At 05:41 PM 6/7/99 +0200, you wrote:
>What I don't understand is why flicker is unacceptable but interlacing
>is mandatory? AFAIK a NTSC TV does 60 frames per second. The even frames
>show the even scanlines of the picture while the odd frames show the
>odd scanlines. A 30 Hz flicker display does pretty much just that,
In VCS terms a single-line-res scanline is actually 2 NTSC scanlines.
"30Hz flicker" flickers an entire sprite on and off, so even when interlace
is added into the signal, that trims out half of the picture information
from each field, but it doesn't help the fact that an entire sprite is
flickering on and off between field 1 and field 2. The flicker will be
noticeable, perhaps more so during vertical movement with the interlace
added back to it by the TBC.
The important thing is that the credits appear legible. It's only a
secondary consideration to generate them on the 2600. So it's mostly an
aesthetic judgement call on my part to use the venetian blind trick rather
than flicker.
>And why do the 60 Hz VCS display have to be artificially interlaced
>when even TV stations use low res 60 Hz graphics for the logo that they
>insert into the TV broadcast or for those scrolling stock prices on the
>bottom of the screen in buisines shows?
I can't speak for that, but I just know that my gear needs to be fed an
interlaced signal. If it isn't there, the TBC will introduce it. Even if
I went direct into the Toaster/Flyer without the TBC, the resulting
Flyerclip will impose interlace onto the signal.
>I think that getting 12 characters this way would be possible, but
>also using the missiles and ball would probably not work. If you
>set the sprite to 3 copies, the coresponding missile would display
>3 copies too. Besides having to do all the extra positioning would make
>the code unnessessary complicated.
Theoretically you could erase the missile's graphics data wherever you
didn't want it to appear. Or what about playfield instead?
=========================================================
== Glenn Saunders --3D Graphics / Videography / Web development-- ==
== krishna@xxxxxxxxxxxxxxx http://www.geocities.com/Hollywood/1698 ==
== Cyberpunks homepage http://cyberpunks.atari.org ==
=========================================================
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