Indirect3D is an attempt to see just how fast JavaScript in browsers has gotten. Also it's a chance to try to better understand how some of the typical 3D graphics pipeline works, by implementing parts of it.
Indirect3D is the (start of) a (partial) pure-software implementation of the Direct3D 9 graphics API in JavaScript and Canvas.
It uses a few logical, not-currently-overridable, defaults, that Direct3D does not. For example, z-buffering is always enabled. There is always a single back buffer. (These two facts are related.)
It also makes pretty heavy use of typed arrays. One consequence is that, as of this writing, I can only make it run in Firefox 4. Theoretically, it should run in Chromium, but for some reason, it doesn't. It doesn't seem to throw any errors, but it doesn't render, either.
Indirect3D is an experiment and toy. It's a fun--to me, anyway--little project I started late one night.
Indirect3D is not a wrapper around WebGL. Hardware is awesome, and the future of the web, but it is not what I'm interested in here. Maybe someday I'll write a Direct3D-style wrapper for WebGL. Who knows, maybe I'll even cover the other DirectX components! (DirectSound => <audio>, DirectPlay => WebSockets, etc.) Probably not, though, that sounds like a lot of work.
It's certainly not something you should use for anything, except as a somewhat-difficult-to-explain demo, I guess?
Like most projects, there's a good chance I'll get bored with and stop work on Indirect3D. It happens a lot.
Before then, I'd like to get all 6 modes for DrawPrimitive() implemented.
So you ignored my advice in "What Indirect3D is not" and want to use it? Well, OK, I guess I can help out.
Check out main.js for an example program, and brush up on your matrix math--though, like Direct3D, most of the real math is safely abstracted away from you.