Scrolling ($2005) two nametables and stop at the last one
Posted: Sat Nov 04, 2017 6:54 am
I have a problem with scrolling two screens (two nametable in all 2KB VRAM). I just wish that at the end of the scrolling would ideally stay on the second nametable ($ 2400). Unfortunately, when the XSCROLL value reaches FF, the second screen is uneven (one pixel).
Two test roms, press any button to start scrolling.
Demo1 - inc scroll, when the value reaches FF, they stop scrolling.
Demo2 - inc scroll, when the value reaches FF, it stops scrolling and set a bit0 in $2000 to change the nametable to 2400. Here is everything ok, the screen stops evenly.
I would, however, without changing $2000 bit0, to do the scrolling so that the screen stopped perfectly on the second nametable. XSCROLL #$FF value secont screen is uneven, and once again the value of 00 is the beginning of the first nametable.
EDIT: Ok, thanks for the info, at least I'm sure now.
Two test roms, press any button to start scrolling.
Demo1 - inc scroll, when the value reaches FF, they stop scrolling.
Demo2 - inc scroll, when the value reaches FF, it stops scrolling and set a bit0 in $2000 to change the nametable to 2400. Here is everything ok, the screen stops evenly.
I would, however, without changing $2000 bit0, to do the scrolling so that the screen stopped perfectly on the second nametable. XSCROLL #$FF value secont screen is uneven, and once again the value of 00 is the beginning of the first nametable.
EDIT: Ok, thanks for the info, at least I'm sure now.