Draw text or image on camera stream (GLSL)

Question

I have a live broadcast application based on grafika examples where I send my video stream over RTMP live.

Now I want to tag my video by overlaying text or a logo on my video stream. I know that this can be done using GLSL filtering, but I have no idea how to implement this based on the sample I linked.

I tried using Alpha blending, but it seems that the two texture formats are somehow incompatible (one of them is TEXTURE_EXTERNAL_OES and the other is TEXTURE_2D), and I just get a black frame in return.

EDIT:

I based my code on the Kickflip API:

class CameraSurfaceRenderer implements GLSurfaceView.Renderer {
    private static final String TAG = "CameraSurfaceRenderer";
    private static final boolean VERBOSE = false;

    private CameraEncoder mCameraEncoder;

    private FullFrameRect mFullScreenCamera;
    private FullFrameRect mFullScreenOverlay;     // For texture overlay

    private final float[] mSTMatrix = new float[16];
    private int mOverlayTextureId;
    private int mCameraTextureId;

    private boolean mRecordingEnabled;

    private int mFrameCount;

    // Keep track of selected filters + relevant state
    private boolean mIncomingSizeUpdated;
    private int mIncomingWidth;
    private int mIncomingHeight;
    private int mCurrentFilter;
    private int mNewFilter;

    boolean showBox = false;


    /**
     * Constructs CameraSurfaceRenderer.
     * <p>
     * @param recorder video encoder object
     */
    public CameraSurfaceRenderer(CameraEncoder recorder) {
        mCameraEncoder = recorder;

        mCameraTextureId = -1;
        mFrameCount = -1;

        SessionConfig config = recorder.getConfig();
        mIncomingWidth = config.getVideoWidth();
        mIncomingHeight = config.getVideoHeight();
        mIncomingSizeUpdated = true;        // Force texture size update on next onDrawFrame

        mCurrentFilter = -1;
        mNewFilter = Filters.FILTER_NONE;

        mRecordingEnabled = false;
    }


    /**
     * Notifies the renderer that we want to stop or start recording.
     */
    public void changeRecordingState(boolean isRecording) {
        Log.d(TAG, "changeRecordingState: was " + mRecordingEnabled + " now " + isRecording);
        mRecordingEnabled = isRecording;
    }

    @Override
    public void onSurfaceCreated(GL10 unused, EGLConfig config) {
        Log.d(TAG, "onSurfaceCreated");
        // Set up the texture blitter that will be used for on-screen display.  This
        // is *not* applied to the recording, because that uses a separate shader.
        mFullScreenCamera = new FullFrameRect(
                new Texture2dProgram(Texture2dProgram.ProgramType.TEXTURE_EXT));
        // For texture overlay:
        GLES20.glEnable(GLES20.GL_BLEND);
        GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
        mFullScreenOverlay = new FullFrameRect(
                  new Texture2dProgram(Texture2dProgram.ProgramType.TEXTURE_2D));
        mOverlayTextureId = GlUtil.createTextureWithTextContent("hello!");
        mOverlayTextureId = GlUtil.createTextureFromImage(mCameraView.getContext(), R.drawable.red_dot);
        mCameraTextureId = mFullScreenCamera.createTextureObject();

        mCameraEncoder.onSurfaceCreated(mCameraTextureId);
        mFrameCount = 0;
    }

    @Override
    public void onSurfaceChanged(GL10 unused, int width, int height) {
        Log.d(TAG, "onSurfaceChanged " + width + "x" + height);
    }

    @Override
    public void onDrawFrame(GL10 unused) {
        if (VERBOSE){
            if(mFrameCount % 30 == 0){
                Log.d(TAG, "onDrawFrame tex=" + mCameraTextureId);
                mCameraEncoder.logSavedEglState();
            }
        }

        if (mCurrentFilter != mNewFilter) {
            Filters.updateFilter(mFullScreenCamera, mNewFilter);
            mCurrentFilter = mNewFilter;
            mIncomingSizeUpdated = true;
        }

        if (mIncomingSizeUpdated) {
            mFullScreenCamera.getProgram().setTexSize(mIncomingWidth, mIncomingHeight);
            mFullScreenOverlay.getProgram().setTexSize(mIncomingWidth, mIncomingHeight);
            mIncomingSizeUpdated = false;
            Log.i(TAG, "setTexSize on display Texture");
        }

        // Draw the video frame.
        if(mCameraEncoder.isSurfaceTextureReadyForDisplay()){
            mCameraEncoder.getSurfaceTextureForDisplay().updateTexImage();
            mCameraEncoder.getSurfaceTextureForDisplay().getTransformMatrix(mSTMatrix);
            //Drawing texture overlay:
            mFullScreenOverlay.drawFrame(mOverlayTextureId, mSTMatrix);
            mFullScreenCamera.drawFrame(mCameraTextureId, mSTMatrix);
        }
        mFrameCount++;
    }

    public void signalVertialVideo(FullFrameRect.SCREEN_ROTATION isVertical) {
        if (mFullScreenCamera != null) mFullScreenCamera.adjustForVerticalVideo(isVertical, false);
    }

    /**
     * Changes the filter that we're applying to the camera preview.
     */
    public void changeFilterMode(int filter) {
        mNewFilter = filter;
    }

    public void handleTouchEvent(MotionEvent ev){
        mFullScreenCamera.handleTouchEvent(ev);
    }

}

(GLSurfaceView), . , CameraEncoder.

Thing is, CameraSurfaceRenderer CameraEncoder ( , ) /.

Answer 1

GL_TEXTURE_EXTERNAL_OES, GL_OES_EGL_image_external OpenGL ES. . , , GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_2D. , OpenGL ES 2.0, , , , #extension GL_OES_EGL_image_external: require. samplerExternalOES GLSL.

https://developer.android.com/reference/android/graphics/SurfaceTexture.html

, -, , , .

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, , Texture2dProgram FullFrame Renderer. GL_TEXTURE_EXTERNAL_OES. , @ draw, , .

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