下面简单介绍几个重要函数：打开脚本“TestHelloUnityVideo”这里面的“loadEngine”即为Agora引擎重要的初始化步骤。

 public void loadEngine(string appId)
    {
        // start sdk
        Debug.Log("initializeEngine");

        if (mRtcEngine != null)
        {
            Debug.Log("Engine exists. Please unload it first!");
            return;
        }

        // init engine
        mRtcEngine = IRtcEngine.GetEngine(appId);

        // enable log
        mRtcEngine.SetLogFilter(LOG_FILTER.DEBUG | LOG_FILTER.INFO | LOG_FILTER.WARNING | LOG_FILTER.ERROR | LOG_FILTER.CRITICAL);
    }

下面的“join”函数，为用户加入房间以及各种回调函数的设计：

 public void join(string channel)
    {
        Debug.Log("calling join (channel = " + channel + ")");

        if (mRtcEngine == null)
            return;

        // set callbacks (optional)
        mRtcEngine.OnJoinChannelSuccess = onJoinChannelSuccess;
        mRtcEngine.OnUserJoined = onUserJoined;
        mRtcEngine.OnUserOffline = onUserOffline;

        // enable video
        mRtcEngine.EnableVideo();
        // allow camera output callback
        mRtcEngine.EnableVideoObserver();

        // join channel
        mRtcEngine.JoinChannel(channel, null, 0);
    }

接下来的“leave”函数，切记在程序退出时记得关闭，不然可能会导致一些bug。

（2）接下来，我们要完成Agora系统的外置视频源输入，有以下内容：

（a）设置Agora的SDK为外置视频源模式，在“join”函数中， mRtcEngine.SetExternalVideoSource(true, false);

请确保你是在调用pushExternalVideoFrame前已调用 setExternalVideoSource， 并将参数 pushMode 设为 true ，不然调用本方法后会一直报错。

    public void join(string channel)
    {
        Debug.Log("calling join (channel = " + channel + ")");

        if (mRtcEngine == null)
            return;
        // set callbacks (optional)
        mRtcEngine.OnJoinChannelSuccess = onJoinChannelSuccess;
        mRtcEngine.OnUserJoined = onUserJoined;
        mRtcEngine.OnUserOffline = onUserOffline;
        // enable video
        mRtcEngine.EnableVideo();
        // allow camera output callback
        mRtcEngine.EnableVideoObserver();

        // 配置外部视频源。
        mRtcEngine.SetExternalVideoSource(true, false);
        // join channel
        mRtcEngine.JoinChannel(channel, null, 0);
        // Optional: if a data stream is required, here is a good place to create it
        int streamID = mRtcEngine.CreateDataStream(true, true);
    }

（b）添加外部视频源推送函数，需要注意的是：

• VIDEO_PIXEL_FORMAT.VIDEO_PIXEL_RGBA;目前已经支持多种视频格式，在unity中不必讲RGBA再转换成BGRA（赞~）
• externalVideoFrame.cropLeft;等四个位置，这里是做视频的裁剪
• externalVideoFrame.rotation = 0;这里在移动端具有重要作用，作为视频的旋转设置

    void ShareCam(Texture2D tex)
    {
        if (tex == null)
            return;
        byte[] bytes = tex.GetRawTextureData();
        int size = Marshal.SizeOf(bytes[0]) * bytes.Length;
        // 查询是否存在 IRtcEngine 实例。
        IRtcEngine rtc = IRtcEngine.QueryEngine();
        if (rtc != null)
        {
            // 创建外部视频帧。
            ExternalVideoFrame externalVideoFrame = new ExternalVideoFrame();
            // 设置视频帧 buffer 类型。
            externalVideoFrame.type = ExternalVideoFrame.VIDEO_BUFFER_TYPE.VIDEO_BUFFER_RAW_DATA;
            // 设置像素格式。
            externalVideoFrame.format = ExternalVideoFrame.VIDEO_PIXEL_FORMAT.VIDEO_PIXEL_RGBA;
            // 应用原始数据。
            externalVideoFrame.buffer = bytes;
            // 设置视频帧宽度（pixel）。
            externalVideoFrame.stride = tex.width;
            // 设置视频帧高度（pixel）。
            externalVideoFrame.height = tex.height;
            // 设置从哪侧移除视频帧的像素。
            externalVideoFrame.cropLeft = 0;
            externalVideoFrame.cropTop = 0;
            externalVideoFrame.cropRight = 0;
            externalVideoFrame.cropBottom = 0;
            // 设置视频帧旋转角度： 0、90、180 或 270。
            externalVideoFrame.rotation = 0;

            // 使用视频时间戳增加 i。
            externalVideoFrame.timestamp = i++;
            // 推送外部视频帧。
            int a = rtc.PushVideoFrame(externalVideoFrame);
        }
    }

（c）依据第二步我们所获得的视频图片数据源（两种哈），形成完整的Agroa外置视频源系统代码：

using System.Collections;
using System.Collections.Generic;
using agora_gaming_rtc;
using agora_utilities;
using UnityEngine;
using UnityEngine.UI;
using System.Globalization;
using System.Runtime.InteropServices;
public class AgoraVideoExtern : MonoBehaviour
{
    public VuforiaImageShare vuforiaShare;
    // instance of agora engine
    private IRtcEngine mRtcEngine;
    //输入创建项目所获得的的id
    [SerializeField]
    public string appId = "";
    //输入视频房间名称
    public string roomName="Agora";
    public InputField inputChan;
    int i = 1000;
    // Start is called before the first frame update
    void Start()
    {
        inputChan.text = roomName;
        loadEngine(appId);
    }
    //加入房间按钮
    public void JoinBtn()
    {
        join(roomName);
    }
    public void loadEngine(string appId)
    {
        // start sdk
        Debug.Log("initializeEngine");
        if (mRtcEngine != null)
        {
            Debug.Log("Engine exists. Please unload it first!");
            return;
        }
        // init engine
        mRtcEngine = IRtcEngine.GetEngine(appId);
        // enable log
        mRtcEngine.SetLogFilter(LOG_FILTER.DEBUG | LOG_FILTER.INFO | LOG_FILTER.WARNING | LOG_FILTER.ERROR | LOG_FILTER.CRITICAL);
    }
    public void join(string channel)
    {
        Debug.Log("calling join (channel = " + channel + ")");

        if (mRtcEngine == null)
            return;
        // set callbacks (optional)
        mRtcEngine.OnJoinChannelSuccess = onJoinChannelSuccess;
        mRtcEngine.OnUserJoined = onUserJoined;
        mRtcEngine.OnUserOffline = onUserOffline;
        // enable video
        mRtcEngine.EnableVideo();
        // allow camera output callback
        mRtcEngine.EnableVideoObserver();

        // 配置外部视频源。
        mRtcEngine.SetExternalVideoSource(true, false);
        // join channel
        mRtcEngine.JoinChannel(channel, null, 0);
        // Optional: if a data stream is required, here is a good place to create it
        int streamID = mRtcEngine.CreateDataStream(true, true);
    }
    void ShareCam(Texture2D tex)
    {
        if (tex == null)
            return;
        byte[] bytes = tex.GetRawTextureData();
        int size = Marshal.SizeOf(bytes[0]) * bytes.Length;
        // 查询是否存在 IRtcEngine 实例。
        IRtcEngine rtc = IRtcEngine.QueryEngine();
        if (rtc != null)
        {
            // 创建外部视频帧。
            ExternalVideoFrame externalVideoFrame = new ExternalVideoFrame();
            // 设置视频帧 buffer 类型。
            externalVideoFrame.type = ExternalVideoFrame.VIDEO_BUFFER_TYPE.VIDEO_BUFFER_RAW_DATA;
            // 设置像素格式。
            externalVideoFrame.format = ExternalVideoFrame.VIDEO_PIXEL_FORMAT.VIDEO_PIXEL_RGBA;
            // 应用原始数据。
            externalVideoFrame.buffer = bytes;
            // 设置视频帧宽度（pixel）。
            externalVideoFrame.stride = tex.width;
            // 设置视频帧高度（pixel）。
            externalVideoFrame.height = tex.height;
            // 设置从哪侧移除视频帧的像素。
            externalVideoFrame.cropLeft = 0;
            externalVideoFrame.cropTop = 0;
            externalVideoFrame.cropRight = 0;
            externalVideoFrame.cropBottom = 0;
            // 设置视频帧旋转角度： 0、90、180 或 270。
            externalVideoFrame.rotation = 0;

            // 使用视频时间戳增加 i。
            externalVideoFrame.timestamp = i++;
            // 推送外部视频帧。
            int a = rtc.PushVideoFrame(externalVideoFrame);
        }
    }
    // implement engine callbacks
    private void onJoinChannelSuccess(string channelName, uint uid, int elapsed)
    {
        Debug.Log("JoinChannelSuccessHandler: uid = " + uid);

      //  GameObject textVersionGameObject = GameObject.Find("VersionText");
      //  textVersionGameObject.GetComponent<Text>().text = "SDK Version : " + getSdkVersion();
    }

    // When a remote user joined, this delegate will be called. Typically
    // create a GameObject to render video on it
    private void onUserJoined(uint uid, int elapsed)
    {
        Debug.Log("onUserJoined: uid = " + uid + " elapsed = " + elapsed);
        // this is called in main thread
        // find a game object to render video stream from 'uid'
        GameObject go = GameObject.Find(uid.ToString());
        if (!ReferenceEquals(go, null))
        {
            return; // reuse
        }
/*
        // create a GameObject and assign to this new user
        VideoSurface videoSurface = makeImageSurface(uid.ToString());
        if (!ReferenceEquals(videoSurface, null))
        {
            // configure videoSurface
            videoSurface.SetForUser(uid);
            videoSurface.SetEnable(true);
            videoSurface.SetVideoSurfaceType(AgoraVideoSurfaceType.RawImage);
            videoSurface.SetGameFps(30);
        }
        */
    }

    public VideoSurface makePlaneSurface(string goName)
    {
        GameObject go = GameObject.CreatePrimitive(PrimitiveType.Plane);

        if (go == null)
        {
            return null;
        }
        go.name = goName;
        // set up transform
        go.transform.Rotate(-90.0f, 0.0f, 0.0f);
        float yPos = Random.Range(3.0f, 5.0f);
        float xPos = Random.Range(-2.0f, 2.0f);
        go.transform.position = new Vector3(xPos, yPos, 0f);
        go.transform.localScale = new Vector3(0.25f, 0.5f, .5f);

        // configure videoSurface
        VideoSurface videoSurface = go.AddComponent<VideoSurface>();
        return videoSurface;
    }

    private const float Offset = 100;
    public VideoSurface makeImageSurface(string goName)
    {
        GameObject go = new GameObject();

        if (go == null)
        {
            return null;
        }
        go.name = goName;

        // to be renderered onto
        go.AddComponent<RawImage>();

        // make the object draggable
        go.AddComponent<UIElementDragger>();
        GameObject canvas = GameObject.Find("Canvas");
        if (canvas != null)
        {
            go.transform.parent = canvas.transform;
        }
        // set up transform
        go.transform.Rotate(0f, 0.0f, 180.0f);
        float xPos = Random.Range(Offset - Screen.width / 2f, Screen.width / 2f - Offset);
        float yPos = Random.Range(Offset, Screen.height / 2f - Offset);
        go.transform.localPosition = new Vector3(xPos, yPos, 0f);
        go.transform.localScale = new Vector3(3f, 4f, 1f);

        // configure videoSurface
        VideoSurface videoSurface = go.AddComponent<VideoSurface>();
        return videoSurface;
    }
    private void onUserOffline(uint uid, USER_OFFLINE_REASON reason)
    {
        // remove video stream
        Debug.Log("onUserOffline: uid = " + uid + " reason = " + reason);
        // this is called in main thread
        GameObject go = GameObject.Find(uid.ToString());
        if (!ReferenceEquals(go, null))
        {
            Object.Destroy(go);
        }
    }
    public void unloadEngine()
    {
        Debug.Log("calling unloadEngine");

        // delete
        if (mRtcEngine != null)
        {
            IRtcEngine.Destroy();  // Place this call in ApplicationQuit
            mRtcEngine = null;
        }
    }
    public void leave()
    {
        Debug.Log("calling leave");

        if (mRtcEngine == null)
            return;

        // leave channel
        mRtcEngine.LeaveChannel();
        // deregister video frame observers in native-c code
        mRtcEngine.DisableVideoObserver();
    }
    void OnApplicationQuit()
    {
        leave();
        unloadEngine();

    }
    // Update is called once per frame
    void Update()
    {
        if (mRtcEngine == null)
            return;
        ShareCam(vuforiaShare.GetSharedImage());
    }
}

这一步我们将两个系统进行融合，下图是简单场景编写，详细内容会在附件连接中提供下载。下图为Agroa的AR识别场景，在开启后将可以看到AR场景并开启外部视频源的数据推送。

在此之前，我们需要将Agroa例程中的“SceneHome”输出为exe可运行程序（请记得licence和BuildSetting添加场景）。

导出后，请先运行编辑器中的AR场景，因为要抢占开发电脑的摄像头（agroa默认取第一个摄像头），创建好系统场景；

之后开启事先导出的Agroa的例程场景，输入频道号“Agora”即可，分别看一下只传输视频和传输AR视频的效果

​

下面是切换了AR渲染后的效果，可以明显看到在右侧客户端画面中，出现了渲染过的3D人物。

待解决的问题

（1）通过传送渲染过的相机，对计算能力的要求，目前本机I7 9700k，1050TI显卡，编辑器内可以达到60帧，是否有更高效的方法？

​（2）仔细观察会发现，左侧屏幕中，Vuforia回调的视频画面是上下反转的，而传到左侧，又反转了一次；是什么问题该如何处理；

（3）仔细观察会发现，右侧原始画面在左侧展示时候，虽然压缩了但是明显的也被裁减了，这是为什么呢？

相关资源

论坛：

Agora开发者中心：https://docs.agora.io/cn

AgoraGit仓库：https://github.com/AgoraIO

本次源代码：

链接：https://pan.baidu.com/s/1DIQNFTrSUHsARhRH_KchNQ
提取码：n8ne