Re: Of time scaling and FPS

[Dmitry Samoyloff <dsamoyloff@yandex.ru>]

11 May 2002 02:54, Steve Baker wrote:
> Dmitry Samoyloff wrote:
> > 9 May 2002 18:23, Miguel A. Osorio wrote:
> > > Katie Lauren Lucas wrote:
> > > > Quoting "Miguel A. Osorio" <maos@gbl.com.br>:
> > > > >       Anyway, on to the FPS problem. Using the method
> > > > > described above, I use
> > > > > delta to scale my time-dependent variables, in order
> > > > > to get some smooth
> > > > > animation. Thing is, I don't. The whole animation
> > > > > looks all jagged up, without using time scaling it
> > > > > goes on fine; do note that, however, I don't know why,
> > > > > the FPS mark keeps jumping about *all the time*, it
> > > > > never settles on some average. Does anyone know a
> > > > > reason for this? Or am I doing the whole time scaling
> > > > > calculation the wrong way?
> > > >
> > > > Yes. Gettime(2) returns the current time in SECONDS.
> > > > You'd be wanting to retrieve it by calling
> > > > gettimeofday(2) which fills in a structure which
> > > > contains seconds and microseconds since 00:00 Jan 1
> > > > 1970.
> > >
> > >       Err, just one small caveat here: the "gettime" thing
> > > was just sort of an alias for an abstract "time fetching"
> > > routine. In my case, I'm using SDL's SDL_GetTicks
> > > function, which returns milliseconds in a portable way.
> > > BTW, are milliseconds precise enough?
> >
> > AFAIK milliseconds is a maximum precision for a portable
> > apps.
>
> I don't know of a machine that doesn't have microsecond
> precision timers *somewhere* - but you may need to write a
> handy wrapper function to use whatever mechanism works best
> for a given OS.

So why SDL gives only a millisecond precision?

Regards, Dmitry Samoyloff