c# – 如何统一显示网格线？

>用方形瓷砖填充场地(完成)
>在每个瓷砖上显示随机数(完成)
>显示网格线(问题在这里)

要创建我的主板,我使用附加到主相机的脚本.
这是我使用的功能：

void BoardSetup()
{
    board = new GameObject("Board");
    boardHolder = board.transform;

    for (int x = 0; x < columns; x++)
    {
        for (int y = 0; y < rows; y++)
        {
            GameObject toInstantiateBackground = snowTile;
            GameObject backgroundInstance = Instantiate(toInstantiateBackground,new Vector3(x,y,0f),Quaternion.identity) as GameObject;
            backgroundInstance.transform.SetParent(boardHolder);

            AddRandomNumber(backgroundInstance,x,y);
        }
    }

    float step = snowTile.GetComponent<SpriteRenderer>().bounds.max[0] - snowTile.GetComponent<SpriteRenderer>().bounds.min[0];
    CreateGrid(new Vector3(0,0),new Vector3(rows-1,columns-1,step);
}

这是我的CreateGrid块：

void CreateLineMaterial()
{

    if (!lineMaterial)
    {
        lineMaterial = new Material("Shader "Lines/Colored Blended" {" +
            "SubShader { Pass { " +
            "    Blend SrcAlpha OneMinusSrcAlpha " +
            "    ZWrite Off Cull Off Fog { Mode Off } " +
            "    BindChannels {" +
            "      Bind "vertex",vertex Bind "color",color }" +
            "} } }");
        lineMaterial.hideFlags = HideFlags.HideAndDontSave;
        lineMaterial.shader.hideFlags = HideFlags.HideAndDontSave;
    }
}

private void CreateGrid(Vector3 start,Vector3 stop,float step)
{
    CreateLineMaterial();
    // set the current material
    lineMaterial.SetPass(0);
    GL.Begin(GL.LINES);
    GL.Color(gridColor);
    // Vertical lines
    for (float x = start[0]; x <= stop[0]; x += step)
    {

        GL.Vertex3(x,0f,0f);
        GL.Vertex3(x,stop[1],0f);
    }
    // Horizontal lines
    for (float y = start[0]; y <= stop[1]; y += step)
    {

        GL.Vertex3(0f,0f);
        GL.Vertex3(stop[0],0f);
    }
    GL.End();
}

我使用了here的例子(并修改了它).

但是当我运行我的游戏时,我只看到了雪地联系和数字

我试图只运行CreateGrid()但在这种情况下我只看到黑屏.