我不断生成的地形有时生成一次，有时生成两次。为什么？

Question

我正在使用 Unity 3D 引擎制作 2D 游戏。我想创造无限重复的地形。我让它无缝地重复，除了有时会同时产生两个地形。它是随机发生的，没有任何充分的理由。有帮助吗？

这是我的地形重生代码：

using UnityEngine;
using System.Collections;
using PlayerPrefs = GamePlayerPrefs;
public class SelfTerrainSpawn : MonoBehaviour {
    // terrain references
    public GameObject first;
    public GameObject second;
    public GameObject third;
    public GameObject fourth;
    public GameObject fifth;
    public GameObject sixth;
    public GameObject seventh;
    public float spawnXPos = 0.0f;
    public float respawnCoordinate = 30.4f;
    public float respawnTriggerCoordinate = -21.7f;
    public bool canSpawn = true;
    public bool starting = true;
    public float random;

    void Start() {
        this.gameObject.transform.position = new Vector2 (0.0f, 31.4f);
        this.gameObject.transform.eulerAngles = new Vector3 (0, 0, 90.0f);
    }


    void Update()
    {
        // if the camera is farther than the number last position minus 16 terrain is spawned
        // a lesser number may make the terrain 'pop' into the scene too early
        // showing the player the terrain spawning which would be unwanted
        if (this.gameObject.transform.position.y <= respawnTriggerCoordinate && canSpawn)
        {
            // turn off spawning until ready to spawn again
            random = Random.Range(0,18);
            SpawnTerrain (random);
            canSpawn = false;
        }
        if (this.gameObject.transform.position.y <= respawnTriggerCoordinate - 10) {
            Destroy (this.gameObject);
        }
    }
    void SpawnTerrain(float rand) {
        if ((rand == 0)) {
            Instantiate (first, new Vector3 (respawnCoordinate, spawnXPos, 0), Quaternion.Euler (0, 0, 0));
        }
        if ((rand >= 1) && (rand <= 4)) {
            Instantiate (second, new Vector3 (respawnCoordinate, spawnXPos, 0), Quaternion.Euler (0, 0, 0));
        }
        if ((rand >= 5) && (rand <= 8)) {
            Instantiate (third, new Vector3 (respawnCoordinate, spawnXPos, 0), Quaternion.Euler (0, 0, 0));
        }
        if ((rand >= 9) && (rand <= 10)) {
            Instantiate (fourth, new Vector3 (respawnCoordinate, spawnXPos, 0), Quaternion.Euler (0, 0, 0));
        }
        if ((rand >= 10) && (rand <= 13)) {
            Instantiate (fifth, new Vector3 (respawnCoordinate, spawnXPos, 0), Quaternion.Euler (0, 0, 0));
        }
        if ((rand >= 13) && (rand <= 15)) {
            Instantiate (sixth, new Vector3 (respawnCoordinate, spawnXPos, 0), Quaternion.Euler (0, 0, 0));
        }
        if ((rand >= 15) && (rand <= 18)) {
            Instantiate (seventh, new Vector3 (respawnCoordinate, spawnXPos, 0), Quaternion.Euler (0, 0, 0));
        }
    }
}

此脚本附加到游戏内部的第一个地形块：

Click here to see an image of the game screen

它也附加到其他两个预制件上。这些预制件中的每一个都有一个脚本，可以让它们在屏幕上缓慢移动。基本上，当一个人的顶部到达相机顶部时，另一个应该在相机上方生成。然后它向下移动并重复。看到我使用了 canSpawn 变量来确保它只生成一次。然而，两个地形会随机生成在彼此之上。谁能给我解决这个问题的方法？

Answer 1

当 rand 为 10、13 或 15 时，您将生成两个地形，因为您的范围检查与这些值重叠。

我不断生成的地形有时生成一次，有时生成两次。为什么？

My endlessly spawning terrain sometimes spawns once and sometimes spawns twice. Why?

c#

rigid-bodies

unity3d