OpenSceneGraph/examples/osgdelaunay/osgdelaunay.cpp

/* OpenSceneGraph example, osgdelaunay.
*
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*  of this software and associated documentation files (the "Software"), to deal
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*
*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
*  THE SOFTWARE.
*/


/** Example of use of delaunay triangulator with constraints.
* this could be a method of generating terrains, a constraint forces certain edges to
* exist in the triangulation.
*/

#include <osgDB/ReadFile>
#include <osgUtil/Optimizer>
#include <osgViewer/Viewer>
#include <osg/CoordinateSystemNode>
#include <osgUtil/DelaunayTriangulator>
#include <osg/Material>
#include <osg/Texture2D>
#include <osg/Projection>
#include <osg/MatrixTransform>
#include <osgUtil/Tessellator> // tessellator triangulates the constrained triangles

#include <osgText/Text>

#include <sstream>
#include <iostream>

/** here are 2 common types of constraint
*  Area - forces an area to be filled; replacement geometry is a canopy and optional wall
*  Linear - constructs a closed loop of constant width around a line.
*/
class WallConstraint: public osgUtil::DelaunayConstraint { // forces lines to eb edge
    // wall constraint - can generate a wall at the coordinates of the constraint
public:
/** if you derive a class from DelaunayConstraint then you can create 
*  a specific geometry creation routine.
    */
    WallConstraint() : height(0), txxrepWall(10), txyrepWall(10)  { }
    
    /** or create a wall around the constraint area: */
    virtual osg::Geometry * makeWallGeometry(void) const;
    
    /** for basic purposes, you can call these routines to make simple fill in geometries */
    virtual osg::DrawArrays* makeWall(void ) const { // build a wall height high around the constraint
        const osg::Vec3Array *_line= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
        return (new osg::DrawArrays(osg::PrimitiveSet::QUAD_STRIP,0,2*_line->size()));
    }
    
    
    virtual osg::Vec3Array *getWall(const float height) const;
    virtual osg::Vec2Array *getWallTexcoords(const float height) const;
    virtual osg::Vec3Array *getWallNormals(void) const {
        osg::ref_ptr<osg::Vec3Array> nrms=new osg::Vec3Array;
        const osg::Vec3Array *vertices= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
        for (unsigned int ipr=0; ipr<getNumPrimitiveSets(); ipr++) {
            const osg::PrimitiveSet* prset=getPrimitiveSet(ipr);
            if (prset->getMode()==osg::PrimitiveSet::LINE_LOOP || 
                prset->getMode()==osg::PrimitiveSet::LINE_STRIP) { // loops and walls
                // start with the last point on the loop
                osg::Vec3 prevp=(*vertices)[prset->index (prset->getNumIndices()-1)];
                for (unsigned int i=0; i<prset->getNumIndices(); i++) {
                    const osg::Vec3 curp=(*vertices)[prset->index (i)];
                    osg::Vec3 nrm=(curp-prevp)^osg::Vec3(0,0,1);
                    nrm.normalize();
                    nrms->push_back(nrm);
                    nrms->push_back(nrm);
                    prevp=curp;
                }
                const osg::Vec3 curp=(*vertices)[prset->index (0)];
                osg::Vec3 nrm=(curp-prevp)^osg::Vec3(0,0,1);
                nrm.normalize();
                nrms->push_back(nrm);
                nrms->push_back(nrm);
            }
        }
        return nrms.release();
    }
    
    
    
    // geometry creation parameters
    void setWallTexrep(const float w,const float h) { txxrepWall=w;txyrepWall=h;}
    
    /** Wall Geometry will return with this texture applied: */
    void setTexture(const char *tx) { texture=tx;}
    /** fence/wall height */
    void setHeight(const float h) { height=h;}
protected:
    float height;
    std::string texture;
    float txxrepWall, txyrepWall;
};
class ArealConstraint: public osgUtil::DelaunayConstraint { // forces edges of an area to fit triangles
    // areal constraint - general nonuniform field, forest, lake etc.
public:
/** if you derive a class from DelaunayConstraint then you can create 
*  a specific geometry creation routine.
    */
    ArealConstraint() : txxrepArea(10), txyrepArea(10),txxrepWall(10), txyrepWall(10) { }
    
    /** return a geometry that fills the constraint.
    */
    virtual osg::Geometry * makeAreal( osg::Vec3Array *points);
    
    /** or create a wall around the constraint area: */
    virtual osg::Geometry * makeWallGeometry( osg::Vec3Array *points) ;
    
    /** for basic purposes, you can call these routines to make simple fill in geometries */
    virtual osg::DrawArrays* makeWall(void ) const;
    virtual osg::Vec3Array *getWall(const float height) const;
    virtual osg::Vec2Array *getWallTexcoords(const float height) const;
    virtual osg::Vec3Array *getWallNormals(void) const;
    /** Canopies are the same triangles as the terrain but offset by height above
    * (height might be 0). */
    virtual osg::DrawArrays* makeCanopy(void ) const;
    virtual osg::Vec3Array *getCanopy(const osg::Vec3Array *points,const float height) const;
    virtual osg::Vec2Array *getCanopyTexcoords(const osg::Vec3Array *points) const;
    virtual osg::Vec3Array *getCanopyNormals(const osg::Vec3Array *points) const;
    
    // geometry creation parameters
    void setTexrep(const float w,const float h) { txxrepArea=w;txyrepArea=h;}
    void setWallTexrep(const float w,const float h) { txxrepWall=w;txyrepWall=h;}
    /** Geometry will return with this texture applied: */
    void setWallTexture(const char *tx) { walltexture=tx;}
    /** Geometry will return with this texture applied: */
    void setTexture(const char *tx) { texture=tx;}
    /** fence/wall height */
    void setHeight(const float h) { height=h;}
    std::string walltexture;
protected:
    float height;
    std::string texture;
    float txxrepArea, txyrepArea;
    float txxrepWall, txyrepWall;
};

class LinearConstraint: public osgUtil::DelaunayConstraint { 
/** forces edges of a "road" to fit triangles
*  if 2 roads cross, then the overlap will be replaced by a 'cross road'
    *  and the roads built up to the cross roads with a texture along its length. */
public:
    LinearConstraint() : osgUtil::DelaunayConstraint(), txxrepAlong(10), txyrepAcross(10), width(2) { }
    
    /** geometry creation parameters */
    /* Width of linear feature (eg road, railway) */
    void setWidth(const float w) { width=w;}
    
    /** Texture repeat distance across linear (often equal to width) and along its length */
    virtual void setTexrep(const float w,const float h) { txyrepAcross=h;txxrepAlong=w; }
    
    /** generate constant width around line - creates the area to be cut into the terrain. */
    virtual void setVertices( osg::Vec3Array *lp, const float width);
    
    /** return a geometry that fills the constraint.
    */
    virtual osg::Geometry *makeGeometry(const osg::Vec3Array *points) ;
    
    /** return normals array - flat shaded */
    osg::Vec3Array* getNormals(const osg::Vec3Array *points);
    
    /** Roads apply a texture proportional to length along the road line. */
    virtual osg::DrawArrays* makeRoad( ) const;
    virtual osg::Vec3Array *getRoadVertices() const;
    virtual osg::Vec2Array *getRoadTexcoords(const osg::Vec3Array *points) ;
    
    virtual osg::Vec3Array *getRoadNormals(const osg::Vec3Array *points) const;
    /** Geometry will return with this texture applied: */
    void setTexture(const char *tx) { texture=tx;}
    
protected:
    osg::ref_ptr<osg::Vec2Array> _tcoords;
    osg::ref_ptr<osg::Vec3Array> _edgecoords;
    float txxrepAlong, txyrepAcross;
    std::string texture;
    float width; // width of a linear feature
    osg::ref_ptr<osg::Vec3Array> _midline; // defines the midline of a road, rail etc.
};

/** a specific type of constaint - that replaces an area with a pyramid */

class pyramid : public osgUtil::DelaunayConstraint {
/** sample user constriant - creates hole in terrain to fit base of pyramid, and
    *  geometry of an Egyptian pyramid to fit the hole. */
public:
    pyramid() : _side(100.) {}
    
    void setpos(const osg::Vec3 p, const float size) { _pos=p;_side=size;}
    
    virtual osg::Geometry * makeGeometry(void) const
        {
        // create pyramid geometry. Centre plus points around base
        const osg::Vec3Array *_line= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
        osg::Geometry *gm=new osg::Geometry;
        osg::Vec3Array *pts=new osg::Vec3Array;
        osg::Vec3Array *norms=new osg::Vec3Array;
        osg::Vec2Array *tcoords=new osg::Vec2Array;
        int ip;
        
        pts->push_back(_pos+osg::Vec3(0,0,_side)*0.5);
        for (ip=0; ip<4; ip++) {
            pts->push_back((*_line)[ip]);
        }
        for (ip=1; ip<5; ip++) {
            osg::Vec3 nrm=((*pts)[ip]-(*pts)[0])^((*pts)[ip==4?0:ip+1]-(*pts)[ip]);
            nrm.normalize(  );
            norms->push_back(nrm);
        }
        
        gm->setNormalBinding(osg::Geometry::BIND_PER_PRIMITIVE);
        gm->setVertexArray(pts);
        osg::StateSet *dstate=   gm->getOrCreateStateSet(  );
        dstate->setMode( GL_LIGHTING, osg::StateAttribute::ON );
        
        osg::Image* image = osgDB::readImageFile("Images/Brick-Std-Orange.TGA");
        if (image)
        {
            osg::Texture2D* txt = new osg::Texture2D;
            txt->setImage(image);
            txt->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::REPEAT );
            txt->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::REPEAT );
            dstate->setTextureAttributeAndModes(0,txt,osg::StateAttribute::ON);
        }
        gm->setNormalArray(norms);
        ////        gm->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::TRIANGLE_FAN,0,6));
        osg::DrawElementsUInt *dui=new osg::DrawElementsUInt(GL_TRIANGLES);
        for (ip=0; ip<4; ip++) {
            dui->push_back(0);
            dui->push_back(ip+1);
            dui->push_back(ip==3?1:ip+2);
        }
        tcoords->push_back(osg::Vec2(2,4));
        tcoords->push_back(osg::Vec2(0,0));
        tcoords->push_back(osg::Vec2(4,0));
        tcoords->push_back(osg::Vec2(0,0));
        tcoords->push_back(osg::Vec2(4,0));
        gm->setTexCoordArray(0,tcoords);
        gm->addPrimitiveSet(dui);
        return gm;
    }
    virtual void calcVertices( void) { // must have a position first
        osg::Vec3Array *edges=new osg::Vec3Array;
        osg::Vec3 valong;
        edges->push_back(_pos+osg::Vec3(0.5,0.5,0)*_side);
        edges->push_back(_pos+osg::Vec3(-0.5,0.5,0)*_side);
        edges->push_back(_pos+osg::Vec3(-0.5,-0.5,0)*_side);
        edges->push_back(_pos+osg::Vec3(0.5,-0.5,0)*_side);
        setVertexArray(edges);
    }
private:
    osg::Vec3 _pos; // where the pyramid is
    float _side ; // length of side
};

float getheight(const float x, const float y)
{ // returns the x,y,height of terrain
    return 150*sin(x*.0020)*cos(y*.0020);
}
osg::Vec3d getpt(const int np)
{ // returns the x,y,height of terrain up to maxp^2 points
    static int maxp =40;
    int i=np/maxp;
    int j=np%maxp;
    // make the random scale 0.00 if you want an equispaced XY grid.
    float x=3000.0/(maxp-1)*i+16.*(float)rand()/RAND_MAX;
    float y=3000.0/(maxp-1)*j+16.*(float)rand()/RAND_MAX;
    float z=getheight(x,y);
    if (np>=maxp*maxp) z=-1.e32;
    return osg::Vec3d(x,y,z);
}
osg::Node* createHUD(const int ndcs,std::string what)
{ // add a string reporting the type of winding rule tessellation applied
    osg::Geode* geode = new osg::Geode();
    
    std::string timesFont("fonts/arial.ttf");
    
    // turn lighting off for the text and disable depth test to ensure its always ontop.
    osg::StateSet* stateset = geode->getOrCreateStateSet();
    stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
    
    // Disable depth test, and make sure that the hud is drawn after everything 
    // else so that it always appears ontop.
    stateset->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);
    stateset->setRenderBinDetails(11,"RenderBin");
    
    osg::Vec3 position(50.0f,900.0f,0.0f);
    osg::Vec3 delta(0.0f,-35.0f,0.0f);
    
    {
        osgText::Text* text = new  osgText::Text;
        geode->addDrawable( text );
        std::ostringstream cue;
        cue<<"Delaunay triangulation with constraints level "<<ndcs <<"\n"<< what;
        
        text->setFont(timesFont);
        text->setPosition(position);
        text->setText(cue.str());
        text->setColor(osg::Vec4(1.0,1.0,0.8,1.0));
        position += delta*(ndcs+2);

#if 0        
        text = new  osgText::Text;
        geode->addDrawable( text );
        
        text->setFont(timesFont);
        text->setPosition(position);
        text->setText("(use 'W' wireframe & 'T' texture to visualise mesh)");
        text->setColor(osg::Vec4(1.0,1.0,0.8,1.0));
        position += delta;
#endif        
    }    
    {
        osgText::Text* text = new  osgText::Text;
        geode->addDrawable( text );
        
        text->setFont(timesFont);
        text->setPosition(position);
        text->setText("Press 'n' to add another constraint.");
        
    }    
    
    // create the hud.
    osg::MatrixTransform* modelview_abs = new osg::MatrixTransform;
    modelview_abs->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
    modelview_abs->setMatrix(osg::Matrix::identity());
    modelview_abs->addChild(geode);
    
    osg::Projection* projection = new osg::Projection;
    projection->setMatrix(osg::Matrix::ortho2D(0,1280,0,1024));
    projection->addChild(modelview_abs);
    
    return projection;
    
}
osg::Group *makedelaunay(const int ndcs)
{ // create a terrain tile. This is just an example!
    // ndcs is the number of delaunay constraints to be applied
    osg::ref_ptr<osg::Group> grp=new osg::Group;
    osg::ref_ptr<osg::Geode> geode=new osg::Geode;
    osg::ref_ptr<osgUtil::DelaunayTriangulator> trig=new osgUtil::DelaunayTriangulator();
    osg::StateSet *stateset=geode->getOrCreateStateSet();
    
    osg::Vec3Array *points=new osg::Vec3Array;
    
    osg::Image* image = osgDB::readImageFile("Images/blueFlowers.png");
    if (image)
    {
        osg::Texture2D* texture = new osg::Texture2D;
        texture->setImage(image);
        texture->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::REPEAT );
        texture->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::REPEAT );
        stateset->setTextureAttributeAndModes(0,texture,osg::StateAttribute::ON);
    }
    
    geode->setStateSet( stateset );
    unsigned int i;
    
    int eod=0;
    while (eod>=0) {
        osg::Vec3d pos=getpt(eod);
        if (pos.z()>-10000) {
            points->push_back(pos);
            eod++;
        } else {
            eod=-9999;
        }
    }
    std::vector < pyramid* > pyrlist;
    osg::ref_ptr<WallConstraint> wc; // This example does not remove the interior
    osg::ref_ptr<ArealConstraint> dc2;
    osg::ref_ptr<ArealConstraint> forest;
    osg::ref_ptr<LinearConstraint> dc3;
    osg::ref_ptr<LinearConstraint> dc6;
    osg::ref_ptr<LinearConstraint> dc6a;
    osg::ref_ptr<LinearConstraint> dc8;
    osg::ref_ptr<LinearConstraint> forestroad;
    osg::ref_ptr<LinearConstraint> forestroad2;
    osg::ref_ptr<LinearConstraint> forestroad3;
    osg::ref_ptr<osgUtil::DelaunayConstraint> dc;
    std::ostringstream what;
    if (1==0) { // add a simple constraint of few points
        osg::ref_ptr<osgUtil::DelaunayConstraint> dc=new osgUtil::DelaunayConstraint;
        osg::Vec3Array *bounds=new osg::Vec3Array;
        unsigned int nmax=4;
        for (i=0 ; i<nmax; i++) {
            float x=910.0+800.0*(i)/(float)nmax,y=810.0+6000*(i-1)*(i-1)/(float)(nmax*nmax);
            bounds->push_back(osg::Vec3(x,y,getheight(x,y)));
        }
        dc->setVertexArray(bounds);
        dc->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_STRIP,0,nmax) );
        
        trig->addInputConstraint(dc.get());
        what << nmax << " point simple constraint\n";
    }
    if (ndcs>0) { // add 5 pyramids
        for (unsigned int ipy=0; ipy<5/*5*/; ipy++) {
            osg::ref_ptr<pyramid> pyr=new pyramid;
            float x=2210+ipy*120, y=1120+ipy*220;
            pyr->setpos(osg::Vec3(x,y,getheight(x,y)),125.0+10*ipy);
            pyr->calcVertices(); // make vertices
            pyr->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,4) );
            trig->addInputConstraint(pyr.get());
            pyrlist.push_back(pyr.get());
        }
        what << 5 << " pyramids\n";
        if (ndcs>1) {
            // add a simple constraint feature - this can cut holes in the terrain or just leave the triangles
            // with edges forced to the constraint.
            dc=new osgUtil::DelaunayConstraint;
            osg::Vec3Array *bounds=new osg::Vec3Array;
            for (i=0 ; i<12; i++) {
                float x=610.0+420*sin(i/3.0),y=610.0+420*cos(i/3.0);
                bounds->push_back(osg::Vec3(x,y,getheight(x,y)));
            }
            dc->setVertexArray(bounds);
            dc->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,12) );
            
            trig->addInputConstraint(dc.get());
            what << 12 << " point closed loop";
            
            if (ndcs>2) {
                wc=new WallConstraint; // This example does not remove the interior
                // eg to force terrain edges that are on ridges in the terrain etc.
                // use wireframe to see the constrained edges.
                // NB this is not necessarily a closed loop of edges.
                // we do however build a wall at the coordinates.
                bounds=new osg::Vec3Array;
                for (i=0 ; i<5; i++) {
                    float x=1610.0+420*sin(i/1.0),y=1610.0+420*cos(i/1.0);
                    bounds->push_back(osg::Vec3(x,y,getheight(x,y)));
                }
                wc->setVertexArray(bounds);
                wc->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_STRIP,0,5) );
                wc->setHeight(12.0);
                trig->addInputConstraint(wc.get());
                what << " with interior removed\n";
                what << 5 << " point wall derived constraint\n";
                
                if (ndcs>3) {
                    // add a removed area and replace it with a different texture
                    dc2=new ArealConstraint;
                    bounds=new osg::Vec3Array;
                    for (i=0 ; i<18; i++) {
                        float x=1610.0+420*sin(i/3.0),y=610.0+220*cos(i/3.0);
                        bounds->push_back(osg::Vec3(x,y,getheight(x,y)));
                    }
                    dc2->setVertexArray(bounds);
                    dc2->setTexrep(100,100); // texture is repeated at this frequency
                    dc2->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,18) );
                    trig->addInputConstraint(dc2.get());
                    what << 18 << " point area replaced\n";
                    
                    if (ndcs>4) {
                        dc3=new LinearConstraint;
                        // a linear feature or 'road'
                        osg::Vec3Array *verts=new osg::Vec3Array;
                        for (i=0 ; i<32; i++) {
                            float x=610.0+50*i+90*sin(i/5.0),y=1110.0+90*cos(i/5.0);
                            verts->push_back(osg::Vec3(x,y,getheight(x,y)));
                        }
                        dc3->setVertices(verts,9.5); // width of road
                        for (osg::Vec3Array::iterator vit=points->begin(); vit!=points->end(); ) {
                            if (dc3->contains(*vit)) {
                                vit=points->erase(vit);
                            } else {
                                vit++;
                            }
                        }
                        trig->addInputConstraint(dc3.get());
                        what << 32 << " point road constraint\n";
                        if (ndcs>5) {
                            // add a removed area and replace it with a 'forest' with textured roof and walls
                            forest=new ArealConstraint;
                            bounds=new osg::Vec3Array;
                            for (i=0 ; i<12; i++) {
                                float x=610.0+420*sin(i/2.0),y=1810.0+420*cos(i/2.0);
                                bounds->push_back(osg::Vec3(x,y,getheight(x,y)));
                            }
                            forest->setVertexArray(bounds);
                            forest->setHeight(50);
                            forest->setWallTexrep(100,50);
                            forest->setTexrep(100,100); // texture is repeated at this frequency
                            forest->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,12) );
                            if (ndcs==6) trig->addInputConstraint(forest.get());
                            what << 12 << " point forest constraint\n";
                            
                            if (ndcs>6) { // add roads that intersect forest
                                osg::ref_ptr<osgUtil::DelaunayConstraint> forestplus=new osgUtil::DelaunayConstraint;
                                forestroad=new LinearConstraint;
                                verts=new osg::Vec3Array;
                                for (i=0 ; i<12; i++) {
                                    int ip=(i-6)*(i-6);
                                    float xp=410.0+20.0*ip;
                                    float y=1210.0+150*i;
                                    verts->push_back(osg::Vec3(xp,y,getheight(xp,y)));
                                }
                                forestroad->setVertices(verts,22); // add road
                                forestplus->merge(forestroad.get());
                                forestroad2=new LinearConstraint;
                                verts=new osg::Vec3Array;
                                for (i=0 ; i<12; i++) {
                                    int ip=(i-6)*(i-6);
                                    float xp=810.0-10.0*ip;
                                    float y=1010.0+150*i;
                                    verts->push_back(osg::Vec3(xp,y,getheight(xp,y)));
                                }
                                forestroad2->setVertices(verts,22); // add road
                                forestplus->merge(forestroad2.get());
                                forestroad3=new LinearConstraint;
                                verts=new osg::Vec3Array;
                                for (i=0 ; i<6; i++) {
                                    int ip=(i-6)*(i-6);
                                    float xp=210.0+140.0*i+ip*10.0;
                                    float y=1510.0+150*i;
                                    verts->push_back(osg::Vec3(xp,y,getheight(xp,y)));
                                }
                                forestroad3->setVertices(verts,22); // add road
                                forestplus->merge(forestroad3.get());
                                forestplus->merge(forest.get());
                                forestplus->handleOverlaps();
                                for (osg::Vec3Array::iterator vit=points->begin(); vit!=points->end(); ) {
                                    if (forestroad->contains(*vit)) {
                                        vit=points->erase(vit);
                                    } else if (forestroad2->contains(*vit)) {
                                        vit=points->erase(vit);
                                    } else if (forestroad3->contains(*vit)) {
                                        vit=points->erase(vit);
                                    } else {
                                        vit++;
                                    }
                                }
                                trig->addInputConstraint(forestplus.get());
                                what << " roads intersect forest constraint\n";
                                if (ndcs>7) {
                                    // this option adds a more complex DC
                                    // made of several (ok 2 - extend your own way) overlapping DC's
                                    osg::ref_ptr<osgUtil::DelaunayConstraint> dcoverlap=new osgUtil::DelaunayConstraint;
                                    float x=1200; float y=1900;
                                    {
                                        verts=new osg::Vec3Array;
                                        dc6=new LinearConstraint;
                                        verts->push_back(osg::Vec3(x-180,y,getheight(x-180,y)));
                                        verts->push_back(osg::Vec3(x+180,y,getheight(x+180,y)));
                                        dc6->setVertices(verts,22); // width of road
                                        dcoverlap->merge(dc6.get());
                                    }
                                    {
                                        dc6a= new LinearConstraint;
                                        verts=new osg::Vec3Array;
                                        verts->push_back(osg::Vec3(x,y-180,getheight(x,y-180)));
                                        verts->push_back(osg::Vec3(x-20,y,getheight(x,y)));
                                        verts->push_back(osg::Vec3(x,y+180,getheight(x,y+180)));
                                        dc6a->setVertices(verts,22); // width of road
                                        dcoverlap->merge(dc6a.get());
                                    }
                                    what << "2 intersecting roads, with added points\n";
                                    if (ndcs>9) {
                                        // add yet more roads
                                        dc8= new LinearConstraint;
                                        verts=new osg::Vec3Array;
                                        float rad=60.0;
                                        for (float theta=0; theta<4*osg::PI; theta+=0.1*osg::PI) {
                                            float xp=x+rad*cos(theta), yp=y+rad*sin(theta);
                                            verts->push_back(osg::Vec3(xp,yp,getheight(xp,yp)));
                                            rad+=2.5;
                                        }
                                        dc8->setVertices(verts,16); // width of road
                                        dcoverlap->merge(dc8.get());
                                        what << "Spiral road crosses several other constraints.";
                                    }
                                    dcoverlap->handleOverlaps();
                                    if (ndcs>8) {
                                        // remove vertices cleans up the texturing at the intersection.
                                        dcoverlap->removeVerticesInside(dc6.get());
                                        dcoverlap->removeVerticesInside(dc6a.get());
                                        if (dc8.valid()) dcoverlap->removeVerticesInside(dc8.get());
                                        what << "    remove internal vertices to improve texturing.";
                                    }
                                    for (osg::Vec3Array::iterator vit=points->begin(); vit!=points->end(); ) {
                                        if (dcoverlap->contains(*vit)) {
                                            vit=points->erase(vit);
                                        } else {
                                            vit++;
                                        }
                                    }
                                    trig->addInputConstraint(dcoverlap.get());
                                }
                            }
                        }
                    }
                }
            }
        }
    } // ndcs>0
    trig->setInputPointArray(points);
    
    /** NB you need to supply a vec3 array for the triangulator to calculate normals into */
    osg::Vec3Array *norms=new osg::Vec3Array;
    trig->setOutputNormalArray(norms);
    
    trig->triangulate();
    osg::notify(osg::WARN) << " End of trig\n " <<std::endl;
    
    // Calculate the texture coordinates after triangulation as 
    //the points may get disordered by the triangulate function
    osg::ref_ptr<osg::Geometry> gm=new osg::Geometry;
    gm->setVertexArray(points); // points may have been modified in order by triangulation.
    /** calculate texture coords for terrain points */
    if (image) {
        float repeat=150.0, ry=150.0; // how often to repeat texture
        osg::Vec2Array *tcoords=new osg::Vec2Array;
        for (osg::Vec3Array::iterator itr=points->begin(); itr!=points->end(); itr++) {
            osg::Vec2 tcatxy((*itr).x()/repeat,(*itr).y()/ry);
            tcoords->push_back(tcatxy);
        }
        gm->setTexCoordArray(0,tcoords);
    }
    gm->addPrimitiveSet(trig->getTriangles());
    gm->setNormalArray(trig->getOutputNormalArray());
    gm->setNormalBinding(osg::Geometry::BIND_PER_PRIMITIVE);
    geode->addDrawable(gm.get());
    if (ndcs>0) {
        for ( std::vector < pyramid* >::iterator itr=pyrlist.begin(); itr!=pyrlist.end(); itr++) {
            trig->removeInternalTriangles(*itr);
            geode->addDrawable((*itr)->makeGeometry()); // this fills the holes of each pyramid with geometry
        }
        
        if (ndcs>2) {
            trig->removeInternalTriangles(dc.get());
            
            wc->setTexture("Images/Brick-Norman-Brown.TGA"); // wall looks like brick
            geode->addDrawable(wc->makeWallGeometry()); // this creates wall at wc drawarrays
            if (ndcs>3) {
                trig->removeInternalTriangles(dc2.get());
                osg::ref_ptr<osg::Vec3Array> arpts=dc2->getPoints(points);
                dc2->setTexture("Images/purpleFlowers.png");
                geode->addDrawable(dc2->makeAreal(arpts.get())); // this creates fill in geometry
                
                if (ndcs>4) { // a simple "road"
                    trig->removeInternalTriangles(dc3.get());
                    dc3->setTexture ("Images/road.png");
                    dc3->setTexrep(40,9.5); // texture is repeated at this frequency
                    geode->addDrawable(dc3->makeGeometry(points)); // this creates road geometry
                    
                    if (ndcs>5) {
                        if (ndcs>6) { //  road & forest overlap - order of removal is important
                            trig->removeInternalTriangles(forestroad.get());
                            trig->removeInternalTriangles(forestroad2.get());
                            trig->removeInternalTriangles(forestroad3.get());
                        }
                        trig->removeInternalTriangles(forest.get());
                        forest->setTexture("Images/forestRoof.png"); 
                        osg::ref_ptr<osg::Vec3Array> locpts=forest->getPoints(points);
                        geode->addDrawable(forest->makeAreal(locpts.get()));

                        forest->setWallTexture("Images/forestWall.png"); 
                        geode->addDrawable(forest->makeWallGeometry(locpts.get()) );
                        for (osg::Vec3Array::iterator vit=(*locpts).begin(); vit!=(*locpts).end(); vit++) {
                            (*vit)+=osg::Vec3(0,0,30);
                        }

                        if (ndcs>6) {//  road & forest overlap
                            forestroad->setTexture ("Images/road.png");
                            forestroad->setTexrep(40,22); // texture is repeated at this frequency
                            geode->addDrawable(forestroad->makeGeometry(points)); // this creates road geometry
                            forestroad2->setTexture ("Images/road.png");
                            forestroad2->setTexrep(40,22); // texture is repeated at this frequency
                            geode->addDrawable(forestroad2->makeGeometry(points)); // this creates road geometry
                            forestroad3->setTexture ("Images/road.png");
                            forestroad3->setTexrep(40,22); // texture is repeated at this frequency
                            geode->addDrawable(forestroad3->makeGeometry(points)); // this creates road geometry
                            if (ndcs>7) {//  several overlapping DC's - add geom
                                trig->removeInternalTriangles(dc6.get());
                                //                            dc6->makeDrawable();
                                //                            dc6a->makeDrawable();
                                dc6->setTexture ("Images/road.png");
                                dc6->setTexrep(40,22); // texture is repeated at this frequency
                                geode->addDrawable(dc6->makeGeometry(points)); // this creates road geometry
                                trig->removeInternalTriangles(dc6a.get());
                                dc6a->setTexture ("Images/road.png");
                                dc6a->setTexrep(40,22); // texture is repeated at this frequency
                                geode->addDrawable(dc6a->makeGeometry(points)); // this creates road geometry
                                if (dc8.valid()) {
                                    trig->removeInternalTriangles(dc8.get());
                                    dc8->setTexture ("Images/road.png");
                                    dc8->setTexrep(40,16); // texture is repeated at this frequency
                                    geode->addDrawable(dc8->makeGeometry(points)); // this creates road geometry
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    grp->addChild(geode.get());
    grp->addChild(createHUD(ndcs,what.str()));
    return grp.release();
}

class KeyboardEventHandler : public osgGA::GUIEventHandler
{ // extra event handler traps 'n' key to re-triangulate the basic terrain.
public:
    
    KeyboardEventHandler(osgViewer::Viewer &vr):
      viewer(vr), iview(0) {}
      
      virtual bool handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter&)
      {
          switch(ea.getEventType())
          {
          case(osgGA::GUIEventAdapter::KEYDOWN):
              {
                  if (ea.getKey()=='n')
                  {
                      iview++;
                      if (iview>10) iview=0;
                      osg::ref_ptr<osg::Node> loadedModel = makedelaunay(iview);
                      viewer.setSceneData(loadedModel.get());
                      return true;
                  }
                  break;
              }
          default:
              break;
          }
          return false;
      }
      
      osgViewer::Viewer &viewer;
      int iview;
};

osg::Vec3Array * WallConstraint::getWall(const float height) const
{ // return array of points for a wall height high around the constraint
    osg::Vec3Array *wall=new osg::Vec3Array;
    if (height>0.0) {
        osg::Vec3 off(0,0,height);
        const osg::Vec3Array *vertices= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
        for (unsigned int ipr=0; ipr<getNumPrimitiveSets(); ipr++) {
            const osg::PrimitiveSet* prset=getPrimitiveSet(ipr);
            if (prset->getMode()==osg::PrimitiveSet::LINE_LOOP ||
                prset->getMode()==osg::PrimitiveSet::LINE_STRIP) { // nothing else loops
                // start with the last point on the loop
                for (unsigned int i=0; i<prset->getNumIndices(); i++) {
                    const osg::Vec3 curp=(*vertices)[prset->index (i)];
                    wall->push_back(curp);
                    wall->push_back(curp+off);
                }
                const osg::Vec3 curp=(*vertices)[prset->index (0)];
                wall->push_back(curp);
                wall->push_back(curp+off);
            }
        }
    }
    return wall;
}
osg::Vec2Array * WallConstraint::getWallTexcoords(const float height) const
{ // return array of points for a wall height high around the constraint
    osg::Vec2Array *tcoords= NULL;
    if (height>0.0) {
        float texrepRound=txxrepWall;
        tcoords= new osg::Vec2Array;
        float circumference=0; // distance around wall to get exact number of repeats of texture
        const osg::Vec3Array *vertices= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
        for (unsigned int ipr=0; ipr<getNumPrimitiveSets(); ipr++) {
            const osg::PrimitiveSet* prset=getPrimitiveSet(ipr);
            osg::Vec3 prevp=(*vertices)[prset->index (prset->getNumIndices()-1)];
                        unsigned int i;
            for (i=0; i<prset->getNumIndices(); i++) {
                const osg::Vec3 curp=(*vertices)[prset->index (i)];
                circumference+=(curp-prevp).length();
                prevp=curp;
            }
            const osg::Vec3 curp=(*vertices)[prset->index (0)];
            circumference+=(curp-prevp).length();
            
            int nround=(int)(circumference/txxrepWall);
            if (nround<1) nround=1; // at least one repeat.
            texrepRound=circumference/nround;
            
            float ds=0;
            prevp=(*vertices)[prset->index (prset->getNumIndices()-1)];
            if (tcoords) {
                for (i=0; i<prset->getNumIndices(); i++) {
                    const osg::Vec3 curp=(*vertices)[prset->index (i)];
                    osg::Vec2 tci=osg::Vec2f(ds/texrepRound,0/txyrepWall);
                    tcoords->push_back(tci);
                    tci=osg::Vec2f(ds/texrepRound,height/txyrepWall);
                    tcoords->push_back(tci);
                    ds+=(curp-prevp).length();
                    prevp=curp;
                }
                osg::Vec2 tci=osg::Vec2f(ds/texrepRound,0/txyrepWall);
                tcoords->push_back(tci);
                tci=osg::Vec2f(ds/texrepRound,height/txyrepWall);
                tcoords->push_back(tci);
            }
        } // per primitiveset
        
    }
    return tcoords;
}
osg::Geometry *WallConstraint::makeWallGeometry() const
{
    osg::ref_ptr<osg::Geometry> gm=new osg::Geometry; // the wall
    if (texture!="") {
        osg::Image* image = osgDB::readImageFile(texture.c_str());
        if (image)
        {
            osg::Texture2D* txt = new osg::Texture2D;
            osg::StateSet* stateset = gm->getOrCreateStateSet();
            txt->setImage(image);
            txt->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::REPEAT );
            txt->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP );
            stateset->setTextureAttributeAndModes(0,txt,osg::StateAttribute::ON);
            osg::Material* material = new osg::Material;
            material->setAmbient(osg::Material::FRONT_AND_BACK,osg::Vec4(1.0f,1.0f,0.0f,1.0f));
            material->setDiffuse(osg::Material::FRONT_AND_BACK,osg::Vec4(1.0f,1.0f,1.0f,1.0f));
            stateset->setAttribute(material,osg::StateAttribute::ON);
            stateset->setMode( GL_LIGHTING, osg::StateAttribute::ON );
        }
    }
    gm->setVertexArray(getWall(height));
    gm->addPrimitiveSet(makeWall());
    gm->setTexCoordArray(0,getWallTexcoords(height));
    gm->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);
    gm->setNormalArray(getWallNormals()); // this creates normals to walls
    
    return gm.release();
}

osg::Vec3Array *ArealConstraint::getWallNormals() const
{
    osg::Vec3Array *nrms=new osg::Vec3Array;
    const osg::Vec3Array *vertices= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
    for (unsigned int ipr=0; ipr<getNumPrimitiveSets(); ipr++) {
        const osg::PrimitiveSet* prset=getPrimitiveSet(ipr);
        if (prset->getMode()==osg::PrimitiveSet::LINE_LOOP) { // nothing else loops
            // start with the last point on the loop
            osg::Vec3 prevp=(*vertices)[prset->index (prset->getNumIndices()-1)];
            for (unsigned int i=0; i<prset->getNumIndices(); i++) {
                const osg::Vec3 curp=(*vertices)[prset->index (i)];
                osg::Vec3 nrm=(curp-prevp)^osg::Vec3(0,0,1);
                nrm.normalize();
                nrms->push_back(nrm);
                nrms->push_back(nrm);
                prevp=curp;
            }
            const osg::Vec3 curp=(*vertices)[prset->index (0)];
            osg::Vec3 nrm=(curp-prevp)^osg::Vec3(0,0,1);
            nrm.normalize();
            nrms->push_back(nrm);
            nrms->push_back(nrm);
        }
    }
    return nrms;
}


osg::Vec3Array * ArealConstraint::getWall(const float height) const
{ // return array of points for a wall height high around the constraint
    osg::Vec3Array *wall=new osg::Vec3Array;
    if (height>0.0) {
        osg::Vec3 off(0,0,height);
        const osg::Vec3Array *vertices= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
        for (unsigned int ipr=0; ipr<getNumPrimitiveSets(); ipr++) {
            const osg::PrimitiveSet* prset=getPrimitiveSet(ipr);
            if (prset->getMode()==osg::PrimitiveSet::LINE_LOOP) { // nothing else loops
                // start with the last point on the loop
                for (unsigned int i=0; i<prset->getNumIndices(); i++) {
                    const osg::Vec3 curp=(*vertices)[prset->index (i)];
                    wall->push_back(curp);
                    wall->push_back(curp+off);
                }
                const osg::Vec3 curp=(*vertices)[prset->index (0)];
                wall->push_back(curp);
                wall->push_back(curp+off);
            }
        }
    }
    return wall;
}

osg::Vec2Array * ArealConstraint::getWallTexcoords(const float height) const
{ // return array of points for a wall height high around the constraint
    osg::Vec2Array *tcoords= NULL;
    if (height>0.0) {
        float texrepRound=txxrepWall;
        tcoords= new osg::Vec2Array;
        float circumference=0; // distance around wall to get exact number of repeats of texture
        const osg::Vec3Array *vertices= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
        for (unsigned int ipr=0; ipr<getNumPrimitiveSets(); ipr++) {
            const osg::PrimitiveSet* prset=getPrimitiveSet(ipr);
            osg::Vec3 prevp=(*vertices)[prset->index (prset->getNumIndices()-1)];
                        unsigned int i;
            for (i=0; i<prset->getNumIndices(); i++) {
                const osg::Vec3 curp=(*vertices)[prset->index (i)];
                circumference+=(curp-prevp).length();
                prevp=curp;
            }
            const osg::Vec3 curp=(*vertices)[prset->index (0)];
            circumference+=(curp-prevp).length();
            
            int nround=(int)(circumference/txxrepWall);
            if (nround<1) nround=1; // at least one repeat.
            texrepRound=circumference/nround;
            
            float ds=0;
            prevp=(*vertices)[prset->index (prset->getNumIndices()-1)];
            if (tcoords) {
                for (i=0; i<prset->getNumIndices(); i++) {
                    const osg::Vec3 curp=(*vertices)[prset->index (i)];
                    osg::Vec2 tci=osg::Vec2f(ds/texrepRound,0/txyrepWall);
                    tcoords->push_back(tci);
                    tci=osg::Vec2f(ds/texrepRound,height/txyrepWall);
                    tcoords->push_back(tci);
                    ds+=(curp-prevp).length();
                    prevp=curp;
                }
                osg::Vec2 tci=osg::Vec2f(ds/texrepRound,0/txyrepWall);
                tcoords->push_back(tci);
                tci=osg::Vec2f(ds/texrepRound,height/txyrepWall);
                tcoords->push_back(tci);
            }
        } // per primitiveset
    }
    return tcoords;
}
osg::DrawArrays* ArealConstraint::makeCanopy( void ) const
{
    return (new osg::DrawArrays(osg::PrimitiveSet::TRIANGLES,0,3*_interiorTris.size()));
}
osg::Vec3Array *ArealConstraint::getCanopy(const osg::Vec3Array *points,const float height) const
{ // returns the array of vertices in the canopy
    osg::Vec3 off(0,0,height);
    osg::Vec3Array *internals=new osg::Vec3Array;
    trilist::const_iterator tritr;
    for (tritr=_interiorTris.begin(); tritr!=_interiorTris.end();tritr++) {
        for (int i=0; i<3; i++) {
            int index=(*tritr)[i];
            internals->push_back((*points)[index]+off);
        }
    }
    return internals;
}
osg::Vec3Array *ArealConstraint::getCanopyNormals(const osg::Vec3Array *points) const
{
    osg::Vec3Array *nrms=new osg::Vec3Array;
    trilist::const_iterator tritr;
    for (tritr=_interiorTris.begin(); tritr!=_interiorTris.end();tritr++) {
        osg::Vec3 e1=(*points)[(*tritr)[1]]-(*points)[(*tritr)[0]];
        osg::Vec3 e2=(*points)[(*tritr)[2]]-(*points)[(*tritr)[0]];
        osg::Vec3 nrm=e1^e2;
        nrm.normalize();
        nrms->push_back(nrm);
    }
    return nrms;
}

osg::Vec2Array *ArealConstraint::getCanopyTexcoords(const osg::Vec3Array *points) const
{
    osg::Vec3Array::const_iterator tritr;
    osg::ref_ptr<osg::Vec2Array> tcoords= new osg::Vec2Array ;
    for (tritr=points->begin(); tritr!=points->end();tritr++) {
                // calculate tcoords for terrain from xy drape.
        osg::Vec2 tci=osg::Vec2f(tritr->x()/txxrepArea, tritr->y()/txyrepArea);
        tcoords->push_back(tci);
    }
    return tcoords.release();
}

osg::DrawArrays * ArealConstraint::makeWall(void) const
{ // build a wall height high around the constraint
    const osg::Vec3Array *_line= dynamic_cast<const osg::Vec3Array*>(getVertexArray());
    return (new osg::DrawArrays(osg::PrimitiveSet::QUAD_STRIP,0,2+2*_line->size()));
}

osg::Geometry *ArealConstraint::makeWallGeometry( osg::Vec3Array *pt) 
{
    osg::ref_ptr<osg::Geometry> gm=new osg::Geometry; // the wall
    osg::ref_ptr<osg::Geometry> edges=new osg::Geometry; // edges of bounds
    edges->setVertexArray(pt);
    osg::DrawElementsUInt *trgeom=getTriangles();
    edges->addPrimitiveSet(trgeom);
    
    osg::ref_ptr<osgUtil::Tessellator> tscx=new osgUtil::Tessellator; // this assembles all the constraints
    tscx->setTessellationType(osgUtil::Tessellator::TESS_TYPE_GEOMETRY);
    tscx->setBoundaryOnly(true);
    tscx->setWindingType( osgUtil::Tessellator::TESS_WINDING_NONZERO); 
    //  find all edges.
    const osg::Vec3Array *points=dynamic_cast<osg::Vec3Array*>(getVertexArray());
    
    tscx->retessellatePolygons(*(edges)); // find all edges
    
    if (walltexture!="") {
        osg::Image* image = osgDB::readImageFile(walltexture.c_str());
        if (image)
        {
            osg::Texture2D* txt = new osg::Texture2D;
            osg::StateSet* stateset = gm->getOrCreateStateSet();
            txt->setImage(image);
            txt->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::REPEAT );
            txt->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP );
            stateset->setTextureAttributeAndModes(0,txt,osg::StateAttribute::ON);
        }
    }
    points=dynamic_cast<osg::Vec3Array*>(edges->getVertexArray());
    int nstart=0;
    osg::ref_ptr<osg::Vec3Array> coords=new osg::Vec3Array;
    osg::ref_ptr<osg::Vec2Array> tcoords=new osg::Vec2Array;
    for (unsigned int i=0; i<edges->getNumPrimitiveSets(); i++) {
        osg::PrimitiveSet *pr=edges->getPrimitiveSet(i);
        if (pr->getMode() == osg::PrimitiveSet::LINE_LOOP) {
            float ds=0;
            for (unsigned int icon=0; icon<pr->getNumIndices(); icon++) {
                unsigned int ithis=pr->index(icon);
                osg::Vec3 pt=                (*points)[ithis];
                coords->push_back(pt);
                coords->push_back(pt+osg::Vec3(0,0,height));
                tcoords->push_back(osg::Vec2(ds/txxrepWall,0));
                tcoords->push_back(osg::Vec2(ds/txxrepWall,1.0));
                if (icon<pr->getNumIndices()-1) ds+=((*points)[pr->index(icon+1)]-(*points)[ithis]).length();
                else ds+=((*points)[pr->index(0)]-(*points)[ithis]).length();
            }
            // repeat first point
            unsigned int ithis=pr->index(0);
            coords->push_back((*points)[ithis]);
            coords->push_back((*points)[ithis]+osg::Vec3(0,0,height));
            tcoords->push_back(osg::Vec2(ds/txxrepWall,0));
            tcoords->push_back(osg::Vec2(ds/txxrepWall,1.0));
            gm->setVertexArray(coords.get());
            gm->setTexCoordArray(0,tcoords.get());
            gm->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUAD_STRIP,nstart,2+2*pr->getNumIndices()));
            nstart+=2+2*pr->getNumIndices();
        }
    }
    
    return gm.release();
}


osg::Geometry * ArealConstraint::makeAreal( osg::Vec3Array *points) 
{
    osg::ref_ptr<osg::Geometry> gm; // the fill in area
    if (_interiorTris.size()>0) {
        gm =new osg::Geometry; // the forest roof
        gm->setVertexArray(points);
        osg::DrawElementsUInt *trgeom=getTriangles();
        gm->addPrimitiveSet(trgeom);
        gm->setNormalArray(getCanopyNormals(points));
        gm->setNormalBinding(osg::Geometry::BIND_PER_PRIMITIVE);
        gm->setTexCoordArray(0,getCanopyTexcoords(points));
        osg::Image* image = osgDB::readImageFile(texture);
        if (image)
        {
            osg::Texture2D* txt = new osg::Texture2D;
            osg::StateSet* stateset = gm->getOrCreateStateSet();
            txt->setImage(image);
            txt->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::REPEAT );
            txt->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::REPEAT );
            stateset->setTextureAttributeAndModes(0,txt,osg::StateAttribute::ON);
            osg::Material* material = new osg::Material;
            material->setAmbient(osg::Material::FRONT_AND_BACK,osg::Vec4(1.0f,1.0f,1.0f,1.0f));
            material->setDiffuse(osg::Material::FRONT_AND_BACK,osg::Vec4(1.0f,1.0f,1.0f,1.0f));
            stateset->setAttribute(material,osg::StateAttribute::ON);
            stateset->setMode( GL_LIGHTING, osg::StateAttribute::ON );
        }
    }
    return gm.release();
}


void LinearConstraint::setVertices( osg::Vec3Array *lp, const float w)
{ // generate constant width around line (calls setvertices(edges))
    osg::ref_ptr<osg::Vec3Array> edges=new osg::Vec3Array;
    _tcoords=new osg::Vec2Array; // texture coordinates for replacement geometry
    _edgecoords=new osg::Vec3Array; // posiiton coordinates for replacement geometry
    width=w;
    _midline=lp;
    float ds=0;
    for(unsigned int i=0;i<lp->size();i++) {
        osg::Vec3 valong;
        osg::Vec3 pos[2];
        
        if (i==0) {
            valong=(*lp)[i+1]-(*lp)[i];
        } else if (i==lp->size()-1) {
            valong=(*lp)[i]-(*lp)[i-1];
        } else {
            valong=(*lp)[i+1]-(*lp)[i-1];
        }
        valong.normalize();
        osg::Vec3 vperp=valong^osg::Vec3(0,0,1);
        pos[0]=(*lp)[i]-vperp*.5*width;
        pos[1]=(*lp)[i]+vperp*.5*width;
        edges->push_back(pos[0]);
        _edgecoords->push_back(pos[0]);
        _tcoords->push_back(osg::Vec2(0/txyrepAcross,ds/txxrepAlong));
        edges->insert(edges->begin() ,pos[1]);
        _edgecoords->insert(_edgecoords->begin() ,pos[1]);
        _tcoords->insert(_tcoords->begin() ,osg::Vec2(width/txyrepAcross,ds/txxrepAlong));
        if (i<lp->size()-1) ds+=((*lp)[i+1]-(*lp)[i]).length();
    }
    setVertexArray(edges.get());
    addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,edges->size()) );
}

osg::DrawArrays* LinearConstraint::makeRoad(void ) const
{
    return     new osg::DrawArrays(osg::PrimitiveSet::QUAD_STRIP,0,2*_midline->size());
    
}

osg::Vec3Array *LinearConstraint::getRoadNormals(const osg::Vec3Array* /*points*/) const
{
    osg::Vec3Array *nrms=new osg::Vec3Array;
    for(unsigned int i=0;i<_midline->size();i++) {
        osg::Vec3 valong; // vector along midline of road
        if (i==0) {
            valong=(*_midline)[i+1]-(*_midline)[i];
        } else if (i==_midline->size()-1) {
            valong=(*_midline)[i]-(*_midline)[i-1];
        } else {
            valong=(*_midline)[i+1]-(*_midline)[i-1];
        }
        osg::Vec3 vperp=valong^osg::Vec3(0,0,1);
        osg::Vec3 nrm=vperp^valong; // normal to linear
        nrm.normalize();
        nrms->push_back(nrm); // repeated for each vertex of linear.
        nrms->push_back(nrm);
    }
    return nrms;
}
osg::Vec3Array *LinearConstraint::getRoadVertices() const
{
    osg::Vec3Array *linearEdges=new osg::Vec3Array;
    for(unsigned int i=0;i<_midline->size();i++) {
        osg::Vec3 valong; // vector along midline of road
        if (i==0) {
            valong=(*_midline)[i+1]-(*_midline)[i];
        } else if (i==_midline->size()-1) {
            valong=(*_midline)[i]-(*_midline)[i-1];
        } else {
            valong=(*_midline)[i+1]-(*_midline)[i-1];
        }
        valong.normalize();
        osg::Vec3 vperp=valong^osg::Vec3(0,0,1); // vector across road
        // sides of linear
        linearEdges->push_back((*_midline)[i]-vperp*.5*width);
        linearEdges->push_back((*_midline)[i]+vperp*.5*width);
    }
    return linearEdges;
}

osg::Vec2Array *LinearConstraint::getRoadTexcoords(const osg::Vec3Array *points)  {
    // need to create a vec2 array from the coordinates that fits the road
    osg::Vec3Array::const_iterator tritr;
    osg::ref_ptr<osg::Vec2Array> tcoords= new osg::Vec2Array ;
    for (tritr=points->begin(); tritr!=points->end();tritr++) {
        osg::Vec2 tci(-1.,-1.);
        int ib=0;
        // osg::Vec3Array *varr=dynamic_cast<osg::Vec3Array*>(getVertexArray());
        bool ptfound=false;
        for (osg::Vec3Array::iterator vit=_edgecoords->begin(); vit!= _edgecoords->end() && !ptfound; vit++) {
            if ((*vit)==(*tritr)) {
                tci=_tcoords->at(ib);
                ptfound=true;
            }
            ib++;
        }
        if (!ptfound) { // search for surrounding points and interpolate
            ib=0;
            osg::Vec3 pminus=(_edgecoords->back()); // need pminus for interpolation
            int ibm1=_edgecoords->size()-1;
            for (osg::Vec3Array::iterator vit=_edgecoords->begin(); vit!= _edgecoords->end() /*&& !ptfound*/; vit++) {
                osg::Vec3 pplus=(*vit)-(*tritr);
                osg::Vec3 dpm=pminus-(*tritr);
                pplus.set (pplus.x(),pplus.y(),0);
                dpm.set (dpm.x(),dpm.y(),0);
                float dprod=pplus*dpm/(pplus.length() * dpm.length());
                if (dprod<-0.9999) { // *tritr lies between....
                    osg::Vec2 tminus=_tcoords->at(ibm1);
                    osg::Vec2 tplus=_tcoords->at(ib);
                    float frac=(dpm.length()/(dpm.length()+pplus.length()));
                    tci=tminus+((tplus-tminus)*frac);
                    ptfound=true;
                }
                ibm1=ib;
                ib++;    
                pminus=(*vit);
            }
        }
        tcoords->push_back(tci);
    }
    // some extra points are not interpolated as they lie between 2 interpolated vertices
    for (tritr=points->begin(); tritr!=points->end();tritr++) {
        int ib=tritr-points->begin();
        osg::Vec2 tci=tcoords->at(ib);
        if (tci.x()<-.99 && tci.y()<-.99) {
            // search through each of the primitivesets
            osg::Vec3Array::const_iterator ptitr;
            //    osg::notify(osg::WARN) << "Not calculated " <<  (*tritr).x() <<"," << (*tritr).y() << std::endl;
            for (ptitr=points->begin(); ptitr!=points->end();ptitr++) {
            }
        }
    }
    return tcoords.release();
}
osg::Vec3Array * LinearConstraint::getNormals(const osg::Vec3Array *points) 
{
    osg::ref_ptr<osg::Vec3Array> norms=new osg::Vec3Array;
    for (osg::DrawElementsUInt::iterator uiitr=prim_tris_->begin(); uiitr!=prim_tris_->end();uiitr+=3) {
        osg::Vec3 e1=(*points)[*(uiitr+1)]-(*points)[(*uiitr)];
        osg::Vec3 e2=(*points)[*(uiitr+2)]-(*points)[*(uiitr+1)];
        osg::Vec3 n=e1^e2;
        n.normalize();
        //    if (n.z()<0) n=-n;
        norms->push_back(n);
    }
    return norms.release();
}

osg::Geometry * LinearConstraint::makeGeometry(const osg::Vec3Array *points) 
{
    osg::ref_ptr<osg::Geometry> gm=new osg::Geometry; // the fill in road/railway
    if (_midline->size()>0) {
        osg::ref_ptr<osg::Vec3Array> locpts=getPoints(points);
        if (texture!="") {
            osg::Image* image = osgDB::readImageFile(texture.c_str());
            if (image)
            {
                osg::Texture2D* txt = new osg::Texture2D;
                osg::StateSet* stateset = gm->getOrCreateStateSet();
                txt->setImage(image);
                txt->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::REPEAT );
                txt->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::REPEAT );
                stateset->setTextureAttributeAndModes(0,txt,osg::StateAttribute::ON);
                osg::Material* material = new osg::Material;
                material->setAmbient(osg::Material::FRONT_AND_BACK,osg::Vec4(1.0f,1.0f,1.0f,1.0f));
                material->setDiffuse(osg::Material::FRONT_AND_BACK,osg::Vec4(1.0f,1.0f,1.0f,1.0f));
                stateset->setAttribute(material,osg::StateAttribute::ON);
                stateset->setMode( GL_LIGHTING, osg::StateAttribute::ON );
            }
            gm->setTexCoordArray(0,getRoadTexcoords(locpts.get()));
        }
        gm->setVertexArray(locpts.get());
        gm->setNormalArray(getNormals(locpts.get()));
        gm->setNormalBinding(osg::Geometry::BIND_PER_PRIMITIVE);
        gm->addPrimitiveSet(getTriangles());
    }
    
    return gm.release();
    
}



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

    // construct the viewer.
    osgViewer::Viewer viewer;

    // create the scene from internal specified terrain/constraints.
    osg::ref_ptr<osg::Node> loadedModel = makedelaunay(0);
    
    // if no model has been successfully loaded report failure.
    if (!loadedModel) 
    {
        std::cout << arguments.getApplicationName() <<": No data loaded" << std::endl;
        return 1;
    }
    
    // optimize the scene graph, remove rendundent nodes and state etc.
    osgUtil::Optimizer optimizer;
    optimizer.optimize(loadedModel.get());
    
    // pass the loaded scene graph to the viewer.
    viewer.setSceneData(loadedModel.get());
    
    // copied from osgtessealte.cpp
    // add event handler for keyboard 'n' to retriangulate
    viewer.addEventHandler(new KeyboardEventHandler(viewer));
    
    return viewer.run();
}