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

Discussion:

Jad Killian

2018-07-27 12:06:29 UTC

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

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L. Voerman

2018-08-15 08:41:02 UTC

Permalink

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

2018-08-15 22:13:28 UTC

Permalink

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

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.

Post by 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).
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
------------------
http://forum.openscenegraph.org/viewtopic.php?p=74401#74401 (http://forum.openscenegraph.org/viewtopic.php?p=74401#74401)
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Julien Valentin

2018-08-15 22:23:23 UTC

Permalink

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

Post by 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

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.

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Jordi Torres

2018-08-16 06:01:08 UTC

Permalink

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.

El jue., 16 ago. 2018 12:30 a. m., Julien Valentin <

Post by 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

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.

Post by 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

Post by Jad Killian
1 face, 4 indices with mode = 5 (TRIANGLE_STRIP).
osg::ref_ptr<osg::Node> node =

osgDB::readNodeFile(filepath.toStdString());

Post by Jad Killian
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.

Post by Jad Killian
Any ideas?
Thanks
------------------
http://forum.openscenegraph.org/viewtopic.php?p=74401#74401 (

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

Post by Jad Killian
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Julien Valentin

2018-08-16 19:40:45 UTC

Permalink

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

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.

Post by 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

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.

Post by 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).
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
------------------
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))
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Julien Valentin

2018-08-16 19:50:42 UTC

Permalink

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

Post by 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

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.

Post by 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

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.

Post by 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).
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
------------------
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))
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