Merge pull request #6 from saurabhb17/master

minor additions

1 files changed, 1788 insertions, 0 deletions

diff --git a/utils/idftools/vrml_layer.cpp b/utils/idftools/vrml_layer.cpp
new file mode 100644
index 0000000..5974371
--- /dev/null
+++ b/utils/idftools/vrml_layer.cpp
@@ -0,0 +1,1788 @@
+/*
+ * file: vrml_layer.cpp
+ *
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2013  Cirilo Bernardo
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+// Wishlist:
+// 1. crop anything outside the board outline on PTH, silk, and copper layers
+// 2. on the PTH layer, handle cropped holes differently from others;
+//    these are assumed to be castellated edges and the profile is not
+//    a closed loop as assumed for all other outlines.
+// 3. a scheme is needed to tell a castellated edge from a plain board edge
+
+
+#include <sstream>
+#include <string>
+#include <iomanip>
+#include <cmath>
+#include <vrml_layer.h>
+
+#ifndef CALLBACK
+#define CALLBACK
+#endif
+
+#define GLCALLBACK(x) (( void (CALLBACK*)() )&(x))
+
+// minimum sides to a circle
+#define MIN_NSIDES 6
+
+static void FormatDoublet( double x, double y, int precision, std::string& strx, std::string& stry )
+{
+    std::ostringstream ostr;
+
+    ostr << std::fixed << std::setprecision( precision );
+
+    ostr << x;
+    strx = ostr.str();
+
+    ostr.str( "" );
+    ostr << y;
+    stry = ostr.str();
+
+    while( *strx.rbegin() == '0' )
+        strx.erase( strx.size() - 1 );
+
+    while( *stry.rbegin() == '0' )
+        stry.erase( stry.size() - 1 );
+}
+
+
+static void FormatSinglet( double x, int precision, std::string& strx )
+{
+    std::ostringstream ostr;
+
+    ostr << std::fixed << std::setprecision( precision );
+
+    ostr << x;
+    strx = ostr.str();
+
+    while( *strx.rbegin() == '0' )
+        strx.erase( strx.size() - 1 );
+}
+
+
+int VRML_LAYER::calcNSides( double aRadius, double aAngle )
+{
+    // check #segments on ends of arc
+    int maxSeg = maxArcSeg * aAngle / M_PI;
+
+    if( maxSeg < 3 )
+        maxSeg = 3;
+
+    int csides = aRadius * M_PI / minSegLength;
+
+    if( csides < 0 )
+        csides = -csides;
+
+    if( csides > maxSeg )
+    {
+        if( csides < 2 * maxSeg )
+            csides /= 2;
+        else
+            csides = (((double) csides) * minSegLength / maxSegLength );
+    }
+
+    if( csides < 3 )
+        csides = 3;
+
+    if( (csides & 1) == 0 )
+        csides += 1;
+
+    return csides;
+}
+
+
+static void CALLBACK vrml_tess_begin( GLenum cmd, void* user_data )
+{
+    VRML_LAYER* lp = (VRML_LAYER*) user_data;
+
+    lp->glStart( cmd );
+}
+
+
+static void CALLBACK vrml_tess_end( void* user_data )
+{
+    VRML_LAYER* lp = (VRML_LAYER*) user_data;
+
+    lp->glEnd();
+}
+
+
+static void CALLBACK vrml_tess_vertex( void* vertex_data, void* user_data )
+{
+    VRML_LAYER* lp = (VRML_LAYER*) user_data;
+
+    lp->glPushVertex( (VERTEX_3D*) vertex_data );
+}
+
+
+static void CALLBACK vrml_tess_err( GLenum errorID, void* user_data )
+{
+    VRML_LAYER* lp = (VRML_LAYER*) user_data;
+
+    lp->Fault = true;
+    lp->SetGLError( errorID );
+}
+
+
+static void CALLBACK vrml_tess_combine( GLdouble coords[3], VERTEX_3D* vertex_data[4],
+        GLfloat weight[4], void** outData, void* user_data )
+{
+    VRML_LAYER* lp = (VRML_LAYER*) user_data;
+
+    // the plating is set to true only if all are plated
+    bool plated = vertex_data[0]->pth;
+
+    if( !vertex_data[1]->pth )
+        plated = false;
+
+    if( vertex_data[2] && !vertex_data[2]->pth )
+        plated = false;
+
+    if( vertex_data[3] && !vertex_data[3]->pth )
+        plated = false;
+
+    *outData = lp->AddExtraVertex( coords[0], coords[1], plated );
+}
+
+
+VRML_LAYER::VRML_LAYER()
+{
+    // arc parameters suitable to mm measurements
+    maxArcSeg = 48;
+    minSegLength = 0.1;
+    maxSegLength = 0.5;
+    offsetX = 0.0;
+    offsetY = 0.0;
+
+    fix = false;
+    Fault = false;
+    idx = 0;
+    hidx = 0;
+    eidx = 0;
+    ord = 0;
+    glcmd   = 0;
+    pholes  = NULL;
+
+    tess = gluNewTess();
+
+    if( !tess )
+        return;
+
+    // set up the tesselator callbacks
+    gluTessCallback( tess, GLU_TESS_BEGIN_DATA, GLCALLBACK( vrml_tess_begin ) );
+
+    gluTessCallback( tess, GLU_TESS_VERTEX_DATA, GLCALLBACK( vrml_tess_vertex ) );
+
+    gluTessCallback( tess, GLU_TESS_END_DATA, GLCALLBACK( vrml_tess_end ) );
+
+    gluTessCallback( tess, GLU_TESS_ERROR_DATA, GLCALLBACK( vrml_tess_err ) );
+
+    gluTessCallback( tess, GLU_TESS_COMBINE_DATA, GLCALLBACK( vrml_tess_combine ) );
+
+    gluTessProperty( tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_POSITIVE );
+
+    gluTessNormal( tess, 0, 0, 1 );
+}
+
+
+VRML_LAYER::~VRML_LAYER()
+{
+    Clear();
+
+    if( tess )
+    {
+        gluDeleteTess( tess );
+        tess = NULL;
+    }
+}
+
+
+void VRML_LAYER::GetArcParams( int& aMaxSeg, double& aMinLength, double& aMaxLength )
+{
+    aMaxSeg = maxArcSeg;
+    aMinLength = minSegLength;
+    aMaxLength = maxSegLength;
+}
+
+bool VRML_LAYER::SetArcParams( int aMaxSeg, double aMinLength, double aMaxLength )
+{
+    if( aMaxSeg < 8 )
+        aMaxSeg = 8;
+
+    if( aMinLength <= 0 || aMaxLength <= aMinLength )
+        return false;
+
+    maxArcSeg = aMaxSeg;
+    minSegLength = aMinLength;
+    maxSegLength = aMaxLength;
+    return true;
+}
+
+
+// clear all data
+void VRML_LAYER::Clear( void )
+{
+    int i;
+
+    fix = false;
+    idx = 0;
+
+    for( i = contours.size(); i > 0; --i )
+    {
+        delete contours.back();
+        contours.pop_back();
+    }
+
+    pth.clear();
+
+    areas.clear();
+
+    for( i = vertices.size(); i > 0; --i )
+    {
+        delete vertices.back();
+        vertices.pop_back();
+    }
+
+    clearTmp();
+}
+
+
+// clear ephemeral data in between invocations of the tesselation routine
+void VRML_LAYER::clearTmp( void )
+{
+    unsigned int i;
+
+    Fault   = false;
+    hidx    = 0;
+    eidx    = 0;
+    ord = 0;
+    glcmd = 0;
+
+    triplets.clear();
+    solid.clear();
+
+    for( i = outline.size(); i > 0; --i )
+    {
+        delete outline.back();
+        outline.pop_back();
+    }
+
+    ordmap.clear();
+
+    for( i = extra_verts.size(); i > 0; --i )
+    {
+        delete extra_verts.back();
+        extra_verts.pop_back();
+    }
+
+    // note: unlike outline and extra_verts,
+    // vlist is not responsible for memory management
+    vlist.clear();
+
+    // go through the vertex list and reset ephemeral parameters
+    for( i = 0; i < vertices.size(); ++i )
+    {
+        vertices[i]->o = -1;
+    }
+}
+
+
+// create a new contour to be populated; returns an index
+// into the contour list or -1 if there are problems
+int VRML_LAYER::NewContour(  bool aPlatedHole )
+{
+    if( fix )
+        return -1;
+
+    std::list<int>* contour = new std::list<int>;
+
+    if( !contour )
+        return -1;
+
+    contours.push_back( contour );
+    areas.push_back( 0.0 );
+
+    pth.push_back( aPlatedHole );
+
+    return contours.size() - 1;
+}
+
+
+// adds a vertex to the existing list and places its index in
+// an existing contour; returns true if OK,
+// false otherwise (indexed contour does not exist)
+bool VRML_LAYER::AddVertex( int aContourID, double aXpos, double aYpos )
+{
+    if( fix )
+    {
+        error = "AddVertex(): no more vertices may be added (Tesselate was previously executed)";
+        return false;
+    }
+
+    if( aContourID < 0 || (unsigned int) aContourID >= contours.size() )
+    {
+        error = "AddVertex(): aContour is not within a valid range";
+        return false;
+    }
+
+    VERTEX_3D* vertex = new VERTEX_3D;
+
+    if( !vertex )
+    {
+        error = "AddVertex(): a new vertex could not be allocated";
+        return false;
+    }
+
+    vertex->x   = aXpos;
+    vertex->y   = aYpos;
+    vertex->i   = idx++;
+    vertex->o   = -1;
+    vertex->pth = pth[ aContourID ];
+
+    VERTEX_3D* v2 = NULL;
+
+    if( contours[aContourID]->size() > 0 )
+        v2 = vertices[ contours[aContourID]->back() ];
+
+    vertices.push_back( vertex );
+    contours[aContourID]->push_back( vertex->i );
+
+    if( v2 )
+        areas[aContourID] += ( aXpos - v2->x ) * ( aYpos + v2->y );
+
+    return true;
+}
+
+
+// ensure the winding of a contour with respect to the normal (0, 0, 1);
+// set 'hole' to true to ensure a hole (clockwise winding)
+bool VRML_LAYER::EnsureWinding( int aContourID, bool aHoleFlag )
+{
+    if( aContourID < 0 || (unsigned int) aContourID >= contours.size() )
+    {
+        error = "EnsureWinding(): aContour is outside the valid range";
+        return false;
+    }
+
+    std::list<int>* cp = contours[aContourID];
+
+    if( cp->size() < 3 )
+    {
+        error = "EnsureWinding(): there are fewer than 3 vertices";
+        return false;
+    }
+
+    double dir = areas[aContourID];
+
+    VERTEX_3D* vp0 = vertices[ cp->back() ];
+    VERTEX_3D* vp1 = vertices[ cp->front() ];
+
+    dir += ( vp1->x - vp0->x ) * ( vp1->y + vp0->y );
+
+    // if dir is positive, winding is CW
+    if( ( aHoleFlag && dir < 0 ) || ( !aHoleFlag && dir > 0 ) )
+    {
+        cp->reverse();
+        areas[aContourID] = -areas[aContourID];
+    }
+
+    return true;
+}
+
+
+bool VRML_LAYER::AppendCircle( double aXpos, double aYpos,
+                               double aRadius, int aContourID,
+                               bool aHoleFlag )
+{
+    if( aContourID < 0 || (unsigned int) aContourID >= contours.size() )
+    {
+        error = "AppendCircle(): invalid contour (out of range)";
+        return false;
+    }
+
+    int nsides = M_PI * 2.0 * aRadius / minSegLength;
+
+    if( nsides > maxArcSeg )
+    {
+        if( nsides > 2 * maxArcSeg )
+        {
+            // use segments approx. maxAr
+            nsides = M_PI * 2.0 * aRadius / maxSegLength;
+        }
+        else
+        {
+            nsides /= 2;
+        }
+    }
+
+    if( nsides < MIN_NSIDES )
+        nsides = MIN_NSIDES;
+
+    // even numbers give prettier results for circles
+    if( nsides & 1 )
+        nsides += 1;
+
+    double da = M_PI * 2.0 / nsides;
+
+    bool fail = false;
+
+    if( aHoleFlag )
+    {
+        fail |= !AddVertex( aContourID, aXpos + aRadius, aYpos );
+
+        for( double angle = da; angle < M_PI * 2; angle += da )
+            fail |= !AddVertex( aContourID, aXpos + aRadius * cos( angle ),
+                                aYpos - aRadius * sin( angle ) );
+    }
+    else
+    {
+        fail |= !AddVertex( aContourID, aXpos + aRadius, aYpos );
+
+        for( double angle = da; angle < M_PI * 2; angle += da )
+            fail |= !AddVertex( aContourID, aXpos + aRadius * cos( angle ),
+                                aYpos + aRadius * sin( angle ) );
+    }
+
+    return !fail;
+}
+
+
+// adds a circle the existing list; if 'hole' is true the contour is
+// a hole. Returns true if OK.
+bool VRML_LAYER::AddCircle( double aXpos, double aYpos, double aRadius,
+                            bool aHoleFlag, bool aPlatedHole )
+{
+    int pad;
+
+    if( aHoleFlag && aPlatedHole )
+        pad = NewContour( true );
+    else
+        pad = NewContour( false );
+
+    if( pad < 0 )
+    {
+        error = "AddCircle(): failed to add a contour";
+        return false;
+    }
+
+    return AppendCircle( aXpos, aYpos, aRadius, pad, aHoleFlag );
+}
+
+
+// adds a slotted pad with orientation given by angle; if 'hole' is true the
+// contour is a hole. Returns true if OK.
+bool VRML_LAYER::AddSlot( double aCenterX, double aCenterY,
+                          double aSlotLength, double aSlotWidth,
+                          double aAngle, bool aHoleFlag, bool aPlatedHole )
+{
+    aAngle *= M_PI / 180.0;
+
+    if( aSlotWidth > aSlotLength )
+    {
+        aAngle += M_PI2;
+        std::swap( aSlotLength, aSlotWidth );
+    }
+
+    aSlotWidth /= 2.0;
+    aSlotLength = aSlotLength / 2.0 - aSlotWidth;
+
+    int csides = calcNSides( aSlotWidth, M_PI );
+
+    double capx, capy;
+
+    capx    = aCenterX + cos( aAngle ) * aSlotLength;
+    capy    = aCenterY + sin( aAngle ) * aSlotLength;
+
+    double ang, da;
+    int i;
+    int pad;
+
+    if( aHoleFlag && aPlatedHole )
+        pad = NewContour( true );
+    else
+        pad = NewContour( false );
+
+    if( pad < 0 )
+    {
+        error = "AddCircle(): failed to add a contour";
+        return false;
+    }
+
+    da = M_PI / csides;
+    bool fail = false;
+
+    if( aHoleFlag )
+    {
+        for( ang = aAngle + M_PI2, i = 0; i < csides; ang -= da, ++i )
+            fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                                capy + aSlotWidth * sin( ang ) );
+
+        ang = aAngle - M_PI2;
+        fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                            capy + aSlotWidth * sin( ang ) );
+
+        capx    = aCenterX - cos( aAngle ) * aSlotLength;
+        capy    = aCenterY - sin( aAngle ) * aSlotLength;
+
+        for( ang = aAngle - M_PI2, i = 0; i < csides; ang -= da, ++i )
+            fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                                capy + aSlotWidth * sin( ang ) );
+
+        ang = aAngle + M_PI2;
+        fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                            capy + aSlotWidth * sin( ang ) );
+    }
+    else
+    {
+        for( ang = aAngle - M_PI2, i = 0; i < csides; ang += da, ++i )
+            fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                                capy + aSlotWidth * sin( ang ) );
+
+        ang = aAngle + M_PI2;
+        fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                            capy + aSlotWidth * sin( ang ) );
+
+        capx    = aCenterX - cos( aAngle ) * aSlotLength;
+        capy    = aCenterY - sin( aAngle ) * aSlotLength;
+
+        for( ang = aAngle + M_PI2, i = 0; i < csides; ang += da, ++i )
+            fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                                capy + aSlotWidth * sin( ang ) );
+
+        ang = aAngle - M_PI2;
+        fail |= !AddVertex( pad, capx + aSlotWidth * cos( ang ),
+                            capy + aSlotWidth * sin( ang ) );
+    }
+
+    return !fail;
+}
+
+
+// adds an arc to the given center, start point, pen width, and angle (degrees).
+bool VRML_LAYER::AppendArc( double aCenterX, double aCenterY, double aRadius,
+                            double aStartAngle, double aAngle, int aContourID )
+{
+    if( aContourID < 0 || (unsigned int) aContourID >= contours.size() )
+    {
+        error = "AppendArc(): invalid contour (out of range)";
+        return false;
+    }
+
+    aAngle = aAngle / 180.0 * M_PI;
+    aStartAngle = aStartAngle / 180.0 * M_PI;
+
+    int nsides = calcNSides( aRadius, aAngle );
+
+    double da = aAngle / nsides;
+
+    bool fail = false;
+
+    if( aAngle > 0 )
+    {
+        aAngle += aStartAngle;
+        for( double ang = aStartAngle; ang < aAngle; ang += da )
+            fail |= !AddVertex( aContourID, aCenterX + aRadius * cos( ang ),
+                                aCenterY + aRadius * sin( ang ) );
+    }
+    else
+    {
+        aAngle += aStartAngle;
+        for( double ang = aStartAngle; ang > aAngle; ang += da )
+            fail |= !AddVertex( aContourID, aCenterX + aRadius * cos( ang ),
+                                aCenterY + aRadius * sin( ang ) );
+    }
+
+    return !fail;
+}
+
+
+// adds an arc with the given center, start point, pen width, and angle (degrees).
+bool VRML_LAYER::AddArc( double aCenterX, double aCenterY, double aStartX, double aStartY,
+                         double aArcWidth, double aAngle, bool aHoleFlag, bool aPlatedHole )
+{
+    aAngle *= M_PI / 180.0;
+
+    // we don't accept small angles; in fact, 1 degree ( 0.01745 ) is already
+    // way too small but we must set a limit somewhere
+    if( aAngle < 0.01745 && aAngle > -0.01745 )
+    {
+        error = "AddArc(): angle is too small: abs( angle ) < 1 degree";
+        return false;
+    }
+
+    double rad = sqrt( (aStartX - aCenterX) * (aStartX - aCenterX)
+                        + (aStartY - aCenterY) * (aStartY - aCenterY) );
+
+    aArcWidth /= 2.0;    // this is the radius of the caps
+
+    // we will not accept an arc with an inner radius close to zero so we
+    // set a limit here. the end result will vary somewhat depending on
+    // the output units
+    if( aArcWidth >= ( rad * 1.01 ) )
+    {
+        error = "AddArc(): width/2 exceeds radius*1.01";
+        return false;
+    }
+
+    // calculate the radii of the outer and inner arcs
+    double  orad    = rad + aArcWidth;
+    double  irad    = rad - aArcWidth;
+
+    int osides  = calcNSides( orad, aAngle );
+    int isides  = calcNSides( irad, aAngle );
+    int csides  = calcNSides( aArcWidth, M_PI );
+
+    double  stAngle     = atan2( aStartY - aCenterY, aStartX - aCenterX );
+    double  endAngle    = stAngle + aAngle;
+
+    // calculate ends of inner and outer arc
+    double  oendx   = aCenterX + orad* cos( endAngle );
+    double  oendy   = aCenterY + orad* sin( endAngle );
+    double  ostx    = aCenterX + orad* cos( stAngle );
+    double  osty    = aCenterY + orad* sin( stAngle );
+
+    double  iendx   = aCenterX + irad* cos( endAngle );
+    double  iendy   = aCenterY + irad* sin( endAngle );
+    double  istx    = aCenterX + irad* cos( stAngle );
+    double  isty    = aCenterY + irad* sin( stAngle );
+
+    if( ( aAngle < 0 && !aHoleFlag ) || ( aAngle > 0 && aHoleFlag ) )
+    {
+        aAngle = -aAngle;
+        std::swap( stAngle, endAngle );
+        std::swap( oendx, ostx );
+        std::swap( oendy, osty );
+        std::swap( iendx, istx );
+        std::swap( iendy, isty );
+    }
+
+    int arc;
+
+    if( aHoleFlag && aPlatedHole )
+        arc = NewContour( true );
+    else
+        arc = NewContour( false );
+
+    if( arc < 0 )
+    {
+        error = "AddArc(): could not create a contour";
+        return false;
+    }
+
+    // trace the outer arc:
+    int i;
+    double  ang;
+    double  da = aAngle / osides;
+
+    for( ang = stAngle, i = 0; i < osides; ang += da, ++i )
+        AddVertex( arc, aCenterX + orad * cos( ang ), aCenterY + orad * sin( ang ) );
+
+    // trace the first cap
+    double  capx    = ( iendx + oendx ) / 2.0;
+    double  capy    = ( iendy + oendy ) / 2.0;
+
+    if( aHoleFlag )
+        da = -M_PI / csides;
+    else
+        da = M_PI / csides;
+
+    for( ang = endAngle, i = 0; i < csides; ang += da, ++i )
+        AddVertex( arc, capx + aArcWidth * cos( ang ), capy + aArcWidth * sin( ang ) );
+
+    // trace the inner arc:
+    da = -aAngle / isides;
+
+    for( ang = endAngle, i = 0; i < isides; ang += da, ++i )
+        AddVertex( arc, aCenterX + irad * cos( ang ), aCenterY + irad * sin( ang ) );
+
+    // trace the final cap
+    capx    = ( istx + ostx ) / 2.0;
+    capy    = ( isty + osty ) / 2.0;
+
+    if( aHoleFlag )
+        da = -M_PI / csides;
+    else
+        da = M_PI / csides;
+
+    for( ang = stAngle + M_PI, i = 0; i < csides; ang += da, ++i )
+        AddVertex( arc, capx + aArcWidth * cos( ang ), capy + aArcWidth * sin( ang ) );
+
+    return true;
+}
+
+
+// tesselates the contours in preparation for a 3D output;
+// returns true if all was fine, false otherwise
+bool VRML_LAYER::Tesselate( VRML_LAYER* holes, bool aHolesOnly )
+{
+    if( !tess )
+    {
+        error = "Tesselate(): GLU tesselator was not initialized";
+        return false;
+    }
+
+    pholes  = holes;
+    Fault   = false;
+
+    if( aHolesOnly )
+        gluTessProperty( tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_NEGATIVE );
+    else
+        gluTessProperty( tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_POSITIVE );
+
+
+    if( contours.size() < 1 || vertices.size() < 3 )
+    {
+        error = "Tesselate(): not enough vertices";
+        return false;
+    }
+
+    // finish the winding calculation on all vertices prior to setting 'fix'
+    if( !fix )
+    {
+        for( unsigned int i = 0; i < contours.size(); ++i )
+        {
+            if( contours[i]->size() < 3 )
+                continue;
+
+            VERTEX_3D* vp0 = vertices[ contours[i]->back() ];
+            VERTEX_3D* vp1 = vertices[ contours[i]->front() ];
+            areas[i] += ( vp1->x - vp0->x ) * ( vp1->y + vp0->y );
+        }
+    }
+
+    // prevent the addition of any further contours and contour vertices
+    fix = true;
+
+    // clear temporary internals which may have been used in a previous run
+    clearTmp();
+
+    // request an outline
+    gluTessProperty( tess, GLU_TESS_BOUNDARY_ONLY, GL_TRUE );
+
+    // adjust internal indices for extra points and holes
+    if( holes )
+        hidx = holes->GetSize();
+    else
+        hidx = 0;
+
+    eidx = idx + hidx;
+
+    if( aHolesOnly && ( checkNContours( true ) == 0 ) )
+    {
+        error = "tesselate(): no hole contours";
+        return false;
+    }
+    else if( !aHolesOnly && ( checkNContours( false ) == 0 ) )
+    {
+        error = "tesselate(): no solid contours";
+        return false;
+    }
+
+    // open the polygon
+    gluTessBeginPolygon( tess, this );
+
+    if( aHolesOnly )
+    {
+        pholes = NULL;  // do not accept foreign holes
+        hidx = 0;
+        eidx = idx;
+
+        // add holes
+        pushVertices( true );
+
+        gluTessEndPolygon( tess );
+
+        if( Fault )
+            return false;
+
+        return true;
+    }
+
+    // add solid outlines
+    pushVertices( false );
+
+    // close the polygon
+    gluTessEndPolygon( tess );
+
+    if( Fault )
+        return false;
+
+    // if there are no outlines we cannot proceed
+    if( outline.empty() )
+    {
+        error = "tesselate(): no points in result";
+        return false;
+    }
+
+    // at this point we have a solid outline; add it to the tesselator
+    gluTessBeginPolygon( tess, this );
+
+    if( !pushOutline( NULL ) )
+        return false;
+
+    // add the holes contained by this object
+    pushVertices( true );
+
+    // import external holes (if any)
+    if( hidx && ( holes->Import( idx, tess ) < 0 ) )
+    {
+        std::ostringstream ostr;
+        ostr << "Tesselate():FAILED: " << holes->GetError();
+        error = ostr.str();
+        return false;
+    }
+
+    if( Fault )
+        return false;
+
+    // erase the previous outline data and vertex order
+    // but preserve the extra vertices
+    while( !outline.empty() )
+    {
+        delete outline.back();
+        outline.pop_back();
+    }
+
+    ordmap.clear();
+    ord = 0;
+
+    // go through the vertex lists and reset ephemeral parameters
+    for( unsigned int i = 0; i < vertices.size(); ++i )
+    {
+        vertices[i]->o = -1;
+    }
+
+    for( unsigned int i = 0; i < extra_verts.size(); ++i )
+    {
+        extra_verts[i]->o = -1;
+    }
+
+    // close the polygon; this creates the outline points
+    // and the point ordering list 'ordmap'
+    solid.clear();
+    gluTessEndPolygon( tess );
+
+    // repeat the last operation but request a tesselated surface
+    // rather than an outline; this creates the triangles list.
+    gluTessProperty( tess, GLU_TESS_BOUNDARY_ONLY, GL_FALSE );
+
+    gluTessBeginPolygon( tess, this );
+
+    if( !pushOutline( holes ) )
+        return false;
+
+    gluTessEndPolygon( tess );
+
+    if( Fault )
+        return false;
+
+    return true;
+}
+
+
+bool VRML_LAYER::pushOutline( VRML_LAYER* holes )
+{
+    // traverse the outline list to push all used vertices
+    if( outline.size() < 1 )
+    {
+        error = "pushOutline() failed: no vertices to push";
+        return false;
+    }
+
+    std::list<std::list<int>*>::const_iterator obeg = outline.begin();
+    std::list<std::list<int>*>::const_iterator oend = outline.end();
+
+    int nc = 0; // number of contours pushed
+
+    int pi;
+    std::list<int>::const_iterator  begin;
+    std::list<int>::const_iterator  end;
+    GLdouble pt[3];
+    VERTEX_3D* vp;
+
+    while( obeg != oend )
+    {
+        if( (*obeg)->size() < 3 )
+        {
+            ++obeg;
+            continue;
+        }
+
+        gluTessBeginContour( tess );
+
+        begin = (*obeg)->begin();
+        end = (*obeg)->end();
+
+        while( begin != end )
+        {
+            pi = *begin;
+
+            if( pi < 0 || (unsigned int) pi > ordmap.size() )
+            {
+                gluTessEndContour( tess );
+                error = "pushOutline():BUG: *outline.begin() is not a valid index to ordmap";
+                return false;
+            }
+
+            // retrieve the actual index
+            pi = ordmap[pi];
+
+            vp = getVertexByIndex( pi, holes );
+
+            if( !vp )
+            {
+                gluTessEndContour( tess );
+                error = "pushOutline():: BUG: ordmap[n] is not a valid index to vertices[]";
+                return false;
+            }
+
+            pt[0]   = vp->x;
+            pt[1]   = vp->y;
+            pt[2]   = 0.0;
+            gluTessVertex( tess, pt, vp );
+            ++begin;
+        }
+
+        gluTessEndContour( tess );
+        ++obeg;
+        ++nc;
+    }
+
+    if( !nc )
+    {
+        error = "pushOutline():: no valid contours available";
+        return false;
+    }
+
+    return true;
+}
+
+
+// writes out the vertex list for a planar feature
+bool VRML_LAYER::WriteVertices( double aZcoord, std::ofstream& aOutFile, int aPrecision )
+{
+    if( ordmap.size() < 3 )
+    {
+        error = "WriteVertices(): not enough vertices";
+        return false;
+    }
+
+    if( aPrecision < 4 )
+        aPrecision = 4;
+
+    int i, j;
+
+    VERTEX_3D* vp = getVertexByIndex( ordmap[0], pholes );
+
+    if( !vp )
+        return false;
+
+    std::string strx, stry, strz;
+    FormatDoublet( vp->x + offsetX, vp->y + offsetY, aPrecision, strx, stry );
+    FormatSinglet( aZcoord, aPrecision, strz );
+
+    aOutFile << strx << " " << stry << " " << strz;
+
+    for( i = 1, j = ordmap.size(); i < j; ++i )
+    {
+        vp = getVertexByIndex( ordmap[i], pholes );
+
+        if( !vp )
+            return false;
+
+        FormatDoublet( vp->x + offsetX, vp->y + offsetY, aPrecision, strx, stry );
+
+        if( i & 1 )
+            aOutFile << ", " << strx << " " << stry << " " << strz;
+        else
+            aOutFile << ",\n" << strx << " " << stry << " " << strz;
+    }
+
+    return !aOutFile.fail();
+}
+
+
+// writes out the vertex list for a 3D feature; top and bottom are the
+// Z values for the top and bottom; top must be > bottom
+bool VRML_LAYER::Write3DVertices( double aTopZ, double aBottomZ,
+                                  std::ofstream& aOutFile, int aPrecision )
+{
+    if( ordmap.size() < 3 )
+    {
+        error = "Write3DVertices(): insufficient vertices";
+        return false;
+    }
+
+    if( aPrecision < 4 )
+        aPrecision = 4;
+
+    if( aTopZ <= aBottomZ )
+    {
+        error = "Write3DVertices(): top <= bottom";
+        return false;
+    }
+
+    int i, j;
+
+    VERTEX_3D* vp = getVertexByIndex( ordmap[0], pholes );
+
+    if( !vp )
+        return false;
+
+    std::string strx, stry, strz;
+    FormatDoublet( vp->x + offsetX, vp->y + offsetY, aPrecision, strx, stry );
+    FormatSinglet( aTopZ, aPrecision, strz );
+
+    aOutFile << strx << " " << stry << " " << strz;
+
+    for( i = 1, j = ordmap.size(); i < j; ++i )
+    {
+        vp = getVertexByIndex( ordmap[i], pholes );
+
+        if( !vp )
+            return false;
+
+        FormatDoublet( vp->x + offsetX, vp->y + offsetY, aPrecision, strx, stry );
+
+        if( i & 1 )
+            aOutFile << ", " << strx << " " << stry << " " << strz;
+        else
+            aOutFile << ",\n" << strx << " " << stry << " " << strz;
+    }
+
+    // repeat for the bottom layer
+    vp = getVertexByIndex( ordmap[0], pholes );
+    FormatDoublet( vp->x + offsetX, vp->y + offsetY, aPrecision, strx, stry );
+    FormatSinglet( aBottomZ, aPrecision, strz );
+
+    bool endl;
+
+    if( i & 1 )
+    {
+        aOutFile << ", " << strx << " " << stry << " " << strz;
+        endl = false;
+    }
+    else
+    {
+        aOutFile << ",\n" << strx << " " << stry << " " << strz;
+        endl = true;
+    }
+
+    for( i = 1, j = ordmap.size(); i < j; ++i )
+    {
+        vp = getVertexByIndex( ordmap[i], pholes );
+        FormatDoublet( vp->x + offsetX, vp->y + offsetY, aPrecision, strx, stry );
+
+        if( endl )
+        {
+            aOutFile << ", " << strx << " " << stry << " " << strz;
+            endl = false;
+        }
+        else
+        {
+            aOutFile << ",\n" << strx << " " << stry << " " << strz;
+            endl = true;
+        }
+    }
+
+    return !aOutFile.fail();
+}
+
+
+// writes out the index list;
+// 'top' indicates the vertex ordering and should be
+// true for a polygon visible from above the PCB
+bool VRML_LAYER::WriteIndices( bool aTopFlag, std::ofstream& aOutFile )
+{
+    if( triplets.empty() )
+    {
+        error = "WriteIndices(): no triplets (triangular facets) to write";
+        return false;
+    }
+
+    // go through the triplet list and write out the indices based on order
+    std::list<TRIPLET_3D>::const_iterator   tbeg    = triplets.begin();
+    std::list<TRIPLET_3D>::const_iterator   tend    = triplets.end();
+
+    int i = 1;
+
+    if( aTopFlag )
+        aOutFile << tbeg->i1 << ", " << tbeg->i2 << ", " << tbeg->i3  << ", -1";
+    else
+        aOutFile << tbeg->i2 << ", " << tbeg->i1 << ", " << tbeg->i3  << ", -1";
+
+    ++tbeg;
+
+    while( tbeg != tend )
+    {
+        if( (i++ & 7) == 4 )
+        {
+            i = 1;
+
+            if( aTopFlag )
+                aOutFile << ",\n" << tbeg->i1 << ", " << tbeg->i2 << ", " << tbeg->i3  << ", -1";
+            else
+                aOutFile << ",\n" << tbeg->i2 << ", " << tbeg->i1 << ", " << tbeg->i3  << ", -1";
+        }
+        else
+        {
+            if( aTopFlag )
+                aOutFile << ", " << tbeg->i1 << ", " << tbeg->i2 << ", " << tbeg->i3  << ", -1";
+            else
+                aOutFile << ", " << tbeg->i2 << ", " << tbeg->i1 << ", " << tbeg->i3  << ", -1";
+        }
+
+        ++tbeg;
+    }
+
+    return !aOutFile.fail();
+}
+
+
+// writes out the index list for a 3D feature
+bool VRML_LAYER::Write3DIndices( std::ofstream& aOutFile, bool aIncludePlatedHoles )
+{
+    if( outline.empty() )
+    {
+        error = "WriteIndices(): no outline available";
+        return false;
+    }
+
+    char mark;
+    bool holes_only = triplets.empty();
+
+    int i = 1;
+    int idx2 = ordmap.size();    // index to the bottom vertices
+
+    if( !holes_only )
+    {
+        mark = ',';
+
+        // go through the triplet list and write out the indices based on order
+        std::list<TRIPLET_3D>::const_iterator   tbeg    = triplets.begin();
+        std::list<TRIPLET_3D>::const_iterator   tend    = triplets.end();
+
+        // print out the top vertices
+        aOutFile << tbeg->i1 << ", " << tbeg->i2 << ", " << tbeg->i3  << ", -1";
+        ++tbeg;
+
+        while( tbeg != tend )
+        {
+            if( (i++ & 7) == 4 )
+            {
+                i = 1;
+                aOutFile << ",\n" << tbeg->i1 << ", " << tbeg->i2 << ", " << tbeg->i3  << ", -1";
+            }
+            else
+            {
+                aOutFile << ", " << tbeg->i1 << ", " << tbeg->i2 << ", " << tbeg->i3  << ", -1";
+            }
+
+            ++tbeg;
+        }
+
+        // print out the bottom vertices
+        tbeg = triplets.begin();
+
+        while( tbeg != tend )
+        {
+            if( (i++ & 7) == 4 )
+            {
+                i = 1;
+                aOutFile << ",\n" << (tbeg->i2 + idx2) << ", " << (tbeg->i1 + idx2) << ", " << (tbeg->i3  + idx2) << ", -1";
+            }
+            else
+            {
+                aOutFile << ", " << (tbeg->i2 + idx2) << ", " << (tbeg->i1 + idx2) << ", " << (tbeg->i3  + idx2) << ", -1";
+            }
+
+            ++tbeg;
+        }
+    }
+    else
+        mark = ' ';
+
+
+    // print out indices for the walls joining top to bottom
+    int lastPoint;
+    int curPoint;
+    int curContour = 0;
+
+    std::list<std::list<int>*>::const_iterator  obeg    = outline.begin();
+    std::list<std::list<int>*>::const_iterator  oend    = outline.end();
+    std::list<int>* cp;
+    std::list<int>::const_iterator  cbeg;
+    std::list<int>::const_iterator  cend;
+
+    i = 2;
+    while( obeg != oend )
+    {
+        cp = *obeg;
+
+        if( cp->size() < 3 )
+        {
+            ++obeg;
+            ++curContour;
+            continue;
+        }
+
+        cbeg      = cp->begin();
+        cend      = cp->end();
+        lastPoint = *(cbeg++);
+
+        // skip all PTH vertices which are not in a solid outline
+        if( !aIncludePlatedHoles && !solid[curContour]
+            && getVertexByIndex( ordmap[lastPoint], pholes )->pth )
+        {
+            ++obeg;
+            ++curContour;
+            continue;
+        }
+
+        while( cbeg != cend )
+        {
+            curPoint = *(cbeg++);
+
+            if( !holes_only )
+            {
+                if( (i++ & 3) == 2 )
+                {
+                    i = 1;
+                    aOutFile << mark << "\n" << curPoint << ", " << lastPoint << ", " << curPoint + idx2;
+                    aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint << ", " << lastPoint + idx2 << ", -1";
+                }
+                else
+                {
+                    aOutFile << mark << " " << curPoint << ", " << lastPoint << ", " << curPoint + idx2;
+                    aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint << ", " << lastPoint + idx2 << ", -1";
+                }
+            }
+            else
+            {
+                if( (i++ & 3) == 2 )
+                {
+                    i = 1;
+                    aOutFile << mark << "\n" << curPoint << ", " << curPoint + idx2 << ", " << lastPoint;
+                    aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint + idx2 << ", " << lastPoint << ", -1";
+                }
+                else
+                {
+                    aOutFile << mark << " " << curPoint << ", " << curPoint + idx2 << ", " << lastPoint;
+                    aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint + idx2 << ", " << lastPoint << ", -1";
+                }
+            }
+
+            mark = ',';
+            lastPoint = curPoint;
+        }
+
+        // check if the loop needs to be closed
+        cbeg = cp->begin();
+        cend = --cp->end();
+
+        curPoint = *(cbeg);
+        lastPoint  = *(cend);
+
+        if( !holes_only )
+        {
+            if( (i++ & 3) == 2 )
+            {
+                aOutFile << ",\n" << curPoint << ", " << lastPoint << ", " << curPoint + idx2;
+                aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint << ", " << lastPoint + idx2 << ", -1";
+            }
+            else
+            {
+                aOutFile << ", " << curPoint << ", " << lastPoint << ", " << curPoint + idx2;
+                aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint << ", " << lastPoint + idx2 << ", -1";
+            }
+        }
+        else
+        {
+            if( (i++ & 3) == 2 )
+            {
+                aOutFile << ",\n" << curPoint << ", " << curPoint + idx2 << ", " << lastPoint;
+                aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint + idx2 << ", " << lastPoint << ", -1";
+            }
+            else
+            {
+                aOutFile << ", " << curPoint << ", " << curPoint + idx2 << ", " << lastPoint;
+                aOutFile << ", -1, " << curPoint + idx2 << ", " << lastPoint + idx2 << ", " << lastPoint << ", -1";
+            }
+        }
+
+        ++obeg;
+        ++curContour;
+    }
+
+    return !aOutFile.fail();
+}
+
+
+// add a triangular facet (triplet) to the ouptut index list
+bool VRML_LAYER::addTriplet( VERTEX_3D* p0, VERTEX_3D* p1, VERTEX_3D* p2 )
+{
+    double  dx0 = p1->x - p0->x;
+    double  dx1 = p2->x - p0->x;
+
+    double  dy0 = p1->y - p0->y;
+    double  dy1 = p2->y - p0->y;
+
+    // this number is chosen because we shall only write 9 decimal places
+    // at most on the VRML output
+    double err = 0.000000001;
+
+    // test if the triangles are degenerate (parallel sides)
+
+    if( dx0 < err && dx0 > -err && dx1 < err && dx1 > -err )
+        return false;
+
+    if( dy0 < err && dy0 > -err && dy1 < err && dy1 > -err )
+        return false;
+
+    double  sl0 = dy0 / dx0;
+    double  sl1 = dy1 / dx1;
+
+    double dsl = sl1 - sl0;
+
+    if( dsl < err && dsl > -err )
+        return false;
+
+    triplets.push_back( TRIPLET_3D( p0->o, p1->o, p2->o ) );
+
+    return true;
+}
+
+
+// add an extra vertex (to be called only by the COMBINE callback)
+VERTEX_3D* VRML_LAYER::AddExtraVertex( double aXpos, double aYpos, bool aPlatedHole )
+{
+    VERTEX_3D* vertex = new VERTEX_3D;
+
+    if( !vertex )
+    {
+        error = "AddExtraVertex(): could not allocate a new vertex";
+        return NULL;
+    }
+
+    if( eidx == 0 )
+        eidx = idx + hidx;
+
+    vertex->x   = aXpos;
+    vertex->y   = aYpos;
+    vertex->i   = eidx++;
+    vertex->o   = -1;
+    vertex->pth = aPlatedHole;
+
+    extra_verts.push_back( vertex );
+
+    return vertex;
+}
+
+
+// start a GL command list
+void VRML_LAYER::glStart( GLenum cmd )
+{
+    glcmd = cmd;
+
+    while( !vlist.empty() )
+        vlist.pop_back();
+}
+
+
+// process a vertex
+void VRML_LAYER::glPushVertex( VERTEX_3D* vertex )
+{
+    if( vertex->o < 0 )
+    {
+        vertex->o = ord++;
+        ordmap.push_back( vertex->i );
+    }
+
+    vlist.push_back( vertex );
+}
+
+
+// end a GL command list
+void VRML_LAYER::glEnd( void )
+{
+    switch( glcmd )
+    {
+    case GL_LINE_LOOP:
+        {
+            // add the loop to the list of outlines
+            std::list<int>* loop = new std::list<int>;
+
+            if( !loop )
+                break;
+
+            double firstX = 0.0;
+            double firstY = 0.0;
+            double lastX = 0.0;
+            double lastY = 0.0;
+            double curX, curY;
+            double area = 0.0;
+
+            if( vlist.size() > 0 )
+            {
+                loop->push_back( vlist[0]->o );
+                firstX = vlist[0]->x;
+                firstY = vlist[0]->y;
+                lastX = firstX;
+                lastY = firstY;
+            }
+
+            for( size_t i = 1; i < vlist.size(); ++i )
+            {
+                loop->push_back( vlist[i]->o );
+                curX = vlist[i]->x;
+                curY = vlist[i]->y;
+                area += ( curX - lastX ) * ( curY + lastY );
+                lastX = curX;
+                lastY = curY;
+            }
+
+            area += ( firstX - lastX ) * ( firstY + lastY );
+
+            outline.push_back( loop );
+
+            if( area <= 0.0 )
+                solid.push_back( true );
+            else
+                solid.push_back( false );
+        }
+        break;
+
+    case GL_TRIANGLE_FAN:
+        processFan();
+        break;
+
+    case GL_TRIANGLE_STRIP:
+        processStrip();
+        break;
+
+    case GL_TRIANGLES:
+        processTri();
+        break;
+
+    default:
+        break;
+    }
+
+    while( !vlist.empty() )
+        vlist.pop_back();
+
+    glcmd = 0;
+}
+
+
+// set the error message
+void VRML_LAYER::SetGLError( GLenum errorID )
+{
+    const char * msg = (const char*)gluErrorString( errorID );
+
+    // If errorID is an illegal id, gluErrorString returns NULL
+    if( msg )
+        error = msg;
+    else
+        error.clear();
+
+    if( error.empty() )
+    {
+        std::ostringstream ostr;
+        ostr << "Unknown OpenGL error: " << errorID;
+        error = ostr.str();
+    }
+}
+
+
+// process a GL_TRIANGLE_FAN list
+void VRML_LAYER::processFan( void )
+{
+    if( vlist.size() < 3 )
+        return;
+
+    VERTEX_3D* p0 = vlist[0];
+
+    int i;
+    int end = vlist.size();
+
+    for( i = 2; i < end; ++i )
+    {
+        addTriplet( p0, vlist[i - 1], vlist[i] );
+    }
+}
+
+
+// process a GL_TRIANGLE_STRIP list
+void VRML_LAYER::processStrip( void )
+{
+    // note: (source: http://www.opengl.org/wiki/Primitive)
+    // GL_TRIANGLE_STRIP​: Every group of 3 adjacent vertices forms a triangle.
+    // The face direction of the strip is determined by the winding of the
+    // first triangle. Each successive triangle will have its effective face
+    // order reverse, so the system compensates for that by testing it in the
+    // opposite way. A vertex stream of n length will generate n-2 triangles.
+
+    if( vlist.size() < 3 )
+        return;
+
+    int i;
+    int end = vlist.size();
+    bool flip = false;
+
+    for( i = 2; i < end; ++i )
+    {
+        if( flip )
+        {
+            addTriplet( vlist[i - 1], vlist[i - 2], vlist[i] );
+            flip = false;
+        }
+        else
+        {
+            addTriplet( vlist[i - 2], vlist[i - 1], vlist[i] );
+            flip = true;
+        }
+    }
+}
+
+
+// process a GL_TRIANGLES list
+void VRML_LAYER::processTri( void )
+{
+    // notes:
+    // 1. each successive group of 3 vertices is a triangle
+    // 2. as per OpenGL specification, any incomplete triangles are to be ignored
+
+    if( vlist.size() < 3 )
+        return;
+
+    int i;
+    int end = vlist.size();
+
+    for( i = 2; i < end; i += 3 )
+        addTriplet( vlist[i - 2], vlist[i - 1], vlist[i] );
+}
+
+
+int VRML_LAYER::checkNContours( bool holes )
+{
+    int nc = 0;     // number of contours
+
+    if( contours.empty() )
+        return 0;
+
+    std::list<int>::const_iterator  begin;
+    std::list<int>::const_iterator  end;
+
+    for( size_t i = 0; i < contours.size(); ++i )
+    {
+        if( contours[i]->size() < 3 )
+            continue;
+
+        if( ( holes && areas[i] <= 0.0 ) || ( !holes && areas[i] > 0.0 ) )
+            continue;
+
+        ++nc;
+    }
+
+    return nc;
+}
+
+
+// push the internally held vertices
+void VRML_LAYER::pushVertices( bool holes )
+{
+    // push the internally held vertices
+    unsigned int i;
+
+    std::list<int>::const_iterator  begin;
+    std::list<int>::const_iterator  end;
+    GLdouble pt[3];
+    VERTEX_3D* vp;
+
+    for( i = 0; i < contours.size(); ++i )
+    {
+        if( contours[i]->size() < 3 )
+            continue;
+
+        if( ( holes && areas[i] <= 0.0 ) || ( !holes && areas[i] > 0.0 ) )
+            continue;
+
+        gluTessBeginContour( tess );
+
+        begin = contours[i]->begin();
+        end = contours[i]->end();
+
+        while( begin != end )
+        {
+            vp = vertices[ *begin ];
+            pt[0]   = vp->x;
+            pt[1]   = vp->y;
+            pt[2]   = 0.0;
+            gluTessVertex( tess, pt, vp );
+            ++begin;
+        }
+
+        gluTessEndContour( tess );
+    }
+
+    return;
+}
+
+
+VERTEX_3D* VRML_LAYER::getVertexByIndex( int aPointIndex, VRML_LAYER* holes )
+{
+    if( aPointIndex < 0 || (unsigned int) aPointIndex >= ( idx + hidx + extra_verts.size() ) )
+    {
+        error = "getVertexByIndex():BUG: invalid index";
+        return NULL;
+    }
+
+    if( aPointIndex < idx )
+    {
+        // vertex is in the vertices[] list
+        return vertices[ aPointIndex ];
+    }
+    else if( aPointIndex >= idx + hidx )
+    {
+        // vertex is in the extra_verts[] list
+        return extra_verts[aPointIndex - idx - hidx];
+    }
+
+    // vertex is in the holes object
+    if( !holes )
+    {
+        error = "getVertexByIndex():BUG: invalid index";
+        return NULL;
+    }
+
+    VERTEX_3D* vp = holes->GetVertexByIndex( aPointIndex );
+
+    if( !vp )
+    {
+        std::ostringstream ostr;
+        ostr << "getVertexByIndex():FAILED: " << holes->GetError();
+        error = ostr.str();
+        return NULL;
+    }
+
+    return vp;
+}
+
+
+// retrieve the total number of vertices
+int VRML_LAYER::GetSize( void )
+{
+    return vertices.size();
+}
+
+
+// Inserts all contours into the given tesselator; this results in the
+// renumbering of all vertices from 'start'. Returns the end number.
+// Take care when using this call since tesselators cannot work on
+// the internal data concurrently
+int VRML_LAYER::Import( int start, GLUtesselator* tess )
+{
+    if( start < 0 )
+    {
+        error = "Import(): invalid index ( start < 0 )";
+        return -1;
+    }
+
+    if( !tess )
+    {
+        error = "Import(): NULL tesselator pointer";
+        return -1;
+    }
+
+    unsigned int i, j;
+
+    // renumber from 'start'
+    for( i = 0, j = vertices.size(); i < j; ++i )
+    {
+        vertices[i]->i = start++;
+        vertices[i]->o = -1;
+    }
+
+    // push each contour to the tesselator
+    VERTEX_3D* vp;
+    GLdouble pt[3];
+
+    std::list<int>::const_iterator cbeg;
+    std::list<int>::const_iterator cend;
+
+    for( i = 0; i < contours.size(); ++i )
+    {
+        if( contours[i]->size() < 3 )
+            continue;
+
+        cbeg = contours[i]->begin();
+        cend = contours[i]->end();
+
+        gluTessBeginContour( tess );
+
+        while( cbeg != cend )
+        {
+            vp = vertices[ *cbeg++ ];
+            pt[0] = vp->x;
+            pt[1] = vp->y;
+            pt[2] = 0.0;
+            gluTessVertex( tess, pt, vp );
+        }
+
+        gluTessEndContour( tess );
+    }
+
+    return start;
+}
+
+
+// return the vertex identified by index
+VERTEX_3D* VRML_LAYER::GetVertexByIndex( int aPointIndex )
+{
+    int i0 = vertices[0]->i;
+
+    if( aPointIndex < i0 || aPointIndex >= ( i0 + (int) vertices.size() ) )
+    {
+        error = "GetVertexByIndex(): invalid index";
+        return NULL;
+    }
+
+    return vertices[aPointIndex - i0];
+}
+
+
+// return the error string
+const std::string& VRML_LAYER::GetError( void )
+{
+    return error;
+}
+
+
+void VRML_LAYER::SetVertexOffsets( double aXoffset, double aYoffset )
+{
+    offsetX = aXoffset;
+    offsetY = aYoffset;
+    return;
+}