commandbufferを使ってレンダリング結果をコピー

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

public class CopyToRenderTex : MonoBehaviour
{
    [SerializeField] private Camera _camera;
    [SerializeField] private RenderTexture _renderTex;
    private CommandBuffer _commandBuffer;

    void Start()
    {

        _commandBuffer = new CommandBuffer();
        _commandBuffer.name = "CaptureScreen";
        _commandBuffer.Blit(BuiltinRenderTextureType.CurrentActive, _renderTex);
        _camera.AddCommandBuffer(CameraEvent.AfterImageEffects, _commandBuffer);

    }

    private void OnGUI(){
        
        GUI.DrawTexture(new Rect(0, 0, 200, 200), _renderTex, ScaleMode.StretchToFill);
        
    }
    
}

でもARFoundationとの併用はうごかなかった。AROCulusionManagerが悪さしている？