[osg-users] Transparency on a drawable
Vincent Bourdier
vincent.bourdier at gmail.com
Tue Jul 15 03:51:02 PDT 2008
Thanks a lot !
I did some changes to have the same osg file, and it work very good now !!!
It seems to be a mix of different settings.
thanks for your help.
Regards,
Vincent.
2008/7/15 dimi christop <dimi_christop at yahoo.com>:
> Ok,
> I fixed your osg file so that it displays varrying tranparency (top
> transparent, bottom opaque).
> I assume this is what you wanted.
> Do an diff on the files and see what you did wrong.... You set the colors
> per primitive and not per vertex.
>
>
>
> ----- Original Message ----
> From: Vincent Bourdier <vincent.bourdier at gmail.com>
> To: OpenSceneGraph Users <osg-users at lists.openscenegraph.org>
> Sent: Tuesday, July 15, 2008 1:19:23 PM
> Subject: Re: [osg-users] Transparency on a drawable
>
> Hi Dimi,
>
> this is my code :
>
> osg::StateSet* state = g->getOrCreateStateSet();
>
> state->setMode(GL_BLEND,osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
> osg::Material* mat = new osg::Material;
> mat->setAlpha(osg::Material::FRONT_AND_BACK, alpha);
> mat->setColorMode(osg::Material::AMBIENT_AND_DIFFUSE);
> state->setAttributeAndModes(mat,osg::StateAttribute::ON |
> osg::StateAttribute::OVERRIDE);
>
> osg::BlendFunc* bf = new osg::BlendFunc(osg::BlendFunc::SRC_ALPHA,
> osg::BlendFunc::ONE_MINUS_SRC_ALPHA );
> state->setAttributeAndModes(bf);
>
> state->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
> state->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
>
> g->setStateSet(state);
>
> there is no difference at all...
>
> thanks for help.
>
> Vincent.
>
>
> 2008/7/15 dimi christop <dimi_christop at yahoo.com>:
>
>> This is because when you set alpha to the vertices and attach also an
>> material
>> and a blending function you have to setColorMode (AMBIENT_DIFFUSE) on the
>> material.
>>
>> Dimi
>>
>> ----- Original Message ----
>> From: Vincent Bourdier <vincent.bourdier at gmail.com>
>> To: OpenSceneGraph Users <osg-users at lists.openscenegraph.org>
>> Sent: Tuesday, July 15, 2008 11:09:23 AM
>> Subject: Re: [osg-users] Transparency on a drawable
>>
>>
>> Hi Paul.
>>
>> Nothing changes with color's alpha changed...
>>
>>
>> 2008/7/15 Paul Speed <pspeed at progeeks.com>:
>>
>>>
>>>
>>> Vincent Bourdier wrote:
>>>
>>>> Hi
>>>>
>>>> Yes, no solutions seems to work on my problem.
>>>> Because all the propositions concern nodes, I permit to remember that I
>>>> am looking at a way to set alpha level on a osg::Geometry ...
>>>>
>>>> On node I already have a method using material : set alpha channel, and
>>>> it works good... But on my geometry nothing look to work good...
>>>>
>>>> This is all my geometry creator code :
>>>>
>>>> osg::ref_ptr<osg::Geometry> builtGeometry(){
>>>>
>>>> double alpha = 0.1;
>>>> osg::Vec4 grey(0.4,0.4,0.4,1.0);
>>>> osg::Vec4 yellow(1.0,1.0,0.0,1.0);
>>>>
>>>
>>> What happens if you put alpha for the fourth value in your color?
>>> -Paul
>>>
>>>
>>>> osg::Geometry* g = new osg::Geometry;
>>>> osg::Vec3Array* vertices = new osg::Vec3Array();
>>>> osg::Vec3Array* normals = new osg::Vec3Array();
>>>> osg::Vec4Array* colors = new osg::Vec4Array();
>>>>
>>>> normals->push_back(osg::Vec3(0,0,1));
>>>> colors->push_back(grey);
>>>>
>>>> //----
>>>> //QUAD
>>>> vertices->push_back(osg::Vec3( _width/2.0, _height + _dist,
>>>> _offset));
>>>> vertices->push_back(osg::Vec3(-_width/2.0, _height + _dist,
>>>> _offset));
>>>> vertices->push_back(osg::Vec3(-_width/2.0, 0.0 + _dist,
>>>> _offset));
>>>> vertices->push_back(osg::Vec3( _width/2.0, 0.0 + _dist,
>>>> _offset));
>>>>
>>>> if(!_empty)
>>>> g->addPrimitiveSet(new
>>>> osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
>>>> else
>>>> g->addPrimitiveSet(new
>>>> osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,4));
>>>>
>>>>
>>>> //-----
>>>> //LINE
>>>>
>>>> vertices->push_back(osg::Vec3(0.0, 1.0, _offset));
>>>> vertices->push_back(osg::Vec3(0.0, _dist, _offset));
>>>> colors->push_back(grey);
>>>> g->addPrimitiveSet(new
>>>> osg::DrawArrays(osg::PrimitiveSet::LINES,4,2));
>>>>
>>>>
>>>> //----
>>>> //LINE_LOOP
>>>>
>>>> vertices->push_back(osg::Vec3( _width/2.0, _height + _dist,
>>>> _offset/2.0));
>>>> vertices->push_back(osg::Vec3(-_width/2.0, _height + _dist,
>>>> _offset/2.0));
>>>> vertices->push_back(osg::Vec3(-_width/2.0, 0.0 + _dist,
>>>> _offset/2.0));
>>>> vertices->push_back(osg::Vec3( _width/2.0, 0.0 + _dist,
>>>> _offset/2.0));
>>>>
>>>> colors->push_back(yellow);
>>>> g->addPrimitiveSet(new
>>>> osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,6,4));
>>>>
>>>> g->setNormalArray(normals);
>>>> g->setVertexArray(vertices);
>>>> g->setColorArray(colors);
>>>>
>>>> g->setNormalBinding(osg::Geometry::BIND_OVERALL);
>>>> g->setColorBinding(osg::Geometry::BIND_PER_PRIMITIVE_SET);
>>>> g->setDataVariance(osg::Object::DYNAMIC);
>>>>
>>>>
>>>> //TRANSPARENCY
>>>>
>>>> osg::StateSet* state = g->getOrCreateStateSet();
>>>>
>>>> state->setMode(GL_BLEND,osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
>>>> osg::Material* mat = new osg::Material;
>>>> mat->setAlpha(osg::Material::FRONT_AND_BACK, alpha);
>>>> state->setAttributeAndModes(mat,osg::StateAttribute::ON |
>>>> osg::StateAttribute::OVERRIDE);
>>>>
>>>> osg::BlendFunc* bf = new
>>>> osg::BlendFunc(osg::BlendFunc::SRC_ALPHA,
>>>> osg::BlendFunc::ONE_MINUS_SRC_ALPHA );
>>>> state->setAttributeAndModes(bf);
>>>>
>>>> state->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
>>>> state->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
>>>>
>>>> g->setStateSet(state);
>>>>
>>>> return g;
>>>> }
>>>>
>>>>
>>>> Thanks for your help.
>>>>
>>>> Regards,
>>>>
>>>> Vincent.
>>>>
>>>> 2008/7/15 dimi christop <dimi_christop at yahoo.com <mailto:
>>>> dimi_christop at yahoo.com>>:
>>>>
>>>>
>>>> Hi Vincent,
>>>> I see you still havent found a solution. So here I send you a
>>>> complete example of transpareny.
>>>> Its a modification of the Viewer example from the Qucik start guide.
>>>> It loads up a cow and overrides the alpha to 0.1.
>>>> Hope you can start from there.
>>>>
>>>> Dimi
>>>>
>>>> // Viewer Example, A minimal OSG viewer
>>>> #include <osgDB/WriteFile>
>>>> #include <osg/Notify>
>>>> #include <osgViewer/Viewer>
>>>> #include <osgDB/ReadFile>
>>>> #include <osg/MatrixTransform>
>>>> #include <osg/Geode>
>>>> #include <osg/Geometry>
>>>> #include <osg/StateSet>
>>>> #include <osg/StateAttribute>
>>>> #include <osg/CullFace>
>>>> #include <osg/Point>
>>>> #include <osg/Light>
>>>> #include <osg/LightSource>
>>>> #include <osg/BlendFunc>
>>>> #include <osg/Material>
>>>> #include <osg/PolygonMode>
>>>> #include <osg/Notify>
>>>> int
>>>> main( int, char ** )
>>>> {
>>>> // Create a Viewer.
>>>> osgViewer::Viewer viewer;
>>>> // Load a model and add it to the Viewer.
>>>> osg::ref_ptr<osg::Node> nde = osgDB::readNodeFile( "cow.osg" );
>>>> // Create StateSet and Material
>>>> osg::StateSet* state2 = nde->getOrCreateStateSet();
>>>> osg::ref_ptr<osg::Material> mat2 = new osg::Material;
>>>> // Set alpha to 0.1
>>>> mat2->setAlpha(osg::Material::FRONT_AND_BACK, 0.1);
>>>> state2->setAttributeAndModes( mat2.get() ,
>>>> osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
>>>> // Turn on blending
>>>> osg::BlendFunc* bf = new
>>>> osg::BlendFunc(osg::BlendFunc::SRC_ALPHA,
>>>> osg::BlendFunc::ONE_MINUS_SRC_ALPHA );
>>>> state2->setAttributeAndModes(bf);
>>>> viewer.setSceneData(nde.get());
>>>> if (!viewer.getSceneData())
>>>> {
>>>> osg::notify( osg::FATAL ) << "Unable to load data file.
>>>> Exiting." << std::endl;
>>>> return 1;
>>>> }
>>>>
>>>> // Display, and main loop.
>>>> return viewer.run();
>>>> }
>>>>
>>>> ----- Original Message ----
>>>> From: Vincent Bourdier <vincent.bourdier at gmail.com
>>>> <mailto:vincent.bourdier at gmail.com>>
>>>> To: OpenSceneGraph Users <osg-users at lists.openscenegraph.org
>>>> <mailto:osg-users at lists.openscenegraph.org>>
>>>> Sent: Tuesday, July 15, 2008 9:04:23 AM
>>>> Subject: Re: [osg-users] Transparency on a drawable
>>>>
>>>> Hi Ulrich
>>>>
>>>> thanks for help.
>>>>
>>>> I use/try this code for the moment :
>>>>
>>>> osg::StateSet* state = g->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, alpha);
>>>> state->setAttributeAndModes(mat,osg::StateAttribute::ON);
>>>> state->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
>>>> state->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
>>>>
>>>> But nothing appear transparent...
>>>>
>>>> Regards,
>>>> Vincent
>>>>
>>>> 2008/7/12 Ulrich Hertlein <u.hertlein at sandbox.de
>>>> <mailto:u.hertlein at sandbox.de>>:
>>>>
>>>>
>>>> Vincent Bourdier wrote:
>>>>
>>>> I do exactly the same things, on Nodes...
>>>>
>>>> stateset->setMode(GL_BLEND,
>>>> osg::StateAttribute::OVERRIDE | osg::StateAttribute::ON );
>>>>
>>>>
>>>> stateset->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
>>>>
>>>>
>>>> Are you sure you're doing this last line? It's not in the code
>>>> snippet you posted initially...
>>>>
>>>> Cheers,
>>>> /ulrich
>>>>
>>>>
>>>> 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);
>>>> }
>>>>
>>>>
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>>>>
>>>>
>>>>
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