Re: PC Vector generator card... (and ESB update)

On Mon, 23 Mar 1998 15:07:11 -0800, Clay Cowgill <ClayC@diamondmm.com> wrote:

>> Sounds Cool!!
>>
>> Can you drive it synchronously? The Cinematronics games do not have a
>> vector
>> generator, each vector is drawn in software (like the Vectrex), and at
>> least one
>> game, Space War, uses software timing to redraw the center star
>> vectors to give
>> it the appearance of variable intensity vectors.
>>
>Hmmmmm. I think I see what you mean. You could probably just have the
>DSP sit there in a busy-loop watching for new values to appear from the
>PC and grab 'em as soon as they show up.

I think that would work beautifully.

>The good part is that the design is effectively "soft". The hardware is
>just the DSP and the D/A's so you can actually change how it works long
>after the hardware is working... As long as the game doesn't display
>more than about 4000 vectors at once you could just treat data RAM as a
>line-list.

4000! Geeze! I think that's plenty! I put a counter in my emulator just to
see how many vectors were being drawn per refresh. Sundance came in the highest
at 457!

I'm sure 4000 vectors of any size are beyond the capabilities of even the Sega
monitor.

>(or whatever you can fit in about 32K bytes of RAM.) Render
>a "frame" into the list and let the DSP draw it. This kind-of imposes a
>"frame rate" on a variable-speed system (like the Vectrex... or
>Cinematronics?), but I suspect that pretty similar to how the emulators
>work?

That's how I did it, but then again the Star in my Space War emulation does not
have the variable intensity effect the real game has. I don't see a problem
with your "draw one vector at a time mode" you talked about earlier...

-Zonn

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Received on Mon Mar 23 15:52:03 1998