LightGlueProject/Unity2021.3.42f1-YejiDemo/Assets/Demo/Scripts/CrossHair.cs

using System;
using UnityEngine;

namespace SmartBowSDK
{
    public class CrossHair : MonoBehaviour
    {
        /// <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;

        private RectTransform _rectTransform;
        private RectTransform _canvasRectTransform;

        void Awake()
        {
            _rectTransform = GetComponent<RectTransform>();
            _canvasRectTransform = GetComponentInParent<Canvas>().GetComponent<RectTransform>();
        }

        void Start()
        {
            InitForLimitBound();
        }

        void LateUpdate()
        {
            if (limitAimInScrren) aimTransform.eulerAngles = LimitAngles(aimTransform.eulerAngles);
            UpdateCrossHairPosition();
        }

        void UpdateCrossHairPosition()
        {
            Ray ray = new Ray(aimTransform.position, aimTransform.forward);
            RaycastHit hitInfo;
            Vector3 hitPoint;
            if (Physics.Raycast(ray, out hitInfo, 100)) hitPoint = hitInfo.point;
            else hitPoint = aimTransform.position + aimTransform.forward * 100f;
            Vector2 viewPoint = Camera.main.WorldToViewportPoint(hitPoint);
            _rectTransform.localPosition = (viewPoint - Vector2.one * 0.5f) * _canvasRectTransform.rect.size;
        }

        #region 限制其显示范围不超出屏幕
        private float _screenWidthHalf;
        private float _screenHeightHalf;
        private float _screenNormal;
        private float _rangeRotateY;
        private float _rangeRotateX;
        /// <summary>
        /// 标记是否出界（-1：未出界；0：左边出界；1：右边出界；2：上边出界；3：下边出界；）
        /// </summary>
        [NonSerialized] public int outBoundIndex = -1;
        void InitForLimitBound()
        {
            Camera camera = Camera.main;
            _rangeRotateX = camera.fieldOfView / 2;
            _screenWidthHalf = Screen.width / 2f;
            _screenHeightHalf = Screen.height / 2f;
            _screenNormal = _screenHeightHalf / Mathf.Tan(_rangeRotateX / 180f * Mathf.PI);
            _rangeRotateY = Mathf.Atan(_screenWidthHalf / _screenNormal) / Mathf.PI * 180f;
        }
        Vector3 LimitAngles(Vector3 angles)
        {
            //Unity默认范围（0，360）格式化为自定义范围（-180，180）
            angles.y = angles.y > 180 ? angles.y - 360 : angles.y;
            angles.x = angles.x > 180 ? angles.x - 360 : angles.x;
            //记录原来的角度
            float angleY = angles.y;
            float angleX = angles.x;
            //记录是否出界
            if (angleY < -_rangeRotateY) outBoundIndex = 0;
            else if (angleY > _rangeRotateY) outBoundIndex = 1;
            else if (angleX < -_rangeRotateX) outBoundIndex = 2;
            else if (angleX > _rangeRotateX) outBoundIndex = 3;
            else outBoundIndex = -1;
            //返回限制边界后的角度
            angles.y = Mathf.Clamp(angleY, -_rangeRotateY, _rangeRotateY);
            float rayLen = _screenNormal / Mathf.Cos(Mathf.Abs(angles.y) / 180 * Mathf.PI);
            float maxRangeRotateX = Mathf.Atan(_screenHeightHalf / rayLen) / Mathf.PI * 180f;
            if (Mathf.Abs(angleX) > Mathf.Abs(maxRangeRotateX)) angles.x = maxRangeRotateX * (angleX > 0 ? 1 : -1);
            return angles;
        }
        #endregion
    }

}