C#代码片段计算表面和顶点法线

using System.Collections.Generic;
using UnityEngine;

public class NormalCalculator : MonoBehaviour
{
    public MeshFilter meshFilter;

    private Mesh mesh;
    private Vector3[] normals;
    private Vector3[] vertices;
    private int[] triangles;

    void Start()
    {
        mesh = meshFilter.mesh;
        vertices = mesh.vertices;
        triangles = mesh.triangles;
        normals = new Vector3[vertices.Length];

        for (int i = 0; i < triangles.Length; i += 3)
        {
            int index1 = triangles[i];
            int index2 = triangles[i + 1];
            int index3 = triangles[i + 2];

            Vector3 side1 = vertices[index2] - vertices[index1];
            Vector3 side2 = vertices[index3] - vertices[index1];
            Vector3 normal = Vector3.Cross(side1, side2).normalized;

            normals[index1] += normal;
            normals[index2] += normal;
            normals[index3] += normal;
        }

        for (int i = 0; i< normals.Length; i++)
        {
            normals[i].Normalize();
        }

        mesh.normals = normals;
    }
}