如何在脚本中访问unity着色器属性？

using UnityEngine;

public class ShaderPropertyAccess : MonoBehaviour
{
    Renderer renderer;
    Material material;
    Shader shader;
    int propertyID;

    void Start()
    {
        renderer = GetComponent<Renderer>();
        material = renderer.material;

        // 获取着色器
        shader = material.shader;

        // 获取属性ID
        propertyID = Shader.PropertyToID("_Color");
    }

    void Update()
    {
        // 访问属性
        Color color = material.GetColor(propertyID);
        color.r += 0.1f * Time.deltaTime;
        color.g += 0.2f * Time.deltaTime;
        color.b += 0.3f * Time.deltaTime;

        material.SetColor(propertyID, color);
    }
}