RE: [stella] RESPx and player positions

Subject: RE: [stella] RESPx and player positions
From: "John Saeger" <john@xxxxxxxxxxx>
Date: Mon, 20 Apr 1998 19:13:31 -0700
> I've always wondered about these delays anyone have an idea why they're
> there?  Also while writing Stella (the emulator) I noticed that Atlantis
> seems to position the left most gun during HBLANK so you would expect it
> to appear at pixel 0, however, they reposition the player ~3
> pixels to the
> left.  This seems to imply that it really positions it at pixel 3 and not
> pixel 0 like the Stella Programming Guide says.  To see what I mean fire
> Atlantis up under PCAE and notice that the left gun is half-way off the
> screen.

Nah.  I think the gun is *really* at position zero.  I think the HMOVE is
spurious; a bug that turns out not to matter.  You know, fiddle with it
until you get it right, and who cares how you got it there... ;-)  Sword
Quest Earthworld has something like this in the opening screen too.  PCAE
shows part of the handle on the right side of the screen.  I think it has
something to do with trying to do an HMOVE which results in a position less
than zero, or something like that.  I think a real VCS ignores any such
request and puts it at zero.  But I'm just guessing... ;-)  But so far, I'm
a firm believer in the RESP during HBLANK putting the object at zero theory.
Does ANYONE know of ANY exceptions??


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