Finally, here's a new example. Create a directory
examples/osgocclusionquery, and place both files there. Please make the
appropriate change to the parent CMakeLists.txt.
Paul Martz
Skew Matrix Software LLC
http://www.skew-matrix.com <http://www.skew-matrix.com/>
303 859 9466
/* OpenSceneGraph example, osganimate.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
// This exampl demonstrates use of OcclusionQueryNode.
//
// In general, you use OcclusionQueryNode by simply attaching a subgraph
// or subgraphs as children, and it performs an OpenGL oclusion query
// to determine whether to draw the subgraphs or not.
//
// You can manually insert OcclusionQueryNodes at strategic locations
// in your scene graph, or you can write a NodeVisitor to insert them
// automatically, as this example shows.
//
// Run this example with no command line arguments, and it creates
// a "stock scene" to show how OcclusionQueryNode can be used.
//
// Or, run this example with a model on the command line, and the
// example uses a NodeVisitor to try to find worthwhile locations
// for OcclusionQueryNodes in your the scene graph.
#include <osg/NodeVisitor>
#include <osg/Geode>
#include <osg/Geometry>
#include <osg/StateSet>
#include <osg/StateAttribute>
#include <osg/PolygonMode>
#include <osg/ColorMask>
#include <osg/PolygonOffset>
#include <osg/Depth>
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgUtil/Optimizer>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgGA/StateSetManipulator>
#include <osg/OcclusionQueryNode>
#include <iostream>
#include <sstream>
// NodeVisitors and utility functions for OcclusionQueryNode
// Create and return a StateSet appropriate for performing an occlusion
// query test (disable lighting, texture mapping, etc). Probably some
// room for improvement here. Could disable shaders, for example.
osg::StateSet*
initOQState()
{
osg::StateSet* state = new osg::StateSet;
// TBD Possible bug, need to allow user to set render bin number.
state->setRenderBinDetails( 9, "RenderBin" );
state->setMode( GL_LIGHTING, osg::StateAttribute::OFF |
osg::StateAttribute::PROTECTED);
state->setTextureMode( 0, GL_TEXTURE_2D, osg::StateAttribute::OFF |
osg::StateAttribute::PROTECTED);
state->setMode( GL_CULL_FACE, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
osg::ColorMask* cm = new osg::ColorMask( false, false, false, false );
state->setAttributeAndModes( cm, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
osg::Depth* d = new osg::Depth( osg::Depth::LEQUAL, 0.f, 1.f, false );
state->setAttributeAndModes( d, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
osg::PolygonMode* pm = new osg::PolygonMode(
osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::FILL );
state->setAttributeAndModes( pm, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
osg::PolygonOffset* po = new osg::PolygonOffset( -1., -1. );
state->setAttributeAndModes( po, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
return state;
}
// Create and return a StateSet for rendering a debug representation of query
geometry.
osg::StateSet*
initOQDebugState()
{
osg::StateSet* debugState = new osg::StateSet;
debugState->setMode( GL_LIGHTING, osg::StateAttribute::OFF |
osg::StateAttribute::PROTECTED);
debugState->setTextureMode( 0, GL_TEXTURE_2D, osg::StateAttribute::OFF |
osg::StateAttribute::PROTECTED);
debugState->setMode( GL_CULL_FACE, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
osg::PolygonMode* pm = new osg::PolygonMode(
osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::LINE );
debugState->setAttributeAndModes( pm, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
osg::PolygonOffset* po = new osg::PolygonOffset( -1., -1. );
debugState->setAttributeAndModes( po, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
return debugState;
}
// Use this visitor to insert OcclusionQueryNodes (OQNs) in the
// visited subgraph. Only one OQN will test any particular node
// (no nesting). See also OcclusionQueryNonFlatVisitor.
class OcclusionQueryVisitor : public osg::NodeVisitor
{
public:
OcclusionQueryVisitor();
virtual ~OcclusionQueryVisitor();
// Specify the vertex count threshold for performing occlusion
// query tests. Nodes in the scene graph whose total child geometry
// contains fewer vertices than the specified threshold will
// never be tested, just drawn. (In fact, they will br treated as
// potential occluders and rendered first in front-to-back order.)
void setOccluderThreshold( int vertices );
int getOccluderThreshold() const;
virtual void apply( osg::OcclusionQueryNode& oqn );
virtual void apply( osg::Group& group );
virtual void apply( osg::Geode& geode );
protected:
void addOQN( osg::Node& node );
// When an OQR creates all OQNs and each OQN shares the same OQC,
// these methods are used to uniquely name all OQNs. Handy
// for debugging.
std::string getNextOQNName();
int getNameIdx() const { return _nameIdx; }
osg::ref_ptr<osg::StateSet> _state;
osg::ref_ptr<osg::StateSet> _debugState;
unsigned int _nameIdx;
int _occluderThreshold;
};
// Find all OQNs in the visited scene graph and set their visibility threshold.
class VisibilityThresholdVisitor : public osg::NodeVisitor
{
public:
VisibilityThresholdVisitor( unsigned int threshold=500 )
: osg::NodeVisitor( osg::NodeVisitor::TRAVERSE_ALL_CHILDREN ),
_visThreshold( threshold ) {}
virtual ~VisibilityThresholdVisitor() {}
virtual void apply( osg::OcclusionQueryNode& oqn );
protected:
unsigned int _visThreshold;
};
// Find all OQNs in the visited scene graph and set the number of frames
// between queries.
class QueryFrameCountVisitor : public osg::NodeVisitor
{
public:
QueryFrameCountVisitor( int count=5 )
: osg::NodeVisitor( osg::NodeVisitor::TRAVERSE_ALL_CHILDREN ),
_count( count ) {}
virtual ~QueryFrameCountVisitor() {}
virtual void apply( osg::OcclusionQueryNode& oqn );
protected:
unsigned int _count;
};
// Find all OQNs in the visited scene graph and enable or disable queries..
class EnableQueryVisitor : public osg::NodeVisitor
{
public:
EnableQueryVisitor( bool enable=true )
: osg::NodeVisitor( osg::NodeVisitor::TRAVERSE_ALL_CHILDREN ),
_enabled( enable ) {}
virtual ~EnableQueryVisitor() {}
virtual void apply( osg::OcclusionQueryNode& oqn );
protected:
bool _enabled;
};
// Find all OQNs in the visited scene graph and enable or disable the
// debug bounding volume display.
class DebugDisplayVisitor : public osg::NodeVisitor
{
public:
DebugDisplayVisitor( bool debug=true )
: osg::NodeVisitor( osg::NodeVisitor::TRAVERSE_ALL_CHILDREN ),
_debug( debug ) {}
virtual ~DebugDisplayVisitor() {}
virtual void apply( osg::OcclusionQueryNode& oqn );
protected:
bool _debug;
};
// Remove all OQNs from the visited scene graph.
class RemoveOcclusionQueryVisitor : public osg::NodeVisitor
{
public:
RemoveOcclusionQueryVisitor();
virtual ~RemoveOcclusionQueryVisitor();
virtual void apply( osg::OcclusionQueryNode& oqn );
protected:
};
// Gather statistics about OQN performance in the visited scene graph.
class StatisticsVisitor : public osg::NodeVisitor
{
public:
StatisticsVisitor( osg::NodeVisitor::TraversalMode
mode=osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN );
virtual ~StatisticsVisitor();
virtual void apply( osg::OcclusionQueryNode& oqn );
void reset();
unsigned int getNumOQNs() const;
unsigned int getNumPassed() const;
protected:
unsigned int _numOQNs;
unsigned int _numPassed;
};
unsigned int countGeometryVertices( osg::Geometry* geom )
{
if (!geom->getVertexArray())
return 0;
// TBD This will eventually iterate over the PrimitiveSets and total the
// number of vertices actually used. But for now, it just returns the
// size of the vertex array.
return geom->getVertexArray()->getNumElements();
}
class VertexCounter : public osg::NodeVisitor
{
public:
VertexCounter( int limit )
: osg::NodeVisitor( osg::NodeVisitor::TRAVERSE_ALL_CHILDREN ),
_limit( limit ),
_total( 0 ) {}
~VertexCounter() {}
int getTotal() { return _total; }
bool exceeded() const { return _total > _limit; }
void reset() { _total = 0; }
virtual void apply( osg::Node& node )
{
// Check for early abort. If out total already exceeds the
// max number of vertices, no need to traverse further.
if (exceeded())
return;
traverse( node );
}
virtual void apply( osg::Geode& geode )
{
// Possible early abort.
if (exceeded())
return;
unsigned int i;
for( i = 0; i < geode.getNumDrawables(); i++ )
{
osg::Geometry* geom = dynamic_cast<osg::Geometry
*>(geode.getDrawable(i));
if( !geom )
continue;
_total += countGeometryVertices( geom );
if (_total > _limit)
break;
}
}
protected:
int _limit;
int _total;
};
OcclusionQueryVisitor::OcclusionQueryVisitor()
: osg::NodeVisitor( osg::NodeVisitor::TRAVERSE_ALL_CHILDREN ),
_nameIdx( 0 ),
_occluderThreshold( 5000 )
{
// Init StateSet for occlusion query geometry.
_state = initOQState();
// Initialize StateSet for debug geometry
_debugState = initOQDebugState();
}
OcclusionQueryVisitor::~OcclusionQueryVisitor()
{
osg::notify( osg::INFO ) <<
"osgOQ: OcclusionQueryVisitor: Added " << getNameIdx() <<
" OQNodes." << std::endl;
}
void
OcclusionQueryVisitor::setOccluderThreshold( int vertices )
{
_occluderThreshold = vertices;
}
int
OcclusionQueryVisitor::getOccluderThreshold() const
{
return _occluderThreshold;
}
void
OcclusionQueryVisitor::apply( osg::OcclusionQueryNode& oqn )
{
// A subgraph is already under osgOQ control.
// Don't traverse further.
return;
}
void
OcclusionQueryVisitor::apply( osg::Group& group )
{
if (group.getNumParents() == 0)
{
// Can't add an OQN above a root node.
traverse( group );
return;
}
int preTraverseOQNCount = getNameIdx();
traverse( group );
if (getNameIdx() > preTraverseOQNCount)
// A least one OQN was added below the current node.
// Don't add one here to avoid hierarchical nesting.
return;
// There are no OQNs below this group. If the vertex
// count exceeds the threshold, add an OQN here.
addOQN( group );
}
void
OcclusionQueryVisitor::apply( osg::Geode& geode )
{
if (geode.getNumParents() == 0)
{
// Can't add an OQN above a root node.
traverse( geode );
return;
}
addOQN( geode );
}
void
OcclusionQueryVisitor::addOQN( osg::Node& node )
{
VertexCounter vc( _occluderThreshold );
node.accept( vc );
if (vc.exceeded())
{
// Insert OQN(s) above this node.
unsigned int np = node.getNumParents();
while (np--)
{
osg::Group* parent = dynamic_cast<osg::Group*>( node.getParent( np
) );
if (parent != NULL)
{
osg::ref_ptr<osg::OcclusionQueryNode> oqn = new
osg::OcclusionQueryNode();
oqn->addChild( &node );
parent->replaceChild( &node, oqn.get() );
oqn->setName( getNextOQNName() );
// Set all OQNs to use the same query StateSets (instead of
multiple copies
// of the same StateSet) for efficiency.
oqn->setQueryStateSets( _state.get(), _debugState.get() );
}
}
}
}
std::string
OcclusionQueryVisitor::getNextOQNName()
{
std::ostringstream ostr;
ostr << "OQNode_" << _nameIdx++;
return ostr.str();
}
//
void
VisibilityThresholdVisitor::apply( osg::OcclusionQueryNode& oqn )
{
oqn.setVisibilityThreshold( _visThreshold );
traverse( oqn );
}
void
QueryFrameCountVisitor::apply( osg::OcclusionQueryNode& oqn )
{
oqn.setQueryFrameCount( _count );
traverse( oqn );
}
void
EnableQueryVisitor::apply( osg::OcclusionQueryNode& oqn )
{
oqn.setQueriesEnabled( _enabled );
traverse( oqn );
}
void
DebugDisplayVisitor::apply( osg::OcclusionQueryNode& oqn )
{
oqn.setDebugDisplay( _debug );
traverse( oqn );
}
RemoveOcclusionQueryVisitor::RemoveOcclusionQueryVisitor()
: osg::NodeVisitor( osg::NodeVisitor::TRAVERSE_ALL_CHILDREN )
{
}
RemoveOcclusionQueryVisitor::~RemoveOcclusionQueryVisitor()
{
}
void
RemoveOcclusionQueryVisitor::apply( osg::OcclusionQueryNode& oqn )
{
if (oqn.getNumParents() == 0)
{
// Even if this is an OQN, can't delete it because it's the root.
traverse( oqn );
return;
}
osg::ref_ptr<osg::OcclusionQueryNode> oqnPtr = &oqn;
unsigned int np = oqn.getNumParents();
while (np--)
{
osg::Group* parent = dynamic_cast<osg::Group*>( oqn.getParent( np ) );
if (parent != NULL)
{
// Remove OQN from parent.
parent->removeChild( oqnPtr.get() );
// Add OQN's children to parent.
unsigned int nc = oqn.getNumChildren();
while (nc--)
parent->addChild( oqn.getChild( nc ) );
}
}
}
StatisticsVisitor::StatisticsVisitor( osg::NodeVisitor::TraversalMode mode )
: osg::NodeVisitor( mode ),
_numOQNs( 0 ),
_numPassed( 0 )
{
}
StatisticsVisitor::~StatisticsVisitor()
{
}
void
StatisticsVisitor::apply( osg::OcclusionQueryNode& oqn )
{
_numOQNs++;
if (oqn.getPassed())
_numPassed++;
traverse( oqn );
}
void
StatisticsVisitor::reset()
{
_numOQNs = _numPassed = 0;
}
unsigned int
StatisticsVisitor::getNumOQNs() const
{
return _numOQNs;
}
unsigned int
StatisticsVisitor::getNumPassed() const
{
return _numPassed;
}
// End NodeVisitors
// KetHandler --
// Allow user to do interesting things with an
// OcclusionQueryNode-enabled scene graph at run time.
class KeyHandler : public osgGA::GUIEventHandler
{
public:
KeyHandler( osg::Node& node )
: _node( node ),
_enable( true ),
_debug( false )
{}
bool handle( const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& )
{
switch( ea.getEventType() )
{
case(osgGA::GUIEventAdapter::KEYUP):
{
if (ea.getKey()==osgGA::GUIEventAdapter::KEY_F6)
{
// F6 -- Toggle osgOQ testing.
_enable = !_enable;
EnableQueryVisitor eqv( _enable );
_node.accept( eqv );
return true;
}
else if (ea.getKey()==osgGA::GUIEventAdapter::KEY_F7)
{
// F7 -- Toggle display of OQ test bounding volumes
_debug = !_debug;
DebugDisplayVisitor ddv( _debug );
_node.accept( ddv );
return true;
}
else if (ea.getKey()==osgGA::GUIEventAdapter::KEY_F8)
{
// F8 -- Gether stats and display
StatisticsVisitor sv;
_node.accept( sv );
std::cout << "osgOQ: Stats: numOQNs " << sv.getNumOQNs() <<
", numPased " << sv.getNumPassed() << std::endl;
return true;
}
else if (ea.getKey()==osgGA::GUIEventAdapter::KEY_F9)
{
// F9 -- Remove all OcclusionQueryNodes
RemoveOcclusionQueryVisitor roqv;
_node.accept( roqv );
return true;
}
else if (ea.getKey()=='o')
{
if (osgDB::writeNodeFile( _node, "saved_model.osg" ))
osg::notify( osg::ALWAYS ) << "osgOQ: Wrote scene graph
to \"saved_model.osg\"" << std::endl;
else
osg::notify( osg::ALWAYS ) << "osgOQ: Wrote failed for
\"saved_model.osg\"" << std::endl;
return true;
}
return false;
}
default:
break;
}
return false;
}
osg::Node& _node;
bool _enable, _debug;
};
// Create a cube with one side missing. This makes a great simple occluder.
osg::ref_ptr<osg::Node>
createBox()
{
osg::ref_ptr<osg::Geode> box = new osg::Geode;
osg::StateSet* state = box->getOrCreateStateSet();
osg::PolygonMode* pm = new osg::PolygonMode(
osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::FILL );
state->setAttributeAndModes( pm,
osg::StateAttribute::ON | osg::StateAttribute::PROTECTED );
osg::ref_ptr<osg::Geometry> geom = new osg::Geometry;
osg::ref_ptr<osg::Vec3Array> v = new osg::Vec3Array;
geom->setVertexArray( v.get() );
{
const float x( 0.f );
const float y( 0.f );
const float z( 0.f );
const float r( 1.1f );
v->push_back( osg::Vec3( x-r, y-r, z-r ) ); //left -X
v->push_back( osg::Vec3( x-r, y-r, z+r ) );
v->push_back( osg::Vec3( x-r, y+r, z+r ) );
v->push_back( osg::Vec3( x-r, y+r, z-r ) );
v->push_back( osg::Vec3( x+r, y-r, z+r ) ); //right +X
v->push_back( osg::Vec3( x+r, y-r, z-r ) );
v->push_back( osg::Vec3( x+r, y+r, z-r ) );
v->push_back( osg::Vec3( x+r, y+r, z+r ) );
v->push_back( osg::Vec3( x-r, y-r, z-r ) ); // bottom -Z
v->push_back( osg::Vec3( x-r, y+r, z-r ) );
v->push_back( osg::Vec3( x+r, y+r, z-r ) );
v->push_back( osg::Vec3( x+r, y-r, z-r ) );
v->push_back( osg::Vec3( x-r, y-r, z+r ) ); // top +Z
v->push_back( osg::Vec3( x+r, y-r, z+r ) );
v->push_back( osg::Vec3( x+r, y+r, z+r ) );
v->push_back( osg::Vec3( x-r, y+r, z+r ) );
v->push_back( osg::Vec3( x-r, y+r, z-r ) ); // back +Y
v->push_back( osg::Vec3( x-r, y+r, z+r ) );
v->push_back( osg::Vec3( x+r, y+r, z+r ) );
v->push_back( osg::Vec3( x+r, y+r, z-r ) );
}
osg::ref_ptr<osg::Vec4Array> c = new osg::Vec4Array;
geom->setColorArray( c.get() );
geom->setColorBinding( osg::Geometry::BIND_OVERALL );
c->push_back( osg::Vec4( 0.f, 1.f, 1.f, 1.f ) );
osg::ref_ptr<osg::Vec3Array> n = new osg::Vec3Array;
geom->setNormalArray( n.get() );
geom->setNormalBinding( osg::Geometry::BIND_PER_PRIMITIVE );
n->push_back( osg::Vec3( -1.f, 0.f, 0.f ) );
n->push_back( osg::Vec3( 1.f, 0.f, 0.f ) );
n->push_back( osg::Vec3( 0.f, 0.f, -1.f ) );
n->push_back( osg::Vec3( 0.f, 0.f, 1.f ) );
n->push_back( osg::Vec3( 0.f, 1.f, 0.f ) );
geom->addPrimitiveSet( new osg::DrawArrays( GL_QUADS, 0, 20 ) );
box->addDrawable( geom.get() );
return box.get();
}
// Make a Geometry that renders slow intentionally.
// To make sure it renders slow, we do the following:
// * Disable display lists
// * Force glBegin/glEnd slow path
// * Lots of vertices and color data per vertex
// * No vertex sharing
osg::ref_ptr<osg::Node>
createRandomTriangles( unsigned int num )
{
osg::ref_ptr<osg::Geode> tris = new osg::Geode;
osg::StateSet* state = tris->getOrCreateStateSet();
osg::StateSet* ss = tris->getOrCreateStateSet();
// Force wireframe. Many gfx cards handle this poorly.
osg::PolygonMode* pm = new osg::PolygonMode(
osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::LINE );
ss->setAttributeAndModes( pm, osg::StateAttribute::ON |
osg::StateAttribute::PROTECTED);
ss->setMode( GL_LIGHTING, osg::StateAttribute::OFF |
osg::StateAttribute::PROTECTED);
osg::ref_ptr<osg::Geometry> geom = new osg::Geometry;
// Disable display lists to decrease performance.
geom->setUseDisplayList( false );
osg::ref_ptr<osg::Vec3Array> v = new osg::Vec3Array;
geom->setVertexArray( v.get() );
v->resize( num*3 );
unsigned int i;
srand( 0 );
#define RAND_NEG1_TO_1 ( ((rand()%20)-10)*.1 )
for (i=0; i<num; i++)
{
osg::Vec3& v0 = (*v)[ i*3+0 ];
osg::Vec3& v1 = (*v)[ i*3+1 ];
osg::Vec3& v2 = (*v)[ i*3+2 ];
v0 = osg::Vec3( RAND_NEG1_TO_1, RAND_NEG1_TO_1, RAND_NEG1_TO_1 );
v1 = osg::Vec3( RAND_NEG1_TO_1, RAND_NEG1_TO_1, RAND_NEG1_TO_1 );
v2 = osg::Vec3( RAND_NEG1_TO_1, RAND_NEG1_TO_1, RAND_NEG1_TO_1 );
}
osg::ref_ptr<osg::Vec4Array> c = new osg::Vec4Array;
geom->setColorArray( c.get() );
// Bind per primitive to force slow glBegin/glEnd path.
geom->setColorBinding( osg::Geometry::BIND_PER_PRIMITIVE );
c->resize( num );
#define RAND_0_TO_1 ( (rand()%10)*.1 )
for (i=0; i<num; i++)
{
osg::Vec4& c0 = (*c)[ i ];
c0 = osg::Vec4( RAND_0_TO_1, RAND_0_TO_1, RAND_0_TO_1, 1. );
}
geom->addPrimitiveSet( new osg::DrawArrays( GL_TRIANGLES, 0, num*3 ) );
tris->addDrawable( geom.get() );
return tris.get();
}
// Create the stock scene:
// Top level Group
// Geode (simple occluder
// OcclusionQueryNode
// Geode with complex, slow geometry.
osg::ref_ptr<osg::Node>
createStockScene()
{
// Create a simple box occluder
osg::ref_ptr<osg::Group> root = new osg::Group();
root->addChild( createBox().get() );
// Create a complex mess of triangles as a child below an
// OcclusionQueryNode. The OQN will ensure that the
// subgraph isn't rendered when it's not visible.
osg::ref_ptr<osg::OcclusionQueryNode> oqn = new osg::OcclusionQueryNode;
oqn->addChild( createRandomTriangles( 20000 ).get() );
root->addChild( oqn.get() );
return root.get();
}
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()+"
demonstrates OpenGL occlusion query in OSG using the OcclusionQueryNode.");
arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+"
[options] [filename(s)]");
arguments.getApplicationUsage()->addCommandLineOption("-h or
--help","Display command line parameters");
// if user request help write it out to cout.
if (arguments.read("-h") || arguments.read("--help"))
{
arguments.getApplicationUsage()->write(std::cout,
osg::ApplicationUsage::COMMAND_LINE_OPTION);
return 1;
}
// report any errors if they have occurred when parsing the program
arguments.
if (arguments.errors())
{
arguments.writeErrorMessages(std::cout);
return 1;
}
osgViewer::Viewer viewer( arguments );
// add the state manipulator
viewer.addEventHandler( new
osgGA::StateSetManipulator(viewer.getCamera()->getOrCreateStateSet()) );
// add the stats handler
viewer.addEventHandler(new osgViewer::StatsHandler);
// add the help handler
viewer.addEventHandler(new
osgViewer::HelpHandler(arguments.getApplicationUsage()));
// load the specified model
osg::ref_ptr<osg::Node> root = osgDB::readNodeFiles( arguments );
if (!root)
{
std::cout << arguments.getApplicationName() <<": No files specified, or
can't load them." << std::endl;
root = createStockScene().get();
if (!root)
{
std::cout << arguments.getApplicationName() <<": Failed to create
stock scene." << std::endl;
return 1;
}
std::cout << "Using stock scene instead." << std::endl;
}
else
{
// Run a NodeVisitor to insert OcclusionQueryNodes in the scene graph.
OcclusionQueryVisitor oqv;
root->accept( oqv );
}
bool optimize = arguments.read( "--opt" );
// 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.
if (optimize)
{
osgUtil::Optimizer optimizer;
optimizer.optimize( root.get() );
}
viewer.setSceneData( root.get() );
KeyHandler* kh = new KeyHandler( *root );
viewer.addEventHandler( kh );
return viewer.run();
}
#this file is automatically generated
SET(TARGET_SRC osgocclusionquery.cpp )
SET(TARGET_ADDED_LIBRARIES osgUtil osgDB )
#### end var setup ###
SETUP_EXAMPLE(osgocclusionquery)
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