[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Of time scaling and FPS

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.

> 	Oh, and since you guys didn't actually say anything about the
> process of calculating the time delta, I suppose it's
> acceptable?

I can't see any problem in your code. The problem is maybe 
somewhere else?

Regards, Dmitry Samoyloff