Making it really walk

So far, you have a couple of legs moving around in a manner that looks pretty realistic. But they are just kind of floating in space there. Earlier in the book, you got something moving with velocity and acceleration, and then had it interact with the environment. It's time to do the same thing here.

This portion of the chapter gets pretty complex, so I'll go through the code one concept at a time. The final file, with all of these concepts incorporated, is RealWalk.as.