绘制 Camera视口 和 FOV

明人不说暗话，直接上码

using System.Collections;
using System.Collections.Generic;
using UnityEngine;



public class CameraFOV : MonoBehaviour
{
    public float _farDistance = 10;//远视口距离
    public float _nearDistance = 3;//近视口距离

    private Camera _camera;
    private Transform _camTrans;


	void Start ()
    {
        _camera = Camera.main;
        _camTrans = _camera.transform;
    }

    void OnDrawGizmos()
    {
        OnDrawFarView();
        OnDrawNearView();
        OnDrawFOV();
    }

    //远视口
    void OnDrawFarView()
    {
        Vector3[] corners = GetCorners(_farDistance);

        // for debugging
        Debug.DrawLine(corners[0], corners[1], Color.yellow); // UpperLeft -> UpperRight
        Debug.DrawLine(corners[1], corners[3], Color.yellow); // UpperRight -> LowerRight
        Debug.DrawLine(corners[3], corners[2], Color.yellow); // LowerRight -> LowerLeft
        Debug.DrawLine(corners[2], corners[0], Color.yellow); // LowerLeft -> UpperLeft


        //中心线
        Vector3 vecStart = _camTrans.transform.position;
        Vector3 vecEnd = vecStart;
        vecEnd += _camTrans.forward * _farDistance;
        Debug.DrawLine(vecStart, vecEnd, Color.red);
    }

    //近视口
    void OnDrawNearView()
    {
        Vector3[] corners = GetCorners(_nearDistance);

        // for debugging
        Debug.DrawLine(corners[0], corners[1], Color.red);//左上-右上
        Debug.DrawLine(corners[1], corners[3], Color.red);//右上-右下
        Debug.DrawLine(corners[3], corners[2], Color.red);//右下-左下
        Debug.DrawLine(corners[2], corners[0], Color.red);//左下-左上
    }

    void OnDrawFOV()
    {
        float halfFOV = (_camera.fieldOfView * 0.5f) * Mathf.Deg2Rad;//一半fov
        float halfHeight = _farDistance * Mathf.Tan(halfFOV);//distance距离位置，相机视口高度的一半

        //起点
        Vector3 vecStart = _camTrans.position;

        //上中
        Vector3 vecUpCenter = vecStart;
        vecUpCenter.y -= halfHeight;
        vecUpCenter.z += _farDistance;

        //下中
        Vector3 vecBottomCenter = vecStart;
        vecBottomCenter.y += halfHeight;
        vecBottomCenter.z += _farDistance;

        Debug.DrawLine(vecStart, vecUpCenter, Color.blue);
        Debug.DrawLine(vecStart, vecBottomCenter, Color.blue);
    }



    //获取相机视口四个角的坐标
    //参数 distance  视口距离
    Vector3[] GetCorners(float distance)
    {
        Vector3[] corners = new Vector3[4];

        //fov为垂直视野  水平fov取决于视口的宽高比  以度为单位


        float halfFOV = (_camera.fieldOfView * 0.5f) * Mathf.Deg2Rad;//一半fov
        float aspect = _camera.aspect;//相机视口宽高比

        float height = distance * Mathf.Tan(halfFOV);//distance距离位置，相机视口高度的一半
        float width = height * aspect;//相机视口宽度的一半

        //左上
        corners[0] = _camTrans.position - (_camTrans.right * width);//相机坐标 - 视口宽的一半
        corners[0] += _camTrans.up * height;//+视口高的一半
        corners[0] += _camTrans.forward * distance;//+视口距离

        // 右上
        corners[1] = _camTrans.position + (_camTrans.right * width);//相机坐标 + 视口宽的一半
        corners[1] += _camTrans.up * height;//+视口高的一半
        corners[1] += _camTrans.forward * distance;//+视口距离

        // 左下
        corners[2] = _camTrans.position - (_camTrans.right * width);//相机坐标 - 视口宽的一半
        corners[2] -= _camTrans.up * height;//-视口高的一半
        corners[2] += _camTrans.forward * distance;//+视口距离

        // 右下
        corners[3] = _camTrans.position + (_camTrans.right * width);//相机坐标 + 视口宽的一半
        corners[3] -= _camTrans.up * height;//-视口高的一半
        corners[3] += _camTrans.forward * distance;//+视口距离

        return corners;
    }
}