I recently watched a video of a presentation Mark Ferrari did at GDC last year. If you're not familiar, he's the bloke wot did these amazing 256-color animations. Turns out he also did a series of pictures that let you cycle through different times of the day by cycling through different 256-color palettes. And you can try those out here. His presentation explains better how he managed it. Anyway, it got me to thinking: What if you could achieve the same sort of thing in a modern game, using special lightmaps? Obviously you'd need more than 256 colors even just for a lightmap, but what if your hypothetical next-gen lighting compiler could dynamically generate a palette of 256 "primary" colors, and then use a 24-bit colorspace where the first 8 bits are one palette index, the next 8 bits are another, and the third value is where on the spectrum between the two the actual texel's color falls. Why would this be useful? Well, right now complex deferred lighting like VRAD produces is incompatible with proper day-night cycles. Presumably every engine that offers them relies exclusively on real-time lighting, which looks good for most cases but has limitations. You're stuck using generic, monochromatic, non-directional soft shadows and hoping it still looks good in conjunction with what your dynamic lights can do in 1/60th of a second. There's a reason Source 2 is still going to be making use of precomputed lighting. But imagine if you could have lighting outside that looks as good as CS:GO. No compromises, no need for fancy hardware; as far as the engine can tell, it is the same system as CS:GO, just with a different method of translating lightmap data into real colors. Your cascading shadow that crawls across the sky will still be doing the heavy lifting of convincing players that time is passing, but now everything else looks just a little more natural. Granted, this is still only useful for natural light. I daresay all artificial lighting in your map would need its own separate lightmap because you could run out of color indexes real quick otherwise depending on how crazy you get with it. But that's not a big deal. Of course, the operative question is, what kind of game could benefit from something like that? I couldn't tell you, honestly. The only games I can think of that actually use day-night cycles right now* are open world games, and those practically need real-time lighting because nobody wants to spend all that time compiling every chunk of a gigantic world nor wasting disk space on that many lightmaps. *OK, technically you could say Dota 2 does, I guess? I still have no idea what the point of that is.