C# - Deteção de blocos

Question

Olá!I

Eu estout tentando construir um script em que um veículo detecta um cubo a sua frente, mas aparece o erro: 'NullReferenceError: Object reference not set to an instance of an object'. Alguém pode ajudar?

using UnityEngine;
using System.Collections;
using System.Linq;
using System;

public class CubesDetectorScript : MonoBehaviour
{

public float angle;

public float output;
public int numObjects;
public float menor_num;
public float[] distances;
public int index;
public Cubes cb;
public GameObject near;

void Start()
{
    menor_num = 0;
    index = 0;
    output = 0;
    numObjects = 0;


}

void Update()
{
    GameObject cubes = GetAllCubes();

    output = 0;
    numObjects = 1;


        float r = 1;
        output += 1f / Mathf.Pow((transform.position - cubes.transform.position).magnitude / r + 1, 2);


    if (numObjects > 0)
        output = output / numObjects;
}

// Get Sensor output value
public float getLinearOutput()
{

    return output;
}




GameObject GetAllCubes()
{
    //This is the line with the error:
    menor_num = Vector3.Distance(transform.position, cb.allCubes[0].transform.position);

    for (int j = 0; j < 10; j++)
    {
        distances[j] = Vector3.Distance(transform.position, cb.allCubes[j].transform.position);

        if (menor_num > distances[j])
        {
            index = j;
            menor_num = distances[j];

        }
    }

  near= GameObject.Find("Cube " + index);

    return near;

}

GameObject[] GetVisibleCubes()
{
    ArrayList visibleCubes = new ArrayList();
    float halfAngle = angle / 2.0f;

    GameObject cubes = GetAllCubes();


        Vector3 toVector = (cubes.transform.position - transform.position);
        Vector3 forward = transform.forward;
        toVector.y = 0;
        forward.y = 0;
        float angleToTarget = Vector3.Angle(forward, toVector);

        if (angleToTarget <= halfAngle)
        {
            visibleCubes.Add(cubes);
        }


    return (GameObject[])visibleCubes.ToArray(typeof(GameObject));
}