Unity3D使用mesh创建一个正方形

using UnityEngine;
using System.Collections;

public class Quad : MonoBehaviour
{
    // Use this for initialization
    void Start () {
        CreateQuad ();
    }

    private float m_width = ;
    private float m_length = ;

    public void CreateQuad()
    {
        /* 1. 顶点，三角形，法线，uv坐标, 绝对必要的部分只有顶点和三角形。
                 如果模型中不需要场景中的光照，那么就不需要法线。如果模型不需要贴材质，那么就不需要UV */
        Vector3[] vertices = new Vector3[];
        Vector3[] normals = new Vector3[];
        Vector2[] uv = new Vector2[];

        vertices [] = new Vector3 (, , );
        uv [] = new Vector2 (, );
        normals [] = Vector3.up;

        vertices [] = new Vector3 (, , m_length);
        uv [] = new Vector2 (, );
        normals [] = Vector3.up;

        vertices [] = new Vector3 (m_width, , m_length);
        uv [] = new Vector2 (, );
        normals [] = Vector3.up;

        vertices [] = new Vector3 (m_width, , );
        uv [] = new Vector2 (, );
        normals [] = Vector3.up;

        /*2. 三角形,顶点索引：
         三角形是由3个整数确定的，各个整数就是角的顶点的index。 各个三角形的顶点的顺序通常由下往上数， 可以是顺时针也可以是逆时针，这通常取决于我们从哪个方向看三角形。 通常，当mesh渲染时，"逆时针" 的面会被挡掉。 我们希望保证顺时针的面与法线的主向一致 */
        int[] indices = new int[];
        indices [] = ;
        indices [] = ;
        indices [] = ;

        indices [] = ;
        indices [] = ;
        indices [] = ;

        Mesh mesh = new Mesh ();
        mesh.vertices = vertices;
        mesh.normals = normals;
        mesh.uv = uv;
        mesh.triangles = indices;
        mesh.RecalculateBounds ();

        MeshFilter filter = this.gameObject.AddComponent<MeshFilter> ();
        if(filter != null)
        {
            filter.sharedMesh = mesh;
        }

        MeshRenderer meshRender = this.gameObject.AddComponent<MeshRenderer> ();
        Shader shader = Shader.Find ("Diffuse");
        meshRender.sharedMaterial = new Material (shader);
    }
}