Re: [stella] Supercharger screens...

Subject: Re: [stella] Supercharger screens...
From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 12 Jan 1999 14:45:38 +0100
At 09:32 11.01.99 -0800, you wrote:
>Hmmm, as I recall the window of opportunity to get a complete display of the
>second set of sprites is only one pixel wide, but I forget the exact timing.
>The demo earlyb.bin rings a bell though...  But I think more experimentation
>is necessary.  I haven't tested all possible positions of the second RESPx
>so there may be other places that the second RESPx could produce a complete
>set of sprites.  But I'm just guessing.  But until all possible combinations
>have been tested, one really can't be sure.

I have experimented with different NUSIZx values and I'm pretty sure
about the five pixel window. The reason why you might think it is only
one pixel could be that one can not position the second hit to RESPx
pixelwise but has to do it cyclewise. One cycle means three pixel more
or less and that can be just outside the window.

But look at your trick18 and my extra18. In your program the second hit
happens 12 cycles or 36 pixels after the first hit. That is one pixel
before the third copy of the sprite would be displayed. In my program
the second hit happens 11 cycles or 33 pixels after the first. That
is four pixel before the third sprite. And the grid demo does the
second hit six cycles or 18 pixels after the first hit. That is three
pixels before the second sprite. All three programs produce three
copies for the second set of sprites.

Other experiments with NUSIZx values for wider spacings between the
sprites show that only hits close before a displayed sprite get you
the full set of sprites for the second hit. So the multisprite trick
must have something to do with the five pixel delay.

Ciao, Eckhard Stolberg

Archives (includes files) at
Unsub & more at

Current Thread