Unity Scene to Equirectangular png (spherical image)

Main.cs

/*
 * This script produces a .png image from an Unity scene.
 * 
 * Result image looks like this : https://fr.wikipedia.org/wiki/Fichier:Paris_s%27éveille_equirectangular_panorama.jpg
 * 
 * inspired from : https://docs.unity3d.com/ScriptReference/RenderTexture.ConvertToEquirect.html 
 *          and    https://docs.unity3d.com/ScriptReference/Camera.RenderToCubemap.html
 *
 * To use it add this script to your scene then run
 */
 
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.Rendering;

public class Main : MonoBehaviour
{
    public RenderTexture cubemapLeftEye;
    public RenderTexture equirect;

    void Start()
    {
        cubemapLeftEye = new RenderTexture(1024, 1024, 24, RenderTextureFormat.ARGB32);
        cubemapLeftEye.dimension = TextureDimension.Cube;
        equirect = new RenderTexture(2048, 1024, 24, RenderTextureFormat.ARGB32);
    }

    void LateUpdate()
    {
        Camera cam = Camera.main;
        cam.RenderToCubemap(cubemapLeftEye, 63, Camera.MonoOrStereoscopicEye.Mono);

        if (equirect == null)
        {
            return;
        }

        cubemapLeftEye.ConvertToEquirect(equirect, Camera.MonoOrStereoscopicEye.Mono);
        //convert to png
        Texture2D tex = new Texture2D(equirect.width, equirect.height);
        tex.ReadPixels(new Rect(0, 0, tex.width, tex.height), 0, 0);
        var bytes = tex.EncodeToPNG();
        System.IO.File.WriteAllBytes("<ADD PATH HERE>/res.png", bytes);
     }
}