WebRender 2 is just the next evolution of WebRender. After we started testing the original one on real sites and apps, we discovered a few performance problems. Glenn had some ideas for how to fix them that involved changing quite a lot of things, and that work is now landed in the tree.

One consequence of this work, other than speed of course, is that it enables things like subpixel AA, which weren't possible before.

Externally we'll probably just call it WebRender. Not many people knew about the first one and most users won't care that it took us a few iterations to perfect :)

We're planning to turn WebRender 2 on as the default very soon.

This is incomplete, but my basic understanding is as follows.

Servo is an experimental web browser in Rust.

WebRender was an experiment inside an experiment, to use a GPU pipeline closer to what a video game does and do painting very quickly. See a previous HN discussion: https://news.ycombinator.com/item?id=11175258

WebRender 2 I'm less familiar with, but it's a continuation on that work. I gather it cuts down on the amount of painting done, so now it does painting fast, and does less of it. I gather it should also enable some new features, like subpixel antialiasing.

Here's the only thing I could easily find via Google [0]:

"The basic design right now is that we draw every pixel of every frame, but there's a lot of overdraw when things overlap. This shows up in the moiré demo where there's a lot of overlap. Also we don't have enough information to do subpixel antialiasing. gw had a great idea to solve both of these problems. The prototype he built uses a ray tracer to trace through all of the objects and draw each pixel only once. That should lead to new features like subpixel AA and also more consistent performance."

More context would be appreciated, though!

[0] https://github.com/servo/servo/wiki/Meeting-2016-03-07

Webrender is a renderer that use gpu techniques similar to how games render.

see https://news.ycombinator.com/item?id=11175258