right, sorry if i wasnt clear enough, heres a basic diagram of what i need to do:

and i think you may be right newblack, either ill have to create my own vector data, or use the "marching squares" technique to determine the vectors of the bitmap ahead of time

although just a plain bitmap to bitmap collision might be impossible, i think i can figure out some logic in a line segment to vector collision

however, id have to figure out which side hits first (*sigh*), and the path of a single side would be really weird and possibly troublesome to calculate

i wanted to avoid this kind of collision, because i was hoping i could fit it into just a single procedure (which even then there's the possibility of multiple bounces)