[osg-users] Transparency on a drawable

Will Dicharry wdicharry at stellarscience.com
Fri Jul 11 08:47:12 PDT 2008


Hi Vincent,

A Drawable (which Geometry inherits from) has an associated StateSet 
object the same way that Geodes (and other classes inheriting Node) do, 
so the same method should work for your geometry as well. See 
http://www.openscenegraph.org/documentation/OpenSceneGraphReferenceDocs/a01139.html 
for more information.

--Will

Vincent Bourdier wrote:
> Thanks for help.
>
> I do exactly the same things, on Nodes...
>
> but this time I am looking on a way to do this only on a geometry (So 
> under a Geode)...
>
> If you have any suggestion..
>
> Regards,
>
> Vincent
>
>
> 2008/7/11 Brian R Hill <bhill22 at csc.com <mailto:bhill22 at csc.com>>:
>
>     This is what I do:
>
>     osg::StateSet * stateset = node->getOrCreateStateSet();
>     osg::Material * mm =
>     dynamic_cast<osg::Material*>(stateset->getAttribute
>     (osg::StateAttribute::MATERIAL));
>     if (!mm)
>     {
>      mm = new osg::Material;
>     }
>     mm->setAlpha(osg::Material::FRONT, transparency);
>     stateset->setAttributeAndModes( mm, osg::StateAttribute::OVERRIDE |
>     osg::StateAttribute::ON);
>     stateset->setMode(GL_BLEND,   osg::StateAttribute::OVERRIDE |
>     osg::StateAttribute::ON );
>     stateset->setMode(GL_LIGHTING,osg::StateAttribute::OVERRIDE |
>     osg::StateAttribute::ON );
>     stateset->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
>
>     Brian
>     -----osg-users-bounces at lists.openscenegraph.org
>     <mailto:osg-users-bounces at lists.openscenegraph.org> wrote: -----
>
>
>     To: "'OpenSceneGraph Users'" <osg-users at lists.openscenegraph.org
>     <mailto:osg-users at lists.openscenegraph.org>>
>     From: "Gordon Tomlinson" <gordon.tomlinson at sensor.com
>     <mailto:gordon.tomlinson at sensor.com>>
>     Sent by: osg-users-bounces at lists.openscenegraph.org
>     <mailto:osg-users-bounces at lists.openscenegraph.org>
>     Date: 07/11/2008 09:59AM
>     Subject: Re: [osg-users] Transparency on a drawable
>
>
>     Vincent
>     You post your initial question at a little over 2 hours ago.. you
>     need to
>     give people time to possibly respond maybe 1-2 days
>     http://www.catb.org/~esr/faqs/smart-questions.html
>     <http://www.catb.org/%7Eesr/faqs/smart-questions.html>
>     also a search of the mailing list archive will throw up quite a few
>     discussions and solutions on this very subject
>
>
>
>
>     From: osg-users-bounces at lists.openscenegraph.org
>     <mailto:osg-users-bounces at lists.openscenegraph.org>
>     [mailto:osg-users-bounces at lists.openscenegraph.org
>     <mailto:osg-users-bounces at lists.openscenegraph.org>] On Behalf Of
>     Vincent
>     Bourdier
>     Sent: Friday, July 11, 2008 8:54 AM
>     To: osg
>     Subject: Re: [osg-users] Transparency on a drawable
>
>
>     No one have any idea of how to set an alpha transparency level on a
>     geometry ?
>     It has no texture, juste one color...
>
>     Thanks,
>
>     Regards,
>
>     Vincent.
>
>
>     2008/7/11 Vincent Bourdier < vincent.bourdier at gmail.com
>     <mailto:vincent.bourdier at gmail.com> >:
>
>     Hi All,
>
>     Just a simple question on how to set a transparency effect on a
>     drawable.
>
>     My geode contains 2 drawables, and I need only one to be
>     transparent...
>
>     I've tried :
>
>
>     double opacity = 0.1;
>
>        osg::StateSet* state = mygometry->getOrCreateStateSet();
>        state->setMode(GL_BLEND,osg::StateAttribute::ON|
>        osg::StateAttribute::OVERRIDE);
>        osg::Material* mat = (osg::Material*)state->getAttribute
>        (osg::StateAttribute::MATERIAL);
>        if(!mat) {
>            mat = new osg::Material;
>            mat->setAlpha(osg::Material::FRONT_AND_BACK, opacity);
>            state->setAttributeAndModes(mat,osg::StateAttribute::ON);
>        }
>
>
>     Lightning is already set to ON...
>
>     But nothing appear transparent...
>
>     Thanks,
>
>     Regards
>        Vincent.
>
>
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-- 
Will Dicharry
Stellar Science Ltd Co

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