lsystem.h

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#ifndef __LSYSTEM_H
#define __LSYSTEM_H


#include <boost/algorithm/string.hpp>
#include <string>
#include <list>
#include "image.h"
#include "image_draw.h"

namespace mimas {

  class lsystem: public object
  {
    public:
      void setLstring(std::string str);
      std::string getLstring();
      void setAxiom(std::string str); 
      void setRule(std::string rule); 
      void setAngleStep(int val); 
      void iterate(int numIterations=1); 
      void setLineLength(double val); 
      template<typename T>void drawLsystem(image<T> &image, int startx, int starty, T colour); 
      lsystem();

    private:
      std::string lstring, axiom, rule;
      int anglestep;
      double d;
  };



  lsystem::lsystem()
  {
    // Example L-system
    // Adrian Mariono's Bush
    setAxiom("F");
    setRule("FF-[-F+F+F]+[+F-F-F]");
    setLstring("++++F");
    setAngleStep(22);
    setLineLength(5.0);
  }


  void lsystem::setLstring(std::string str)
  {
    lstring=str;
  }


  std::string lsystem::getLstring()
  {
    return lstring;
  }


  void lsystem::setAxiom(std::string str)
  {
    axiom=str;
  }


  void lsystem::setRule(std::string str)
  {
    rule=str;
  }



  void lsystem::setAngleStep(int val)
  {
    anglestep=val;
  }


  void lsystem::iterate(int numIterations)
  {
    if (numIterations<1) return;

    for (int i=0; i<numIterations; i++)
      boost::replace_all(lstring,axiom,rule);
  }


  void lsystem::setLineLength(double val)
  {
    // distance to move when drawing
    d=val;
  }

  template<typename T>
    void lsystem::drawLsystem(image<T> &image, int startx, int starty, T colour)
    {
      std::list<double> xlist;
      std::list<double> ylist;
      std::list<int> anglelist;

      double x=(double)startx,y=(double)starty;
      int angle=0; // initial angle
      double theta;

      for (int i=0; i<(int)lstring.length(); i++)
      {
        double newx, newy;
        theta=M_PI*(double)angle/180.0;
        switch(lstring[i])
        {
          case 'F' :
            newx=(x+d*cos(theta));
            newy=(y-d*sin(theta));
            drawLine(image,(int)x,(int)y,(int)newx,(int)newy,colour);
            x=newx;
            y=newy;
            break;
          case '+' :
            angle+=anglestep;
            break;
          case '-' : 
            angle-=anglestep;
            break;
          case '[':
            xlist.push_back(x);
            ylist.push_back(y);
            anglelist.push_back(angle);
            break;
          case ']':
            if (anglelist.size()>0)
            {
              x=xlist.back();
              y=ylist.back();
              angle=anglelist.back();
              xlist.pop_back();
              ylist.pop_back();
              anglelist.pop_back();
            }
            break;
          default:
            break;
        }

      }

    }


};


#endif

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