Unity网格生成：RowParent_0与RowParent_9无子物体原因咨询

问题描述 #

使用Unity的GridGenerator脚本生成网格时，层级结构中的RowParent_0和RowParent_9没有子物体，运行无报错，咨询该现象是否符合逻辑及出现原因。

相关脚本代码 #

using UnityEngine;

public class GridGenerator : MonoBehaviour
{
    public GameObject gridCellPrefab;
    public int gridWidth = 10;
    public int gridHeight = 10;

    private GameObject[] wallParents = new GameObject[4];
    private GameObject gridContainer;
    private GameObject[] rowParents; // Parents for each row of grid cells

    void Start()
    {
        CreateGridContainer();
        GenerateGrid();
    }

    void CreateGridContainer()
    {
        gridContainer = GameObject.Find("GridContainer");
        if (gridContainer == null)
        {
            gridContainer = new GameObject("GridContainer");
            gridContainer.transform.parent = this.transform;
        }

        // Initialize wall parent objects
        string[] wallNames = { "TopWallParent", "LeftWallParent", "RightWallParent", "BottomWallParent" };
        for (int i = 0; i < wallParents.Length; i++)
        {
            wallParents[i] = new GameObject(wallNames[i]);
            wallParents[i].transform.parent = gridContainer.transform;
        }

        // Initialize row parent objects
        rowParents = new GameObject[gridHeight];
        for (int i = 0; i < gridHeight; i++)
        {
            rowParents[i] = new GameObject("RowParent_" + i);
            rowParents[i].transform.parent = gridContainer.transform;
        }
    }

    public void GenerateGrid()
    {
        // Clear previous grid
        foreach (Transform child in gridContainer.transform)
        {
            Destroy(child.gameObject);
        }
        CreateGridContainer(); // Recreate wall and row parents

        // Generate new grid
        for (int x = 0; x < gridWidth; x++)
        {
            for (int z = 0; z < gridHeight; z++)
            {
                GameObject cell = Instantiate(gridCellPrefab, new Vector3(x * 1.5f, 0, z * 1.5f), Quaternion.identity);
                cell.name = "GridCell_" + x + "_" + z;
                cell.tag = "GridCell";
                cell.GetComponent<Renderer>().material.color = new Color(0.945f, 1f, 0f);

                // Adjust parent based on position
                if (x == 0)
                {
                    cell.transform.parent = wallParents[0].transform;
                    cell.name = "TopWallCell_" + z;
                }
                else if (z == 0)
                {
                    cell.transform.parent = wallParents[1].transform;
                    cell.name = "LeftWallCell_" + x;
                }
                else if (z == gridHeight - 1)
                {
                    cell.transform.parent = wallParents[2].transform;
                    cell.name = "RightWallCell_" + x;
                }
                else if (x == gridWidth - 1)
                {
                    cell.transform.parent = wallParents[3].transform;
                    cell.name = "BottomWallCell_" + z;
                }
                else
                {
                    cell.transform.parent = rowParents[z].transform;
                }
            }
        }
    }
}

原因分析 #

这个现象完全符合代码逻辑，核心原因在于单元格父物体的条件判断顺序和规则：

• 当z=0（对应RowParent_0）时，只要x≠0（x=0的情况已被第一个x==0条件归类到TopWallParent），就会触发z==0的判断，将单元格放到LeftWallParent，永远不会走到最后的else分支（不会赋值给RowParent_0）。
• 当z=gridHeight-1（即z=9，对应RowParent_9）时，只要x≠0，就会触发z==gridHeight-1的判断，将单元格放到RightWallParent，同样不会走到else分支。
• 只有当单元格同时满足x≠0、x≠gridWidth-1、z≠0、z≠gridHeight-1时，才会被赋值给对应的RowParent[z]。

结论 #

该现象是代码设计的正常结果，并非错误。RowParent_0和RowParent_9会被创建，但永远不会有子物体，因为它们对应的z轴行的所有单元格都被归类到墙的父物体中了。

内容的提问来源于stack exchange，提问作者Daniel Lip