Render the view frustum of a camera in Unity

When you select a camera in the Unity editor, gray lines indicate where the view frustum is. When it's deselected the lines are obviously not rendered. Sometimes however, we do want to see these lines even if the camera is not selected, for example when implementing custom culling code as I am doing at the moment. For that I found a nice piece of code on the Unity forums. I put it into a monobehaviour: attach the following to a camera and the frustum will be rendered in the editor.

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(Camera))]
public class FrustumViewer : MonoBehaviour
{
 void Update()
 {
  DrawFrustum(this.camera);
 }

 void DrawFrustum ( Camera cam ) {
  Vector3[] nearCorners = new Vector3[4]; //Approx'd nearplane corners
  Vector3[] farCorners = new Vector3[4]; //Approx'd farplane corners
  Plane[] camPlanes = GeometryUtility.CalculateFrustumPlanes( cam ); //get planes from matrix
  
  Plane temp = camPlanes[1]; camPlanes[1] = camPlanes[2]; camPlanes[2] = temp; //swap [1] and [2] so the order is better for the loop
  for ( int i = 0; i < 4; i++ ) {
   nearCorners[i] = Plane3Intersect( camPlanes[4], camPlanes[i], camPlanes[( i + 1 ) % 4] ); //near corners on the created projection matrix
   farCorners[i] = Plane3Intersect( camPlanes[5], camPlanes[i], camPlanes[( i + 1 ) % 4] ); //far corners on the created projection matrix
  }
  
  for ( int i = 0; i < 4; i++ ) {
   Debug.DrawLine( nearCorners[i], nearCorners[( i + 1 ) % 4], Color.red, Time.deltaTime, true ); //near corners on the created projection matrix
   Debug.DrawLine( farCorners[i], farCorners[( i + 1 ) % 4], Color.blue, Time.deltaTime, true ); //far corners on the created projection matrix
   Debug.DrawLine( nearCorners[i], farCorners[i], Color.green, Time.deltaTime, true ); //sides of the created projection matrix
  }
 }
 
 
 
 Vector3 Plane3Intersect ( Plane p1, Plane p2, Plane p3 ) { //get the intersection point of 3 planes
  return ( ( -p1.distance * Vector3.Cross( p2.normal, p3.normal ) ) +
          ( -p2.distance * Vector3.Cross( p3.normal, p1.normal ) ) +
          ( -p3.distance * Vector3.Cross( p1.normal, p2.normal ) ) ) /
   ( Vector3.Dot( p1.normal, Vector3.Cross( p2.normal, p3.normal ) ) );
 }
}