How to add 3D accelerated graphics to server version?

I'm using an Odroid C2 and need some newer software packages than those found in the Ubuntu 16.04 repositories, so I installed the legacy (3.14.79) version of the Debian server edition of Armbian, then upgraded it to Debian 9.  I've installed xorg, lightdm, etc and now have a very functional desktop.

However, I want to install a 3D CAD program that **I think** would perform better if I had 3D accelerated graphics installed.

I'm a complete noob when it comes to 3D graphics drivers.  I assume they're not installed, as I see this on my Orange Pi PC 2 running the desktop version of Ubuntu:

$ lsmod | grep mali
mali_drm                2732  1
drm                   178255  2 mali_drm
mali                  123146  0
ump                    29379  3 mali

but nothing on my Odroid C2.  I can't find the drivers in any directory on my system, either.

How would I go about installing them?

-Jim