WebGL is inherently a vector-to-raster technology, it’s always backed by a pixel buffer. One might argue that even PDFjs works this way with its calls to the canvas API.
What are you trying to do? Why is webgl the key here?
Basically I am looking to render pdf of architectural drawings onto webgl (because 2d context is too slow), and maintain the vector information in the drawings (ie lines, arcs). I know webgl is eventually raster, but I want to pan/zoom while retaining the crispness of vector lines.