Hi. I have a sketch in wich I create an arraylist of balls that flow in a pipe. Now I want to create diferent pipes, so I created a pipe class. I had a line inside the draw function that created new balls and was this:

 

balls.add(new ball(int(random(leftborder,rightborder)), int(random(0,height))));

 

and woked correctly.

 

Now I´ve moved this line inside the pipe class, for the balls to be created inside their pipe. The line is inside a function called inicialize() inside the pipe class.

 

A message appears:

 

the constructor pipes.ball (int, int) is undefined.

 

Pipes is the name of the file.

 

This is the complete code:

 

class Pipe{
 float leftborder;
 float rightborder;
 float pipediam;
 float middle;
 float reslenght = 100;
 float respoint;
 float vaverage = 4;
 // pipe rendered
 int pipesize = 60;
 float rightside;
 float leftside;
 Pipe(float leftborder0, float rightborder0, float pipediam0){
   leftborder = leftborder0;
   rightborder = rightborder0;
   pipediam = pipediam0;
   rightside = middle + pipesize/2;
   leftside = middle - pipesize / 2;
 }
 void inicialize(){
  middle =(leftborder + rightborder)/2;
  respoint = height/2;
  for (int i = 0; i < population; i++){
    balls.add(new ball(int(random(leftborder,rightborder)), int(random(0,height))));
  }
 }
 void bounceAndRender(){
  for(int i=0;i<balls.size();i++){  
    ball b = (ball) balls.get(i);  
    //separate from walls
    if(b.pos.x>rightborder-b.r+c){b.pos.x=rightborder;}
    if(b.pos.x<leftborder + b.r-c){b.pos.x=leftborder;}
    if(b.pos.y>height-b.r+c){b.pos.y-=5;}
    //repulsion between balls 
    for(int j=i+1;j<balls.size();j++){
      ball b2 = (ball) balls.get(j);
      PVector dx=PVector.sub(b2.pos,b.pos);
      if (dx.mag() < suck){
        dx.normalize();
        dx.mult(repulsion);
        b2.force.add( dx);
        dx.mult(-1);
        b.force.add( dx);
      }
    }
    //repulsion to walls
    if (b.pos.x < suck + leftborder){
      b.force.x = b.force.x + repulsion;
    }
    if (b.pos.x > rightborder - suck){
      b.force.x = b.force.x - repulsion;
    }
    b.update();
    // corrections
    if (b.v.y < 0){b.v.y = 0;}
   
    b.render();
    if (b.pos.y > height){
     b.pos.y = 0;
    }  
  }
 }

 void render(){
   fill(20,20,2000);
   rect (leftside - 4, 0, 4 , (height - reslenght)/2);
   rect (rightside, 0, 4 , (height - reslenght)/2);
   rect (leftside - 4, (height + reslenght)/2, 4 , (height - reslenght)/2);
   rect (rightside, (height + reslenght)/2, 4 , (height - reslenght)/2);
   ellipse(leftside - 2 , respoint, 0.5* pipesize, reslenght);
   ellipse (rightside + 2, respoint, 0.5 * pipesize, reslenght);
   fill (255);
   ellipse(leftside - 6 , respoint, 0.5* pipesize, reslenght);
   ellipse (rightside + 6, respoint, 0.5 * pipesize, reslenght);
 }
}
class ball{
  PVector pos;
  PVector v;
  PVector force;
  color c;
  int r=3;
  float f = 0.1;
  float g = 0.1;
  Pipe pipe;
  ball(int x0, int y0 , Pipe pipe0){
    pos=new PVector(x0,y0);
    v=new PVector(0,4);
    force = new PVector (0,0);
    pipe = pipe0;
  }
  void update(){
    v.y =  pipe.vaverage * (0.5 +(1 - sq(pos.x - pipe.middle)/sq(pipe.pipediam/2)));  
    v.add (force);
    //add some chaos
    v.x = v.x + random(-0.3,0.3);
    count++;
    //v.y = v.y + g ;
    pos.add(v);
    v.x = v.x*0.5;
    force.x = 0;
    force.y = 0;
  }
  void render(){
     
      float posx;
      float posy;
     
    
     
      if ((pos.y > pipe.respoint - pipe.reslenght/2)&& (pos.y < respoint + pipe.reslenght/2)){
        float xini = pipe.leftside + 0.25 * pipe.pipesize* (1 - abs(pos.y - pipe.respoint) /pipe.reslenght);
         posx = xini + (pipe.pipesize - 2 * (xini - pipe.leftside))  * (pos.x - pipe.leftborder)/pipe.pipediam;
      }
      else
      {
        posx = pipeleftside + pipe.pipesize * (pos.x - pipe.leftborder)/pipe.pipediam;
      }
      ellipse(int(posx),int(pos.y),2.5,2.5);
     

    //}
  }
}
Pipe thepipe;
float count;
int width=800;
int height=600;
float g=2;
ArrayList balls= new ArrayList();
float k=1;//factor to increment distance between balls
float c= 4;//maximun penetrance in walls
//float vlim=10;//maximum speed
float population=1000;//population limit
float suck = 20;// distance of influence

//float visc;

float repulsion = 0.1;

void setup(){
 
  noStroke();
  size(width,height);
  thepipe = new Pipe( width/2-600/2, width/2 + 600/2, 600);
  thepipe.inicialize();
 
 
}
void draw(){
  fill (250,150);
  thepipe.render();
  rect(0,0,width, height);
  thepipe.bounceAndRender();
   

}