unity 根据顶点位置变换顶点颜色

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class HeightCOlor : MonoBehaviour
{
    public Gradient coloring;
    public SkinnedMeshRenderer meshRenderer;
    public float top = 10;
    public float buttom = 0;
    void OnEnable()
    {
      Mesh mesh=  meshRenderer.sharedMesh;
      Vector3[] v3=  mesh.vertices;
        List<Color> lc = new List<Color>();
        for (int i = 0; i < v3.Length; i++)
        {
            Color c= coloring.Evaluate(v3[i].y / (top - buttom));
            Debug.Log(c);
            lc.Add(new Color(c.r, c.g, c.b));
        }
        mesh.colors = lc.ToArray();
    }
}

c#脚本↑

Shader "Custom/Surface Shader" {
	Properties {
		_MainTex ("Base (RGB)", 2D) = "white" {}
	}
	SubShader {
		Tags { "RenderType"="Opaque" }
		LOD 200
		
		CGPROGRAM
		#pragma surface surf Lambert

		sampler2D _MainTex;

		struct Input {
			float2 uv_MainTex;
			half4 color : COLOR;
		};

		void surf (Input IN, inout SurfaceOutput o) {
			half4 c = tex2D (_MainTex, IN.uv_MainTex);
			// 叠加色
			//o.Albedo = c.rgb * IN.color.rgb;
			//o.Alpha = c.a * IN.color.a;
			//纯色
			o.Albedo =  IN.color.rgb;
			o.Alpha =  IN.color.a;
		}
		ENDCG
	} 
	FallBack "Diffuse"
}

surface shader脚本↑