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Hello Everybody,
Ive been experimenting with adding different values into NESMAS and i came across something wierd. Instead of starting with value #$00 at the $2005 store i added values like #$20, #$40, #$80, #$99.
Values like #$20, #$40, #$80 made the text scroll on a different row (vertically). While #$99 made the screen flicker but i think that has to do with vblank or sumpthing. Why does this happen? I would have thought that entering these values would start the scroll futher on down the line. Am i embarking on a journey into the magical world of vertical scrolling. Any tips on veritcal scrolling? Or any tips on how to make it got the from left to right?

Yes, the second value you write to $2005 controls the vertical pixel position. You might get flickering if you rely on sprite 0 and there aren't any opaque tiles to trigger it.

What are opaque tiles?

An opaque pixel is any pixel that is not colored with index 0. An opaque tile is any tile that contains an opaque pixel. Many games' screen splits rely on sprite 0 timing, which requires an opaque pixel of sprite 0 to overlap an opaque pixel of the background.