Hmmmm....
Well, there is a DB Pro demo program, with source, that shows a side-scroller of an airplane flying over hills and shooting stuff.....
1. Change the background scrolling from horizontal to vertical, and
2. Change the texture to white snowflakes on a transparent black background (use a paint program....)
That should get you closer to what you want....
You might still have a problem since you are scrolling the background. Maybe not - it might look just fine....
If not - it might be possible to turn off writes to the Z-buffer for
just those writes. Dunno....
If you can get this to work, it would probably be more efficient than
trying to use a particle generator.
Willy