[stella] Weird horizontal positioning?

Subject: [stella] Weird horizontal positioning?
From: emooney@xxxxxxxxxxxxxxxx (Erik Mooney)
Date: Sat, 12 Apr 1997 06:00:57 GMT
For whatever reason, it seems that player graphics display one pixel
further right than missiles and balls when identical code for positioning
and identical HMOVE values is used for both.  After RESPx, there's a
five-pixel delay before the player serial graphics begin, but a four-pixel
delay for missiles and the ball.  This seems to be reproducible both on PC
Atari and the Supercharger, and happens both with the Air-Sea Battle
fine-coarse convert routine and a standard subtract-15 convert.  Anyone
else notice this?  (For that matter, has anyone else written anything using
missiles and balls, or is everyone just working on sprites?)

Also, I discovered a flaw in PC Atari's emulation.. if missile 0 is
one-copy single-width, hitting RESMP0 resets the missile's horizontal
position to line up with the fourth bit of the player.. on the real Stella
under the same conditions, the missile's horizontal position becomes even
with the _fifth_ pixel of the player.  Both the fourth and fifth pixels can
be considered the "center" of the 8-bit wide player, so this inconsistency
does kinda make sense =)

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