gbadev.org forum archive

This is a read-only mirror of the content originally found on forum.gbadev.org (now offline), salvaged from Wayback machine copies. A new forum can be found here.

DS development > Question about scrolling

#81652 - Linkiboy - Sun Apr 30, 2006 10:20 pm

Hi. I'm working with PA_Lib right now and just manipulating various examples for learning purposes. I am looking at the third platformer example, and I'm trying to get Y scrolling. However when I attempt to, the sprite gets all jumpy, the X and Y are in the negatives. Anyone who looked at this example, can you please help me out? Thanks.

#81663 - tepples - Mon May 01, 2006 12:30 am

When X and Y go negative, you need to watch out whether bits get overwritten. See the GBA beginners' FAQ "Q: Why do my sprites become corrupt when I move them off the top or the left side of the screen?"
_________________
-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.

#81768 - Linkiboy - Mon May 01, 2006 11:06 pm

Hmm I Don't think I worded it in the best way possible, because I was in a hurry. The sprite isnt jumbled, it just falls off the bottom of the screen, comes back from the top, and lands on nothingness. HOWEVER! The collision is still there as if the level were invisible! What the doodle is going on?