FunctionGenBox boxes[] = new FunctionGenBox[4];
FunctionGenBox drag;

void setup() {
  size(640,480);
  frameRate(30);

  for(int i=0; i<boxes.length; i++) {
    boxes[i] = new FunctionGenBox(150, (int)random(30, 300));
    boxes[i].x = i * 175.;
    boxes[i].y = height / 2. - 75;

    boxes[i].setAll(boxes);     // let boxes be aware of the rest
  }

  // let each box see the rest


  drag = null;
}

void draw() {
  background(200);

  fill(225);
  rect(0, height / 2. - 80, width, 160);

  for(int i=0; i<boxes.length; i++) {
    boxes[i].stepAndRender();
  }
}

void mouseDragged() {
  if (drag != null) {
    drag.moveBy(mouseX - pmouseX, 0);//mouseY - pmouseY);
  }
}

void mousePressed() {
  for(int i=0; i<boxes.length; i++) {
    drag = null;
    // check for mouse over
    if(mouseX >= boxes[i].x && mouseX <= boxes[i].x + boxes[i].w &&
       mouseY >= boxes[i].y && mouseY <= boxes[i].y + boxes[i].h) {
      
      drag = boxes[i];
      break;
    }
  }
  
  
}