetComponent<ParentComponent>(entity);
+
+			if(transform.IsDirty)
+			{
+				transform.LocalTransform = .Translation(transform.Position) * .RotationX(transform.Rotation.X) *
+					.RotationY(transform.Rotation.Y) * .RotationZ(transform.Rotation.Z) * .Scaling(transform.Scale);
+				transform.Frame = _frame;
+				transform.IsDirty = false;
+
+				if(parent == null)
+				{
+					transform.WorldTransform = transform.LocalTransform;
+				}
+			}
+
+			if(parent != null)
+			{
+				var parentTransform = UpdateEntity(parent.Entity, world);
+
+				// Parent transform is newer than our transform or was updated this frame
+				if(parentTransform.Frame >= transform.Frame)
+				{
+					transform.WorldTransform = parentTransform.WorldTransform * transform.LocalTransform;
+					transform.Frame = parentTransform.Frame;
+				}
+			}
+
+			return transform;
+		}
+	}
+}