RaycastWithRenderTexture.cs

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

public class RaycastWithRenderTexture : MonoBehaviour
{
	[SerializeField] Transform cursor = null;
	[SerializeField] Camera rtCamera = null;

	RaycastHit hit;

	[SerializeField] float offset = 0.3f;

	void Update ()
	{
		var inputPos = Input.mousePosition;
		var viewportPos = new Vector2(inputPos.x / Screen.width, inputPos.y / Screen.height);
		var ray = rtCamera.ViewportPointToRay(viewportPos);

		if( Physics.Raycast(ray, out hit)){
			cursor.localPosition = hit.point + hit.normal * offset ;
		}
	}
}