Cool! Re: [stella] Inspired by Roger

Subject: Cool! Re: [stella] Inspired by Roger
From: "Roger Williams" <mer02@xxxxxxxxxxxxx>
Date: Sat, 20 Apr 2002 10:32:15 -0700
From: Manuel Polik <cybergoth@xxxxxxxx>

> > How about sorting the sprite list DURING THE KERNAL?  
> Well, that is actually the only part of your brilliant 
> idea I don't get.

I think you've just proven it's unnecessary.  The important thing
is to do the single bubble-pass per displayed frame, and doing
it outside of the kernal simplifies the hell out of the kernal.
(You don't want to hear about the 4-state state machine).  My
idea would have made the sprites flicker a lot more, to not much
overall benefit.

> Ok, attached are binary + source of a demo that does 
> something I called FlickerSort.
> The idea behind this is exactly what you said, except I 
> sort the sprite list OUTSIDE THE KERNEL :-)
> In the kernel I do just skip the sprites that are not to 
> draw this frame, so I don't waste more than maybe 10 or 
> so cycles inside the kernel, thus having displayed _all_ 
> sprites at normal resolution...

Seems to work great, too!

> Ok, the new FlickerSort is actually soooooo quick, that 
> the demo bin handles 16(!) sprites at once. (Don't know, 
> where the limits are, but that number of sprites is 
> already way to much for my needs. 
> Might be cool to use for 'They've Risen' or any Robotron 
> clone, though! (Smash T.V. anyone?)

Also makes Glenn's idea to use my co-ordinate conversions
for an ASSAULT clone seem a little less far-fetched.

> The display kernel itself is still buggy though... I'll 
> try to finally fix that tomorrow...
> hope you don't mind that I'm proving your concept, 
> Roger? I just had to try that! :-)

Hey, it's great!  Usually I have to write my OWN code!
Seriously, I was going through a lot of unnecessary work
to do the once-through swap pass and the kernal at
the same time, so you've helped me a great deal.

--Roger Williams

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