RE: [stella] Space Instigators - Final Version (?)

Subject: RE: [stella] Space Instigators - Final Version (?)
From: Christopher Tumber <christophertumber@xxxxxxxxxx>
Date: Fri, 18 Oct 2002 17:49:45 -0400
Nicolas wrote:

> I´ve tested SP17 with PCAE 2.1 and there seems to be a problem with the
>frame when you start displaying the invaders. It moves up and down one
>scanline each frame. The score and the bonus invader (let´s call him that
>way) are stable. Also the frame is stable when the player fires.

Dennis wrote:
>The screen tends to jitter a little. Not jump just kind of a little
>vertical jitter during game play. Also the screen rolls when the Reset
>button is pressed. If you hold down Reset you can really see this.

Eric wrote:
>Nope, this was with sp17.  You kernel sounds mucho complex.  Much worse
>than my unrolled & chunked kernel for Skeleton.  Hmm, could you be
>overrunning your VBLANK timer?  That would shift the screen down & add some
>scanlines.  I'll have to play with -v9 and see if I get more than 262

Hmm, now I'm worried. I've run it on StellaX, Pcaewin and z26 (as well as a real console) and it seems fine. However, 
I have just moved a bunch more code from the Vertical Sync into the Overscan. I had had this problem earlier, particularly 
when the Saucer was onscreen in later stages of a level (It's more calcs to draw less Instigators), but moving Saucer 
code into the Overscan seemed to solve it. Maybe I didn't quite move enough?

Anyway, I'll have the final-final posted in a bit...


Archives (includes files) at
Unsub & more at

Current Thread