Re: Playing Vector Games on the Big Screen

Neil Bradley wrote:

> > > Each set of 9 pixels (1 marker, 8 data) is 1 draw command, with R,G,B,X,Y,? sent each time.
> > > Each of these outputs drives 1 DAC,almost all can set each cycle. Max throughput possible is 2Mhz!
>
> > very interesting approach, it may just work... 8-bit is actually
> > plenty for most vector games, and 2Mhz, is more than enough... you

Asteroids is Mono... (but maybe using 12-bit DAC's instead of 8-bit)
Lets say... 500 points per frame x 60 fps = 30,000 points per second (pps) x 3 = 150,000 distinct 8 bit
outputs per second, or about 150KB / Second bandwidth...

1000 x 5 (XYRGB) x 20 = 100,000 pps for Empire Strikes back...

>
>
> Asteroids runs at 6MHZ. I wouldn't call 2Mhz "enough"... unless this is
> just to drive lasers. I'm thinking vector monitors...

Asteroids is Mono... (but maybe using 12-bit DAC's instead of 8-bit)
Lets say... 500 points per frame x 60 fps = 30,000 points per second (pps) x 3 (XYI) = 150,000 distinct 8
bit outputs per second, or about 150KB / Second bandwidth...

1000 x 5 (XYRGB) x 30 = 150,000 pps for starwars

so my estimate... at 2mhz you have 13 milliseconds of instruction time per point

other factors... Asteroids was Monochrome 2 color, but I think it was capable of 8 shades... others
like Tempest Star Wars, used 2 or 4 shades... so there is signifigant bandwidth reduction there as well

and 6mhz? is that the main Processor or the State Machine Processor? the State Machine Processor drew
all the vectors which it read not actual vectors, but instructions on how to build the vectors from shared
memory from the main processor

>
> > just need to be able to output the frames at a fixed rate, 60fps
> > (200-600 Vector Points) for Asteroids and I think 20fps (1000+ vector
> > points) for Star Wars
>
> It's 45fps for Asteroids and 30fps for Star Wars.
>
> -->Neil
>
> -------------------------------------------------------------------------------
> Neil Bradley chown -R us:us /*base*
> Synthcom Systems, Inc.
> ICQ #29402898
>
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Received on Thu May 30 11:33:08 2002