I'm truly sorry if the above drivel is either impossible or insane; as an embedded guy this is most definitely way outside my wheelhouse. I should get back to repairing my oscilloscope.
WebGL is more or less just a set of standardized (JavaScript) bindings to OpenGL ES... which is actually ran as DirectX I'm sure in some places...
Everything required to draw high-performance hardware accelerated text already exists in most browsers before even getting to these bindings, which would furthermore require accessing a redundant glyph renderer.
That is to say, WebGL wouldn't provide you much gain. Though, I'm sure some very amusing post-processing could then be done to your code.
Perhaps the future of programming is in the web with lens flare.
Tangentially, Ace[0] appears to be the only editor outside Vim proper that has managed to implement a half decent Vim mode. It's the only such editor I've come across where visual block editing doesn't end in fits of rage.
[0]: https://ace.c9.io/