Lightmap unwrap efficiency

With the level of visual quality as high as The SOE_Project's, efficiency is a constant concern and I am constantly collaborating with our engineers to confirm that our benchmarks are accurate and that the game is as performant as we think it is when we are so far from a testable product.

Main memory budget has been our biggest obstacle due to our standard environmental shaders having so many components. I saw our lightmaps as a place to trim a lot of fat, as I did an audit of our buildings and other lightmapped structures, and found that many of them had been poorly lightmap unwrapped.

Reunwrapping these assets was a way to cut our texture budget in half. For every scene, we might have 40-50 large shared textures loaded into main memory. At the same time, we would have a few hundred lightmaps, one for each building.

By revisiting these UV unwraps and making better use of the space, we were able to drop our lightmap sizes by a power of two, which accounted for about half of our current memory usage for textures.

Before:

After:

UV set #1 hand-unwrapped

UV set #2 hand-unwrapped