Progress report (no preview build yet)

Sorry for the lack of preview build, I was stuck in the last few days making a (initially intended to be) small detour. Not sure if you noticed, but to get rain to work, I had to add quite a few new shader sets, and possibly a few more would need to be added later.

(This way, if there is no rain, AC would use shaders that don’t even mention it, so whatever performance hit rain could add because of additional shader complexity wouldn’t happen.)

And, well, there was this very old idea (more like hope, really) to get dynamic shadows at some point. Those would need their own shader sets, so they could remain optional and not affect FPS if disabled. A few days ago I had an idea on how they could work and thought, maybe it would be a good thing to add them sooner and then design the rest around them instead of making the whole thing incompatible with that idea. And, truth be told, it took longer than I anticipated, since I ran into a few problems.

But they work now! 15 1024×1024 shadow maps, plus extra 16 256×256 shadow maps for something less important. They are quite slow, taking about 1.8 ms on my new 2080 card on highest settings in this scene. But those settings could be tuned down, resolution can be halved without losing too much in quality, maybe not all of those big track lights would need dynamic shadow maps and so on. And, have to say, they work faster than I expected.

Had to use exponential shadow maps instead of regular ones, because a lot of track spot lights are too close to 180°, so regular PCF shadows looked very, very pixelated. Exponential shadow maps have their own issues (like a tradeoff between pretty limited range vs light leaking), but here range is limited, so I think they should work all right. Here are shadows in detail, notice how quality drops with wider spot angle.

There is some other progress too — I reworked wipers animation (now with a proper intermittent mode and options for car configs to redefine wiper modes), optimized regular AC shadows a bit and a few other things. I tried to get a preview build working today, but unfortunately ran into some new issues with those dynamic shadows I had to fix, very sorry about that (not that it’s perfect now, it still behaves weirdly in replays with too many lights visible at once, but I think that is mainly the question of fine tuning that could be done later). Hopefully I’ll get something ready tomorrow. And also, I’d want to work on some public update now, without the rain yet, but with other new features that are ready by now.

Thank you so much for your support! I’ll get back to work on rain tomorrow, now not worrying anymore if it would be compatible with dynamic shadows or not.