Help with using 3D code for a 2D game.(It's probably an easy fix)

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

public class FOVscript : MonoBehaviour { public float viewRadius; [Range(0, 360)] public float viewAngle; public float meshResolution;

 public LayerMask solid;

 public MeshFilter viewMeshFilter;
 Mesh viewMesh;

 void Start()
 {
     viewMesh = new Mesh();
     viewMesh.name = "View Mesh";
     viewMeshFilter.mesh = viewMesh;
 }
 void LateUpdate()
 {
    DrawFieldOfView();
 }
 public Vector3 DirFromAngle(float angleInDegrees, bool angleIsGlobal)
 {
     if (!angleIsGlobal)
     {
         angleInDegrees += transform.eulerAngles.y;
     }
     return new Vector2(Mathf.Sin(angleInDegrees * Mathf.Deg2Rad), Mathf.Cos(angleInDegrees * Mathf.Deg2Rad));
 }

 ViewCastInfo ViewCast(float globalAngle)
 {
     Vector3 dir = DirFromAngle(globalAngle, true);
     RaycastHit hit;
     if (Physics.Raycast(transform.position, dir, out hit, viewRadius, solid))
     {
         return new ViewCastInfo(true, hit.point, hit.distance, globalAngle);
     }
     else
     {
         return new ViewCastInfo(false, transform.position + dir * viewRadius, viewRadius, globalAngle);
     }
 }

 void DrawFieldOfView()
 {
     int stepCount = Mathf.RoundToInt(viewAngle * meshResolution);
     float stepAngleSize = viewAngle / stepCount;
     List<Vector3> viewPoints = new List<Vector3>();
     for (int i = 0; i <= stepCount; i++)
     {
         float angle = transform.eulerAngles.y - viewAngle / 2 + stepAngleSize * i;
         Debug.DrawLine(transform.position, transform.position + DirFromAngle(angle, true) * viewRadius, Color.red);
         ViewCastInfo newViewCast = ViewCast(angle);
         viewPoints.Add(newViewCast.point);
     }
     int vertexCount = viewPoints.Count + 1;
     Vector3[] vertices = new Vector3[vertexCount];
     int[] triangles = new int[(vertexCount - 2) * 3];

     vertices[0] = Vector3.zero;
     for(int i = 0; i < vertexCount - 1; i++)
     {
         vertices[i + 1] = transform.InverseTransformPoint(viewPoints[i]);

         if(i < vertexCount - 2)
         {
         triangles[i * 3] = 0;
         triangles[i * 3 + 1] = i + 1;
         triangles[i * 3 + 2] = i + 2;
         }
     }
     viewMesh.Clear();
     viewMesh.vertices = vertices;
     viewMesh.triangles = triangles;
     viewMesh.RecalculateNormals();
 }
 public struct ViewCastInfo
 {
     public bool hit;
     public Vector3 point;
     public float dst;
     public float angle;

     public ViewCastInfo(bool _hit, Vector3 _point, float _dst, float _angle)
     {
         hit = _hit;
         point = _point;
         dst = _dst;
         angle = _angle;
     }
 }

 void OnDrawGizmosSelected()
 {
     Vector3 viewAngleA = DirFromAngle(-viewAngle / 2, false);
     Vector3 viewAngleB = DirFromAngle(viewAngle / 2, false);
     Gizmos.DrawWireSphere(transform.position, viewRadius);
     Gizmos.DrawLine(transform.position, transform.position + viewAngleA * viewRadius);
     Gizmos.DrawLine(transform.position, transform.position + viewAngleB * viewRadius);
 }

}