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

[Duncan Murdoch]

On 29/07/2020 5:35 p.m., Byron Dom via R-help 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.

shade3d() is purely written in R:  so just type "shade3d" and you'll see 
that it's a generic function.  Most commonly it is used on objects of 
type "mesh3d", so type "rgl:::shade3d.mesh3d" and you can see the full 
source.  It makes calls to other R functions; C++ doesn't come in until 
it has chosen to draw triangles or quadrilaterals.  I think you probably 
don't care about how those are drawn, but let me know if you are.

The arrow3d function is also a pure R function, but not a generic.  You 
can see the source by typing "arrow3d".

Duncan Murdoch