public override void Create()
{
    m_Clear = new ClearColorPass { renderPassEvent = RenderPassEvent.BeforeRenderingOpaques };
    m_Capture = new CapturePass();
    m_Restore = new RestorePass();
}

public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
{
    // 只处理游戏相机，Scene 视图、预览窗口保持原样
    if (renderingData.cameraData.cameraType != CameraType.Game)
        return;
    m_Capture.renderPassEvent = captureEvent;
    // 贴回去的时机：后处理之后、FinalBlit 之前
    m_Restore.renderPassEvent = RenderPassEvent.AfterRenderingPostProcessing;
    if (clearColorBeforeOpaques)
        renderer.EnqueuePass(m_Clear);
    renderer.EnqueuePass(m_Capture);
    renderer.EnqueuePass(m_Restore);
}

public override void SetupRenderPasses(ScriptableRenderer renderer, in RenderingData renderingData)
{
    if (renderingData.cameraData.cameraType != CameraType.Game)
        return;
    // 快照的格式与相机颜色缓冲一致（HDR 时是浮点格式），但不需要深度、不需要 MSAA
    var desc = renderingData.cameraData.cameraTargetDescriptor;
    desc.depthBufferBits = 0;
    desc.msaaSamples = 1;
    RenderingUtils.ReAllocateIfNeeded(ref m_Snapshot, desc, FilterMode.Bilinear, TextureWrapMode.Clamp, name: "_FrameSnapshot");
    m_Capture.Setup(m_Snapshot);
    m_Restore.Setup(m_Snapshot);
}

protected override void Dispose(bool disposing)
{
    m_Snapshot?.Release();
}

class ClearColorPass : ScriptableRenderPass
{
    public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
    {
        // 没有调用 ConfigureTarget，执行到这里时 URP 已经绑定了相机颜色/深度缓冲
        var cmd = CommandBufferPool.Get();
        cmd.ClearRenderTarget(RTClearFlags.Color, Color.black, 1f, 0);
        context.ExecuteCommandBuffer(cmd);
        CommandBufferPool.Release(cmd);
    }
}

class CapturePass : ScriptableRenderPass
{
    RTHandle m_Destination;
    public CapturePass() { profilingSampler = new ProfilingSampler("Cookbook Snapshot Capture"); }

    public void Setup(RTHandle destination) { m_Destination = destination; }

    public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData)
    {
        // 告诉 URP 这个 Pass 的输出目标，URP 才知道之后的 Pass 需要重新绑定相机目标
        ConfigureTarget(m_Destination);
    }

    public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
    {
        // 相机颜色缓冲在 Execute 里现取：后处理开启时 URP 用两个缓冲交替（swap buffer），
        // 在 SetupRenderPasses 里缓存的句柄不一定是此刻正在画的那一个
        var source = renderingData.cameraData.renderer.cameraColorTargetHandle;
        var cmd = CommandBufferPool.Get();
        using (new ProfilingScope(cmd, profilingSampler))
        {
            // 开了 MSAA 时，相机颜色缓冲是多重采样纹理，“解析”（resolve）之前直接采样它，
            // 读到的可能是上一次解析留下的旧内容。这里显式解析到快照里，读到的才是此刻的画面。
            if (source.rt != null && source.rt.antiAliasing > 1)
                cmd.ResolveAntiAliasedSurface(source.rt, m_Destination.rt);
            else
                Blitter.BlitCameraTexture(cmd, source, m_Destination);
        }
        context.ExecuteCommandBuffer(cmd);
        CommandBufferPool.Release(cmd);
    }
}

class RestorePass : ScriptableRenderPass
{
    RTHandle m_Snapshot;
    public RestorePass() { profilingSampler = new ProfilingSampler("Cookbook Snapshot Restore"); }
    public void Setup(RTHandle snapshot) { m_Snapshot = snapshot; }

    public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
    {
        // 后处理会在两个颜色缓冲之间来回切换（swap buffer），所以在 Execute 里现取“当前”的相机颜色缓冲
        var target = renderingData.cameraData.renderer.cameraColorTargetHandle;
        var cmd = CommandBufferPool.Get();
        using (new ProfilingScope(cmd, profilingSampler))
            Blitter.BlitCameraTexture(cmd, m_Snapshot, target);
        context.ExecuteCommandBuffer(cmd);
        CommandBufferPool.Release(cmd);
    }
}