[Openal-devel] Distance units

[pclare at sensaura.creative.com]

"Andrew McDonald" <myrmecophagavir at hotmail.com> wrote on 15/03/2005
22:37:57:
> I don't see why everyone's getting so excited about whether or not we
have
> units. Effectively we
> *do* - the OpenAL distance unit and the OpenAL time unit (which is
already a
> second I believe in the
> spec). It's just that they aren't explicitly related to any "real" units.
It's
> actually an
> assumption we're making that the original 343.3 is in metres per second -
it
> might just as well be
> an unhelpful default speed of sound in feet per hour for some random
> atmosphere. In fact it's simply
> in the same units as the velocity values in the doppler equation.
<snip>

Yes, but the point I was making is that distance units have a use beyond
Doppler calculations.  In order to render a 3D positioned sound I would
ideally like to know the actual distance in metres (or feet or whatever).
I can calculate basic gain rolloff without knowing the units, but I can do
a better job of rendering if I do know the absolute distance between source
and listener.

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