DXFWriterNodeVisitor.h

// -*-c++-*-

/*
 * Wavefront DXF loader for Open Scene Graph
 *
 * Copyright (C) 2001 Ulrich Hertlein <u.hertlein@web.de>
 *
 * Modified by Robert Osfield to support per Drawable coord, normal and
 * texture coord arrays, bug fixes, and support for texture mapping.
 *
 * Writing support added 2007 by Stephan Huber, http://digitalmind.de,
 * some ideas taken from the dae-plugin
 *
 * The Open Scene Graph (OSG) is a cross platform C++/OpenGL library for
 * real-time rendering of large 3D photo-realistic models.
 * The OSG homepage is http://www.openscenegraph.org/
 */

 #ifndef DXF_WRITER_NODE_VISITOR_HEADER__
 #define DXF_WRITER_NODE_VISITOR_HEADER__


#include <string>
#include <stack>
#include <sstream>

#include <osg/Notify>
#include <osg/Node>
#include <osg/MatrixTransform>
#include <osg/Geode>

#include <osg/Geometry>
#include <osg/StateSet>
#include <osg/Material>
#include <osg/Texture2D>
#include <osg/TexGen>
#include <osg/TexMat>

#include <osgDB/Registry>
#include <osgDB/ReadFile>
#include <osgDB/FileUtils>
#include <osgDB/FileNameUtils>


#include <map>
#include <set>
#include <iostream>
struct Layer
{
public:
    Layer(const std::string name="",unsigned int color=7) : _name(name),_color(color)  { }
    std::string _name;
    unsigned int _color;
};

// reuse aci class for autocad colors, see http://bitsy.sub-atomic.com/~moses/acadcolors.html for samples
#include "aci.h"
class AcadColor
{
public:
    AcadColor()
    {
        int index=10;
        for (int ii=10*3;ii<256*3; ) {
            // find RGB for each Autocad index colour
            unsigned int red = (int)floor(aci::table[ii++]*255.0f);
            unsigned int green = (int)floor(aci::table[ii++]*255.0f);
            unsigned int blue = (int)floor(aci::table[ii++]*255.0f);
            unsigned int rgb = (red<<16) + (green<<8) + blue;
            _indexColors[rgb]=index++;
        }
        //
    }

    // returns Autocad index color for supplied RGB.
    // if no exact match is found returns nearest color based on hue
    //  also adds match to cache for future lookups.
    int findColor(unsigned int rgb)
    {
        int aci = 255;
        ColorMap::const_iterator itr = _indexColors.find(rgb);
        if (itr != _indexColors.end() ) {
            aci = itr->second;
        } else {
            // not found - match based on hue
            aci = nearestColor(rgb);

            // add matching colour to list to cache
            _indexColors[rgb]=aci;
        }
        return aci;
    }

protected:
    // returns hue as an angle in range 0-360, saturation and value as 0-1
    void hsv(unsigned int rgb,float &hue,float &sat,float &value)
    {
        int red = rgb>>16;
        int green = (0x0000ff00&rgb)>>8;
        int blue = 0x000000ff&rgb;
        int H=std::max(std::max(red,green),blue);
        int L=std::min(std::min(red,green),blue);

        value = (float)H/255.0f;  // note hsv and hsl define v differently!
        sat=(float)(H-L)/(float)H;

        if (H==L) {
            hue=0.0;
        }else if (H==red) {
            hue=360.0 + (60.0 * (float)(green-blue)/(float)(H-L));
            if ( hue > 360 ) { hue-=360; }
        } else if (H==green) {
            hue=120.0 + (60.0 * (float)(blue-red)/(float)(H-L));
        } else if (H==blue) {
            hue=240.0 + (60.0 * (float)(red-green)/(float)(H-L));
        } else {
            hue = 0.0;
        }
    }

    int  nearestColor(unsigned int rgb)
    {
        //- match based on hue
        float h;
        float s;
        float v;
        hsv(rgb,h,s,v);

        // aci index format is
        // last digit odd = 50% sat, even=100%
        // last digit 0,1 = 100% value, 2,3=80%, 4,5=60% 6,7=50%, 8,9=30%
        //  first two digits are hue angle /1.5 but count starts at 10, first 9 values are dummy named colours
        int aci=10 + (int)(h/1.5);
        aci -= (aci%10); // ensure last digit is zero

        if ( v < 0.3 ) {
            aci += 9;
        } else if ( v < 0.5 ) {
            aci += 6;
        } else if ( v < 0.6 ) {
            aci += 4;
        } else if ( v < 0.8 ) {
            aci += 2;
        } else {
            // last digit=0;
        }

        if ( s<0.5 ) {
            aci += 1;
        }

        return aci;
    }



protected:

    typedef std::map<unsigned int, unsigned char> ColorMap;
    ColorMap _indexColors; // maps RGB to autocad index colour
    ColorMap _hueColors; // maps hue angle to autocad index colour
};

class DXFWriterNodeVisitor: public osg::NodeVisitor {

    public:
        DXFWriterNodeVisitor(std::ostream& fout) :
            osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN),
            _fout(fout),
            _currentStateSet(new osg::StateSet()),
            _count(0),
            _firstPass(true),
            _writeTriangleAs3DFace(true)
        {


        }

        static unsigned int getNodeRGB(osg::Geometry *geo,unsigned int index=0)
        {
            osg::Vec4Array* data=static_cast<osg::Vec4Array*>(geo->getColorArray());
            if ( data && index<data->size() ) {
                return (data->at(index).asABGR())>>8;
            }
            return 0;
        }


        bool writeHeader(const osg::BoundingSphere &bound);// call after first pass to trigger draw pass
        void writeFooter();

        void buildColorMap();

        virtual void apply(osg::Geode &node);

         virtual void apply(osg::Group &node)
        {
            osg::NodeVisitor::traverse( node );

        }

        void traverse (osg::Node &node)
        {
            pushStateSet(node.getStateSet());

            osg::NodeVisitor::traverse( node );

            popStateSet(node.getStateSet());
        }

        void pushStateSet(osg::StateSet* ss)
        {
          if (NULL!=ss) {
            // Save our current stateset
            _stateSetStack.push(_currentStateSet.get());

            // merge with node stateset
            _currentStateSet = static_cast<osg::StateSet*>(_currentStateSet->clone(osg::CopyOp::SHALLOW_COPY));
            _currentStateSet->merge(*ss);
          }
        }


        void popStateSet(osg::StateSet* ss)
        {
            if (NULL!=ss) {
              // restore the previous stateset
              _currentStateSet = _stateSetStack.top();
              _stateSetStack.pop();
            }
        }

        int getNodeAcadColor(osg::Geometry* /*geo*/,int /*index*/=0) { return 0;}

    protected:
        struct CompareStateSet
        {
            bool operator()(const osg::ref_ptr<osg::StateSet>& ss1, const osg::ref_ptr<osg::StateSet>& ss2) const
            {
                return ss1->compare(*ss2, true) < 0;
            }
        };


    private:

        DXFWriterNodeVisitor& operator = (const DXFWriterNodeVisitor&) { return *this; }

        // first pass get layer names and draw types
        void makeGeometryLayer(osg::Geometry* geo);

        // second pass - output data
        void processGeometry(osg::Geometry* geo, osg::Matrix& m);


        void processArray(osg::Array* array, const Layer& layer,const osg::Matrix& m = osg::Matrix::identity());

        void processStateSet(osg::StateSet* stateset);

        std::string getLayerName(const std::string& defaultValue = "");

        typedef std::stack<osg::ref_ptr<osg::StateSet> > StateSetStack;




        std::ostream&                            _fout;
        std::list<std::string>                    _nameStack;
        StateSetStack                            _stateSetStack;
        osg::ref_ptr<osg::StateSet>                _currentStateSet;

        unsigned int             _count;
        std::vector<Layer>       _layers;
        bool                     _firstPass;
        Layer                    _layer;

        bool                     _writeTriangleAs3DFace;

        AcadColor                _acadColor;


};

#endif