First of all, since this is my first post - hi everyone!
I have a question about implementing vertical scrolling.
I was following the tutorial written by bunnyboy: http://nintendoage.com/auth/forum/messa ... adid=36958
I implemented the vertical scrolling in a very similar way to the horizontal scrolling that's implemented in the tutorial - initially I fill an entire nametable and the bottom row of the other one. I decrement the scrolling register by 1 in each frame. When it wraps to 255 I set it to 239 and swap the nametables. When the scroll register is a multiple of 8 I copy a new background row in the right place, and when it's a multiple of 32 I copy new attribute row.
Everything seems to be working fine when I was using the PAL emulation (I'm using FCEUXSDP, later I've also tried FCEUX and I saw the same issue). However when I've disabled the emulation, it stopped working - screen starts flickering, artifacts show up everywhere, and so on.
Does anyone know what may be causing this issue?
I have a question about implementing vertical scrolling.
I was following the tutorial written by bunnyboy: http://nintendoage.com/auth/forum/messa ... adid=36958
I implemented the vertical scrolling in a very similar way to the horizontal scrolling that's implemented in the tutorial - initially I fill an entire nametable and the bottom row of the other one. I decrement the scrolling register by 1 in each frame. When it wraps to 255 I set it to 239 and swap the nametables. When the scroll register is a multiple of 8 I copy a new background row in the right place, and when it's a multiple of 32 I copy new attribute row.
Everything seems to be working fine when I was using the PAL emulation (I'm using FCEUXSDP, later I've also tried FCEUX and I saw the same issue). However when I've disabled the emulation, it stopped working - screen starts flickering, artifacts show up everywhere, and so on.
Does anyone know what may be causing this issue?