static void export_vrml_circle( MODEL_VRML& aModel, LAYER_NUM layer,
        double startx, double starty,
        double endx, double endy, double width )
{
    VRML_LAYER* vlayer;

    if( !GetLayer( aModel, layer, &vlayer ) )
        return;

    if( width < aModel.minLineWidth )
        width = aModel.minLineWidth;

    starty = -starty;
    endy = -endy;

    double hole, radius;

    radius = Distance( startx, starty, endx, endy ) + ( width / 2);
    hole = radius - width;

    if( !vlayer->AddCircle( startx, starty, radius, false ) )
        throw( std::runtime_error( vlayer->GetError() ) );

    if( hole > 0.0001 )
    {
        if( !vlayer->AddCircle( startx, starty, hole, true ) )
            throw( std::runtime_error( vlayer->GetError() ) );
    }
}
static void export_vrml_zones( MODEL_VRML& aModel, BOARD* aPcb )
{

    double scale = aModel.scale;
    double x, y;

    for( int ii = 0; ii < aPcb->GetAreaCount(); ii++ )
    {
        ZONE_CONTAINER* zone = aPcb->GetArea( ii );

        VRML_LAYER* vl;

        if( !GetLayer( aModel, zone->GetLayer(), &vl ) )
            continue;

        if( !zone->IsFilled() )
        {
            zone->SetFillMode( 0 ); // use filled polygons
            zone->BuildFilledSolidAreasPolygons( aPcb );
        }
        const CPOLYGONS_LIST& poly = zone->GetFilledPolysList();

        int nvert = poly.GetCornersCount();
        int i = 0;

        while( i < nvert )
        {
            int seg = vl->NewContour();
            bool first = true;

            if( seg < 0 )
                break;

            while( i < nvert )
            {
                x = poly.GetX(i) * scale;
                y = -(poly.GetY(i) * scale);

                if( poly.IsEndContour(i) )
                    break;

                if( !vl->AddVertex( seg, x, y ) )
                    throw( std::runtime_error( vl->GetError() ) );

                ++i;
            }

            // KiCad ensures that the first polygon is the outline
            // and all others are holes
             vl->EnsureWinding( seg, first ? false : true );

            if( first )
                first = false;

            ++i;
        }
    }
}
static void export_vrml_arc( MODEL_VRML& aModel, LAYER_NUM layer,
                             double centerx, double centery,
                             double arc_startx, double arc_starty,
                             double width, double arc_angle )
{
    VRML_LAYER* vlayer;

    if( !GetLayer( aModel, layer, &vlayer ) )
        return;

    if( width < aModel.minLineWidth )
        width = aModel.minLineWidth;

    centery = -centery;
    arc_starty = -arc_starty;

    if( !vlayer->AddArc( centerx, centery, arc_startx, arc_starty, width, arc_angle, false ) )
        throw( std::runtime_error( vlayer->GetError() ) );

}
static void export_vrml_line( MODEL_VRML& aModel, LAYER_NUM layer,
        double startx, double starty,
        double endx, double endy, double width )
{
    VRML_LAYER* vlayer;

    if( !GetLayer( aModel, layer, &vlayer ) )
        return;

    if( width < aModel.minLineWidth)
        width = aModel.minLineWidth;

    starty = -starty;
    endy = -endy;

    double  angle   = atan2( endy - starty, endx - startx ) * 180.0 / M_PI;
    double  length  = Distance( startx, starty, endx, endy ) + width;
    double  cx  = ( startx + endx ) / 2.0;
    double  cy  = ( starty + endy ) / 2.0;

    if( !vlayer->AddSlot( cx, cy, length, width, angle, false ) )
        throw( std::runtime_error( vlayer->GetError() ) );
}
static void export_vrml_edge_module( MODEL_VRML& aModel, EDGE_MODULE* aOutline,
                                     double aOrientation )
{
    LAYER_NUM layer = aOutline->GetLayer();
    double  x   = aOutline->GetStart().x * aModel.scale;
    double  y   = aOutline->GetStart().y * aModel.scale;
    double  xf  = aOutline->GetEnd().x * aModel.scale;
    double  yf  = aOutline->GetEnd().y * aModel.scale;
    double  w   = aOutline->GetWidth() * aModel.scale;

    switch( aOutline->GetShape() )
    {
    case S_SEGMENT:
        export_vrml_line( aModel, layer, x, y, xf, yf, w );
        break;

    case S_ARC:
        export_vrml_arc( aModel, layer, x, y, xf, yf, w, aOutline->GetAngle() / 10 );
        break;

    case S_CIRCLE:
        export_vrml_circle( aModel, layer, x, y, xf, yf, w );
        break;

    case S_POLYGON:
        {
            VRML_LAYER* vl;

            if( !GetLayer( aModel, layer, &vl ) )
                break;

            int nvert = aOutline->GetPolyPoints().size() - 1;
            int i = 0;

            if( nvert < 3 ) break;

            int seg = vl->NewContour();

            if( seg < 0 )
                break;

            while( i < nvert )
            {
                CPolyPt corner( aOutline->GetPolyPoints()[i] );
                RotatePoint( &corner.x, &corner.y, aOrientation );
                corner.x += aOutline->GetPosition().x;
                corner.y += aOutline->GetPosition().y;

                x = corner.x * aModel.scale;
                y = - ( corner.y * aModel.scale );

                if( !vl->AddVertex( seg, x, y ) )
                    throw( std::runtime_error( vl->GetError() ) );

                ++i;
            }
            vl->EnsureWinding( seg, false );
        }
        break;

    default:
        break;
    }
}