Re: [stella] Yet Another Final Version...

Subject: Re: [stella] Yet Another Final Version...
From: Christopher Tumber <christophertumber@xxxxxxxxxx>
Date: Wed, 23 Oct 2002 17:31:27 -0400
>All the below may be true, but let us have-at the code sometime, please.

I'll be posting the code at some point but it's currently uncomented and somehwat complex...

>I predict that should you do that, all of these issues will be dealt with
>and the impossible may be possible after all.
>Thomas, in particular, creates cycles out of thin air... and I'd sure love
>to see the issues mentioned (staggered movement, etc) tackled in order that
>we'd have a closer-to-original than this amazing effort already is.

Well, I really don't think staggered is possible. There are a couple ways to do this but I think it would be a case of  "The cure is worse than the disease".

At the moment there are 10 Instigators-drawing-routines and the appropriate routine is copied into RAM depending upon the vertical position. All 5 rows share this routine, with RESP0/RESP1 instructions turned on/off for each row, between drawing each row. You could recopy a different routine into RAM after each row but then you're going to add a couple scanlines between rows of Instigators.

The only other thing I can see doing would be to make the drawing routine more flexible with a variable length pause before it starts drawing Instigators on that row (as opposed to 10 hard-coded routines). However, the reason I have 10 custom routines is in order to squeeze in the other things that need to be done on a row (specifically, keeping track of the scanline and drawing a shot) around the series of STA RESP0/STA RESP1.

However, as mentioned those routines are really tight with at most a spare cycle (and no STA WSYNC). Well, maybe if you could cut out a cycle or two since you only need to shift over 1 cycle, then maybe you could switch between STA RESP0 and STA RESP0,x for the first sprite. Then you'd just need to assure the first STA RESP0 didn't use the ,x (which is certainly not the case now).

Umm, okay, I'll conceed to "theoretically possible".....

At the moment I don't really want to think about it....

>BTW, can I buy one of the original carts?  I asked first!

Carts will be available after Nov 5...


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