You have xorg, which is the newer version of xfree86.

What you'll need for 3D programming using the OpenGL API are the following packages:
mesa-libGL
mesa-libGL-devel
mesa-libGLU
mesa-libGLU-devel
mesa-libOSMesa
mesa-libOSMesa-devel
freeglut
freeglut-devel
You can install all of those using yum, if they aren't already installed. You can check if they are installed, like this:
rpm -qa | egrep -i '(mesa|glut)'