smart-bow-infrared/Assets/WildAttack/Scripts/UI/CrossHair.cs

using System;
using UnityEngine;
namespace WildAttack
{
    /// <summary>
    /// 准星ui
    /// </summary>
    public class CrossHair : MonoBehaviour
    {
        #region Members
        public static CrossHair instance;
        /// <summary>
        /// 瞄准器，基于其位置发射射线，射线的hitpoint转屏幕坐标，该坐标即准心坐标
        /// </summary>
        public Transform aimTransform;
        /// <summary>
        /// 是否限制瞄准器在屏幕范围内
        /// </summary>
        public bool limitAimInScrren;

        public RectTransform _rectTransform;
        private RectTransform _canvasRectTransform;
        #endregion

        #region Lifecycle
        void Awake()
        {
            instance = this;
            _rectTransform = GetComponent<RectTransform>();
            _canvasRectTransform = GetComponentInParent<Canvas>().GetComponent<RectTransform>();
        }


        public void LateUpdate()
        {
            UpdateCrossHairPosition(GameMananger.GetInstance().hitPoint);

            // 不同射击模式
            //ShootTypeEnum type = GameMananger.GetInstance().GetShootType();
            //if ( type == ShootTypeEnum.FixedScreen ) {
            //    //if (limitAimInScrren) aimTransform.eulerAngles = LimitAngles(aimTransform.eulerAngles);
            //    hitPoint = CrossHairTransRaycast();
            //    UpdateCrossHairPosition(hitPoint);
            //}
            //else if ( type == ShootTypeEnum.FixedCrossHair ) {
            //    Camera.main.transform.LookAt(CrossHairTransRaycast());
            //}
            //else if ( type == ShootTypeEnum.moreScreen ) {
            //    hitPoint = CrossHairTransRaycast();
            //    UpdateCrossHairPosition(hitPoint);
            //    CheckCrossHair();
            //}
        }
        #endregion

        #region Functions
        public void UpdateCrossHairPosition(Vector3 hitPoint)
        {

            Vector2 viewPoint = Camera.main.WorldToViewportPoint(hitPoint);
            _rectTransform.localPosition = (viewPoint - Vector2.one * 0.5f) * _canvasRectTransform.rect.size;
        }

        public void ResetCrossHair()
        {
            _rectTransform.anchoredPosition = new Vector2(_canvasRectTransform.rect.width / 2, _canvasRectTransform.rect.height / 2);
        }
        #endregion
    }
}