FilterContext
BuildGeometryFilter::push( FeatureList& input, const FilterContext& context )
{
    reset();

    OE_DEBUG << LC 
        << context.toString() << std::endl;

    bool ok = true;
    for( FeatureList::iterator i = input.begin(); i != input.end(); i++ )
        if ( !push( i->get(), context ) )
            ok = false;

    // In a feature class with one point-per-feature, you end up with one geometry per point,
    // which results is (a) very bad performance and (b) geometries with a zero bbox that therefore
    // don't draw. This is not a total solution (won't work for a single point, isn't friendly for
    // doing feature-selection, etc.) but is a workable temporary fix. In the future we're going
    // to replace this filter anyway with something more highly optimized (a la osgGIS).
    //
    // however...seems that MERGE_GEOMETRY destroys almost everything except for points!!
    if ( _mergeGeometry == true )
    {
        osgUtil::Optimizer optimizer;
        optimizer.optimize( _geode.get(), osgUtil::Optimizer::MERGE_GEOMETRY );
    }

    if ( ok )
    {
        if ( !_style.empty() && _geode.valid() )
        {
            // could optimize this to only happen is lines or points were created ..
            const LineSymbol* lineSymbol = _style.getSymbol<LineSymbol>();
            float size = 1.0;
            if (lineSymbol)
                size = lineSymbol->stroke()->width().value();

            _geode->getOrCreateStateSet()->setAttribute( new osg::Point(size), osg::StateAttribute::ON );
            _geode->getOrCreateStateSet()->setAttribute( new osg::LineWidth(size), osg::StateAttribute::ON );

            const PointSymbol* pointSymbol = _style.getSymbol<PointSymbol>();
            if ( pointSymbol && pointSymbol->size().isSet() )
                _geode->getOrCreateStateSet()->setAttribute( 
                    new osg::Point( *pointSymbol->size() ), osg::StateAttribute::ON );
        }

        _result = _geode.release();

        if ( context.hasReferenceFrame() )
        {
            osg::MatrixTransform* delocalizer = new osg::MatrixTransform( context.inverseReferenceFrame() );
            delocalizer->addChild( _result.get() );
            _result = delocalizer;
        }
    }
    else
    {
        _result = 0L;
    }

    FilterContext outCx( context );
    outCx.setReferenceFrame( osg::Matrixd::identity() ); // clear the ref frame.
    return outCx;
}