Baby boy won't smile at Dad

Hi guys, I am a dad of a lovely 6 month old boy. I love him but I also am a hardcore gamer. Due to this, I usually spend a lot of time gaming and I seldom cuddle my baby boy. 

Just recently, he doesn't smile at me. He only smiles at her mom and nanny, but not me. Is there anything that I can do? Any advise is appreciated, thanks!