Hi Robert -- Here's the "prettied up" CompositeViewer code for displaying
the view frustum. Seems like "osgthirdpersonview" would be an appropriate
name for this example.
Paul Martz
Skew Matrix Software LLC
http://www.skew-matrix.com <http://www.skew-matrix.com/>
303 859 9466
/* OpenSceneGraph example, osgthirdpersonview.
*
* 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 code is originally Copyright (c) 2008 Skew Matrix Software LLC,
// but you may use the code under the terms of the OSGPL as described above.
// This example demonstrates how CompositeViewer can be used to
// provide a third person view of another view, including eyepoint and
// view frustum.
//
// The code creates a CompositeViewer with two Views. Each of the two
// Views has its own window. One View is the typical scene view,
// showing the loaded model(s).
//
// The second View is a third person view showing not just the loaded
// model(s), but also a wireframe representation of the first View's
// frustum. Interactions with the first View are reflect5ed in the
// second View's displayed frustum.
//
// Command line arguments are taken to be models for display. If you
// specify no command line arguments, the code attempts to load cow.osg.
#include <osg/Geometry>
#include <osg/DisplaySettings>
#include <osg/MatrixTransform>
#include <osg/LineWidth>
#include <osgDB/ReadFile>
#include <osgViewer/CompositeViewer>
#include <osgGA/TrackballManipulator>
// Given a Camera, create a wireframe representation of its
// view frustum. Create a default representation if camera==NULL.
osg::Node*
makeFrustumFromCamera( osg::Camera* camera )
{
// Projection and ModelView matrices
osg::Matrixd proj;
osg::Matrixd mv;
if (camera)
{
proj = camera->getProjectionMatrix();
mv = camera->getViewMatrix();
}
else
{
// Create some kind of reasonable default Projection matrix.
proj.makePerspective( 30., 1., 1., 10. );
// leave mv as identity
}
// Get near and far from the Projection matrix.
const double near = proj(3,2) / (proj(2,2)-1.0);
const double far = proj(3,2) / (1.0+proj(2,2));
// Get the sides of the near plane.
const double nLeft = near * (proj(2,0)-1.0) / proj(0,0);
const double nRight = near * (1.0+proj(2,0)) / proj(0,0);
const double nTop = near * (1.0+proj(2,1)) / proj(1,1);
const double nBottom = near * (proj(2,1)-1.0) / proj(1,1);
// Get the sides of the far plane.
const double fLeft = far * (proj(2,0)-1.0) / proj(0,0);
const double fRight = far * (1.0+proj(2,0)) / proj(0,0);
const double fTop = far * (1.0+proj(2,1)) / proj(1,1);
const double fBottom = far * (proj(2,1)-1.0) / proj(1,1);
// Our vertex array needs only 9 vertices: The origin, and the
// eight corners of the near and far planes.
osg::Vec3Array* v = new osg::Vec3Array;
v->resize( 9 );
(*v)[0].set( 0., 0., 0. );
(*v)[1].set( nLeft, nBottom, -near );
(*v)[2].set( nRight, nBottom, -near );
(*v)[3].set( nRight, nTop, -near );
(*v)[4].set( nLeft, nTop, -near );
(*v)[5].set( fLeft, fBottom, -far );
(*v)[6].set( fRight, fBottom, -far );
(*v)[7].set( fRight, fTop, -far );
(*v)[8].set( fLeft, fTop, -far );
osg::Geometry* geom = new osg::Geometry;
geom->setVertexArray( v );
osg::Vec4Array* c = new osg::Vec4Array;
c->push_back( osg::Vec4( 1., 1., 1., 1. ) );
geom->setColorArray( c );
geom->setColorBinding( osg::Geometry::BIND_OVERALL );
GLushort idxLines[8] = {
0, 5, 0, 6, 0, 7, 0, 8 };
GLushort idxLoops0[4] = {
1, 2, 3, 4 };
GLushort idxLoops1[4] = {
5, 6, 7, 8 };
geom->addPrimitiveSet( new osg::DrawElementsUShort(
osg::PrimitiveSet::LINES, 8, idxLines ) );
geom->addPrimitiveSet( new osg::DrawElementsUShort(
osg::PrimitiveSet::LINE_LOOP, 4, idxLoops0 ) );
geom->addPrimitiveSet( new osg::DrawElementsUShort(
osg::PrimitiveSet::LINE_LOOP, 4, idxLoops1 ) );
osg::Geode* geode = new osg::Geode;
geode->addDrawable( geom );
geode->getOrCreateStateSet()->setMode( GL_LIGHTING,
osg::StateAttribute::OFF | osg::StateAttribute::PROTECTED );
// Create parent MatrixTransform to transform the view volume by
// the inverse ModelView matrix.
osg::MatrixTransform* mt = new osg::MatrixTransform;
mt->setMatrix( osg::Matrixd::inverse( mv ) );
mt->addChild( geode );
return mt;
}
int
main( int argc,
char ** argv )
{
osg::ArgumentParser arguments( &argc, argv );
osg::ref_ptr< osg::Group > root = new osg::Group;
// Child 0: We'll replace this every frame with an updated representation
// of the view frustum.
root->addChild( makeFrustumFromCamera( NULL ) );
osg::ref_ptr< osg::Node > scene;
scene = osgDB::readNodeFiles( arguments );
if (!scene)
{
// User didn't specify anything, or file(s) didn't exist.
// Try to load the cow...
osg::notify( osg::WARN ) << arguments.getApplicationName() << ": Could
not find specified files. Trying \"cow.osg\" instead." << std::endl;
if ( !(scene = osgDB::readNodeFile( std::string( "cow.osg" ) ) ) )
{
osg::notify( osg::FATAL ) << arguments.getApplicationName() << ":
No data loaded." << std::endl;
return 1;
}
}
root->addChild( scene.get() );
osgViewer::CompositeViewer viewer( arguments );
// Turn on FSAA, makes the lines look better.
osg::DisplaySettings::instance()->setNumMultiSamples( 4 );
// Create View 0 -- Just the loaded model.
{
osgViewer::View* view = new osgViewer::View;
viewer.addView( view );
view->setUpViewInWindow( 10, 10, 640, 480 );
view->setSceneData( scene.get() );
view->setCameraManipulator( new osgGA::TrackballManipulator );
}
// Create view 1 -- Contains the loaded moel, as well as a wireframe
frustum derived from View 0's Camera.
{
osgViewer::View* view = new osgViewer::View;
viewer.addView( view );
view->setUpViewInWindow( 10, 510, 640, 480 );
view->setSceneData( root.get() );
view->setCameraManipulator( new osgGA::TrackballManipulator );
}
while (!viewer.done())
{
// Update the wireframe frustum
root->removeChild( 0, 1 );
root->insertChild( 0, makeFrustumFromCamera(
viewer.getView( 0 )->getCamera() ) );
viewer.frame();
}
return 0;
}
#this file is automatically generated
SET(TARGET_SRC osgthirdpersonview.cpp )
#### end var setup ###
SETUP_EXAMPLE(osgthirdpersonview)
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