RE: Sega Multigame and Vector Generator Card...

G'day folks,

Well, if the ships on Space Wars aren't animated well on a 19" screen,
then that explains why only Barrier had a 25" screen. There's no
animation in Barrier, and anytime someone brought up a 25" screen for
one of the later games this issue probably came up.

I still like Paul's idea of having intensity differ within any given
vector, even if we can't make vectors fade to black (due to speed
constraints of the monitor). If I may speculate for a moment, wouldn't
it be difficult to specify via software how you wanted the intensity for
a vector to change? Let's say I wanted the intensity to increase slowly
for the first third of a vector, stay at the highest level for the
middle of the vector and finally return to the original intensity in the
last third of the vector.

I think varying intensity within any given vector would also support
first person games with "fading perspective with distance" nicely. All
those lines that go off into the distance would be easy to fade as you
get further off in the distance (but of course you wouldn't be able to
fade completely to black unfortunately). Am I getting too much into
game design when the monitor hasn't even been finished?!

                Steven S Ozdemir
                sso@dsc.com

>----------
>From: zonn@zonn.com[SMTP:zonn@zonn.com]
>Sent: Wednesday, December 17, 1997 10:47 AM
>To: vectorlist@spies.com
>Cc: zonn@zonn.com
>Subject: Re: Sega Multigame and Vector Generator Card...
>
>On Tue, 16 Dec 1997 15:00:38 -0800, Clay Cowgill <clayc@diamondmm.com> wrote:
>
>>>> Moving "fractional" portions of pixels/dots/whatever is handy for
>>>> rate-control and makes really fluid movement easy from the software side.
>>>> Just gives you some easy dynamic range to play with. No real reason to
>>>> "need" it though.
>>>
>>>Well ya, you need fractional pixels/dots to get variable slope without
>>>using bresenham.
>>
>>Well, sorta-- you need it for calculation, but not necessarily for
>>plotting. (Anything smaller than the discernable resolution of the tube
>>could be left out...)
>>
>>>> Actually, I bet the dot size of the (focused) beam on a 19" raster tube
>>>>is
>>>> probably larger than the lower bit or two of resolution from a 12bit DAC.
>>>> (Not to mention the shadow-mask.)
>>>
>>>Good point. But some may want to run on a B/W monitor and then you need
>>>all the resolution you can get. That wouldn't be me though.
>
>If you watch the slow floating of a ship on Space War you can see the ship
>*jump* from one position to the next as it moves across the screen. It's
>very
>subtle but noticeable. The Cinematronics uses a 1024 x 768 (or thereabouts)
>grid for the starting points of it's vectors -- or about the resolution of
>10bit
>DACs. Since it's noticeable on a 19" screen it would sure be nice to have
>higher resolutions available for the possibilities of larger screens.
>
>The jumps are very small using the 10bit resolution, 12bits would be 1/4 of
>that
>jump and would be very hard to discern. I think it would also be smaller
>than
>the thickness of the trace -- the jumps on Space War seem to be about the
>same
>size as the trace. The disadvantage of 12bits is that your clock rate must
>be 4
>times faster than the asteroids DVG to maintain the same slew rate --
>probably
>not a problem. I wasn't able to find any serial DACs (I didn't do all that
>thorough of a search) that worked at this speed, you might have to stick with
>parallel loaded DACs.
>
><snip>
>
>>>It just hit me! The 2nd order system (using ddx & ddy) would allow
>>>another feature: Variable intensity along a line. Rather than using
>>>them to draw a curve, you could use them to simply alter the speed
>>>of a straight line draw. It'd be cool to have vectors that fade to
>>>black (as the beam speeds up).
>
>This might not work. I was comparing the speed of the vector generators with
>the slew rates of the monitors, and as it is they run the monitors pretty
>close
>to their maximum speed. Unfortunately you wouldn't be able to fade a trace
>by
>drawing faster simply because you can't draw any faster. If the ability to
>draw
>faster was available I'm sure Atari (or whoever) would have already taken
>advantage of it. I imagine the speed of the monitors was used to set the
>speed
>of the DVG and AVG, and not the other way around.
>
>-Zonn
>
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>
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Received on Wed Dec 17 11:06:30 1997