Unity中Mesh使用MeshTopology.Lines模式绘制线条及MeshTopology.Quads模式绘制网格参考
Unity中MeshFilter中的Mesh默认情况下使用MeshTopology.Trigangles类型绘制网格，就是通常的绘制三角形网格，实际上Mesh有五种绘制模式，对应MeshTopology的枚举，分别是
| Triangles | 网格由三角形构成。 |
| Quads | 网格由四边形构成。 |
| Lines | 网格由线条构成。 |
| LineStrip | 网格是线条带。 |
| Points | 网格由点构成。 |
这里以Lines和Quads为例说明Trigangles方式之外的绘制方式。
参考代码如下：
using System.Collections.Generic;
using UnityEngine;public class LineMeshTest : MonoBehaviour
{[SerializeField]Material material;void Start(){GameObject circle = new GameObject("Circle");circle.transform.SetParent(transform);circle.transform.localPosition = new Vector3(-5, 0, 0);MeshFilter filterCircle = circle.AddComponent<MeshFilter>();Mesh meshCircle = GetCircleMesh(2);filterCircle.mesh = meshCircle;MeshRenderer renderCircle = circle.AddComponent<MeshRenderer>();renderCircle.material = material;GameObject quad = new GameObject("Quad");quad.transform.SetParent(transform);quad.transform.localPosition = new Vector3(5, 0, 0);MeshFilter filterQuad = quad.AddComponent<MeshFilter>();Mesh meshQuad = GetQuadMesh(5);filterQuad.mesh = meshQuad;MeshRenderer rendeQuad = quad.AddComponent<MeshRenderer>();rendeQuad.material = material;}Mesh GetCircleMesh(float radius){List<Vector3> vertexList = new();List<int> indexList = new List<int>();float radDelta = Mathf.PI / 36;for (float i = 0; i < 72f; i++){float rad = radDelta * i;Vector3 vert = new(radius * Mathf.Cos(rad), radius * Mathf.Sin(rad), 0);vertexList.Add(vert);}indexList.Add(0);for (int i = 1; i < 72; i++){indexList.Add(i);indexList.Add(i);}indexList.Add(0);Mesh mesh = new();mesh.SetVertices(vertexList);mesh.SetIndices(indexList.ToArray(), MeshTopology.Lines, 0);return mesh;}Mesh GetQuadMesh(float size){float s = size * 0.5f;Vector3[] vertices = new[] { new Vector3(s, s, 0), new Vector3(s, -s, 0), new Vector3(-s, -s, 0), new Vector3(-s, s, 0) };int[] indices = new[] { 0, 1, 2, 3 };Mesh mesh = new Mesh();mesh.SetVertices(vertices);mesh.SetIndices(indices, MeshTopology.Quads, 0);return mesh;}
}
这个例子里面使用Mesh绘制了一个圆形线条，注意这两行语句：
mesh.SetIndices(indexList.ToArray(), MeshTopology.Lines, 0);mesh.SetIndices(indices, MeshTopology.Quads, 0);