同一个对象在 C# 中一次又一次地被实例化

Question

我是编码初学者。几天来，我一直在尝试重新制作流行的手机游戏 'Crossy Road'。当我尝试创建关卡生成脚本时，我运行遇到了问题。我面临的问题是，当我尝试运行domly 实例化 3 个不同的对象时，（在本例中为草、路和水）只生成草。如果有人能告诉我为什么它一直重复实例化 'Grass' 对象，我将不胜感激。我正在 Unity 5 中重新创建游戏。代码如下——

using UnityEngine;
using System.Collections;

public class LevelGenerationScript : MonoBehaviour {

public GameObject Water;
public GameObject Road;
public GameObject Grass;
int firstRand;
int secondRand;
int distPlayer = 10;

Vector3 intPos = new Vector3(0,0,0);

void Update () 
{
    if (Input.GetButtonDown("up")) 
    {
        firstRand = Random.Range(1,4);
        if(firstRand == 1)
        {
            secondRand = Random.Range(1,8);
            for(int i = 0;i < secondRand; i++)
            {
                intPos = new Vector3(0,0,distPlayer);
                distPlayer += 1;
                GameObject GrassIns = Instantiate(Grass) as GameObject;
                GrassIns.transform.position = intPos;
            }

            if(firstRand == 2)
            {
                secondRand = Random.Range(1,8);
                for(int i = 0;i < secondRand; i++)
                {
                    intPos = new Vector3(0,0,distPlayer);
                    distPlayer += 1;
                    GameObject RoadIns = Instantiate(Road) as GameObject;
                    RoadIns.transform.position = intPos;
                }

                if(firstRand == 3)
                {
                    secondRand = Random.Range(1,8);
                    for(int i = 0;i < secondRand; i++)
                    {
                        intPos = new Vector3(0,0,distPlayer);
                        distPlayer += 1;
                        GameObject WaterIns = Instantiate(Water) as GameObject;
                        WaterIns.transform.position = intPos;
                    }
                }
            }
        }
    }
}
}

如果有人能告诉我错误，我将不胜感激。谢谢！

Answer 1

您已将其他对象的代码放置在 firstRand 为 1 时调用的代码组中。(FirstRand ==2) 和 (FirstRand ==3) 在此位置永远不会为真，您写的是无法到达的代码。

Answer 2

您的声明 if (firstRand == 2) 永远不会到达，因为它包含在 if (firstRand ==1) 声明中。

您需要像这样构建您的 if 语句：

if (firstRand == 1)
{
   ...
}

if (firstRand == 2)
{
   ...
}

if (firstRand == 3)
{
   ...
}

如果您想改进代码，请执行以下操作：

firstRand = Random.Range(1,4);
secondRand = Random.Range(1,8);
GameObject instance = null;

for (int i = 0; i < secondRand; i++)
{
    intPos = new Vector3(0, 0, distPlayer);
    distPlayer += 1;

    switch (firstRand)
    {
        case 1:
            instance = Instantiate(Grass) as GameObject;
            break;
        case 2:
            instance = Instantiate(Road) as GameObject;
            break;
        case 3:
            instance = Instantiate(Water) as GameObject;
            break;
    }

    instance.transform.position = intPos;
}

同一个对象在 C# 中一次又一次地被实例化

The Same Object is Getting Instantiated again and again in C#

c#

unity5