RajawaliVR how to draw Crosshair?

Question

I have started using RajawaliVR framework.

I am able to display photo sphere images and able to change dynamically on click.

But now I want to change image without click. But how ?

I have rough idea to do this but stuck at implementation.

I have draw one circle on photo sphere image at particular x,y position say x=1935 and y=1495.

Image size is = 3840 X 2160.

Now when center of my eyeview is match to circle point on image at (x=1935 and y=1495) want to change image.

Please See the picture below for more clarity.