As with most first-person WebGL projects, things go wrong when the mouse pointer leaves the canvas area. Is there anything that can be done to "capture" the pointer (that isn't horribly open to abuse...)?

The Point Lock API[1], not yet implemented except in experimental branches.

[1]https://developer.mozilla.org/en/API/Mouse_Lock_API

It's already there. If you run the demo with a dev version of Chrome going into fullscreen mode locks the mouse cursor and gives you more traditional FPS controls. This should be making its way into the stable versions of several browsers within the next few months.

Google Maps does something to capture the mouse - unless you mean without buttons being held.

The performance was amazing even on my aging desktop system. Running Ubuntu 11.10 and Chrome browser.

This should not be surprising considering that your GPU is rendering geometry from 1999

It also uses less CPU time than most WebGL demos I try.

Agreed.

Insightful.

Direct link http://media.tojicode.com/q3bsp/

Would it be possible to throw in a server, add a few grains of socket.io and make this multiplayer ? I don't see why not, and it would make it a much more appealing experiment.