Installing "rgl" package in R, Mac OSX El Captian

Question

I'm new to programming in R so I apologise in advance if I seem naive. I want to be able to do some principal components analysis on my data in 3D. I read that the "pca3d" function is good for this, but I need to download the "rgl" library. When I use install.packages it asks:

install.packages("rgl")

  There is a binary version available but the source version is later:
   binary    source needs_compilation
rgl 0.95.1201 0.95.1367              TRUE

Do you want to install from sources the package which needs compilation?
y/n: n

I have tried installing it as both binary and source, but nothing seems to work. If I try loading the binary version, I get this error:

Error : .onLoad failed in loadNamespace() for 'rgl', details:
  call: dyn.load(file, DLLpath = DLLpath, ...)
error: unable to load shared object '/Library/Frameworks/R.framework/Versions/3.2/Resources/library/rgl/libs/rgl.so':
dlopen(/Library/Frameworks/R.framework/Versions/3.2/Resources/library/rgl/libs/rgl.so, 6): Library not loaded: /opt/X11/lib/libGLU.1.dylib
Referenced from: /Library/Frameworks/R.framework/Versions/3.2/Resources/library/rgl/libs/rgl.so
  Reason: image not found
Error: package or namespace load failed for ‘rgl’

If I say "yes" to installing from source, I get the following error:

configure: error: X11 not found but required, configure aborted.
ERROR: configuration failed for package ‘rgl’
* removing ‘/Library/Frameworks/R.framework/Versions/3.2/Resources/library/rgl’
* restoring previous ‘/Library/Frameworks/R.framework/Versions/3.2/Resources/library/rgl’
Warning in install.packages :
 installation of package ‘rgl’ had non-zero exit status

I've been searching for hours on how to make this work so if someone could run through how I should go about installing the rgl package then I would be extremely grateful!

Thanks, Claire

Answer 1

After talking with a colleague all I had to do was download XQuartz from here to install X11, and then install the source package again. Now it works!

Answer 2

Downloading XQuartz completely solved everything after I wasted hours trying to come up with a solution to this problem.