244 lines
8.7 KiB
C++
244 lines
8.7 KiB
C++
#include <osg/Node>
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#include <osg/Geometry>
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#include <osg/Notify>
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#include <osg/Texture3D>
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#include <osg/TexGen>
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#include <osgGA/TrackballManipulator>
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#include <osgGA/FlightManipulator>
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#include <osgGA/DriveManipulator>
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#include <osgDB/Registry>
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#include <osgDB/ReadFile>
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#include <osgGLUT/glut>
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#include <osgGLUT/Viewer>
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//
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// A simple demo demonstrating different texturing modes,
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// including using of texture extensions.
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//
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typedef std::vector< osg::ref_ptr<osg::Image> > ImageList;
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class ConstructStateCallback : public osg::NodeCallback
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{
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public:
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ConstructStateCallback() {}
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osg::StateSet* constructState()
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{
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// read 4 2d images
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osg::ref_ptr<osg::Image> image_0 = osgDB::readImageFile("Images/lz.rgb");
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osg::ref_ptr<osg::Image> image_1 = osgDB::readImageFile("Images/reflect.rgb");
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osg::ref_ptr<osg::Image> image_2 = osgDB::readImageFile("Images/tank.rgb");
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osg::ref_ptr<osg::Image> image_3 = osgDB::readImageFile("Images/skymap.jpg");
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if (!image_0 || !image_1 || !image_2 || !image_3)
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{
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std::cout << "Warning: could not open files."<<std::endl;
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return new osg::StateSet;
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}
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if (image_0->getPixelFormat()!=image_1->getPixelFormat() || image_0->getPixelFormat()!=image_2->getPixelFormat() || image_0->getPixelFormat()!=image_3->getPixelFormat())
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{
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std::cout << "Warning: image pixel formats not compatible."<<std::endl;
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return new osg::StateSet;
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}
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// get max 3D texture size
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GLint textureSize = osg::Texture3D::getExtensions(0,true)->maxTexture3DSize();
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if (textureSize > 256)
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textureSize = 256;
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// scale them all to the same size.
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image_0->scaleImage(textureSize,textureSize,1);
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image_1->scaleImage(textureSize,textureSize,1);
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image_2->scaleImage(textureSize,textureSize,1);
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image_3->scaleImage(textureSize,textureSize,1);
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// then allocated a 3d image to use for texturing.
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osg::Image* image_3d = new osg::Image;
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image_3d->allocateImage(textureSize,textureSize,4,
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image_0->getPixelFormat(),image_0->getDataType());
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// copy the 2d images into the 3d image.
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image_3d->copySubImage(0,0,0,image_0.get());
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image_3d->copySubImage(0,0,1,image_1.get());
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image_3d->copySubImage(0,0,2,image_2.get());
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image_3d->copySubImage(0,0,3,image_3.get());
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image_3d->setInternalTextureFormat(image_0->getInternalTextureFormat());
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// set up the 3d texture itself,
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// note, well set the filtering up so that mip mapping is disabled,
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// gluBuild3DMipsmaps doesn't do a very good job of handled the
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// inbalanced dimensions of the 256x256x4 texture.
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osg::Texture3D* texture3D = new osg::Texture3D;
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texture3D->setFilter(osg::Texture3D::MIN_FILTER,osg::Texture3D::LINEAR);
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texture3D->setFilter(osg::Texture3D::MAG_FILTER,osg::Texture3D::LINEAR);
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texture3D->setImage(image_3d);
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// create a texgen to generate a R texture coordinate, the geometry
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// itself will supply the S & T texture coordinates.
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// in the animateStateSet callback well alter this R value to
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// move the texture through the 3d texture, 3d texture filtering
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// will do the blending for us.
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osg::TexGen* texgen = new osg::TexGen;
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texgen->setMode(osg::TexGen::OBJECT_LINEAR);
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texgen->setPlane(osg::TexGen::R, osg::Vec4(0.0f,0.0f,0.0f,0.2f));
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// create the StateSet to store the texture data
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osg::StateSet* stateset = new osg::StateSet;
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stateset->setTextureMode(0,GL_TEXTURE_GEN_R,osg::StateAttribute::ON);
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stateset->setTextureAttribute(0,texgen);
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stateset->setTextureAttributeAndModes(0,texture3D,osg::StateAttribute::ON);
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return stateset;
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}
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void animateState(osg::StateSet* stateset)
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{
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// here we simply get any existing texgen, and then increment its
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// plane, pushing the R coordinate through the texture.
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osg::StateAttribute* attribute = stateset->getTextureAttribute(0,osg::StateAttribute::TEXGEN);
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osg::TexGen* texgen = dynamic_cast<osg::TexGen*>(attribute);
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if (texgen)
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{
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texgen->setPlane(osg::TexGen::R, texgen->getPlane(osg::TexGen::R)+osg::Vec4(0.0f,0.0f,0.0f,0.001f));
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}
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}
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virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)
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{
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osg::StateSet* stateset = node->getStateSet();
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if (stateset)
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{
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// we have an exisitng stateset, so lets animate it.
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animateState(stateset);
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}
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else
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{
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// no state exist yet, so we must be in the first
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// pass, so lets create our stateset with all the
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// textures in it.
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stateset = constructState();
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if (stateset) node->setStateSet(stateset);
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}
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// note, callback is repsonsible for scenegraph traversal so
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// should always include call the traverse(node,nv) to ensure
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// that the rest of cullbacks and the scene graph are traversed.
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traverse(node,nv);
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}
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};
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/** create 2,2 square with center at 0,0,0 and aligned along the XZ plan */
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osg::Drawable* createSquare(float textureCoordMax=1.0f)
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{
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// set up the Geometry.
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osg::Geometry* geom = new osg::Geometry;
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osg::Vec3Array* coords = new osg::Vec3Array(4);
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(*coords)[0].set(-1.0f,0.0f,1.0f);
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(*coords)[1].set(-1.0f,0.0f,-1.0f);
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(*coords)[2].set(1.0f,0.0f,-1.0f);
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(*coords)[3].set(1.0f,0.0f,1.0f);
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geom->setVertexArray(coords);
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osg::Vec3Array* norms = new osg::Vec3Array(1);
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(*norms)[0].set(0.0f,-1.0f,0.0f);
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geom->setNormalArray(norms);
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geom->setNormalBinding(osg::Geometry::BIND_OVERALL);
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osg::Vec2Array* tcoords = new osg::Vec2Array(4);
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(*tcoords)[0].set(0.0f,textureCoordMax);
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(*tcoords)[1].set(0.0f,0.0f);
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(*tcoords)[2].set(textureCoordMax,0.0f);
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(*tcoords)[3].set(textureCoordMax,textureCoordMax);
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geom->setTexCoordArray(0,tcoords);
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geom->addPrimitive(osgNew osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
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return geom;
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}
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osg::Node* createModel()
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{
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// create the geometry of the model, just a simple 2d quad right now.
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osg::Geode* geode = new osg::Geode;
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geode->addDrawable(createSquare());
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// normally we'd create the stateset's to contain all the textures
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// etc here, but, the above technique uses osg::Image::scaleImage and
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// osg::Image::copySubImage() which are implemented with OpenGL utility
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// library, which unfortunately can't be used until we have a valid
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// OpenGL context, and at this point in initilialization we don't have
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// a valid OpenGL context, so we have to delay creation of state until
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// there is a valid OpenGL context. I'll manage this by using an
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// app callback which will create the state during the first traversal.
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// A bit hacky, and my plan is to reimplement the osg::scaleImage and
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// osg::Image::copySubImage() without using GLU which will get round
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// this current limitation.
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geode->setAppCallback(new ConstructStateCallback());
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return geode;
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}
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int main( int argc, char **argv )
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{
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// initialize the GLUT
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glutInit( &argc, argv );
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// create the commandline args.
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std::vector<std::string> commandLine;
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for(int i=1;i<argc;++i) commandLine.push_back(argv[i]);
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// initialize the viewer.
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osgGLUT::Viewer viewer;
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viewer.setWindowTitle(argv[0]);
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// configure the viewer from the commandline arguments, and eat any
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// parameters that have been matched.
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viewer.readCommandLine(commandLine);
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// configure the plugin registry from the commandline arguments, and
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// eat any parameters that have been matched.
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osgDB::readCommandLine(commandLine);
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// create a model from the images.
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osg::Node* rootNode = createModel();
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if (rootNode)
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{
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// add model to viewer.
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viewer.addViewport( rootNode );
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// register trackball, flight and drive.
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viewer.registerCameraManipulator(new osgGA::TrackballManipulator);
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viewer.registerCameraManipulator(new osgGA::FlightManipulator);
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viewer.registerCameraManipulator(new osgGA::DriveManipulator);
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viewer.open();
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viewer.run();
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}
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return 0;
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}
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