Hi
I am trying to set the object transparency from 1.0 -> 0.0 and vice versa;
but when I start changing the alpha of the material the object becomes dark.
I have changed the material parameters but without success; when I look in
the loaded model (for example cow.osg) for material, the material is always
null.
I have modified the osgviewer example and attached it.
Could s.o. give me a hint what I am doing wrong ?
Thanks
Dieter
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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
*
* This application is open source and may be redistributed and/or modified
* freely and without restriction, both in commericial and non commericial
applications,
* as long as this copyright notice is maintained.
*
* This application is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <osgDB/ReadFile>
#include <osgUtil/Optimizer>
#include <osg/CoordinateSystemNode>
#include <osg/Switch>
#include <osgText/Text>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgGA/TrackballManipulator>
#include <osgGA/FlightManipulator>
#include <osgGA/DriveManipulator>
#include <osgGA/KeySwitchMatrixManipulator>
#include <osgGA/StateSetManipulator>
#include <osgGA/AnimationPathManipulator>
#include <osgGA/TerrainManipulator>
#include <osg/Material>
#include <osg/BlendFunc>
#include <iostream>
int doAlpha;
float currentAlpha;
osg::ref_ptr<osg::Node> loadedModel;
void setAlpha()
{
if ( doAlpha == 1)
currentAlpha +=.01;
if ( doAlpha == 2)
currentAlpha -=.01;
if (loadedModel.valid())
{
osg::StateSet *ss = loadedModel ->getOrCreateStateSet();
osg::Material* blendMaterial = 0;
blendMaterial =
(osg::Material*)(ss->getAttribute(osg::StateAttribute::MATERIAL));
if(blendMaterial ==0)
{
blendMaterial = new osg::Material();
}
if (doAlpha == 1)
{
if (currentAlpha <1.0)
{
blendMaterial->setAlpha(
osg::Material::FRONT_AND_BACK, currentAlpha);
}
else
{
blendMaterial->setAlpha(
osg::Material::FRONT_AND_BACK, 1.0);
doAlpha = 0;
}
}
else if (doAlpha == 2)
{
if (currentAlpha > .0)
{
blendMaterial->setAlpha(
osg::Material::FRONT_AND_BACK, currentAlpha);
}
else
{
blendMaterial->setAlpha(
osg::Material::FRONT_AND_BACK, 0.0);
doAlpha = 0;
}
}
osg::BlendFunc *bl = new osg::BlendFunc();
bl->setFunction(osg::BlendFunc::SRC_ALPHA,
osg::BlendFunc::ONE_MINUS_SRC_ALPHA);
ss->setAttributeAndModes(bl, osg::StateAttribute::ON
|osg::StateAttribute::OVERRIDE);
ss->setMode(GL_BLEND, osg::StateAttribute::ON
|osg::StateAttribute::OVERRIDE);
ss->setAttributeAndModes(blendMaterial ,osg::StateAttribute::ON
|osg::StateAttribute::OVERRIDE);
ss->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
loadedModel->setStateSet( ss ); // not neccessary
if (currentAlpha >=1 )
{
doAlpha = 0;
ss->setMode(GL_BLEND, osg::StateAttribute::OFF);
ss->setAttributeAndModes(blendMaterial,osg::StateAttribute::OFF);
}
if (currentAlpha < 0)
doAlpha = 1;
}
}
int main(int argc, char** argv)
{
// use an ArgumentParser object to manage the program arguments.
osg::ArgumentParser arguments(&argc,argv);
arguments.getApplicationUsage()->setApplicationName(arguments.getApplicationName());
arguments.getApplicationUsage()->setDescription(arguments.getApplicationName()+"
is the standard OpenSceneGraph example which loads and visualises 3d models.");
arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+"
[options] filename ...");
arguments.getApplicationUsage()->addCommandLineOption("--image
<filename>","Load an image and render it on a quad");
arguments.getApplicationUsage()->addCommandLineOption("--dem
<filename>","Load an image/DEM and render it on a HeightField");
arguments.getApplicationUsage()->addCommandLineOption("-h or
--help","Display command line parameters");
arguments.getApplicationUsage()->addCommandLineOption("--help-env","Display
environmental variables available");
arguments.getApplicationUsage()->addCommandLineOption("--help-keys","Display
keyboard & mouse bindings available");
arguments.getApplicationUsage()->addCommandLineOption("--help-all","Display
all command line, env vars and keyboard & mouse bindings.");
arguments.getApplicationUsage()->addCommandLineOption("--SingleThreaded","Select
SingleThreaded threading model for viewer.");
arguments.getApplicationUsage()->addCommandLineOption("--CullDrawThreadPerContext","Select
CullDrawThreadPerContext threading model for viewer.");
arguments.getApplicationUsage()->addCommandLineOption("--DrawThreadPerContext","Select
DrawThreadPerContext threading model for viewer.");
arguments.getApplicationUsage()->addCommandLineOption("--CullThreadPerCameraDrawThreadPerContext","Select
CullThreadPerCameraDrawThreadPerContext threading model for viewer.");
// if user request help write it out to cout.
bool helpAll = arguments.read("--help-all");
unsigned int helpType = ((helpAll || arguments.read("-h") ||
arguments.read("--help"))? osg::ApplicationUsage::COMMAND_LINE_OPTION : 0 ) |
((helpAll || arguments.read("--help-env"))?
osg::ApplicationUsage::ENVIRONMENTAL_VARIABLE : 0 ) |
((helpAll || arguments.read("--help-keys"))?
osg::ApplicationUsage::KEYBOARD_MOUSE_BINDING : 0 );
if (helpType)
{
arguments.getApplicationUsage()->write(std::cout, helpType);
return 1;
}
osgViewer::Viewer viewer(arguments);
// report any errors if they have occurred when parsing the program
arguments.
if (arguments.errors())
{
arguments.writeErrorMessages(std::cout);
return 1;
}
if (arguments.argc()<=1)
{
arguments.getApplicationUsage()->write(std::cout,osg::ApplicationUsage::COMMAND_LINE_OPTION);
return 1;
}
// set up the camera manipulators.
{
osg::ref_ptr<osgGA::KeySwitchMatrixManipulator> keyswitchManipulator =
new osgGA::KeySwitchMatrixManipulator;
keyswitchManipulator->addMatrixManipulator( '1', "Trackball", new
osgGA::TrackballManipulator() );
keyswitchManipulator->addMatrixManipulator( '2', "Flight", new
osgGA::FlightManipulator() );
keyswitchManipulator->addMatrixManipulator( '3', "Drive", new
osgGA::DriveManipulator() );
keyswitchManipulator->addMatrixManipulator( '4', "Terrain", new
osgGA::TerrainManipulator() );
std::string pathfile;
char keyForAnimationPath = '5';
while (arguments.read("-p",pathfile))
{
osgGA::AnimationPathManipulator* apm = new
osgGA::AnimationPathManipulator(pathfile);
if (apm || !apm->valid())
{
unsigned int num =
keyswitchManipulator->getNumMatrixManipulators();
keyswitchManipulator->addMatrixManipulator(
keyForAnimationPath, "Path", apm );
keyswitchManipulator->selectMatrixManipulator(num);
++keyForAnimationPath;
}
}
viewer.setCameraManipulator( keyswitchManipulator.get() );
}
// add the state manipulator
viewer.addEventHandler( new
osgGA::StateSetManipulator(viewer.getCamera()->getOrCreateStateSet()) );
// add the thread model handler
viewer.addEventHandler(new osgViewer::ThreadingHandler);
// add the window size toggle handler
viewer.addEventHandler(new osgViewer::WindowSizeHandler);
// add the stats handler
viewer.addEventHandler(new osgViewer::StatsHandler);
// add the help handler
viewer.addEventHandler(new
osgViewer::HelpHandler(arguments.getApplicationUsage()));
// add the record camera path handler
viewer.addEventHandler(new osgViewer::RecordCameraPathHandler);
// add the LOD Scale handler
viewer.addEventHandler(new osgViewer::LODScaleHandler);
// load the data
loadedModel = osgDB::readNodeFiles(arguments);
if (!loadedModel)
{
std::cout << arguments.getApplicationName() <<": No data loaded" <<
std::endl;
return 1;
}
// any option left unread are converted into errors to write out later.
arguments.reportRemainingOptionsAsUnrecognized();
// report any errors if they have occurred when parsing the program
arguments.
if (arguments.errors())
{
arguments.writeErrorMessages(std::cout);
return 1;
}
// optimize the scene graph, remove redundant nodes and state etc.
osgUtil::Optimizer optimizer;
optimizer.optimize(loadedModel.get());
viewer.setSceneData( loadedModel.get() );
viewer.realize();
doAlpha = 2;
currentAlpha = 1.0;
osg::Timer_t start_tick=osg::Timer::instance()->tick();
while(!viewer.done() )
{
osg::Timer_t end_tick=osg::Timer::instance()->tick();
// starts after 5 sec - only to see the difference
if (osg::Timer::instance()->delta_s(start_tick,end_tick) > 5.)
setAlpha();
viewer.frame();
}
//return viewer.run();
}
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