Comment by pcwalton

This is really neat. Though in practice if you are using this kind of thing I'm pretty sure you will want to combine it with atlasing (i.e. construct an atlas of glyphs via render to texture). That's because it's a waste of time to rerasterize glyphs in the FS every frame (which appears to be 200+ lines) instead of caching the results and reducing the per-frame work to a 5-line FS that just blits. In most apps pans are more common than zooms and the same glyphs are used over and over, so this usually ends up being a win. Using atlases also reduces the number of raster operations because the same glyphs tend to appear on the page repeatedly, and by using atlases you rasterize each glyph only once. Even more importantly, though, atlasing gives you the ability to reuse a blitting fragment shader to render other content (images, figures, etc.) as well as glyphs from the atlas in order to reduce state changes.