Proper way of updating a texture outside Unity

Hi.
I want to use to progressively stream videos from urls, but display the video in Unity3D.
I first tested it with a surfaceview in a native android app and it works brilliantly.
However, I need this functionality to be contained into an aar library and use it as a plugin for Unity.
I am VERY close to make it work (or so it seems), but I know my lack of OpenGL knowledge is not letting me advance.
Should the texture be created in Unity-side or in the plugin-side?
When should it be re-created and how?
When should it be destroyed and how?

I tried several combinations and only a black texture is shown. Audio works in each case.
The code is a mess, as now I'm still in the "discovering" stage and I'm trying everything I can think of.
I didn't delete all the comments, so you can see what other approaches I used. I also put some questions in the comments.
I know the solution needs unity+exoplayer+opengl+android knowledge at the same time, so I also asked this on SO and linked the posts to each other. Hopefully, I can combine the answers I get here with those ones and come up with the solution.

Android side:

Code (CSharp):

1. public class ExoPlayerForUnity {
2.     static SurfaceTexture surfaceTexture;
3.     static Surface surface;
4.  
5.     static Context getUnityContext() {
6.         try {
7.             Class<?> unityPlayerClass = Class.forName("com.unity3d.player.UnityPlayer");
8.             Field currentActivity = unityPlayerClass.getField("currentActivity");
9.             Object o = currentActivity.get(null);
10.             return (Context)o;
11.         } catch (ClassNotFoundException e) {
12.             e.printStackTrace();
13.         } catch (NoSuchFieldException e) {
14.             e.printStackTrace();
15.         } catch (IllegalAccessException e) {
16.             e.printStackTrace();
17.         }
18.  
19.         return null;
20.     }
21.  
22.  
23.     public static int init( String uriString) {
24.  
25.         Uri videoURI = Uri.parse(uriString);
26.  
27.         final Activity unityContext = (Activity)getUnityContext();
28.  
29.         final Handler handler = new Handler();
30. //        BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
31. //        TrackSelection.Factory videoTrackSelectionFactory = new AdaptiveVideoTrackSelection.Factory(bandwidthMeter);
32. //        TrackSelection.Factory videoTrackSelectionFactory = new FixedTrackSelection.Factory();
33. //        TrackSelector trackSelector = new DefaultTrackSelector(mainHandler, videoTrackSelectionFactory);
34.         TrackSelector trackSelector = new DefaultTrackSelector(handler, null);
35.         LoadControl loadControl = new DefaultLoadControl();
36.         final SimpleExoPlayer player = ExoPlayerFactory.newSimpleInstance(unityContext, trackSelector, loadControl, null, false);
37.  
38.         DefaultBandwidthMeter defBandwidthMeter = new DefaultBandwidthMeter();
39.         DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(unityContext,
40.                 Util.getUserAgent(unityContext, "yourApplicationName"), defBandwidthMeter);
41.         ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();
42.         MediaSource videoSource = new ExtractorMediaSource(videoURI,
43.                 dataSourceFactory, extractorsFactory, new Handler(), new ExtractorMediaSource.EventListener() {
44.             @Override
45.             public void onLoadError(IOException error) {
46.                 error.printStackTrace();
47.             }
48.         });
49.  
50.  
51.         // Maybe useful?: http://stackoverflow.com/questions/33324753/how-to-use-unity-createexternaltexture-on-android
52.         int[] textures = new int[1];
53.         GLES20.glGenTextures(1, textures, 0);
54.         final int texture = textures[0];
55.  
56. //        //GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
57. //        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, texture);
58. //        //GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGB, 1024, 512, 0, GLES20.GL_RGB, GLES20.GL_UNSIGNED_BYTE, null);
59. //        GLES20.glTexParameteri( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR );
60. //        GLES20.glTexParameteri( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR );
61. //        GLES20.glTexParameteri( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE );
62. //        GLES20.glTexParameteri( GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE );
63. //        GLES20.glBindTexture( GLES20.GL_TEXTURE_2D, 0 );
64.  
65.         GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture);
66.         GLES20.glTexParameteri( GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR );
67.         GLES20.glTexParameteri( GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR );
68.         GLES20.glTexParameteri( GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE );
69.         GLES20.glTexParameteri( GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE );
70.         GLES20.glBindTexture( GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0 );
71.  
72.  
73.  
74.         // TODO work with attachToGLContext maybe?
75.         surfaceTexture = new SurfaceTexture(texture);
76.  
77.         surfaceTexture.setOnFrameAvailableListener(new SurfaceTexture.OnFrameAvailableListener() {
78.             @Override
79.             public void onFrameAvailable(final SurfaceTexture sf) {
80.                 handler.post(new Runnable() {
81.                     @Override
82.                     public void run() {
83.                         // Should I use this or update it in Unity-side with tex.UpdateTextureExternal(tex.GetNativeTexturePtr()) ?
84.                         //GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture);
85.                         //sf.updateTexImage();
86.                         //GLES20.glBindTexture( GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0 );
87.                     }
88.                 });
89.             }
90.         });
91.  
92.         surface = new Surface(surfaceTexture);
93.  
94.         Timer t = new Timer();
95.         t.schedule(
96.                 new TimerTask() {
97.                     @Override
98.                     public void run() {
99.                         Log.v("ExoPlayerForUnity", "buff: " + player.getBufferedPercentage());
100.                     }
101.                 }, 3000, 1000
102.         );
103.  
104.         player.setVideoSurface(surface);
105.         player.prepare(videoSource);
106.         player.setPlayWhenReady(true);
107.  
108.         return texture;
109.     }
110. }

Unity side:

Code (CSharp):

1. public class ExoTestPlugin : MonoBehaviour
2. {
3.     new Renderer renderer;
4.     Texture2D rt;
5.     //RenderTexture rt; // maybe this?
6.     AndroidJavaClass jc;
7.     int texName;
8.     float curScale = 0f;
9.  
10.     void init()
11.     {
12.         renderer = GetComponent<Renderer>();
13.         Camera.onPreRender += OnPreRender2;
14.  
15.         jc = new AndroidJavaClass("com.thefallengames.exoplayerforunity.ExoPlayerForUnity");
16.  
17.         texName = jc.CallStatic<int>("init", 0, "http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4");
18.    
19.  
20.         //rt = new Texture2D(640, 360, TextureFormat.RGBA32, true, true);
21.         //rt = new Texture2D(640, 360, TextureFormat.ETC2_RGBA8, true, true);
22.         //rt = new RenderTexture(640, 360, 24, RenderTextureFormat.Default, RenderTextureReadWrite.Default);
23.         //rt.Create();
24.  
25.         rt = Texture2D.CreateExternalTexture(1024, 512, TextureFormat.ETC_RGB4, true, true, (IntPtr)texName);
26.  
27.         renderer.material.mainTexture = rt;
28.     }
29.  
30.     void Update () {
31.  
32.         // Here I'm just starting the playback on first tap and then toggling between 2x and 1x scale on any subsequent taps
33.         if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Ended)
34.         {
35.             if (curScale == 0f)
36.             {
37.                 curScale = 1f;
38.                 init();
39.  
40.                 return;
41.             }
42.  
43.             if (curScale == 2f)
44.                 curScale = .5f;
45.             else
46.                 curScale = 2f;
47.             transform.localScale *= curScale;
48.         }
49.     }
50.  
51.     void OnPreRender2(Camera cam)
52.     {
53.         if (jc == null) // not inited
54.             return;
55.  
56.         if (UnityEngine.Random.Range(0, 60) != 0) // updating ~once per second only, just for debugging
57.             return;
58.  
59.         rt.UpdateExternalTexture((IntPtr)texName);
60.     }
61.  
62.  
63.  
64. }

 

any luck with that?

 

Nope

 

I think it has to do with GL_TEXTURE_EXTERNAL_OES and unity. It has to use that external source somehow