It was surprisingly easy to get hybrid graphics to work.
I'm using the closed source nvidia-drivers and won't cover noveau in this post.
Check if nvidia is added to your make.conf:
VIDEO_CARDS="nvidia i915 intel"
Add Bumblebee Overlay:
layman -a bumblebee
Emerge Bumblebee and nvidia-drivers:
Check the Bumblebee config file in /etc/bumblebee/bumblebee.conf:
# The Driver used by Bumblebee server. If this value is not set (or empty),
# auto-detection is performed. The available drivers are nvidia and nouveau
# (See also the driver-specific sections below)
Add Bumblebee to autostart:
rc-update add bumblebee default
Add your user to the bumblebee group:
usermod -a -G bumblebee <user>
That's it so far, but there's still a small problem.
Bumblebee will start a desktop manager as soon as you boot. I'm using slim for that and it's working well.
Install any desktop manager you like and set it up before rebooting.
To use nvidia for special tools use:
Remember to rebuild bbswitch every time you update your kernel:
emerge -1 bbswitch