[游戏开发]【unity 3d】--- 瞄准镜效果

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 镜头缩放
/// </summary>
public class MouseDemo : MonoBehaviour
{
    private bool isFar = true;
    //将缩放等级做成一个数组
    public float[] zoomLevel;
    private int index;
    private void Update()
    {
        //_Camera1();//调用方法1
        //_Camera2();//调用方法2
        //_Camera3();//调用方法3
        _Camera4();
    }
    /// <summary>
    ///方法1： 瞄准镜效果
    /// </summary>
    private void _Camera1()
    {
        if (Input.GetMouseButtonDown(1))
        {
            isFar = !isFar;//修改布尔值
        }
        if (isFar)
            Camera.main.fieldOfView = 20;
        else
            Camera.main.fieldOfView = 60;
    }
    /// <summary>
    /// 方法2：逐渐拉进或拉远
    /// </summary>
    private void _Camera2()
    {
        if (Input.GetMouseButtonDown(1))
        {
            isFar = !isFar;//修改布尔值
        }
        if (isFar)//拉远20--》60
        {
            if (Camera.main.fieldOfView < 60)
                Camera.main.fieldOfView += 2;
        }
        else//拉进60--》20
        {
            if (Camera.main.fieldOfView > 20)
                Camera.main.fieldOfView -= 2;
        }
    }
    /// <summary>
    /// 方法3：由快到慢拉进或拉远
    /// </summary>
    private void _Camera3()
    {
        if (Input.GetMouseButtonDown(1))
        {
            isFar = !isFar;//修改布尔值
        }
        if (isFar)//拉远20--》60
        {//由快到慢 无线接近终点（不能等于终点）
            Camera.main.fieldOfView=
                Mathf.Lerp(Camera.main.fieldOfView, 60, 0.1f);
            //取绝对值
            if (Mathf.Abs(Camera.main.fieldOfView - 60) <= 0.1f)
                Camera.main.fieldOfView = 60;

        }
        else//拉进60--》20
        {
            Camera.main.fieldOfView =
                Mathf.Lerp(Camera.main.fieldOfView, 20, 0.1f);
            if (Mathf.Abs(Camera.main.fieldOfView - 20) <= 0.1f)
                Camera.main.fieldOfView = 20;
        }
    }
    /// <summary>
    /// 方法4：假设存在多个变量
    /// </summary>
    private void _Camera4()
    {
        if (Input.GetMouseButtonDown(1))
        {
            //如果索引小于数组长度-1则加一，否则为0；
            //index = index < zoomLevel.Length - 1 ? index + 1 : 0;
            index = (index + 1) % zoomLevel.Length;
        }
        Camera.main.fieldOfView = Mathf.Lerp(Camera.main.fieldOfView, zoomLevel[index], 0.1f);
        if (Mathf.Abs(Camera.main.fieldOfView - zoomLevel[index]) < 0.1f)
            Camera.main.fieldOfView = zoomLevel[index];
    }
}