Hello
Please, I would like to show you some lines of the code I use for a project. In
one scene, I can ask some geodes to:
- change their color emission (the objective is to seem them with a kind of red
colour)
- change their opacity (with a value from 0 to 1 : 0 is fully invisible geode,
1 is fully opaque)
1) In the creation of the scene, I do this:
osg::ref_ptr<osg::StateSet> stateSet;
for (all geodes in the scene)
{
stateSet = new osg::StateSet();
osg::Material* material = dynamic_cast< osg::Material* >(
stateSet->getAttribute(osg::StateAttribute::MATERIAL));
if (material == NULL)
stateSet->setAttributeAndModes( new osg::Material ) ;
geode->getStateSet()->setAttributeAndModes(material,
osg::StateAttribute::OVERRIDE);
geode->getStateSet()->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
geode->getStateSet()->setBinName("transparent");
geode->getStateSet()->setBinNumber(0);
}
stateSet = NULL;
2) When I want to change the color emission of a geode, I do this:
osg::Material *material;
for (all geodes in the scene)
{
material = (osg::Material *)
geode->getStateSet()->getAttribute(osg::StateAttribute::MATERIAL);
if (ChangeColour)
{
material->setColorMode(osg::Material::EMISSION);
material->setEmission(osg::Material::FRONT_AND_BACK, osg::Vec4(1.0f,
0.0f, 0.0f, 1.0f));
geode->getOrCreateStateSet()->setAttributeAndModes(material,
osg::StateAttribute::OVERRIDE);
}
else
{
material->setColorMode(osg::Material::OFF);
material->setEmission(osg::Material::FRONT_AND_BACK, osg::Vec4(0.f, 0.f,
0.0f, 1.0f));
geode->getOrCreateStateSet(g)->setAttributeAndModes(material,
osg::StateAttribute::OFF);
}
}
material = NULL;
3) When I want to change the opacity/transparency level of the geode, I do this:
ApplyOpacity (float Opacity, Geode geode)
{
osg::Material * material = (osg::Material *)
geode->getStateSet()->getAttribute(osg::StateAttribute::MATERIAL);
if (Opacity != 1.)
{
material->setTransparency(osg::Material::FRONT_AND_BACK, 1. - Opacity);
geode->getStateSet()->setRenderBinDetails(0, "transparent");
geode->getStateSet()->setMode( GL_BLEND, osg::StateAttribute::ON );
geode->getStateSet()->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
geode->getStateSet()->setAttributeAndModes(material,
osg::StateAttribute::OVERRIDE);
}
else
{
geode->getStateSet()->setMode( GL_BLEND, osg::StateAttribute::OFF );
geode->getStateSet()->setAttributeAndModes(material,
osg::StateAttribute::OFF);
}
}
...
It mainly works, it's even compatible : I can both apply a red colour and a
transparency to a same geode.
However:
- if I set an opacity of 0.5 to one geode... if after I put a red colour... it
is OK... but if after I come back to opacity=1, the red colour disappears
- same way, if i put 0.5 opacity and red colour and if I remove the red
colour, the transparency disappears.
The problem probably comes from the setAttributeAndModes(..., OFF) but if I
don't use those lines, I lose the visual aspect of the geode.
I really don't know how make those 2 effects comaptible...
If you have an idea ?
Thank you very much!
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=34814#34814
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