[osg-users] Change picked points' color ---why can't work in the pick function?

[Yexin W]

Hi,

Guys, I have a pick problem. What I want to do is loading 10 points with their loactions and colors. I want to use poly pick, and use another color to show the picked points.  
The loading points process is as follows:


Code:

osg::ref_ptr<osg::Geometry> geom = new osg::Geometry();
osg::ref_ptr<osg::Vec3Array> v = new osg::Vec3Array;
osg::ref_ptr<osg::Vec4Array> clr = new osg::Vec4Array;
v->push_back(osg::Vec3(0.0, 0.0, 0.0));
... // 10 points in total
clr->push_back(osg::Vec4(1.0, 0.0, 1.0, 1.0f));
...// set the color 
geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::POINTS, 0, v->size()));
// after set the color and normal, add the geometry to Geode node
geode->addDrawable(geom.get());





Then I want to use ploy pick, the problem is : when I put the following codes in the pick() function in Pickhandler class, I found out that the color of the picked premitiveset has been changed, however, nothing changed in the view window. The following codes are in pick function:


Code:

if (picker->containsIntersections())
{
osgUtil::PolytopeIntersector::Intersections intersections = picker->getIntersections();
osgUtil::PolytopeIntersector::Intersections::iterator iter;
for (iter = intersections.begin(); iter != intersections.end(); iter++)
{
osg::NodePath nodepath = (*iter).nodePath; 
node = (nodepath.size() >= 1) ? nodepath[nodepath.size() - 1] : 0; 
int pointIndex = (*iter).primitiveIndex; 
osg::Geode * geode = dynamic_cast<osg::Geode*> (node);
osg::Geometry * geom = dynamic_cast<osg::Geometry*>(geode->getDrawable(0));
osg::Vec4Array * clrary = dynamic_cast<osg::Vec4Array*>(geom->getColorArray());
clrary->operator [] (pointIndex) = osg::Vec4(0.0, 1.0, 0.0, 1.0f);
geom->setColorBinding(osg::Geometry::BIND_PER_VERTEX);
node->addUpdateCallback(new CessnaCallback()); // not helpful
viewer->updateTraversal(); //not helpful
//viewer->run();//not helpful
}
}





First, I thought may be the colors have not been changed, so I tested changing several points' color in the main function, like this:


Code:

osg::Geode * geode1 = dynamic_cast<osg::Geode*> (nodePt.get());
osg::Geometry * geom = dynamic_cast<osg::Geometry*>(geode1->getDrawable(0));
osg::Vec4Array * clrary = dynamic_cast<osg::Vec4Array*>(geom->getColorArray());
clrary->operator [] (10) = osg::Vec4(0.0, 1.0, 0.0, 1.0f);
clrary->operator [] (6) = osg::Vec4(0.0, 1.0, 0.0, 1.0f);
clrary->operator [] (2) = osg::Vec4(0.0, 1.0, 0.0, 1.0f);
geom->setColorBinding(osg::Geometry::BIND_PER_VERTEX);



 	
It changed the colors! So it confuses me why it can't work in the pick function? Any body any idears?
Any ideas and suggestions would be appreciated! 


Thank you!

Cheers,
Yexin

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