Wow, nothing has been posted here in a while. But, alas, I have recently begun a beast of a project! The screen won't look like much, but I think it's pretty exciting stuff:
( EDIT: SCREEN WON'T SHOW UNLESS YOU ARE LOGGED IN, because the SMF 2.0.2 is smarter than the old version :/ )
I'm working on "splatting" shadows for a sort of tile-based 3D terrain. What you see in the screenshot is simply a merge of the texture and the shadow into one sprite (uses the "surface" functions). I'm not the best at explaining, but it should make sense when I get it further along.
Using GM's native 3D functions, I really have no options for much of anything, and shadow casting is no exception. However, I don't want to use something like GMOgre, or Ultimate3D, because I don't need all that extra stuff they have on top of support for shadow casting; it would needlessly bloat my game. Since I just need to mimic dynamic shadows (this is obviously an early step that does not show dynamic shadows), this is the most solid way I could come up with that will have no problem with tears or distortion, as all other shadow wrapping examples out there seem to have. And it won't use any third-party resources either.
Some time in the future, I will have the terrain engine coded and a screenshot of that will help it make sense, if it doesn't already.
EDIT (x2):
Here's a better pic, and you don't have to be signed in to see it.
Shows that it works with multiple shadows too, which is good since I will have multiple shadows being cast onto the terrain: