Unity3D 绘制扇形/环形

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class Cone : MonoBehaviour {

    public float anglefov = ;
    public int quality = ;
    public int[] triangles;
    public Vector2[] uvs;
    public Vector3[] vertices;
    public Vector3[] normals;

    public float dist_min = 0.0f;
    public float dist_max = 1f;

    public MeshFilter meshFilter;

    // Use this for initialization
    void Awake () {
        triangles = new int[quality *  * ];
        vertices = new Vector3[quality *  + ];
        uvs = new Vector2[vertices.Length];
        normals = new Vector3[vertices.Length];

        meshFilter = GetComponent<MeshFilter>();
    }

    // Update is called once per frame
    void Update () {

        meshFilter.mesh.Clear();

        Vector3 pos = Vector3.zero;//transform.position;
        float angle_lookat = transform.eulerAngles.y;
        float angle_fov = anglefov;

        float angle_start = angle_lookat - angle_fov;
        float angle_end = angle_lookat + angle_fov;
        float angle_delta = (angle_end - angle_start) / quality;

        float angle_curr = angle_end;

        for (int i = ; i < quality + ; i++)
        {
            Vector3 sphere_curr = new Vector3();
            sphere_curr.z = Mathf.Cos(Mathf.Deg2Rad * angle_curr);
            sphere_curr.x = Mathf.Sin(Mathf.Deg2Rad * angle_curr);

            Vector3 pos_curr_min = pos + sphere_curr * dist_min;
            Vector3 pos_curr_max = pos + sphere_curr * dist_max;

            vertices[ * i + ] = pos_curr_min;
            vertices[ * i + ] = pos_curr_max;

            uvs[ * i + ] = new Vector2((float)(quality-i) / quality, );
            uvs[ * i + ] = new Vector2((float)(quality-i) / quality, );

            normals[ * i + ] = Vector3.up;
            normals[ * i + ] = Vector3.up;

            angle_curr -= angle_delta;
        }

        for (int i = ; i < quality; i++)
        {
            //  5---3---1
            //  |  /|  /|
            //  | / | / |
            //  |/  |/  |
            //  4---2---0

            int index_min_cur = i *  + ;
            int index_max_cur = i *  + ;
            int index_min_next = i *  + ;
            int index_max_next = i *  + ;

            triangles[ * i + ] = index_min_cur;
            triangles[ * i + ] = index_min_next;
            triangles[ * i + ] = index_max_cur;
            triangles[ * i + ] = index_min_next;
            triangles[ * i + ] = index_max_next;
            triangles[ * i + ] = index_max_cur;

        }

        meshFilter.sharedMesh.vertices = vertices;
        meshFilter.sharedMesh.triangles = triangles;
        meshFilter.sharedMesh.uv = uvs;
    }
}