Thanks PuyBaret for reply.

The resources you provided proved helpful for me. I also got solution to my problem under the PhotoRenderer.java:

// Set the point the camera is pointed to
Point3 target = new Point3(
camera.getX() - (float)(Math.sin(yaw) * pitchCos),
camera.getZ() - (float)Math.sin(pitch),
camera.getY() + (float)(Math.cos(yaw) * pitchCos));
Vector3 up = new Vector3(0, 1, 0);
transform = Matrix4.lookAt(eye, target, up);

I am trying to understand more these classes.

thanks again.