Hi,
1. for transparent walls we use our own node (derived from "Effect") - see code
below
2. for "tinting" objects, we also use an effect node derived from "Effect" -
see code below
Used by themselves, everything works fine. But if we have a "tinted" object
behind a "transparent" object, the "tinting" effect is gone (see screenshot).
Code for transparency effect:
Code:
void define_passes()
{
// implement pass #1
{
// s.a. http://www.mail-archive.com//msg13796.html
osg::ref_ptr<osg::StateSet> stateSet = new osg::StateSet;
// mat
osg::Material* mat = new osg::Material;
mat->setAlpha(osg::Material::FRONT_AND_BACK, alpha);
stateSet->setAttributeAndModes(mat, osg::StateAttribute::ON |
osg::StateAttribute::OVERRIDE);
// backface culling, führt dazu dass innere Rückseiten nicht
angezeigt werden
osg::CullFace* cull = new osg::CullFace();
cull->setMode(osg::CullFace::BACK);
stateSet->setAttributeAndModes(cull, osg::StateAttribute::ON);
// turn on blending
osg::BlendFunc* bf = new
osg::BlendFunc(osg::BlendFunc::SRC_ALPHA, osg::BlendFunc::ONE_MINUS_SRC_ALPHA );
stateSet->setMode(GL_BLEND, osg::StateAttribute::ON |
osg::StateAttribute::OVERRIDE);
stateSet->setAttributeAndModes(bf);
// rendering hints
stateSet->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
// lighting
stateSet->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
addPass(stateSet.get());
}
}
Code for "coloring" effect:
Code:
void define_passes()
{
// implement pass #1 - draw original with a little offset
{
osg::ref_ptr<osg::StateSet> ss = new osg::StateSet;
osg::ref_ptr<osg::PolygonOffset> polyoffset = new
osg::PolygonOffset;
polyoffset->setFactor(1.0f);
polyoffset->setUnits(1.0f);
ss->setAttributeAndModes(polyoffset.get(),
osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON);
addPass(ss.get());
}
// implement pass #2 - draw "tinted"
{
osg::ref_ptr<osg::StateSet> ss = new osg::StateSet;
// Material überschreiben
ss->setAttributeAndModes(_wf_mat.get(),
osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON);
// notwendig, damit alpha greift
ss->setMode(GL_BLEND,osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
addPass(ss.get());
}
}
See attached image:
The fire extinguisher should be all yellow, but behind the transparent wall -
it is as if it was rendered without the effect.
I hope someone can sched some light on this issue?
Thank you!
Florian
PS sorry if the code snippets come out weird, leading space for indentation
somehow goes wrong...[/img][/code]
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=56477#56477
Attachments:
http://forum.openscenegraph.org//files/transparency_bug_132.png
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