Andy Walker (awalker++at++multigen.com)
Tue, 7 Apr 1998 14:52:41 -0700
I am not sure how Performer deals with the OpenFlight construct of
external references and instances. My experience in the past was that
externals and instances are turned into unique elements in memory not
just pointers to one piece of memory. So in this case a flight file
with a lot of externals and instances could grow much larger.
Does your database use external references and instances extensively?
Andy Walker
> -----Original Message-----
> From: Angus Dorbie [SMTP:dorbie++at++sgi.com]
> Sent: Tuesday, April 07, 1998 2:15 PM
> To: Steve Baker
> Cc: Allen, Donna N; 'SGI Performer Users Group'; Reynolds, Berton
> Subject: Re: Too Big?
>
> Steve Baker wrote:
> >
> > On Tue, 7 Apr 1998, Allen, Donna N wrote:
> >
> > > hi,
> > >
> > > I'm trying to load a 152MB Open Flight database with about 150 KB
> of
> > > texture into perfly on an Indigo 2 Extreme with 250 MH processor
> and 256
> > > MB Ram. I crashes with a memory allocation error. I would think
> 256MB
> > > ram would be enough for this. Is this too big?
> >
> > Sounds like it. You are assuming that the size of a '.flt' file on
> disk
> > is somehow a 1:1 correspondance with the amount of memory that a
> similar
> > Performer data structure will consume in main memory. This is very
> far
> > from the truth (although I confess that I don't know what the actual
> > ratio is likely to be).
>
> A flt file should take up much less memory than disk space in
> Performer.
>
> However textures are not embeded in the OpenFlight file format and
> you'd
> have to add those to memory useage so what I just said is probably
> untrue
> for many textured databases. And during the loading phase a texture
> will exist in main memory, in OpenGL, plus MIP maps. Ultimately
> you won't have a host copy but you still have a copy in system memory
> in the GL even if it's currently downloaded to texture memory.
>
> Cheers,Angus.
>
> --
> "Only the mediocre are always at their best." -- Jean Giraudoux
>
> For advanced 3D graphics Performer + OpenGL based examples and tutors:
> http://www.dorbie.com/
> ======================================================================
> =
> List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
> Submissions: info-performer++at++sgi.com
> Admin. requests: info-performer-request++at++sgi.com
=======================================================================
List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
Submissions: info-performer++at++sgi.com
Admin. requests: info-performer-request++at++sgi.com
This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:57:13 PDT