Hi all, I'm currently working on an example that uses osgShadow::ViewDependentShadowMap for generating dynamic shadows on a large area of buildings. It can work correctly on a huge city which is created by CityEngine and then converted to OSG styled scene graph. It also generates aliasing issues as expected, but I'm still looking for some good solutions to reduce such problem and want to discuss them in this thread if possible. My test program and a simple shader file can be found in attachement.
I've already read a similar topic at: http://lists.openscenegraph.org/htdig.cgi/osg-users-openscenegraph.org/2011-August/053731.html And I believe it is necessary to apply some filters on the shadow map (the test shader file simply uses PCF here) and increase the texture resolution as well. But for huge scene, a 4096-sized RTT texture will be a heavy burden. So I wonder if there are some more methods to choose, for example, is it possible to change the internal format of the texture to GL_DEPTH_COMPONENT32 to improve the shadow comparision process? Meanwhile, is it necessary to perform a screen space blurring to reduce the aliasing effect? It is a serious problem for my scene now as I can't use a very high resolution. Could anyone suggest some other possible methods on the post-processing level? To be honest, the ViewDependentShadowMap is the best shadow solution for me at present as it is easy to be integrated with custom shaders and embedded into a deferred shading framework. The test city models are about 180MB. If any of you think it important for digging into the problem. I'd like to share them freely, too, as I believe these automatically generated models should not have any copyrights with them. :-) Cheers, Wang Rui
#include <osg/AnimationPath>
#include <osg/PolygonMode>
#include <osg/Texture2D>
#include <osg/Geometry>
#include <osg/Geode>
#include <osg/MatrixTransform>
#include <osgDB/ReadFile>
#include <osgShadow/ShadowedScene>
#include <osgShadow/SoftShadowMap>
#include <osgShadow/LightSpacePerspectiveShadowMap>
#include <osgShadow/ParallelSplitShadowMap>
#include <osgShadow/ViewDependentShadowMap>
#include <osgGA/TrackballManipulator>
#include <osgViewer/ViewerEventHandlers>
#include <osgViewer/Viewer>
int main( int argc, char** argv )
{
unsigned int rcvShadowMask = 0x1;
unsigned int castShadowMask = 0x2;
osg::ref_ptr<osg::Program> program = new osg::Program;
program->addShader( osgDB::readShaderFile("shadowRenderer.frag") );
osg::ref_ptr<osg::MatrixTransform> city = new osg::MatrixTransform;
city->addChild( osgDB::readNodeFile("city_root.osgb") );
city->setNodeMask( rcvShadowMask|castShadowMask );
city->getOrCreateStateSet()->setMode( GL_LIGHTING, osg::StateAttribute::OFF );
city->getOrCreateStateSet()->setAttribute( program.get() );
osg::ref_ptr<osg::LightSource> light = new osg::LightSource;
light->getLight()->setPosition( osg::Vec4(1.0, 1.0, 1.0, 0.0) );
osg::ref_ptr<osgShadow::ViewDependentShadowMap> sm = new osgShadow::ViewDependentShadowMap;
osg::ref_ptr<osgShadow::ShadowSettings> settings = new osgShadow::ShadowSettings;
settings->setShaderHint( osgShadow::ShadowSettings::NO_SHADERS );
settings->setTextureSize( osg::Vec2s(2048, 2048) );
settings->setMinimumShadowMapNearFarRatio( 0.05 );
osg::ref_ptr<osgShadow::ShadowedScene> shadowRoot = new osgShadow::ShadowedScene;
shadowRoot->setShadowTechnique( sm.get() );
shadowRoot->setShadowSettings( settings.get() );
shadowRoot->setReceivesShadowTraversalMask( rcvShadowMask );
shadowRoot->setCastsShadowTraversalMask( castShadowMask );
shadowRoot->addChild( city.get() );
shadowRoot->addChild( light.get() );
osg::ref_ptr<osgDB::Options> options = new osgDB::Options("dds_flip");
options->setObjectCacheHint( osgDB::Options::CACHE_IMAGES );
osgDB::Registry::instance()->setOptions( options.get() );
osgDB::Registry::instance()->getOrCreateSharedStateManager();
osgViewer::Viewer viewer;
viewer.setSceneData( shadowRoot.get() );
viewer.addEventHandler( new osgViewer::StatsHandler );
return viewer.run();
}
shadowRenderer.frag
Description: Binary data
_______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
