Fake shadows with a projected material?

Hey all,

Just wondering if there’s a way that you can fake shadows in a scene with a projected material of some sorts? I’ve got some windows with a material effect of rain running down them and I wanted to create a similar material for the shadows of the rain drops on the floor and walls. Decals wouldn’t work because of stretching and I tried using a light function but it just looks wrong because it’s adding light to the area instead of shadows. Any ideas on how to accomplish something like this?

Here’s a video of the effect on the windows and using a light function for the floor/walls:

Well, I got the light function working a lot better than my first attempt. I didn’t realize that white would block the light in my texture masks so that fixed things mostly. I’m wondering if it’s possible though to have a light function project the material without actually casting light on the world.