MAMEWorld Forums - EmuChat - Re: Shadow Gangs (NeoGeo), scrolling issue going right only.

> When are you updating your spritelist? it looks almost like you're doing it mid-frame
> and getting some sprites from one frame and some sprites from the next on certain
> lines
>
> maybe there's more processing going on when moving right?

Update on the issue, as I think I am getting something with my tests:

I wait for vsync signal to start setting value in VRAM.
What I was doing is update the position of around 20 * 3 = 60 background sprites + some char sprites 10 enemies that are 4 sprites width ( around 40 sprites).
In total let's say 100 sprites position updates.

When the game is running at 60 fps, I didn't notice the issue, but when it goes under I can see it.

But during my test, I still simulated under 60 fps, but this time for the draw updates after the sync signal, I chained the sprites, and used the sticky bit.
This lead to very few position updates, (3 for the backgrounds, and 10 for the enemies)
Doing this, I didn't see this issue anymore, even if the game is very slow.
(I guess because now writing to VRAM after the sync signal is very fast?)

That means, I need to rewrite how I draw the backgrounds and sprites, and be mindful of this small leeway between the Vsync signal and when the electron beam is back at top left of the screen again?

That's what I think is happening, so then this sticky bit on the NeoGeo is of huge importance then?
How does the Genesis manages the drawing (I think it has no sticky)

Edited by shadowgangs (11/10/23 08:59 PM)