https://blog.csdn.net/puppet_master/article/details/72669977

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

public class CommandBufferTest : MonoBehaviour
{

    private CommandBuffer commandBuffer = null;
    private RenderTexture renderTexture = null;
    private Renderer targetRenderer = null;
    public GameObject targetObject = null;
    public Material replaceMaterial = null;

    void OnEnable()
    {
        targetRenderer = targetObject.GetComponentInChildren<Renderer>();
        renderTexture = RenderTexture.GetTemporary(512, 512, 16, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Default, 4);
        commandBuffer = new CommandBuffer();
        commandBuffer.SetRenderTarget(renderTexture);
        commandBuffer.ClearRenderTarget(true, true, Color.gray);
        Material mat = replaceMaterial == null ? targetRenderer.sharedMaterial : replaceMaterial;
        commandBuffer.DrawRenderer(targetRenderer, mat);
        this.GetComponent<Renderer>().sharedMaterial.mainTexture = renderTexture;
        Camera.main.AddCommandBuffer(CameraEvent.AfterForwardOpaque, commandBuffer);
    }

    void OnDisable()
    {
        Camera.main.RemoveCommandBuffer(CameraEvent.AfterForwardOpaque, commandBuffer);
        commandBuffer.Clear();
        renderTexture.Release();
    }
}