c# - Null Reference instance Object GameObject.FindWithTag("Player").transform.parent = Level Unity

Question

您好，我在一个无限的世界中工作，当我开始游戏时出现此错误

“NullReferenceException：对象引用未设置为对象的实例 TerrainController.InitialLoad ()（在 Assets/Scripts/TerrainController.cs：73）TerrainController.Start（）（在 Assets/Scripts/TerrainController.cs：64）”

事实是我不知道如何解决它，我需要帮助。

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

公共类地形控制器：MonoBehaviour {

[SerializeField]
private GameObject terrainTilePrefab = null;
[SerializeField]
private Vector3 terrainSize = new Vector3(20, 1, 20);
public Vector3 TerrainSize { get { return terrainSize; } }
[SerializeField]
private Gradient gradient;
[SerializeField]
private float noiseScale = 3, cellSize = 1;
[SerializeField]
private int radiusToRender = 5;
[SerializeField]
private Transform[] gameTransforms;
[SerializeField]
private Transform water;
public Transform Water { get { return water; } }
[SerializeField]
private int seed;
[SerializeField]
private GameObject[] placeableObjects;
public GameObject[] PlaceableObjects { get { return placeableObjects; } }
[SerializeField]
private Vector3[] placeableObjectSizes;//the sizes of placeableObjects, in matching order
public Vector3[] PlaceableObjectSizes { get { return placeableObjectSizes; } }
[SerializeField]
private int minObjectsPerTile = 0, maxObjectsPerTile = 20;
public int MinObjectsPerTile { get { return minObjectsPerTile; } }
public int MaxObjectsPerTile { get { return maxObjectsPerTile; } }
[SerializeField]
private float destroyDistance = 1000;
[SerializeField]
private bool usePerlinNoise = true;
[SerializeField]
private Texture2D noise;
public static float[][] noisePixels;

private Vector2 startOffset;

private Dictionary<Vector2, GameObject> terrainTiles = new Dictionary<Vector2, GameObject>();

private Vector2[] previousCenterTiles;
private List<GameObject> previousTileObjects = new List<GameObject>();
public Transform Level { get; set; }
private Vector2 noiseRange;

private void Awake()
{
    if (noise)
        noisePixels = GetGrayScalePixels(noise);
    GenerateMesh.UsePerlinNoise = usePerlinNoise;
    noiseRange = usePerlinNoise ? Vector2.one * 256 : new Vector2(noisePixels.Length, noisePixels[0].Length);
}

private void Start()
{
    InitialLoad();
}

public void InitialLoad()
{
    DestroyTerrain();

    Level = new GameObject("Level").transform;
    water.parent = Level;
    GameObject.FindWithTag("Player").transform.parent = Level;
    foreach (Transform t in gameTransforms)
        t.parent = Level;

    float waterSideLength = radiusToRender * 2 + 1;
    water.localScale = new Vector3(terrainSize.x / 10 * waterSideLength, 1, terrainSize.z / 10 * waterSideLength);

    Random.InitState(seed);
    //choose a random place on perlin noise
    startOffset = new Vector2(Random.Range(0f, noiseRange.x), Random.Range(0f, noiseRange.y));
    RandomizeInitState();
}

private void Update()
{
    //save the tile the player is on
    Vector2 playerTile = TileFromPosition(GameObject.FindWithTag("Player").transform.localPosition);
    //save the tiles of all tracked objects in gameTransforms (including the player)
    List<Vector2> centerTiles = new List<Vector2>();
    centerTiles.Add(playerTile);
    foreach (Transform t in gameTransforms)
        centerTiles.Add(TileFromPosition(t.localPosition));

    //if no tiles exist yet or tiles should change
    if (previousCenterTiles == null || HaveTilesChanged(centerTiles))
    {
        List<GameObject> tileObjects = new List<GameObject>();
        //activate new tiles
        foreach (Vector2 tile in centerTiles)
        {
            bool isPlayerTile = tile == playerTile;
            int radius = isPlayerTile ? radiusToRender : 1;
            for (int i = -radius; i <= radius; i++)
                for (int j = -radius; j <= radius; j++)
                    ActivateOrCreateTile((int)tile.x + i, (int)tile.y + j, tileObjects);
            if (isPlayerTile)
                water.localPosition = new Vector3(tile.x * terrainSize.x, water.localPosition.y, tile.y * terrainSize.z);
        }
        //deactivate old tiles
        foreach (GameObject g in previousTileObjects)
            if (!tileObjects.Contains(g))
                g.SetActive(false);

        //destroy inactive tiles if they're too far away
        List<Vector2> keysToRemove = new List<Vector2>();//can't remove item when inside a foreach loop
        foreach (KeyValuePair<Vector2, GameObject> kv in terrainTiles)
        {
            if (Vector3.Distance(GameObject.FindWithTag("Player").transform.position, kv.Value.transform.position) > destroyDistance && !kv.Value.activeSelf)
            {
                keysToRemove.Add(kv.Key);
                Destroy(kv.Value);
            }
        }
        foreach (Vector2 key in keysToRemove)
            terrainTiles.Remove(key);

        previousTileObjects = new List<GameObject>(tileObjects);
    }

    previousCenterTiles = centerTiles.ToArray();
}

//Helper methods below

private void ActivateOrCreateTile(int xIndex, int yIndex, List<GameObject> tileObjects)
{
    if (!terrainTiles.ContainsKey(new Vector2(xIndex, yIndex)))
    {
        tileObjects.Add(CreateTile(xIndex, yIndex));
    }
    else
    {
        GameObject t = terrainTiles[new Vector2(xIndex, yIndex)];
        tileObjects.Add(t);
        if (!t.activeSelf)
            t.SetActive(true);
    }
}

private GameObject CreateTile(int xIndex, int yIndex)
{
    GameObject terrain = Instantiate(
        terrainTilePrefab,
        Vector3.zero,
        Quaternion.identity,
        Level
    );
    //had to move outside of instantiate because it's a local position
    terrain.transform.localPosition = new Vector3(terrainSize.x * xIndex, terrainSize.y, terrainSize.z * yIndex);
    terrain.name = TrimEnd(terrain.name, "(Clone)") + " [" + xIndex + " , " + yIndex + "]";

    terrainTiles.Add(new Vector2(xIndex, yIndex), terrain);

    GenerateMesh gm = terrain.GetComponent<GenerateMesh>();
    gm.TerrainSize = terrainSize;
    gm.Gradient = gradient;
    gm.NoiseScale = noiseScale;
    gm.CellSize = cellSize;
    gm.NoiseOffset = NoiseOffset(xIndex, yIndex);
    gm.Generate();

    Random.InitState((int)(seed + (long)xIndex * 100 + yIndex));//so it doesn't form a (noticable) pattern of similar tiles
    PlaceObjects po = gm.GetComponent<PlaceObjects>();
    po.TerrainController = this;
    po.Place();
    RandomizeInitState();

    return terrain;
}

private Vector2 NoiseOffset(int xIndex, int yIndex)
{
    Vector2 noiseOffset = new Vector2(
        (xIndex * noiseScale + startOffset.x) % noiseRange.x,
        (yIndex * noiseScale + startOffset.y) % noiseRange.y
    );
    //account for negatives (ex. -1 % 256 = -1, needs to loop around to 255)
    if (noiseOffset.x < 0)
        noiseOffset = new Vector2(noiseOffset.x + noiseRange.x, noiseOffset.y);
    if (noiseOffset.y < 0)
        noiseOffset = new Vector2(noiseOffset.x, noiseOffset.y + noiseRange.y);
    return noiseOffset;
}

private Vector2 TileFromPosition(Vector3 position)
{
    return new Vector2(Mathf.FloorToInt(position.x / terrainSize.x + .5f), Mathf.FloorToInt(position.z / terrainSize.z + .5f));
}

private void RandomizeInitState()
{
    Random.InitState((int)System.DateTime.UtcNow.Ticks);//casting a long to an int "loops" it (like modulo)
}

private bool HaveTilesChanged(List<Vector2> centerTiles)
{
    if (previousCenterTiles.Length != centerTiles.Count)
        return true;
    for (int i = 0; i < previousCenterTiles.Length; i++)
        if (previousCenterTiles[i] != centerTiles[i])
            return true;
    return false;
}

public void DestroyTerrain()
{
    water.parent = null;
    if(GameObject.FindWithTag("Player") != null)
    {
        GameObject.FindWithTag("Player").transform.parent = null;
    }
    foreach (Transform t in gameTransforms)
        t.parent = Level;
    Destroy(Level);
    terrainTiles.Clear();
}

private static string TrimEnd(string str, string end)
{
    if (str.EndsWith(end))
        return str.Substring(0, str.LastIndexOf(end));
    return str;
}

public static float[][] GetGrayScalePixels(Texture2D texture2D)
{
    List<float> grayscale = texture2D.GetPixels().Select(c => c.grayscale).ToList();

    List<List<float>> grayscale2d = new List<List<float>>();
    for (int i = 0; i < grayscale.Count; i += texture2D.width)
        grayscale2d.Add(grayscale.GetRange(i, texture2D.width));

    return grayscale2d.Select(a => a.ToArray()).ToArray();
}

}

标签： c#unity3d

Answer 1

也许您的玩家标签没有分配给您的对象或者您的玩家标签更改了名称，您需要先检查玩家标签名称是否正确，打开调试模式进行测试