public class ChangeRotationSystem : ReactiveSystem<GameEntity>
    {
        public ChangeRotationSystem(Contexts context) : base(context.game)
        {
        }

        protected override void Execute(List<GameEntity> entities)
        {
            foreach (GameEntity entity in entities)
            {
                Transform trans = entity.interactionDemoView.transform;
                var angle = entity.interactionDemoMoveDirection.direction;
                trans.rotation = Quaternion.AngleAxis(angle-90, Vector3.forward);// 问题行
            }
        }

        protected override bool Filter(GameEntity entity)
        {
            return entity.hasInteractionDemoView &&
                entity.hasInteractionDemoMoveDirection;
        }

        protected override ICollector<GameEntity> GetTrigger(IContext<GameEntity> context)
        {
            return context.CreateCollector(GameMatcher.InteractionDemoMoveDirection);
        }
    }

代码块中的问题行trans.rotation = Quaternion.AngleAxis(angle-90, Vector3.forward)，为什么这里angle要减去90？我在课中得知angle计算出来就是应该飞机应该旋转的正确角度，自己试验不减90的话，飞机头确实不会朝向目标坐标，但是减去90又不知道为什么，麻烦老师解答，感谢