If GPU is cheap and CPU is expensive, draw one tri every frame and don't worry about the rest. If CPU is cheap and GPU is expensive, do a glyph per quad and some basic dirty rectangles if needed.

Sounds much like "backwards" raytracing in 3D, except with some special rules for an orthographic projection.

I know that "except with" makes it sound like a narrow refinement, but I suppose the history of computer display hardware likely has it the other way around.

There's even more depth one can go into here: subpixel positioning. To correctly draw glyphs that may be on subpixel positions, you need to rasterize and cache glyphs separately for each subpixel position (with some limited amount of precision, to balance cache usefulness and accuracy).

However I have a feeling that describing an entire Unicode-aware text stack here may not be useful, especially if TFA seems to only care about simple-script monospace LTR.