Quote:
Originally Posted by jotd
@mcgeezer out of curiosity: but the "sliding window" technique you're describing needs you to write on a big memory range right?
Doing my calculations, if you need to scroll horizontally a 3200 wide tiled image (10 screens worth) you need 3200/16 = 200 bytes ahead which is very small (but you have 4 or 5 bitplanes so make it 1kb), but is that the same vertically wise? Vertically wise you don't divide by 16. 1 pixel = +40 bytes times the number of bitplanes.
|
It's not the same for vertical scrolling, the most efficient use of vertical scrolling is using video splitting (i think mentioned above), but it comes at a price of complexity.
My current project will need to do vertical scrolling also, but I'm just going to use two screens to do it and move down to single buffering as not alot happens on the game when vertical scrolling is in progress.
I would approach DD by not having any vertical scrolling at all, only use horizontal scrolling and when you want to move up and down just move the display window accordingly.