Installing rgl on Ubuntu and Mac: X11 not found

Question

I have seen this question here: Error in loading rgl package with Mac OS X but there is no mentioning about installation error, which is my case. I cannot install rgl<

Answer 1

On Ubuntu 16.04 and 18.04, you might get this issue when trying to install rgl from CRAN:

checking for X... no configure: error: X11 not found but required, configure aborted.

ERROR: configuration failed for package ‘rgl’

Credit is due to this blog which solved my problems at installing rgl:

http://solaimurugan.blogspot.ca/2015/09/3d-data-visualization-using-r-configure.html

In case the link above disappears, the solution, as outlined in the blog is:

sudo apt-get install xorg 
sudo apt-get install libx11-dev 
sudo apt-get install libglu1-mesa-dev 

More recently, installing rgl on a fresh ubuntu 16.04 install also requires a further step (as noted in the comments below), if you get this error:

fatal error: ft2build.h: No such file or directory

This is solved with:

sudo apt-get install libfreetype6-dev

Then installing rgl from CRAN should just work.