用Mesh绘制空心柱体，水管效果

目录

1.主要思路

2.代码展示

3.效果展示

1.主要思路

上下两面圆环，内外是展开的两个矩形面，通过Mesh依次绘制图形。

2.代码展示

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

/// <summary>
/// 水管
/// </summary>
[RequireComponent(typeof(MeshFilter))]
[RequireComponent(typeof(MeshRenderer))]
public class DrawConduit : MonoBehaviour
{
   
    [SerializeField]
    Texture2D texture;
    void Start()
    {
        DrawCustomConduit(2,1,8,30);
        GetComponent<MeshRenderer>().material.mainTexture = texture;
    }

    /// <summary>
    /// 绘制自定义空心柱体（水管）
    /// </summary>
    /// <param name="r1">外半径</param>
    /// <param name="r2">内半径</param>
    /// <param name="height">高度</param>
    /// <param name="num">分割数 棱数</param>
    private void DrawCustomConduit(float r1,float r2,float height,int n)
    {
        Mesh mesh = GetComponent<MeshFilter>().mesh;

        List<Vector3> verties = new List<Vector3>();
        List<Vector2> uvlists = new List<Vector2>();
        //角度
        float angle = (2 * Mathf.PI) / n;
        //外部顶点
        List<Vector3> outcircleVs = new List<Vector3>();
        //内部顶点
        List<Vector3> incircleVs = new List<Vector3>();
        //上方圆环
        for (int i = 0; i < n + 1; i++)
        {
            //外圆
            float x = Mathf.Sin(angle * i) * r1;
            float y = Mathf.Cos(angle * i) * r1;
            float uvx = i / (float)n;
            verties.Add(new Vector3(x, (height / 2), y));
            //存储外圆上点
            outcircleVs.Add(new Vector3(x, (height / 2), y));

            uvlists.Add(new Vector2(uvx, 1));
            //内圆
            float intx = Mathf.Sin(angle * i) * r2;
            float inty = Mathf.Cos(angle * i) * r2;
            verties.Add(new Vector3(intx, (height / 2), inty));
            //存储内圆上点
            incircleVs.Add(new Vector3(intx, (height / 2), inty));

            uvlists.Add(new Vector2(uvx, 0));
        }

        //下方圆环
        for (int i = 0; i < n + 1; i++)
        {
            float x = Mathf.Sin(angle * i) * r1;
            float y = Mathf.Cos(angle * i) * r1;
            verties.Add(new Vector3(x, -(height / 2), y));
            outcircleVs.Add(new Vector3(x, -(height / 2), y));

            float uvx = i / (float)n;
            uvlists.Add(new Vector2(uvx, 1));
            //内圆
            float intx = Mathf.Sin(angle * i) * r2;
            float inty = Mathf.Cos(angle * i) * r2;

            verties.Add(new Vector3(intx, -(height / 2), inty));
            incircleVs.Add(new Vector3(intx, -(height / 2), inty));

            uvlists.Add(new Vector2(uvx, 0));
        }

        //上下两个外圈的点 为后面画外部矩形做准备
        for (int i = 0; i < outcircleVs.Count; i++)
        {
            verties.Add(outcircleVs[i]);
            float uvx = i / (float)(outcircleVs.Count / 2);
            if (i <= (outcircleVs.Count / 2))
            {
                uvlists.Add(new Vector2(uvx, 1));
            }
            else
            {
                uvlists.Add(new Vector2(uvx - 1, 0));
            }

        }

        //上下两个内圈的点  为后面画内部矩形做准备
        for (int i = 0; i < incircleVs.Count; i++)
        {
            verties.Add(incircleVs[i]);
            float uvx = i / (float)(incircleVs.Count / 2);
            if (i <= (incircleVs.Count / 2))
            {
                uvlists.Add(new Vector2(uvx, 1));
            }
            else
            {
                uvlists.Add(new Vector2(uvx - 1, 0));
            }
        }

        mesh.vertices = verties.ToArray();
        mesh.uv = uvlists.ToArray();
        //print("verties" + verties.Count);
        //print("uvlists" + uvlists.Count);
        List<int> indices = new List<int>();

        //通过连接上部圆环
        for (int i = 0; i < n + 1; i++)
        {
            if (i < n)
            {
                indices.Add(2 * i);
                indices.Add(2 * (i + 1));
                indices.Add(2 * (i + 1) + 1);

                indices.Add(2 * i);
                indices.Add(2 * (i + 1) + 1);
                indices.Add(2 * i + 1);
            }
        }
        //连接下部圆环
        for (int i = 0; i < n + 1; i++)
        {
            if (i < n)
            {
                indices.Add(2 * i + 2 * (n + 1));
                indices.Add(2 * (i + 1) + 1 + 2 * (n + 1));
                indices.Add(2 * (i + 1) + 2 * (n + 1));

                indices.Add(2 * i + 2 * (n + 1));
                indices.Add(2 * i + 1 + 2 * (n + 1));
                indices.Add(2 * (i + 1) + 1 + 2 * (n + 1));
            }
        }
        //连接外部矩形
        for (int i = 0; i < n + 1; i++)
        {
            indices.Add(i + 4 * (n + 1));
            indices.Add(i + 5 * (n + 1));
            indices.Add(i + 4 * (n + 1) + 1);

            indices.Add(i + 4 * (n + 1) + 1);
            indices.Add(i + 5 * (n + 1));
            indices.Add(i + 5 * (n + 1) + 1);

            //0 3 1  1 3 4                    
        }
        //连接内部矩形
        for (int i = 0; i < n; i++)
        {
            indices.Add(i + 6 * (n + 1));
            indices.Add(i + 6 * (n + 1) + 1);
            indices.Add(i + 7 * (n + 1));

            indices.Add(i + 6 * (n + 1) + 1);
            indices.Add(i + 7 * (n + 1) + 1);
            indices.Add(i + 7 * (n + 1));
        }
        //下标路径点赋给mesh
        mesh.triangles = indices.ToArray();
        Material mat = new Material(Shader.Find("Standard"));

        GetComponent<MeshRenderer>().material = mat;
        mesh.RecalculateNormals();

    }
}

可通过uv坐标贴图,给Textrue附上不同的纹理材质。修改DrawCustomConduit(）方法里面的参数可以设置不同的需求效果。

3.效果展示