You're right--I was hoping that the issue was transient, but it doesn't seem so. :/

Well, there are other sites that you might try! Perhaps look to TIGSource, or a dedicated site like Fiverr. (Others may have other and/or better suggestions!)

Oh, I forgot about this thread! 

21st Century Moose said:

When setting up your attrib pointers, are you using glVertexAttribPointer or glVertexAttribIPointer for the a_texref attrib?

It turns out that I should have used done this in my C code, as you said. I asked this somewhere else and someone …

Thank you so much for the solution. It was indeed the typo.