Parallax scrolling vertical

[Coolcrab]

I was wondering if there are any examples on how to do parallax scrolling in Bb. Something like the background in Flappy.

For my game I'd like to move it vertically though.

 

I've looked around but it doesn't seem to be documented? Or I'm looking for the wrong keyword.

Edited August 20, 2018 by Coolcrab

[+Random Terrain]

Seems like parallax scrolling simply means that horizontal strips are moving at different speeds (the lowest strip on the screen scrolls the fastest and the highest strip on the screen scrolls the slowest).

 

The standard kernel scrolls the whole playfield and you only have two sprites, so it would be kind of hard to have strips that scroll at different speeds. There is no horizontal playfield scrolling for the DPC+ kernel at this time, so you'd have to use some of the sprites to simulate strips moving at different speeds.

[Mr SQL]

This is something that ANTIC powered display lists on the Atari 5200/400/800 are uniquely suited for.

 

Soft Display lists have been added to Flashback BASIC and SuperCharger BASIC so an implementation is likely possible for a future DPC+ kernel, here is a thread with a display list demo showing the screen divided into four horizontal strips all scrolling in different directions and at different speeds:

 

http://atariage.com/forums/topic/251949-display-list-interrupt-demo/