> How is it done on the original arcade boards?
With Atari AVG/DVG, dedicated vector generator hardware. e.g. Load up a
list of lines to draw, tell the vector state machine to go draw it. The
CPU isn't involved in the actual drawing process.
> And what kind of latency are
> we talking here?
Tens to hundreds of nanoseconds.
> As for the OS, I imagine the hardware being platform independent, people
> would just need to write platform dependent software to work with it. I feel
> like we shouldn't rule out any OS. I've developed many a MIDI controller
> that uses MIDI over USB, and I can't detect any latency from that, even when
> I move 5 faders at once, which is a whole lot of data being crammed through
> the pipe.
That's not much, actually. Assuming running status, that's 2 bytes per
fader, times 5, assuming 10 bits, that's around ~3.1ms for those
controllers. It's hard to detect <4-5ms latency-wise. Usually MIDI
interfaces like the Steinberg Midex8 buffer MIDI data in the unit itself
ahead of the time it's sent out the actual ports in order to tighten
timing.
There's a difference between something running at 31.5khz and a few
hundred nanoseconds, though. Basically when the beam is being drawn,
you've got to be able to cut the Z at the right time, otherwise it'll
overshoot the target and you'll wind up with sloppy endpoints.
-->Neil
----------------------------------------------------------------------------
C. Neil Bradley - Excessive process falsely elevates the incapable and ties
the hands of the exceptional.
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Received on Tue Apr 17 14:49:31 2012
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