DynamicPoolMesh

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[ExecuteInEditMode]
public class DynamicPoolMesh : MonoBehaviour
{
    public float height = 4;


    [Range(0,10)]
    public float leftWidth = 2;
    [Range(0,10)]
    public float middleWidth = 4;
    [Range(0,10)]
    public float rightWidth = 4;

    public Sprite RefSprite;
    
    void Start()
    {
        UpdateMesh();
    }

    private void OnValidate()
    {
        
        GetComponent<MeshRenderer>().sharedMaterial.mainTexture = RefSprite.texture;
        UpdateMesh();
    }

    /*
     *  1________2______________5_______6
     * |        |               |       |
     * |        |               |       |
     * |        |               |       |
     * |        |               |       |
     * 0----L---3-------M-------4--R----7       
     */
    private void UpdateMesh()
    {
        Mesh mesh = new Mesh();
        Vector3[] vertices = new Vector3[8];
        int[] triangles = new int[18];
        Vector2[] uv = new Vector2[8];
        float totalWidth = leftWidth + middleWidth + rightWidth;
        #region 顶点位置
    
        vertices[0] = new Vector3(0, 0, 0); 
        vertices[1] = new Vector3(0, height, 0); 
        vertices[2] = new Vector3(leftWidth, height, 0); 
        vertices[3] = new Vector3(leftWidth, 0, 0);
        vertices[4] = new Vector3(leftWidth+middleWidth, 0, 0); 
        vertices[5] = new Vector3(leftWidth+middleWidth, height, 0); 
        vertices[6] = new Vector3(totalWidth, height, 0); 
        vertices[7] = new Vector3(totalWidth, 0, 0);

        #endregion 顶点位置

        #region 顶点索引
        //顺时针索引
        triangles[0] = 0; 
        triangles[1] = 1;
        triangles[2] = 3; 
        
        triangles[3] = 3; 
        triangles[4] = 1;
        triangles[5] = 2; 
        
        triangles[6] = 3; 
        triangles[7] = 2; 
        triangles[8] = 5; 
        
        triangles[9] = 5; 
        triangles[10] = 4; 
        triangles[11] = 3; 
        
        triangles[12] = 4; 
        triangles[13] = 5; 
        triangles[14] = 7; 
        
                
        triangles[15] = 7; 
        triangles[16] = 5; 
        triangles[17] = 6;
        #endregion

        #region UV
        var border = RefSprite.border; //X=left, Y=bottom, Z=right, W=top.
        var size = RefSprite.textureRect;
        var uvLeft = border.x / size.width;
        var uvRight = border.z / size.width;
        uv[0] = new Vector2(0, 0); 
        uv[1] = new Vector2(0, 1); 
        uv[2] = new Vector2(uvLeft, 1); 
        
        uv[3] = new Vector2(uvLeft, 0); 
        uv[4] = new Vector2(uvRight, 0); 
        uv[5] = new Vector2(uvRight, 1); 
        uv[6] = new Vector2(1, 1); 
        uv[7] = new Vector2(1, 0); 
        

        #endregion UV
       

        mesh.vertices = vertices;
        mesh.triangles = triangles;
        mesh.uv = uv;

        GetComponent<MeshFilter>().mesh = mesh;
    }


}