How do they do it? There's some specifics with Ninja Gaiden, as they have a HUD, and "Floor", I'm mostly looking for a way to control the BG tiles in a controlled way (Up/down, left/right) without freaking everything out.
I managed to create something that will scroll forever in 1 direction while leaving the player control, but can't figure out how to "stop" it in a controlled way, or reverse it (Perhaps need 4 controls, 1 for each direction, that can be told to loop X times, then stop??) I don't know enough about these calls to figure it out myself, so hoping to source the hive mind. If you have any insight, appreciated!
LDA UpDown CMP #$01 BNE NotFinalBossScreen movement: INC yScroll INC XScrollNo LDX #20 CMP XScrollNo BEQ moveBack JMP movement ;RTS moveBack: DEC yScroll LDA #01 STA UpDown