Really nice, any plans on showing this on a 3D map? You might be interested in my project, Procedural GL JS: a mobile-first 3D mapping engine with emphasis on user experience. Live demo here: https://felixpalmer.github.io/procedural-gl-js/ (I've also posted separately in this thread).
Wow! This is beautiful and fast. You should be proud of yourself.
There is another project (https://shadowmap.org) that casts shadows in 3D. You might want to reach out to them. For me, I use ray-tracing per pixel because I want more control/information on a per-pixel basis. For example, when will the sun hit the particular location.
