Dear God please tell me if this is even possible.

[malice936]

I have spent the last 6 HOURS trying to do one simple thing, transform a rectangular image into a right triangle without distorting the pixel placement vertically. I have used EVERY transform tool, looked through every filter, and for the life of me I cannot figure out how to do this. So PLEASE if anyone can tell me if this is possible, and if so how I can do it, it would be greatly appreciated.