This isn’t quite the update I wanted to make, but it’s something. I’ve just uploaded a new example project and Unity package stuff to the engine integration page.
Working with Unity’s shader system has been a big learning experience, and I’m slowly coming to understand how it all works (and how my initial attempts have failed to do things The Unity Way, as it were). I’m in the process of reworking the shaders to make use of the (startlingly deep) Unity shader macros, and when that’s done I’ll post another update, and it will cause attenuation and light cookies to all work in the nice simple way you’d expect Unity stuff to work. In the meantime, this smaller release fixes the problem a few people have reported involving weird specular lighting appearing where the alpha channel is set to zero and should thus not be visible (this turned out to be a schrödinbug relating to multipass lighting and blend modes), and adds the experimental new implementation of per texel lighting (both the palette and regular shaders have new versions with this feature).
I should also mention something that came up on the forums, which is an unfortunate development regarding performance of Unity on mobile platforms. It seems that Unity2D relies heavily on dynamic batching to keep its performance up to acceptable levels on mobile. However, dynamic batching gets broken by multipass lighting, which is how Unity handles all per-pixel lighting as far as I can see, and so this is causing some performance issues. I currently don’t have a good solution to this – for a while it looked like this would be solvable with a hackish application of Unity’s per-vertex lights, and making use of them in a special fragment shader, but I’m not really comfortable claiming an official solution to a problem that involves such unofficial methods (and I definitely shouldn’t promise they’re going to work on all present and future platforms Unity supports!). One possible solution is static batching, but that’s a Unity Pro feature. Another possible solution is a script that automatically groups tiles together into bigger tiles, which is essentially a custom static batching solution – I’d happily write such a script and distribute it if it would help people out. I’ll keep looking for solutions. In the meantime, you need not buy Sprite Lamp to test such performance issues on your game/hardware – any normal map will do the job.