Hi, I am having problems with my Sprite #0 hit detection. In Super Mario Brothers, the status bar stays put while the "level" graphics scroll just fine...except for the bottom row of pixels in the status menu, which scrolls right along with the "level". Naturally, I think that something is screwy with my Sprite #0 detection, so I consulted Yoshi's document to make sure I had all of the specifics right. However, the diagram given in Yoshi's document does not make sense to me.

Specifically, it indicates that the Sprite #0 flag will be raised one row later than it should intuitively be raised. I searched through all the postings I could find on this topic and saw that someone else had noticed the same thing, but nobody had an answer for it. So one of my questions is, should the sprite #0 flag be set when the first non-transparent pixel of the sprite #0 hits the first non-transparent pixel of the background, or does the sprite colors have to be a specific index, because from Yoshi's document it appears that not only do pixels from both sources have to be non-transparent, but they also have to be equivalent to "2".

Sorry if this question is not very coherent, but I'd basically just like any comments anyone might have on how they implemented sprite #0 detection and things to watch out for. Any help would be greatly appreciated.
Thanks