Re: [stella] Emulator Hazards

Subject: Re: [stella] Emulator Hazards
From: emooney@xxxxxxxxxxxxxxxx (Erik Mooney)
Date: Sat, 27 Sep 1997 14:04:46 GMT
>4) Default sprite positioning on the emulator isn't the same as it is on
>   a real 2600. While working on my virtual pet I started my first two
>   sprites out on the position they default to on the emulator
>   (which is the far right hand side). Set up all my values to make them
>   walk back and forth across the screen and when I played it on a real
>   2600 everything was WAY off. The default sprite position on a 2600
>   is actually about 1/3 the way in from the right. I suppose this is
>   really my fault for being lazy. I should have put the sprite right where
>   I wanted it from the start instead of relying on the default. But it
>   seemed redundant at the time.

Actually, the 2600's default sprite position should be random, and the
emulator default sprite position is wherever the author puts it.  But, are
you doing the standard "zero everything" loop at the beginning?  When you
do that, you hit the sprite positioning registers, so they'll always end up
at the same place.

>So you really DO need a supercharger if you want to be absolutely certain
>that your programme will work as you intend it to on a real 2600.

Or a custom EPROM development system :)

>I also think I may have found a way to attach a file to a message. I'm
>going to try it out. If it works then my next message should have a
>demo of what I've done so far. It doesn't do anything yet except
>show the "need" sprite, "critter" sprite and "action" sprite (and the
>critter sprite is dead to boot (and no he's not Kenny)).

Yeah, we got the attachment... I haven't tried it yet though.

>Also... for those of you out there who have been reluctant to programme
>anything because you're intimidated by the difficulty of the 2600 or
>a lack of machine language programming skill, there's really nothing
>better than to just jump right into it and write a very simple programme.

And then beg this list for help when you don't realize you're leaving VSYNC
active the entire frame? ;)

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Current Thread
  • [stella] Emulator Hazards
    • crackers - Fri, 26 Sep 1997 23:37:08 -0400 (EDT)
      • Erik Mooney - Sat, 27 Sep 1997 10:02:29 -0400 (EDT) <=
      • crackers - Sat, 27 Sep 1997 15:30:02 -0400 (EDT)
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