Re: [stella] VDEL...

Subject: Re: [stella] VDEL...
From: Manuel Polik <cybergoth@xxxxxxxx>
Date: Sat, 23 Feb 2002 18:35:17 +0100
Hi Eckhard!

>> Uhm... there is something done in Combat with VDEL 
>> can't do quicker & shorter without?!?

>With VDEL you can update one
>of the players at anytime you want during the two 

Hm... how would that work? Could you post some little 

>If you are using the stack, you would have to save and 
>the stack pointer, which would require one extra byte 
in the
>RAM. And I don't think the timing with the TSX would 
>properly. All attempts at this method that I have seen 
>always off by one or two pixels for one of the writes. 

I tried doing it this way, when I started coding the 
intro for Starfire. Unfortunately I don't remember if I 
got it working or not, and at some point Thomas had the 
stella-at-the-movies drawing routine finished, which I 
was only talking about all the time, and so he took over 
the project at that point :-)

>isn't much of a problem for a score display, since the 
>usually don't use all 8 pixels anyway, but a 48 pixels 
>display doesn't seem possible with this trick.

AFAIR, Robin Harbrons 6 char routine in the archive 
works fine without VDEL. However - I'm not sure, if it 
can do an image or not. Might be just as you describe.

>> - Just imagine what cool stuff could've been done if 
>> VDEL would delay any GRPX write exactly until the 
>> line! 

>I can imagine a lot if interesting effects that would 
>possible, if the VCS had different hardware. But then 
>would be less of a challenge and less fun to program 
>don't you think? ;-)

Well, there'd still be enough of a challenge left to 
write a good game in 4K, even without all the timing 
nonsense :-)


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