[osg-users] Converting PrimitiveSet to use triangles instead of triangle strips / fans?

[Jad Killian]

Hi,

When I import a .obj file with readNodeFile, the result is a triangle strip instead of triangles. Even if the .obj file is a simple square with 4 vertices and 2 triangular faces, the resulting primitive set in the geode geometry contains
1 face, 4 indices with mode = 5 (TRIANGLE_STRIP).

I tried using the osg::Optimizer, but it doesn't seem to do anything:



Code:
osg::ref_ptr<osg::Node> node = osgDB::readNodeFile(filepath.toStdString());

osgUtil::Optimizer optimizer;
optimizer.optimize(node, osgUtil::Optimizer::INDEX_MESH);



for optimizer flags I tried INDEX_MESH, TESSELLATE_GEOMETRY, DEFAULT_OPTIMIZATIONS, nothing seems to work.

Any ideas?

Thanks

------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=74401#74401





_______________________________________________
osg-users mailing list
osg-...@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org

[L. Voerman]

I tend to use 

set OSG_OPTIMIZER=INDEX_MESH VERTEX_POSTTRANSFORM VERTEX_PRETRANSFORM

for these, but there might be something else preventing the optimizer from changing your geometry.

set OSG_OPTIMIZER=STATIC_OBJECT_DETECTION  INDEX_MESH VERTEX_POSTTRANSFORM VERTEX_PRETRANSFORM MERGE_GEOMETRY MERGE_GEODES

might do the trick

Laurens.

[Julien Valentin]

INDEX_mesh don't reindex indexed
I fix it on my branch introducing a forceReindex parameter to the IndexMeshVisitor and use it witout an attached Optimizer

L. Voerman wrote:
> I tend to use set OSG_OPTIMIZER=INDEX_MESH VERTEX_POSTTRANSFORM VERTEX_PRETRANSFORM
>
> for these, but there might be something else preventing the optimizer from changing your geometry.
> set OSG_OPTIMIZER=STATIC_OBJECT_DETECTION  INDEX_MESH VERTEX_POSTTRANSFORM VERTEX_PRETRANSFORM MERGE_GEOMETRY MERGE_GEODES
>
> might do the trick
> Laurens.
>
>
> On Wed, Aug 15, 2018 at 9:10 AM Jad Killian < ()> wrote:
>
>
> > Hi,
> >
> > When I import a .obj file with readNodeFile, the result is a triangle strip instead of triangles. Even if the .obj file is a simple square with 4 vertices and 2 triangular faces, the resulting primitive set in the geode geometry contains
> > 1 face, 4 indices with mode = 5 (TRIANGLE_STRIP).
> >
> > I tried using the osg::Optimizer, but it doesn't seem to do anything:
> >
> >
> >
> > Code:
> > osg::ref_ptr<osg::Node> node = osgDB::readNodeFile(filepath.toStdString());
> >
> > osgUtil::Optimizer optimizer;
> > optimizer.optimize(node, osgUtil::Optimizer::INDEX_MESH);
> >
> >
> >
> > for optimizer flags I tried INDEX_MESH, TESSELLATE_GEOMETRY, DEFAULT_OPTIMIZATIONS, nothing seems to work.
> >
> > Any ideas?
> >
> > Thanks
> >
> > ------------------
> > Read this topic online here:

> > http://forum.openscenegraph.org/viewtopic.php?p=74401#74401 (http://forum.openscenegraph.org/viewtopic.php?p=74401#74401)
> >
> >
> >
> >
> >
> > _______________________________________________
> > osg-users mailing list
> > ()
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org (http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org)
> >
>
>
> ------------------
> Post generated by Mail2Forum

------------------------
Twirling twirling twirling toward freedom

------------------
Read this topic online here:

http://forum.openscenegraph.org/viewtopic.php?p=74538#74538

[Julien Valentin]

https://github.com/openscenegraph/OpenSceneGraph/pull/596

http://forum.openscenegraph.org/viewtopic.php?p=74539#74539

[Jordi Torres]

Hi, 

There is an option in the obj plugin to avoid tristrips. It's probably better to try this cause tristripping is not cheap depending on the geometry. 

From the top of my head is something like "noTrisStripPolygons". 

Hope it helps.

[Julien Valentin]

Hi Jordi
I admit I haven't read the question but the topic title remind me of a pr i haven't made...
Should'nt it be default obj plugin behavior not to strip instead of an option one have to set?
Is this pr valid to you?
https://github.com/openscenegraph/OpenSceneGraph/pull/597
Cheers

> > > > http://forum.openscenegraph.org/viewtopic.php?p=74401#74401 (http://forum.openscenegraph.org/viewtopic.php?p=74401#74401) (http://forum.openscenegraph.org/viewtopic.php?p=74401#74401 (http://forum.openscenegraph.org/viewtopic.php?p=74401#74401))

> > > >
> > > >
> > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > osg-users mailing list
> > > >   ()

> > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org (http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org) (http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org (http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org))

> > > >
> > > >
> > >
> > >
> > >   ------------------
> > > Post generated by Mail2Forum
> > >
> >
> >
> > ------------------------
> > Twirling twirling twirling toward freedom
> >
> > ------------------
> > Read this topic online here:

> > http://forum.openscenegraph.org/viewtopic.php?p=74538#74538 (http://forum.openscenegraph.org/viewtopic.php?p=74538#74538)

> >
> >
> >
> >
> >
> > _______________________________________________
> > osg-users mailing list
> > ()
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org (http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org)
> >
>
>
> ------------------
> Post generated by Mail2Forum

------------------------
Twirling twirling twirling toward freedom

------------------
Read this topic online here:

http://forum.openscenegraph.org/viewtopic.php?p=74556#74556

[Julien Valentin]

Oups made mistake in given pr good one is
I should have also remove the comment talking about perf enancement (so 90's)
Tristrip is good for HW but Optimizer generate multiple patch so duplicate one prim set into several (Draw Overhead)
Indexed Triangles nowadays have realy good perf

https://github.com/openscenegraph/OpenSceneGraph/pull/598

http://forum.openscenegraph.org/viewtopic.php?p=74557#74557