multi direction scrolling help

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iamooos
Posts: 16
Joined: Tue Oct 18, 2022 2:37 pm

multi direction scrolling help

Post by iamooos »

just trying to figure some things out, i tried to make a multi directional scrolling in C with (horizontal scrolling)[vertical mirroring]
in mapper 0

(i know this is the least recommended, i wasn't expecting too much with it)

so basically it mostly works (although there is no diagonal scroll at all, and scrolling up is disabled for now),
but when i go left some part of the screen won't update correctly.... i really dont mind the graphical glitches at the top, so long as it works correctly. i just want to make a repository of different types of scrolling samples to have as reference basically

maybe someone can help out?

i uploaded the whole project to github.

https://github.com/iamoose/Nes_scrollin ... m_scroller


and the actual rom is here:

https://github.com/iamoose/Nes_scrollin ... roller.nes

(there's a download button at the bottom)


i believe its writing glitchy to the screen because maybe my code is doing too many reads to some address and corrupting the tiles.
but i really dont know whats going on. debugging will just show me asm code that i can't make heads or tails of, probably

or maybe i reached the limit of what you can do with mapper0 already, i don't know.

oh i forgot, the assembled code is here

https://github.com/iamoose/Nes_scrollin ... scroller.s
iamooos
Posts: 16
Joined: Tue Oct 18, 2022 2:37 pm

Re: multi direction scrolling help

Post by iamooos »

i finally fixed it.

it wasn't any corruption of the attribute or any other tables. i was just dumb, i was off in my math by 1.

there's only one small bug now, hopefully i can fix that one too, this one only happens sometimes which is the tricky part.


the updated rom now scrolls very well!!

https://github.com/iamoose/Nes_scrollin ... roller.nes
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