OpenSceneGraph/examples/osgimpostor/osgimpostor.cpp

#include <osg/Geometry>
#include <osg/Impostor>
#include <osg/Material>
#include <osg/MatrixTransform>
#include <osg/Quat>
#include <osg/Geode>

#include <osgUtil/InsertImpostorsVisitor>

#include <osgDB/ReadFile>

#include <osgProducer/Viewer>

#include "TestManipulator.h"


#include <iostream>
#include <list>

// container storing all house nodes
typedef osg::ref_ptr<osg::Node>	NodePtr;
typedef std::list<NodePtr>		NodeContainer;
typedef NodeContainer::iterator	NodeIterator;

NodeContainer					nodes;

//
osg::Group * Root = 0;

const int HOUSES_SIZE = 25000;		// total number of houses
double XDim = 5000.0f;				// area dimension +/- XDim
double ZDim = 5000.0f;				// area dimension +/- YDim

int GridX = 20;						// number of grids in x direction
int GridY = 20;						// number of grids in y direction

bool UseImpostor = true;			// use impostor (or do not use)

float Threshold = 3000.0f;			// distance where impostor are shown

// create houses and store nodes in container
void CreateHouses()
{
	int i;

	GLubyte indices[48] = {
		0, 2, 1,
		3, 2, 0,
		0, 4, 7,
		7, 3, 0,
		0, 1, 5,
		5, 4, 0,
		1, 6, 5,
		2, 6, 1,
		2, 3, 7,
		2, 7, 6,
		4, 8, 7,
		5, 6, 9,
		4, 5, 8,
		8, 5, 9,
		6, 7, 8,
		8, 9, 6
	};

	// use the same color, normal and indices for all houses.
        osg::Vec4Array* colors = new osg::Vec4Array(1);
	(*colors)[0] = osg::Vec4(1.0f, 1.0f, 1.0f, 1.0f);

	// normals
	osg::Vec3Array * normals = new osg::Vec3Array(16);
	(*normals)[0] = osg::Vec3( 0.0f,  -0.0f, -1.0f);
	(*normals)[1] = osg::Vec3( 0.0f,  -0.0f, -1.0f);
	(*normals)[2] = osg::Vec3( 0.0f,  -1.0f,  0.0f);
	(*normals)[3] = osg::Vec3( 0.0f,  -1.0f,  0.0f);
	(*normals)[4] = osg::Vec3( 1.0f,  -0.0f,  0.0f);
	(*normals)[5] = osg::Vec3( 1.0f,  -0.0f,  0.0f);
	(*normals)[6] = osg::Vec3( 0.0f, 1.0f,  0.0f);
	(*normals)[7] = osg::Vec3( 0.0f, 1.0f,  0.0f);
	(*normals)[8] = osg::Vec3(-1.0f,  -0.0f,  0.0f);
	(*normals)[9] = osg::Vec3(-1.0f,  -0.0f,  0.0f);
	(*normals)[10] = osg::Vec3( 0.0f,  -0.928477f, 0.371391f);
	(*normals)[11] = osg::Vec3( 0.0f, 0.928477f, 0.371391f);
	(*normals)[12] = osg::Vec3( 0.707107f,  0.0f, 0.707107f);
	(*normals)[13] = osg::Vec3( 0.707107f,  0.0f, 0.707107f);
	(*normals)[14] = osg::Vec3(-0.707107f,  0.0f, 0.707107f);
	(*normals)[15] = osg::Vec3(-0.707107f,  0.0f, 0.707107f);

	// coordIndices
	osg::UByteArray* coordIndices = new osg::UByteArray(48,indices);

        // share the primtive set.
        osg::PrimitiveSet* primitives = new osg::DrawArrays(osg::PrimitiveSet::TRIANGLES,0,48);

	for (int q = 0; q < HOUSES_SIZE; q++)
	{
		float xPos = ((static_cast<double> (rand()) /
					  static_cast<double> (RAND_MAX))
					 * 2.0 * XDim) - XDim;

		float yPos = ((static_cast<double> (rand()) /
					  static_cast<double> (RAND_MAX))
					 * 2 * ZDim) - ZDim;

		float scale = 10.0f;
                
                osg::Vec3 offset(xPos,yPos,0.0f);

		// coords
		osg::Vec3Array* coords = new osg::Vec3Array(10);
		(*coords)[0] = osg::Vec3( 0.5f, -0.7f, 0.0f);
		(*coords)[1] = osg::Vec3( 0.5f,  0.7f, 0.0f);
		(*coords)[2] = osg::Vec3(-0.5f, 0.7f, 0.0f);
		(*coords)[3] = osg::Vec3(-0.5f, -0.7f, 0.0f);
		(*coords)[4] = osg::Vec3( 0.5f, -0.7f, 1.0f);
		(*coords)[5] = osg::Vec3( 0.5f,  0.7f, 1.0f);
		(*coords)[6] = osg::Vec3(-0.5f,  0.7f, 1.0f);
		(*coords)[7] = osg::Vec3(-0.5f, -0.7f, 1.0f);
		(*coords)[8] = osg::Vec3( 0.0f, -0.5f, 1.5f);
		(*coords)[9] = osg::Vec3( 0.0f,  0.5f, 1.5f);

		for (i = 0; i < 10; i++)
		{
			(*coords)[i] = (*coords)[i] * scale + offset;
		}


		// create geometry
		osg::Geometry * geometry = new osg::Geometry();
                
		geometry->addPrimitiveSet(primitives);
                
		geometry->setVertexArray(coords);
                geometry->setVertexIndices(coordIndices);
                
		geometry->setColorArray(colors);
		geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
                
		geometry->setNormalArray(normals);
		geometry->setNormalBinding(osg::Geometry::BIND_PER_PRIMITIVE);

		osg::Geode * geode = new osg::Geode();
		geode->addDrawable(geometry);
		
		nodes.push_back(geode);
	}
}

void LayoutAsGrid()
{
	// calculate bounding box
	osg::BoundingBox bbox;
	for (NodeIterator node = nodes.begin(); node != nodes.end(); ++node)
		bbox.expandBy((*node)->getBound());

	// setup grid information
	osg::Group ** groups = new osg::Group*[GridX * GridY];
        int i;
	for (i = 0; i < GridX * GridY; i++)
		groups[i] = new osg::Group();

	float xGridStart = bbox.xMin();
	float xGridSize = (bbox.xMax() - bbox.xMin()) / GridX;

	float yGridStart = bbox.yMin();
	float yGridSize = (bbox.yMax() - bbox.yMin()) / GridY;

	// arrange buildings into right grid
	for (NodeIterator nodeIter = nodes.begin(); nodeIter != nodes.end(); ++nodeIter)
	{
		osg::Node * node = nodeIter->get();
		osg::Vec3 center = node->getBound().center();
		
		int x = (int)floor((center.x() - xGridStart) / xGridSize);
		int z = (int)floor((center.y() - yGridStart) / yGridSize);

		groups[z * GridX + x]->addChild(node);
	}
 
	// add nodes to building root    
	for (i = 0; i < GridX * GridY; i++)
	{
		osg::StateSet * stateset = new osg::StateSet();

		osg::Material * material = new osg::Material();
		osg::Vec4 color = osg::Vec4(
			0.5f + (static_cast<double> (rand()) / (2.0*static_cast<double> (RAND_MAX))),
			0.5f + (static_cast<double> (rand()) / (2.0*static_cast<double> (RAND_MAX))),
			0.5f + (static_cast<double> (rand()) / ( 2.0*static_cast<double>(RAND_MAX))),
			1.0f);
			
		material->setAmbient(osg::Material::FRONT_AND_BACK, color);
		material->setDiffuse(osg::Material::FRONT_AND_BACK, color);
		stateset->setAttributeAndModes(material, osg::StateAttribute::ON);

		groups[i]->setStateSet(stateset);

		if (UseImpostor)
		{
			osg::Impostor * impostor = new osg::Impostor();
			impostor->setImpostorThreshold(static_cast<float> (Threshold));
			impostor->addChild(groups[i]);
			impostor->setRange(0, 0.0f, 1e7f);
			impostor->setCenter(groups[i]->getBound().center());
			Root->addChild(impostor);
		}
		else
		{
			Root->addChild(groups[i]);
		}
	}

	delete[] groups;
}


int main( int argc, char **argv )
{
    // use an ArgumentParser object to manage the program arguments.
    osg::ArgumentParser arguments(&argc,argv);

    // set up the usage document, in case we need to print out how to use this program.
    arguments.getApplicationUsage()->setDescription(arguments.getApplicationName()+" is the example which demonstrates use impostors - hierachical image cache.");
    arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+" [options] filename ...");
    arguments.getApplicationUsage()->addCommandLineOption("-h or --help","Display this information");

    // construct the viewer.
    osgProducer::Viewer viewer(arguments);

    // set up the value with sensible default event handlers.
    viewer.setUpViewer(osgProducer::Viewer::STANDARD_SETTINGS);
    
    // add local test manipulator more suitable for testing impostors.
    unsigned int pos = viewer.addCameraManipulator(new TestManipulator);
    viewer.selectCameraManipulator(pos);
    
    // get details on keyboard and mouse bindings used by the viewer.
    viewer.getUsage(*arguments.getApplicationUsage());

    // if user request help write it out to cout.
    if (arguments.read("-h") || arguments.read("--help"))
    {
        arguments.getApplicationUsage()->write(std::cout);
        return 1;
    }

    // any option left unread are converted into errors to write out later.
    arguments.reportRemainingOptionsAsUnrecognized();

    // report any errors if they have occured when parsing the program aguments.
    if (arguments.errors())
    {
        arguments.writeErrorMessages(std::cout);
        return 1;
    }


    // load the nodes from the commandline arguments.
    osg::Node* model = osgDB::readNodeFiles(arguments);
    if (model)
    {
        // the osgUtil::InsertImpostorsVisitor used lower down to insert impostors
        // only operators on subclass of Group's, if the model top node is not
        // a group then it won't be able to insert an impostor.  We therefore
        // manually insert an impostor above the model.
        if (dynamic_cast<osg::Group*>(model)==0)
        {
            const osg::BoundingSphere& bs = model->getBound();
            if (bs.valid())
            {

                osg::Impostor* impostor = new osg::Impostor;

                // standard LOD settings
                impostor->addChild(model);
                impostor->setRange(0,0.0f,1e7f);
                impostor->setCenter(bs.center());

                // impostor specfic settings.
                impostor->setImpostorThresholdToBound(5.0f);

                model = impostor;

            }
        }

        // we insert an impostor node above the model, so we keep a handle
        // on the rootnode of the model, the is required since the
        // InsertImpostorsVisitor can add a new root in automatically and
        // we would know about it, other than by following the parent path
        // up from model.  This is really what should be done, but I'll pass
        // on it right now as it requires a getRoots() method to be added to
        // osg::Node, and we're about to make a release so no new features! 
        osg::Group* rootnode = new osg::Group;
        rootnode->addChild(model);


        // now insert impostors in the model using the InsertImpostorsVisitor.
        osgUtil::InsertImpostorsVisitor ov;

        // traverse the model and collect all osg::Group's and osg::LOD's.
        // however, don't traverse the rootnode since we want to keep it as
        // the start of traversal, otherwise the insertImpostor could insert
        // and Impostor above the current root, making it nolonger a root!
        model->accept(ov);

        // insert the Impostors above groups and LOD's
        ov.insertImpostors();
    }
    else
    {
        // no user model so we'll create our own world.
	model = Root = new osg::Group();
	CreateHouses();
	LayoutAsGrid();
    }

    // add model to viewer.
    viewer.setSceneData(model);

    // register trackball, flight and drive.

    // create the windows and run the threads.
    viewer.realize();

    while( !viewer.done() )
    {
        // wait for all cull and draw threads to complete.
        viewer.sync();

        // update the scene by traversing it with the the update visitor which will
        // call all node update callbacks and animations.
        viewer.update();
         
        // fire off the cull and draw traversals of the scene.
        viewer.frame();
        
    }
    
    // wait for all cull and draw threads to complete.
    viewer.sync();
    

    return 0;
}