Draw a line between Anchors with ARcore and OpenGL

Question

I'm building my app around this Agora ARcore Demo based on Google's hello_ar_java Sample APP.

I have tried using OpenGL and Sceneform togheter with no success: How to draw a line between anchors on the plane with ARcore without arFragment

From what I read I have to use OpenGL to draw a line, using GL_LINES or GL_LINE_STRIP

This is how I am proceeding:

public void onDrawFrame(GL10 gl) {
    // Clear screen to notify driver it should not load any pixels from previous frame.
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);

    if (mSession == null) {
        return;
    }
    // Notify ARCore session that the view size changed so that the perspective matrix and
    // the video background can be properly adjusted.
    mDisplayRotationHelper.updateSessionIfNeeded(mSession);

    try {
        // Obtain the current frame from ARSession. When the configuration is set to
        // UpdateMode.BLOCKING (it is by default), this will throttle the rendering to the
        // camera framerate.
        Frame frame = mSession.update();
        Camera camera = frame.getCamera();

        // Handle taps. Handling only one tap per frame, as taps are usually low frequency
        // compared to frame rate.
        MotionEvent tap = queuedSingleTaps.poll();
        if (tap != null && camera.getTrackingState() == TrackingState.TRACKING) {
            for (HitResult hit : frame.hitTest(tap)) {
                // Check if any plane was hit, and if it was hit inside the plane polygon
                Trackable trackable = hit.getTrackable();
                // Creates an anchor if a plane or an oriented point was hit.
                if ((trackable instanceof Plane && ((Plane) trackable).isPoseInPolygon(hit.getHitPose()))
                        || (trackable instanceof Point
                        && ((Point) trackable).getOrientationMode()
                        == Point.OrientationMode.ESTIMATED_SURFACE_NORMAL)) {
                    // Hits are sorted by depth. Consider only closest hit on a plane or oriented point.
                    // Cap the number of objects created. This avoids overloading both the
                    // rendering system and ARCore.
                    if (anchors.size() >= 250) {
                        anchors.get(0).detach();
                        anchors.remove(0);
                    }
                    // Adding an Anchor tells ARCore that it should track this position in
                    // space. This anchor is created on the Plane to place the 3D model
                    // in the correct position relative both to the world and to the plane.
                    anchors.add(hit.createAnchor());
                    break;
                }
            }
        }

        // Draw background.
        mBackgroundRenderer.draw(frame);

        // If not tracking, don't draw 3d objects.
        if (camera.getTrackingState() == TrackingState.PAUSED) {
            return;
        }

        // Get projection matrix.
        float[] projmtx = new float[16];
        camera.getProjectionMatrix(projmtx, 0, 0.1f, 100.0f);

        // Get camera matrix and draw.
        float[] viewmtx = new float[16];
        camera.getViewMatrix(viewmtx, 0);

        // Compute lighting from average intensity of the image.
        final float lightIntensity = frame.getLightEstimate().getPixelIntensity();

        if (isShowPointCloud()) {
            // Visualize tracked points.
            PointCloud pointCloud = frame.acquirePointCloud();
            mPointCloud.update(pointCloud);
            mPointCloud.draw(viewmtx, projmtx);

            // Application is responsible for releasing the point cloud resources after
            // using it.
            pointCloud.release();
        }

        // Check if we detected at least one plane. If so, hide the loading message.
        if (mMessageSnackbar != null) {
            for (Plane plane : mSession.getAllTrackables(Plane.class)) {
                if (plane.getType() == Plane.Type.HORIZONTAL_UPWARD_FACING
                        && plane.getTrackingState() == TrackingState.TRACKING) {
                    hideLoadingMessage();
                    break;
                }
            }
        }

        if (isShowPlane()) {
            // Visualize planes.
            mPlaneRenderer.drawPlanes(
                    mSession.getAllTrackables(Plane.class), camera.getDisplayOrientedPose(), projmtx);
        }

        // Visualize anchors created by touch.
        float scaleFactor = 1.0f;

        for (Anchor anchor : anchors) {
            if (anchor.getTrackingState() != TrackingState.TRACKING) {
                continue;
            }
            // Get the current pose of an Anchor in world space. The Anchor pose is updated
            // during calls to session.update() as ARCore refines its estimate of the world.
            anchor.getPose().toMatrix(mAnchorMatrix, 0);


            // Update and draw the model and its shadow.
            mVirtualObject.updateModelMatrix(mAnchorMatrix, mScaleFactor);
            mVirtualObjectShadow.updateModelMatrix(mAnchorMatrix, scaleFactor);
            mVirtualObject.draw(viewmtx, projmtx, lightIntensity);
            mVirtualObjectShadow.draw(viewmtx, projmtx, lightIntensity);
        }

        sendARViewMessage();
    } catch (Throwable t) {
        // Avoid crashing the application due to unhandled exceptions.
        Log.e(TAG, "Exception on the OpenGL thread", t);
    }
}

The code I find online expects a list of coordinates to draw a line. In my case I have several Anchors that need to be connected, I don't have a list of points. What is the easiest way to draw line using OpenGL-ES (android)

Somehow I am allowed to pass coordinates, but a line is generated for each Anchor, not connected to the previous one. Or many lines are displayed that are not connected in any way to the Anchors

Any suggestions for passing the coordinates of the tap or Anchors to the Line class?