I'm excited enough to post an early screenshot of my prototype. I just got dynamic directional lighting to work! I have a sun which arcs across the sky and acts as a directional light source with color being dependent on its position in the sky. The sky color is also a function of the sun position in the sky, so I have a nice, seamless transition between day and night.

Early Morning:


Mid Afternoon:


Evening Sunset:


Midnight:



It's not perfect (and it doesn't have to be for prototyping), but I'm starting to get a lot better at writing HLSL shaders. I'm not going to bother writing any shadow code though, that's just excessive polish (and I don't know how, aside from expensive ray tracing through the scene).