plib-devel

[Plib-devel] Model Formats

[Ben W. <be...@bg...>]

Hello everybody

I was looking for a list of model formats that ssg can load. At one point
Steve had mentioned that some new model type where added to the model
loading functions but I was unable to find any type of list to say which
ones. 

Thanks Ben

RE: [Plib-devel] Model Formats

[Dave M. <dp...@ef...>]

here are the new loaders that were recently added to SSG:

- with texture support

	ssgLoadASE.cxx	-- 3dsmax ASE (ascii export) format
	ssgLoadOBJ.cxx	-- wavefront OBJ format

- geometry only

	ssgLoadDXF.cxx	-- autodesk DXF
	ssgLoadTRI.cxx	-- triangles format that matches AC3D triangle format

here are the old loaders

	ssgLoad3ds.cxx	-- Per Liedman's 3ds loader
	ssgLoadAC.cxx	-- Steve Baker's AC loader
	ssgLoadSSG.cxx	-- native SSG format

	ssgLoadVRML.cxx   -- doesn't work yet

> -----Original Message-----
> From: pli...@li...
> [mailto:pli...@li...]On Behalf Of Ben Woodhead
> Sent: Tuesday, July 04, 2000 7:00 AM
> To: pli...@li...
> Subject: [Plib-devel] Model Formats
> 
> 
> Hello everybody
> 
> I was looking for a list of model formats that ssg can load. At one point
> Steve had mentioned that some new model type where added to the model
> loading functions but I was unable to find any type of list to say which
> ones. 
> 
> Thanks Ben

Re: [Plib-devel] Model Formats

[Steve B. <sjb...@ai...>]

Dave McClurg wrote:
> 
> here are the new loaders that were recently added to SSG:
> 
> - with texture support
> 
>         ssgLoadASE.cxx  -- 3dsmax ASE (ascii export) format
>         ssgLoadOBJ.cxx  -- wavefront OBJ format
> 
> - geometry only
> 
>         ssgLoadDXF.cxx  -- autodesk DXF
>         ssgLoadTRI.cxx  -- triangles format that matches AC3D triangle format
> 
> here are the old loaders
> 
>         ssgLoad3ds.cxx  -- Per Liedman's 3ds loader
>         ssgLoadAC.cxx   -- Steve Baker's AC loader
>         ssgLoadSSG.cxx  -- native SSG format
> 
>         ssgLoadVRML.cxx   -- doesn't work yet

The AC3D and SSG loaders are not "old" - they work correctly and have
texture support.

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

[Plib-devel] _ssgShareState bug

[Dave M. <dp...@ef...>]

regarding the bug in _ssgShareState() ... i can't reproduce the problem !?!?

i am using the latest PLIB from CVS and tux_aqfh-1.0.10.tar.gz from the
tux_aqfh
website.  then i commented back in the _ssgShareState() function

      //st = data -> st ;
      st = _ssgShareState ( data -> st ) ;

and with new ssg lib and new relinked tux_aqfh, i have no problems.  i even
traced
into the _ssgShareState() function and it seems to be working.  This is
under win32.

perhaps i forgot what the bug was.  didn't it crash tux_aqfh right away?

thanks,
-- Dave McClurg

Re: [Plib-devel] Model Formats

[Steve B. <sjb...@ai...>]

Ben Woodhead wrote:

> I was looking for a list of model formats that ssg can load. At one point
> Steve had mentioned that some new model type where added to the model
> loading functions but I was unable to find any type of list to say which
> ones.

So far:

  ASE SSG 3ds DXF TRI AC3D OBJ VRML 

Of these, I know that AC3D and SSG work well, I'm not so sure
about the others because I don't use them much.

Dave:

  Can you comment?

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

RE: [Plib-devel] Model Formats

[Dave M. <dp...@ef...>]

Steve wrote:
> The AC3D and SSG loaders are not "old" - they work correctly and have
> texture support.

I'm sorry Steve.  Ben asked about "new" model loaders and I just wanted
to categorize the loaders according to age.  The AC3D and SSG loaders
are the oldest and therefore the most stable and tested.

> > I was looking for a list of model formats that ssg can load. At
> one point
> > Steve had mentioned that some new model type where added to the model
> > loading functions but I was unable to find any type of list to say which
> > ones.
>
> So far:
>
>   ASE SSG 3ds DXF TRI AC3D OBJ VRML
>
> Of these, I know that AC3D and SSG work well, I'm not so sure
> about the others because I don't use them much.
>
> Dave:
>
>   Can you comment?
>

The TRI loader was just a quicky I did because it was easy.  It is
the same TRI format that AC3D uses.  I think it comes from Wavefront.

The 3ds loader was created by Per Liedman.  It is a very important
*binary* format.  AFAIK, it works correctly and supports textures.
Per?

The DXF loader was adapted from John Burkardt's IVCON.  With
Wolfram Kuss' help I've updated it to support quads, polylines,
and MxN polymeshes.  It doesn't support textures, which are not
in the DXF specification, but it is a widely supported format
and a good way to import geometry into SSG.

The ASE loader is the one I wrote and use.  I have tested it and
feel confident that it works correctly.  It has texture support.
I'm willing to help anyone use it or improve it.  Any copy of MAX
has the source code for the ASE export plugin.  I'm working on
adding animation support which will require new SSG entities.

The OBJ loader was adapted from John Burkardt's IVCON.  I added
texture support after looking at how Andreas Umbach handled it
in gltron.  The Wavefront OBJ format is wonderfully simple and elegant.

http://www.cica.indiana.edu/graphics/object_specs/OBJ.format.txt

The "Nebula Device" project (http://www.radonlabs.de/) liked the
OBJ format so much they extended it and use the "n3d" extension.
But AFAICT, Wavefront OBJ lacks animation support.  Otherwise,
I would dump ASE and switch over to it.

I hope to cleanup and improve the OBJ loader soon so it can import
the object names and other things I missed the first time.  Also,
the exporter currently lacks texture support.

Many of these loaders have an exporter.  The exporter feature was
mainly needed for PPE (pretty poly editor).  If you want to *save*
a scene graph, you should use ssgSaveSSG() which supports all the
SSG entities.  Otherwise, you'll lose information.

Another *big* todo item is to add ssgIndexArray to the _ssgCreateFunc
so it can support Mark's ssgVertexArray.cxx module.  That would
make large ASE models load and render faster since they are
naturally in indexed array form.

If someone has a specific use for an improved OBJ or ASE loader,
please let me know.  The added motivation always helps.

--Dave McClurg

Re: [Plib-devel] Model Formats

[Steve B. <sjb...@ai...>]

Dave McClurg wrote:

> If someone has a specific use for an improved OBJ or ASE loader,
> please let me know.  The added motivation always helps.

Annoyingly, the current need is to be able to import models built
in Blender - this would be very useful for the guys who want to
build models for TuxKart under Linux.

The snag appears to be (although I'm not a blender expert) that it
only exports DXF (no texture - yuk!) and VRML (not supported under
PLIB - ack!) 

Another *cool* approach might be to write a blender plugin to
link in PLIB and hence read/write SSG or any of the other formats
we support.  Seems like the Blender guys should be interested
in that since they are short of file formats and we could get
them a bunch in very short order.

Does anyone out there know how to write blender plugins?

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

RE: [Plib-devel] Model Formats

[Dave M. <dp...@ef...>]

Steve wrote:
> Annoyingly, the current need is to be able to import models built
> in Blender - this would be very useful for the guys who want to
> build models for TuxKart under Linux.
>
> The snag appears to be (although I'm not a blender expert) that it
> only exports DXF (no texture - yuk!) and VRML (not supported under
> PLIB - ack!)
>
Interesting...  I wanted to do a "#VRML V1.0 ascii" loader for PLIB a while
back with the specific goal of importing models created in blender.
End-users can grab a free copy of blender and create models for our games.
If that makes sense to you as well, I'll put some work into it and see what
happens.

Thanks,
--Dave

Re: [Plib-devel] Model Formats

[Steve B. <sjb...@ai...>]

Dave McClurg wrote:
> 
> Steve wrote:
> > Annoyingly, the current need is to be able to import models built
> > in Blender - this would be very useful for the guys who want to
> > build models for TuxKart under Linux.
> >
> > The snag appears to be (although I'm not a blender expert) that it
> > only exports DXF (no texture - yuk!) and VRML (not supported under
> > PLIB - ack!)
> >
> Interesting...  I wanted to do a "#VRML V1.0 ascii" loader for PLIB a while
> back with the specific goal of importing models created in blender.
> End-users can grab a free copy of blender and create models for our games.
> If that makes sense to you as well, I'll put some work into it and see what
> happens.

Yes - that would be very useful.  I wonder what kind of a subset
of VRML blender actually produces?  A totally general VRML loader
is quite a big deal.

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

RE: [Plib-devel] Model Formats

[Dave M. <dp...@ef...>]

> Dave McClurg wrote:
> > 
> > Steve wrote:
> > > Annoyingly, the current need is to be able to import models built
> > > in Blender - this would be very useful for the guys who want to
> > > build models for TuxKart under Linux.
> > >
> > > The snag appears to be (although I'm not a blender expert) that it
> > > only exports DXF (no texture - yuk!) and VRML (not supported under
> > > PLIB - ack!)
> > >
> > Interesting...  I wanted to do a "#VRML V1.0 ascii" loader for 
> PLIB a while
> > back with the specific goal of importing models created in blender.
> > End-users can grab a free copy of blender and create models for 
> our games.
> > If that makes sense to you as well, I'll put some work into it 
> and see what
> > happens.
> 
> Yes - that would be very useful.  I wonder what kind of a subset
> of VRML blender actually produces?  A totally general VRML loader
> is quite a big deal.
> 

I grabbed the latest blender (version 1.8) and the tutor files.  I
exported the spider2 and teapot models as "wrl" files (VRML 1.0).

I then built the "VRML 1.0 syntax checker" from the DIVE toolkit
which syntax checks VRML 1.0 files.  After a couple minor tweaks to
the grammar for trailing commas and empty lists, the syntax checker
successfully parsed spider2.wrl and teapot.wrl !

I looked at the wrl files and AFAICT adding semantic actions to the
parser to capture the necessary information for SSG should be *very*
do-able.  Blender spits out Coordinate3 lists followed by an
IndexedFaceList.  Looks easy enough to follow and should work well
with Mark's ssgVertexArray.cxx module.

I think I now have a clear path now to adding a VRML 1.0 loader to
SSG.  I'll try to kick it out this week.

-- Dave McClurg

RE: [Plib-devel] Model Formats

[Per L. <li...@ho...>]

On Wed, 05 Jul 2000, Dave McClurg wrote:
> The 3ds loader was created by Per Liedman.  It is a very important
> *binary* format.  AFAIK, it works correctly and supports textures.
> Per?

The last time I checked, which was some time ago, the loader worked, but it
didn't seem to hard to find strange models that would cause somewhat awkward
results...which is kind of disappointing, I must confess. I and Paolo Leoncini
are discussing some changes to improve the performance. I also think Paolo has a
more up to date opinion of how well the loader actually works.

> Another *big* todo item is to add ssgIndexArray to the _ssgCreateFunc
> so it can support Mark's ssgVertexArray.cxx module.  That would
> make large ASE models load and render faster since they are
> naturally in indexed array form.

I must have a look at this stuff, since it definitely sounds like something the
3ds-loader could use...

Regards,
Per Liedman

-- 
   / Per Liedman
  / li...@ho...
 / www.mdstud.chalmers.se/~md6pl
/ 031-825659 / 0705-520455