// press any key to reset, drag-release mouse to distribute points

void setup() {
  size(400,300);
  reset();
}

int num=69;
Ball[] b=new Ball[num];
boolean moving=false; // if balls are moving to the line
int d=0; // current recorded mouse point
int[] recx=new int[num];
int[] recy=new int[num];
int dSS;

void draw(){
  background(10,20,30);
  for (int i=0;i<num;i++){

    if (!moving){
	b[i].move();
    } 
    else {
	//repeat();
	stroke(255,255,0);
	if (i>0){
	  line(recx[i],recy[i],recx[i-1],recy[i-1]);
	}
	b[i].x+=(recx[i]-b[i].x)*.05;
	b[i].y+=(recy[i]-b[i].y)*.05;
    }
    b[i].show();
  }
}

void mouseDragged(){
  moving=false;
  if (d==0){
    for (int i=0;i<num;i++){
	recx[i]=mouseX; // reset previous draw;
	recy[i]=mouseY;
    }
  }
  if (mousePressed==true){
    for (int i=1;i<d;i++){
	stroke(255);
	line(recx[i],recy[i],recx[i-1],recy[i-1]);
    }
  }
  if (d<num){   
    recx[d]=mouseX;
    recy[d]=mouseY;
    d++;
  } 
}

void mouseReleased(){
  if (d<num){ //i use it  when mouse records number (recx, recy) is smaller than particle number (num)  
    dSS=-1;
    for (int i=d;i<num;i++){
	if (d>0){ 
	  dSS+=2;
	  //println(i+"="+dSS);
	  if(i>dSS){
	    recx[i]=recx[i-dSS]; //so empty mouse records are filled with previous mouse records 
	    recy[i]=recy[i-dSS]; // not elegant.... i know... any better ideas?
	  }
	}
    }

  }
  moving=true;
  d=0;
}

void reset(){
  for (int i=0;i<num;i++){
    b[i]=new Ball(random(-2,2),width/2,random(height));
  }
}

void keyReleased(){
  reset();
  moving=false;
}

class Ball{
  float speed;
  float x;
  float y;
  Ball (float _speed, float _x, float _y) {
    speed=_speed;
    x=_x;
    y=_y;
  }

  void move(){
    x+=speed;
    borders();
  }

  void show(){
    noFill();
    stroke(255,0,0);
    ellipse(x,y,5,5);
  }
  
  void borders(){
  if (x<0){
    x=width;
  }
  if (x>width){
    x=0;
  }
  }
}