changing_speed_of_balls_with_scroll

import java.util.Random;
import controlP5.*;

Random randa = new Random();
ControlP5 cp5;

int button_height =30, pozX =2, button_width = 106, h = 0, hi = 1;
int pozXSet = pozX + button_width, control = 10, currentIndex = 0;
int control2 = control, MaxFar = 100, Multi = 10, start;
float mass, radius, G_const = 0.6673, scrollMovement = 0, pozYSet[] = new float[2];
boolean stopStart = false;//true - everything is working , false - everything is stoped
boolean field = false;//true -  central field , false -  homogeneous field
boolean information = false;
boolean[] scrollMenuOpenByMouse = new boolean[5];
ArrayList<Circum> cir = new ArrayList<Circum>(control);
PVector  grav = new PVector(0.00, 5.00);
PVector  air_re = new PVector(0.004, 0.004);
PVector  inic = new PVector(0.0005, 0.0005);
PVector air;
String buttonName;



void setup() {
  //fullScreen(P2D, 1);
  size(1500, 800, P2D);
  stroke(255);
  background(255);

  cp5 = new ControlP5(this);

  //creating buttons

  cp5.addButton("Menu").setPosition(pozX, 1).setSize(button_width, button_height);
  cp5.addButton("Reset").setPosition(pozX, button_height).setSize(button_width, button_height);
  hi++;
  cp5.addButton("StartStop").setPosition(pozX, button_height * hi).setSize(button_width, button_height).setCaptionLabel("Uruchomienie programu");
  hi++;
  cp5.addButton("Homogen").setPosition(pozX, button_height * hi).setSize(button_width, button_height).setCaptionLabel(" Pole jednorodne").setVisible(false).setValue(1);
  hi++;
  cp5.addButton("Central").setPosition(pozX, button_height * hi).setSize(button_width, button_height).setCaptionLabel(" Pole centralne").setVisible(false).setValue(1);

  //creating random circles
  for (int i = 0; i <control; i++)
  {
    mass = 20 * randa.nextFloat() + 4;
    radius = mass * 2;
    float pozX = width * new Random().nextFloat();
    float pozY = height * new Random().nextFloat();
    float border= 10;

    //Checking whether circles are overlapping or outside the screen boundary.
    if (i!=0)
    {
      for (int j = 0; j <i; j++)
      {
        while (PVector.sub(new PVector(pozX, pozY), cir.get(j).point).mag() <= cir.get(j).radius + radius + border || pozY - radius <= border || pozY + radius >= height - border || pozX - radius <= border || pozX + radius >= width - border) {
          pozX = (width * new Random().nextFloat()) - radius;
          pozY = (height * new Random().nextFloat()) - radius;
        }
      }
    }

    cir.add(new Circum(pozX, pozY, radius, mass));
    cir.get(i).velocity = new PVector(0, 0);
    cir.get(i).acceleration = new PVector(0, 0);
    cir.get(i).gre = new PVector(0, 0);
  }
}

void StartStop() {

  stopStart = !stopStart;

  if (stopStart)
  {
    cp5.getController("StartStop").setCaptionLabel("Zatrzymanie programu");
  } else
  {
    cp5.getController("StartStop").setCaptionLabel("Uruchomienie programu");
  }
}

void ball_setup()
{
  for (int i = control - 1; i >= 0; i--)
  {
    cir.remove(i);
  }

  for (int i = 0; i<control; i++)
  {
    mass = 8 * randa.nextFloat() + 4;
    radius = mass  * 4;
    float pozX = width * new Random().nextFloat();
    float pozY = height * new Random().nextFloat();
    float border= 10;

    //Checking whether circles are overlapping or outside the screen boundary.
    if (i!=0)
    {
      for (int j = 0; j <i; j++)
      {
        while (PVector.sub(new PVector(pozX, pozY), cir.get(j).point).mag() <= cir.get(j).radius + radius + border || pozY - radius <= border || pozY + radius >= height - border || pozX - radius <= border || pozX + radius >= width - border) {
          pozX = (width * new Random().nextFloat());
          pozY = (height * new Random().nextFloat());
        }
      }
    }

    cir.add(new Circum( pozX, pozY, radius, mass));
    cir.get(i).velocity = new PVector(0,0);
    cir.get(i).acceleration = new PVector(0, 0);
    cir.get(i).gre = new PVector(0, 0);
  }
}

void checkForCollision()
{
  for (int i = 0; i<cir.size() -1; i++)
  {
    for (int j = i + 1; j<cir.size(); j++)
    {
      //calculating distance between object
      PVector lengthFrom_i_to_j= PVector.sub( cir.get(j).point, cir.get(i).point);
      float oldDist = lengthFrom_i_to_j.mag();
      float min_dyst = cir.get(j).radius + cir.get(i).radius;
      //checking for collision
      if (oldDist <= min_dyst)
      {
        collision(cir.get(i), cir.get(j), oldDist, min_dyst, lengthFrom_i_to_j);
      }
    }
  }
}

void collision(Circum con1, Circum con2, float dist_, float min_, PVector lock)
{
  float u1, u2, distance = dist_, min_dyst = min_;

  //static collision
  float distanceCorrection = (min_dyst-distance)/2.0;
  PVector correctionVector = lock.normalize().mult(distanceCorrection);
  con2.point.add(correctionVector);
  con1.point.sub(correctionVector);

  //dynamic collision

  // Defining the X axis
  PVector dirX = lock.copy();
  dirX.normalize();
  // Defining the Y axis
  PVector dirY = new PVector(dirX.y, -dirX.x);

  // X coordinates of velocities
  float vx1 = dirX.dot(con1.velocity);
  float vx2 = dirX.dot(con2.velocity);
  // Y coordinates of velocities
  float vy1 = dirY.dot(con1.velocity);
  float vy2 = dirY.dot(con2.velocity);

  // Applying the collision to X coordinates
  u1 = (2 * vx2 * con2.mass + vx1 * (con1.mass - con2.mass)) / (con1.mass + con2.mass);
  u2 = (2 * vx1 * con1.mass + vx2 * (con2.mass - con1.mass)) / (con1.mass + con2.mass);

  // Turning velocities back into vectors
  PVector vel1 = PVector.mult(dirX, u1);
  PVector vel2 = PVector.mult(dirX, u2);
  vel1.add(PVector.mult(dirY, vy1));
  vel2.add(PVector.mult(dirY, vy2));

  con1.velocity = vel1;
  con2.velocity = vel2;
}

void centralField()
{
  float dem = 0, dividerx = 0, dividery = 0, Distance;
  PVector grav_atract = new PVector(0, 0);
  ArrayList<PVector> reverseGravity = new ArrayList<PVector>(cir.size());

  if (stopStart)
  {
    for (int i = 0; i < cir.size(); i++)
    {
      reverseGravity.add(new PVector(0, 0));
    }

    for (int i = 0; i<cir.size(); i++)
    {
      //Calculation of the mass center
      dem += cir.get(i).mass;
      dividerx += cir.get(i).mass * cir.get(i).point.x;
      dividery += cir.get(i).mass * cir.get(i).point.y;

      for (int j = i + 1; j<cir.size(); j++)
      {

        //calculating distance between object
        PVector lengthFrom_i_to_j= PVector.sub( cir.get(j).point, cir.get(i).point);
        PVector lengthFrom_j_to_i= PVector.sub( cir.get(i).point, cir.get(j).point);

        Distance = lengthFrom_i_to_j.mag();
        lengthFrom_i_to_j.normalize();
        lengthFrom_j_to_i.normalize();

        //adding gravity
        float strength = (G_const * cir.get(i).mass * cir.get(j).mass)/(Distance * Distance);
        lengthFrom_i_to_j.mult(strength );
        lengthFrom_j_to_i.mult(strength );

        reverseGravity.get(j).add(lengthFrom_j_to_i);

        grav_atract.add(lengthFrom_i_to_j);
      }

      grav_atract.add( reverseGravity.get(i));
      cir.get(i).setSpeed(grav_atract);
      grav_atract.mult(0);

      for (int k = 0; k<reverseGravity.size(); k++)
      {
        reverseGravity.get(k).mult(0);
      }

      //checkForCollision();
    }
  }

  checkForCollision();

  for (int i = 0; i<cir.size(); i++)
  {
    //cir.get(i).border();
    cir.get(i).drawing();
  }

  //Drawing a center of mass
  pushMatrix();
  strokeWeight(6);
  fill(50, 0, 255 );
  stroke(255, 0, 50);
  point((dividerx/dem), (dividery/dem));
  popMatrix();
}

void homogeneousField()
{
  PVector  air_replica = new PVector(0.004, 0.004);
  PVector  grav = new PVector(0.00, 3.00);
  PVector air;

  if (stopStart)
  {
    for (int i = 0; i<cir.size(); i++)
    {//Adding gravity
      cir.get(i).setSpeed(grav);
      air = air_replica.copy();

      if (cir.get(i).velocity.x>0 ||cir.get(i).velocity.y>0)
      {
        air.mult(-1);
      }
      //adding motion resistance
      cir.get(i).setSpeed(air);
    }
  }

  checkForCollision();

  for (int j = 0; j<cir.size(); j++)
  {
    //cir.get(j).border();
    cir.get(j).drawing();
  }
}

void mouseWheel(MouseEvent event) {
  start = millis();
  scrollMovement = constrain(event.getCount()*Multi + scrollMovement, -MaxFar, MaxFar);
}

void mousePressed() {

  if (!stopStart)
  {
    if (field)
    {
      for (int i = 0; i<cir.size(); i++)
      {
        float d = dist(mouseX, mouseY, cir.get(i).point.x, cir.get(i).point.y);
        if (d <= cir.get(i).radius ) {
          currentIndex = i;
          if (mouseButton == CENTER)
          {
            scrollMenuOpenByMouse[0] = true;
          }
        }
      }
    } else
    {
      for (int j = 0; j<cir.size(); j++)
      {
        float d = dist(mouseX, mouseY, cir.get(j).point.x, cir.get(j).point.y);
        if (d <= cir.get(j).radius) {
          currentIndex = j;
          if (mouseButton == CENTER)
          {
            scrollMenuOpenByMouse[1] = true;
          }
        }
      }
    }
  }
}

void mouseReleased() {
  if (!stopStart)
  {
    if (field)
    {
      if (scrollMenuOpenByMouse[0]) {
        scrollMenuOpenByMouse[0] = false;
      }
    } else
    {
      if (scrollMenuOpenByMouse[1]) {
        scrollMenuOpenByMouse[1] = false;
      }
    }
  }
}

void changeVelocityByTheMouse(int currentIndex)
{
  int i = currentIndex;
  PVector diff = new PVector(0, 0), position= new PVector(0, 0), result = new PVector(0, 0);

  if (!stopStart)
  {
    if (field)
    {
      if (scrollMenuOpenByMouse[0])
      {
        position = cir.get(currentIndex).point;
        diff = PVector.sub(new PVector(mouseX, mouseY), position);
        diff.normalize();
        diff.mult(scrollMovement);
        result.add(diff);
      } else
      {
        cir.get(currentIndex).acceleration.add(result);
      }
    } else
    {
      if (scrollMenuOpenByMouse[1])
      {
        position = cir.get(currentIndex).point;
        diff = PVector.sub(new PVector(mouseX, mouseY), position);
        diff.normalize();
        diff.mult(scrollMovement);
        result.add(diff);
      } else
      {
        cir.get(currentIndex).acceleration.add(result);
      }
    }
  }


  line(position.x, position.y, result.x + position.x, result.y + position.y);
  circle(diff.x, diff.y, 10);
  result.set(0, 0);
}

void Homogen() {

  CentralButton(false);
}

void Central() {

  CentralButton(true);
}

void Reset()
{
  background(255);
  ball_setup();
}

void CentralButton(boolean i)
{
    field = i;
    setting();
}

void Menu()
{
  information = !information;
}


void Disclosures_set(String name)
{
  pozYSet = cp5.getController(name).getPosition();
  cp5.getController("Set").setPosition(pozXSet, pozYSet[1]);
  cp5.getController("input").setPosition(pozXSet, pozYSet[1]+button_height);
  buttonName = name;
  cp5.getController("Set").show();
  cp5.getController("input").show();
}

void ButtonManagement()
{
  if (information)
  {
    cp5.get(Button.class, "Homogen").setVisible(true);
    cp5.get(Button.class, "Central").setVisible(true);

  } else  if (information == false)
  {
    cp5.get(Button.class, "Homogen").setVisible(false);
    cp5.get(Button.class, "Central").setVisible(false);
  }
}

void setting()
{
    float pozX = 0, pozY = 0;

    for (int i = control - 1; i >= 0; i--)
    {
      cir.remove(i);
    }

    if ( field == true)
    {

      for (int i = 0; i <control2; i++)
      {
        mass = 8 * randa.nextFloat() + 4;
        radius = mass  * 4;
        pozX = width * new Random().nextFloat();
        pozY = height * new Random().nextFloat();
        float border= 10;

        //Checking whether circles are overlapping or outside the screen boundary.
        if (i!=0)
        {
          for (int j = 0; j <i; j++)
          {
            while (PVector.sub(new PVector(pozX, pozY), cir.get(j).point).mag() <= cir.get(j).radius + radius + border || pozY - radius <= border || pozY + radius >= height - border || pozX - radius <= border || pozX + radius >= width - border) {
              pozX = (width * new Random().nextFloat());
              pozY = (height * new Random().nextFloat());
            }
          }
        }

        cir.add(new Circum(pozX, pozY, radius, mass));
        cir.get(i).velocity = new PVector(0, 0);
      }
      control = control2;
    } else if ( field == false)
    {

      for (int i = 0; i<control2; i++)
      {
        mass = 8 * randa.nextFloat() + 4;
        radius = mass  * 2;
        pozX = (width * new Random().nextFloat()) - radius;
        pozY =  (height * new Random().nextFloat()) - radius;

        cir.add(new Circum( pozX, pozY, radius, mass));
        cir.get(i).setSpeed(inic);
      }
      control = control2;
    }
  }

void draw() {
  background(200);

  if (field)
  {
    centralField();
  } else
  {
    homogeneousField();
  }

   if (!stopStart)
  {
    changeVelocityByTheMouse(currentIndex);
  }

  ButtonManagement();
}

class Circum {
  int max_vel = 15;
  float radius, mass;
  float ref = 0.5;
  float springness = 0.9999;
  PVector  point = new PVector(0, 0);
  PVector  acceleration = new PVector(0, 0);
  PVector  velocity = new PVector(new Random().nextInt(max_vel) + 0.05, -1 * (new Random().nextInt(max_vel) + 0.05));
  PVector gre = new PVector(0, 0);
  String[] fieldName = new String[3];
  float[] fieldValue  = new float[3];

  Circum() {
    mass = 5 * new Random().nextFloat() + 1;
    radius = mass * 4;
    point.x = (width * new Random().nextFloat()) - radius;
    point.y =  (height * new Random().nextFloat()) - radius;
  }

  Circum(float x_, float y_, float r_, float m_) {
    this();
    point.x = x_;
    point.y = y_;
    radius = r_;
    mass = m_;
  }

  void setSpeed(PVector force) {
    PVector f = force.copy();
    acceleration.add(PVector.div( f, mass));
    velocity.add(acceleration);
    point.add(velocity);
    gre = acceleration.copy();

    // If out of bounds
    if (point.y - radius <= 0)
    {
      velocity.y *= -springness;
      point.y = 0 + radius;
    } else if (point.y + radius >= height)
    {
      velocity.y *= -springness;
      point.y = height - radius ;
    }
    if (point.x - radius <= 0)
    {
      velocity.x *= -springness;
      point.x = 0 + radius;
    } else if (point.x + radius >= width)
    {
      velocity.x *= -springness;
      point.x = width - radius;
    }

    acceleration.mult(0);
  }

  void drawing() {

    fill((map(velocity.y, -max_vel, max_vel, 50, 255)), (map(gre.y, -2, 2, 50, 100)), (map(point.y, 0, width, 1, 255)) );
    stroke((map(point.x, 0, height, 100, 255)), (map(gre.x, -2, 2, 50, 100)), (map(velocity.x, -max_vel, max_vel, 50, 255)));
    circle(point.x, point.y, 2 * radius);

    strokeWeight(2);
    stroke(255, 255, 255);
    PVector dir = velocity.copy();
    dir.normalize().mult(radius);
    dir = PVector.add(dir, point);
    line(point.x, point.y, dir.x, dir.y);
  }
}