Re: [stella] Revolutionary Horizontal position discovered!

Subject: Re: [stella] Revolutionary Horizontal position discovered!
From: Dennis Debro <ddebro@xxxxxxxxxxxxx>
Date: Wed, 30 Oct 2002 15:10:36 -0500
Hi Manuel!
> Actually, you can call this wherever you want, even 
> midscreen. I think the routine presented could be even 
> tweaked to reposition an object in a single scannline - 
> without using any table!

When I saw your post my eyes opened wide. I LOVE IT!! Now to try to implement it during the kernal of Climber :)

> One thing that is left to test, is wether the new 
> discovered routine is working precisely on the borders. 
> With very small values, the RESP may come too early, 
> with very high values the cycle limit per scannline 
> might get exceeded...
> And another thing: Battlezone does the black HMOVE lines 
> on the whole visible screen, I don't know how/if the 
> algorithm works without that.

I'm the HMOVE lines for Climber too. I just placed this routine as a test during VBLANK to position the main player and it works great. There does seem to be a little wall on the left where the player seems to bounce off before continuing left but I'm sure that could be adjusted.

> I don't need this technique for Star Fire at all, 
> because all my repositioning is way more complex and 
> therefore table driven, but I thought others might never 
> ever use the old ugly Air-Sea-Battle thing again :-)

Hey, I'm using the old Air-Sea Battle positioning routine (don't look). I figured if it worked why fix it. That is until later when you need the ROM space :)

Thanks Manuel, I'll play around with this and see what I get.

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