Re: [stella] the B. Watson's problem...

Subject: Re: [stella] the B. Watson's problem...
From: "B. Watson" <atari@xxxxxxxxxxxxxx>
Date: Mon, 20 Aug 2001 09:50:37 -0400 (EDT)
On Mon, 20 Aug 2001 cybergoth@xxxxxxxx wrote:

> Hi B. Watson!
> > <snip>
> Some comments:
> - This isn't really a 2-line kernel, it's just a *forced* one.
> You're doing only one line and expand it via the second STA WSYNC.
> - To avoid your problem, you can do the playfield on the first line and the sprites on the second for example.


> - Having both sta HMOVE & sta HMCLR inside the kernel is senseless 
> (in your case). Do that once outside the kernel.

double D'oh!

> - Learn how to enable the missile via PHP, find the trick in the combat
> source for example. All your branching would be reduced to 
> cpy evpos
> php
> if the stack is set/reset properly before and after the kernel


> - Learn how to display sprites properly via subtractions, there's
> no need to have tons of bytes zeroed out in the ROM. Find
> examples of this technique in the Stella archive under the
> 'Gunfight' topic. Thomas posted some detailed hints *how* it's done
> there. Find it utilised in (some :-)) Gunfight sources as well.

Yeah, the zeroed bytes seemed wasteful, also in an early version they
caused me grief because they crossed a page boundary..

At the moment, I'm late for work, but when I get home I'm going to sit
down with your email and my code and spend some time cleaning house. I
just wish I could get this kind of useful advice in code reviews at work!

Actually... I spent a lot of time yesterday figuring out how to get
multiple moving objects (re-use both players 6 times, one ship and
5 enemies)... The source is a complete mess right now, but I'm
attaching a rom image to this message, if anyone has time to look
at this, let me know what you think...




If a trainstation is the place where trains stop, what is a workstation?

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