int fc;

void setup() {
  size(400,400,P3D); 
  fc=0;
  //smooth(); 
  maxD=5;
  initHair();
}

void draw() {
  background(255);
  fc++; 
  if (fc==20) {
    mouseInit=true;
    //saveFrame("C:/Documents and Settings/Marcus/Mijn documenten/Processing artwork/Hairfield-####.tga");
  }
  if (mouseInit) {
    mouseInit=false;
    initHair();
  }
  updateHair();
}


boolean mouseInit=false;
void mousePressed() {
  mouseInit=true;
}

int nr_hairs;
Hair[] hair;
int maxD;

void initHair() {
  background(255); 
  fc=0;
  nr_hairs=5000; 
  maxD++; 
  maxD=(int)random(5,200);
  hair=new Hair[nr_hairs];
  for (int i=0;i<nr_hairs;i++) {
    hair[i]=new Hair(i);
  }
}

void updateHair() {
  for (int i=0;i<nr_hairs;i++) {
    hair[i].update();
  }
}

class Hair {
  int id;
  float len;
  float dir, rot;
  float x1,y1,x2,y2;
  color c;
  Hair(int id) {
    this.id=id;
    len=random(5,18);
    dir=random(TWO_PI);
    rot=random(-0.05,0.05);
    x1=random(width+40)-20; 
    y1=random(height+40)-20;
    if (random(1)<0.9) {
      int br=(int)random(75); 
      c=color(br,br,br,50);
    } 
    else {
      int br=(int)random(75); 
      c=color(br+75,br,br,50);
    }
  }

  void update() {

    for (int i=0;i<500;i++) {
      float d=dist(x1,y1,hair[i].x1,hair[i].y1);
      if (d>1&&d<maxD) {
        float tdir=hair[i].dir;
        if (tdir<0) {
          tdir+=TWO_PI;
        }
        if (dir<0) {
          dir+=TWO_PI;
        }
        if (abs(tdir-dir)<PI) {
          rot+=0.01/d;
        } 
        else {
          rot-=0.01/d;
        }
      }
      dir+=rot;
      rot*=0.99;
    }
    dir*=0.5;
    x2=x1+len*cos(dir);
    y2=y1+len*sin(dir);
    stroke(c); 
    line(x1,y1,x2,y2);
  }

}