[R] Accessing the C++ source associated with the rgl function shade3d

[Duncan Murdoch]

On 29/07/2020 6:34 p.m., Jeff Newmiller wrote:
> To begin with, don't assume it is in C++... R supports multiple compiled languages, and rgl appears to have both C++ and C in it.

Also a few thousand lines of Javascript, but in this case, the 
interesting code is all in R.

> 
> I googled "r rgl github" and found an online copy of the src (source) files right away. The official way is to find the CRAN package page and download the tar.gz file and extract the files. Either way, you get the whole package source code this way.

If you're using RStudio, a really convenient way to view the source for 
a package whose source is on Github (maybe the majority of packages 
these days?) is to create a new project from it.  Then you can use the 
built-in search functions to jump to the source of any function.

For rgl, you can get a copy of the Github mirror of the source by 
specifying the "Repository URL" as "https://github.com/rforge/rgl", and 
the "Project directory name" as "pkg/rgl".  (The source is hosted in 
Subversion on R-forge.r-project.org, but Subversion is less familiar to 
most people these days and R-forge is pretty old-fashioned, so I'd go 
with Github instead.  There are some irritating things about Github.)

Once you've got it in RStudio, you can type "shade3d" in the "Go to 
file/function" box, and it will offer the generic as well as the two 
methods shade3d.mesh3d and shade3d.shapelist3d.

This kind of search is probably also possible in other front ends (ESS 
etc.), and some purists probably know how to set it all up in command 
line BSD Unix, but I don't.

Duncan Murdoch

> I am afraid I don't have time to dig into the source to identify which file you need. Keeping in mind that the rgl package is an interface to lower level code, beware that you may need to leave the R code to find what you are looking for... in which case you would be dealing with a different code base and community of coders.
> 
> On July 29, 2020 2:35:33 PM PDT, Byron Dom via R-help <r-help using r-project.org> wrote:
>> How can I access the C++ source associated with the rgl function
>> shade3d. More specifically, I'm interested in the part of the code used
>> by arrow3d to draw arrow heads.
>>
>> I'm not familiar with how GitHub is organized and I've put in a lot of
>> effort doing searches there and on the web in general. The result has
>> been a few fragments of rgl C++ code but not what I'm looking for.
>>
>>
>> 	[[alternative HTML version deleted]]
>>
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