Integrating Vuforia with External Native (C++) Rendering Engine

Hey All,

I am attempting to integrate Vuforia with my company's C++ Rendering Engine. Essentially, I want to use Vuforia to encapsulate the camera API and perform the object tracking component of my AR app while I perform all the rendering with our company's engine. Since vuforia supports rendering to an OpenGL texture, I figured I would create an external texture, tell vuforia to use that texture, then after vuforia updated it with the latest camera image, I would pass the texture binding down to my c++ engine to use for rendering the background. This is all done on the rendering thread of my app (via a callback) and looks like this:

        if (!mTextureCreated)             {                 // create the openGL texture that the camera will render / blit to                 int[] tmp = new int[1];                 GLES20.glGenTextures(1, tmp, 0);                 videoBackgroundTex.videoBackgroundTextureID= tmp[0];

                GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, videoBackgroundTex.videoBackgroundTextureID);                 GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GlTextureWrapS, GLES20.GL_CLAMP_TO_EDGE);                 GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GlTextureWrapT, GLES20.GL_CLAMP_TO_EDGE);                 GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GlTextureMinFilter, GLES20.GL_NEAREST);                 GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GlTextureMagFilter, GLES20.GL_NEAREST);

                mTextureCreated = true;             }                         if (!mTextureLinked)             {

                // tell vuforia to use the texture we created

                if (!Renderer.getInstance().setVideoBackgroundTexture(videoBackgroundTex))                 {                     Log.Error("AR-Demo", "Unable to set video background texture");                     return;                 }                 mTextureLinked = true;             }

            // update video background tex

            State state = TrackerManager.getInstance().getStateUpdater().UpdateState();             Renderer.getInstance().begin(state);             if (!Renderer.getInstance().updateVideoBackgroundTexture())             {                 Log.Error("AR-Demo", "Unable to update video background texture");                 return;             }             Renderer.getInstance().end();

            /* pass texture updated by updateVideoBackgroundTexture to my C++ engine here */

This however never seems to actually populate the contents of that texture binding. Every time I bind it to a sampler in our engine the texture looks completely black. So is this method for 'populating' the texture with the camera image invalid? If so, is there a better way to go about doing this?

I also noticed that during a call to Vuforia.OnResume, I recieve an exception with the following error: ""RenderManager: Could not retrieve a valid GLSurfaceView in view hierarchy, therefore cannot set any render mode". In our app, we cannot use a GLSurfaceView because this class not only provides a render target surface but also performs OpenGL context management which interferes with our rendering engine's OpenGL context creation / management. So we instead render to a plain SurfaceView so that we can manage the context ourselves. Does vuforia currently support this kind of workflow or do you have to use a GLSurfaceView?

Any help is appreciated,

Alex