gistfile1.txt

import igeo.*;
import processing.pdf.*;

void setup(){ 
  size(480,360,IG.GL);
  beginRecord(PDF, "everything.pdf");
  for(int i=0; i < 1; i++){ //Changing I < Value Changes charges
    new LineAgent(new IParticle(IRand.pt(-40,-40,0,40,40,0)).hide().fric(0.2), IRand.dir(IG.zaxis).len(2));
  }
  for(int i=0; i < 20; i++){
    new IAttractor(IRand.pt(-200,-200,0,200,200,0)).linear(50).intensity(-30); //repulsion force
  }
  IG.bg(1.0,1.0,1.0);
  IG.top();
}

class LineAgent extends IParticle{ 
  LineAgent parent;
  boolean isColliding;
  IVec dir;
    
  LineAgent(IParticle parent, IVec dir){
    super(parent.pos().cp(dir));
    if(parent instanceof LineAgent){
      this.parent = (LineAgent)parent;
    }
    isColliding=false;
    hide(); // hide point
    this.dir = dir;
    fric(0.2);
  }
  
  void interact(ArrayList agents){ 
    if(time()==0){ //only in the first time 
      for(int i=0; i < agents.size(); i++){
        if(agents.get(i) instanceof LineAgent){
          LineAgent lineAgent = (LineAgent)agents.get(i); 
          if(lineAgent!=this){ //agents include "this"
            if(lineAgent.parent!=null && lineAgent.pos().dist(pos()) < pos().dist(parent.pos())*2){
              IVec intxn = IVec.intersectSegment(lineAgent.parent.pos(),lineAgent.pos(),parent.pos(),pos());
              if( intxn != null && !intxn.eq(parent.pos()) && !lineAgent.isColliding ){
                isColliding = true;
                return;
              }
            }
          }
        }
      }
    }
  }
  
  void update(){
    if( isColliding ){ 
      del();
    }
    else{
      if(time()==0 && alive()){
        if(parent!=null && parent.alive()){
          ISpringLine ln = new ISpringLine(this, parent,100);
          double t = -cos(IG.time()*0.015)*0.5+0.5; 
          ln.hsb( 0.7-t*0.2, 1, 0.8-t*0.2, 0.5); // color by time
          if(parent.parent!=null && parent.parent.alive()){
            IStraightenerCurve st = 
		new IStraightenerCurve(this,parent,parent.parent).tension(100);
            st.hsb( 0.7-t*0.2, 1, 0.8-t*0.2, 0.5);
          }
        }
      }
      if(time()==4){
        IVec dir2 = dir.cp();
        double angle = PI*0.12 ;
        if( IRand.pct(50) ){ 
          dir.rot(angle);
          dir2.rot(-angle);
        }
        else{
          dir.rot(-angle);
          dir2.rot(angle);
        }
        new LineAgent(this, dir);
        if( IRand.pct(20) ){ // 20% branching probability
          new LineAgent(this,dir2);
        }
      }
    }
  }
}

void keyPressed() {
  if (key=='R');{
    endRecord();
    exit();
  }
}