source: experimental/TerrainTest/ReaderWriterTerrainMod.cpp

#include "ReaderWriterTerrainMod.h"
#include <osg/KdTree>

ReaderWriterTerrainMod::ReaderWriterTerrainMod()
{
        supportsExtension( "terrainmod", "Terrain modification pseudo loader");
        //supportsExtension( "*", "Terrain modification pseudo loader");


        extensionToAdd = ".terrainmod";
}

ReaderWriterTerrainMod::ReadResult ReaderWriterTerrainMod::readNode( const std::string& file, const osgDB::ReaderWriter::Options* options) const
{
        // Check if its a valid file for this pseudo loader
        std::string ext = osgDB::getLowerCaseFileExtension( file );
        if( !acceptsExtension(ext) )
                return ReadResult::FILE_NOT_HANDLED;

        // Strip the pseudo-loader extension
    std::string realName = osgDB::getNameLessExtension( file );

        // check if stripped file exists
        std::string fileName = osgDB::findDataFile( realName, options );
        if( fileName.empty() )
                return ReadResult::FILE_NOT_FOUND;

        // Check and postphone KdTree creation
        bool doKdTreeBuilder = (options && options->getBuildKdTreesHint()!=Options::NO_PREFERENCE) ?
                options->getBuildKdTreesHint() == Options::BUILD_KDTREES :
                                osgDB::Registry::instance()->getBuildKdTreesHint() == Options::BUILD_KDTREES;
        // If options are available: Save it'S original KdTree Hint.
        Options::BuildKdTreesHint originalHint = Options::NO_PREFERENCE;
        if(options)
        {
                originalHint = options->getBuildKdTreesHint();
                const_cast<osgDB::ReaderWriter::Options*>(options)->setBuildKdTreesHint(Options::DO_NOT_BUILD_KDTREES);
        }

        // Load real file
        osg::Node *node = osgDB::readNodeFile( fileName, options );
    if( !node )
    {
        // propagate the read failure upwards
        OSG_WARN << "Subfile \"" << fileName << "\" could not be loaded" << std::endl;
        return ReadResult::FILE_NOT_HANDLED;
    }

        // Traverse through loaded graph and
        // a) check for PagedLOD and modify all filenames of external references
        // b) modify tile if it is inside a modification ROI
        // This ensures ensures that higher LODs are loaded via terrainmod pseudo loader as well.
        ModificationVisitor modVisitor(extensionToAdd);
        node->accept( modVisitor );

        // Finally create KdTree and restore options
        if(doKdTreeBuilder)
        {
                osg::ref_ptr<osg::KdTreeBuilder> builder = osgDB::Registry::instance()->getKdTreeBuilder();
                node->accept(*builder);
        }
        // Restore original KdTree Hint
        if(options) const_cast<osgDB::ReaderWriter::Options*>(options)->setBuildKdTreesHint(originalHint);

        return node;
}

// Add ourself to the Registry to instantiate the reader/writer.
REGISTER_OSGPLUGIN(terrainmod, ReaderWriterTerrainMod)