Raycasterを試す

rayCaster.cs

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

public class rayCaster : MonoBehaviour
{
    [SerializeField, Range(5, 30)]
    int raySize = 10;

    public GameObject block;

    //private int count = 0;
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void FixedUpdate()
    {
        
    }

    private void Update()
    {

        if (Input.GetMouseButtonDown(0))
        {
            var obj = getRayObj();
            if (obj.Item1 == null) return;

            Destroy(obj.Item1);
        }
        else if (Input.GetMouseButtonDown(1))
        {
            (GameObject obj, Vector3 v_normal) = getRayObj();
            if (obj == null) return;

            Vector3 pos_obj = obj.transform.localPosition + v_normal;
            Instantiate(block,pos_obj,Quaternion.identity);
        }
    }

    private (GameObject,Vector3) getRayObj()
    {
        int centerX = Screen.width / 2;
        int centerY = Screen.height / 2;
        var pos = new Vector3(centerX, centerY, 0.1f);
        Ray ray = Camera.main.ScreenPointToRay(pos);
        var hit = new RaycastHit();

        if (Physics.Raycast(ray, out hit, raySize))
        {
            //RayCast Debug
            Debug.Log($"{hit.collider.gameObject.name}");
            Debug.DrawRay(ray.origin, ray.direction * 10, Color.red, 2, false);
            
            return (hit.collider.gameObject,hit.normal);
        }
        else
        {   
            return (null, hit.normal);
        }
    }
}