This minimal package passed rhub::check_for_cran(). The package borrows contents in yixuan/miniGPU.

However, to decieve the Linux building environment provided by rhub::check_for_cran() (which, merely based on my experience on one CRAN publication, has the same configuration as the real CRAN server), several modifications are needed:

1. In /src/loader/icd_dispatch.h lines 66 and 68, #include <GL/gl.h> and #include <GLES/gl.h> are changed to #include "GL/gl.h" and #include "GLES/gl.h".

2. Respectively, two subdirectories GL and GLES are created in /src/loader. Those two hold two versions of gl.h found online.

If the above changes are not made, rhub::check_for_cran() would freak out over the failure of finding gl.h.

The package function runs correctly under Windows. I can observe surge in GPU consumption. Currently I don't care whether the function would run correctly under Linux,

..and it doesn't. Just tested it on Ubuntu 16.04 on a virtual machine on Windows. Lots of explanations could be made, like did I install Nvidia driver on Ubuntu? Don't have time investigating it now.