IIUC, we need gibbs sampling(to compute the weight updates) instead of using the gradient based forward and backward passes with today's NNetworks that we are used to. Any one understand why that is so?
I might be mistaken, but I think this is partly because of the undirected structure of RBMs, so you can't build a computational graph in the same way as with feed-forward networks.
This doesn't make motion capture obsolete: 1) Mocap can be applied to rigged characters and 2) mocap can animate full-body rigs not just facial expressions.
Could you tell me a bit more about why you want to write C++ in the browser? What things are you doing that are so CPU intensive that C++ is higher productivity then just JS?