Impostors

Impostors replace objects within the scene at a certain distance, using render to texture and a texture manager to draw them in as few render calls as possible. Here's a video of it in action. You can grab the latest source code here, though it needs a rewrite; I learned a lot about how not to do Impostors while making this!

I jotted down the things I learned while making this as a work in progress toward the design of version 2, you can read it here